finalwithwrappers.htm - Generated by SEC Publisher for SEC Filing


FACTS	WHAT DOES PRINCIPAL FUNDS DO WITH YOUR PERSONAL INFORMATION?

	Financial companies choose how they share your personal information. Federal law gives
Why?	consumers the right to limit some but not all sharing. Federal law also requires us to tell you
	how we collect, share, and protect your personal information. Please read this notice carefully
	to understand what we do.

	The types of personal information we collect and share depend on the product or service you
	have with us. This information can include:
	•	Social Security number and income
What?	•	Assets and transaction history
	•	Account transactions and account balances
	When you are no longer our customer, we continue to share your information as described in
	this notice

	All financial companies need to share customers’ personal information to run their everyday
How?	business. In the section below, we list the reasons financial companies can share their
	customers’ personal information; the reasons Principal Funds chooses to share; and whether
	you can limit this sharing.

REASONS WE CAN SHARE YOUR PERSONAL			DOES PRINCIPAL	CAN YOU LIMIT THIS
INFORMATION			FUNDS SHARE?	SHARING?
For our everyday business purposes—such as to
process your transactions, maintain your account(s),
			Yes	No
respond to court orders and legal investigations, or report
to credit bureaus

For our marketing purposes—to offer our products and
			Yes	No
services to you

For joint marketing with other financial companies			No	We don’t share

For our affiliates’ everyday business purposes—
			Yes	No
information about your transactions and experiences

For our affiliates’ everyday business purposes—
			No	We don’t share
information about your creditworthiness

For nonaffiliates to market to you			No	We don’t share


Questions?	Call 1-800-222-5852 or go to www.principalfunds.com/customer-support/contact-us

EE11865PFI-03


Page 2 Who we are Who is providing this notice?	Principal Funds includes Principal Funds, Inc., Principal Funds Distributor, Inc., and Principal Diversified Select Real Asset Fund.
What we do How does Principal Funds protect my personal information? How does Principal Funds collect my personal information?	To protect your personal information from unauthorized access and use, we use security measures that comply with federal law. These measures include computer safeguards and secured files and buildings. We collect your personal information, for example, when you • Open an account or seek advice about your investments •Direct us to buy securities or make deposits, or withdrawals from your account • Give us your contact information or show your government issued ID We also collect your personal information from others, such as affiliates, or other companies.

Why can’t I limit all sharing?	Federal law gives you the right to limit only •sharing for affiliates’ everyday business purposes—information about your creditworthiness • affiliates from using your information to market to you • sharing for nonaffiliates to market to you State laws and individual companies may give you additional rights to limit sharing.
Definitions Affiliates	Companies related by common ownership or control. They can be financial and nonfinancial companies.
	•	Our affiliates include companies of Principal Financial Group^®

Nonaffiliates	Companies not related by common ownership or control. They can be financial and nonfinancial companies.
	•	Principal Funds does not share with nonaffiliates so they can market to you.

Joint marketing	A formal agreement between nonaffiliated financial companies that together market financial products or services to you.
	•	Principal Funds does not jointly market.
Other important information

This Privacy Notice governs information that you provide to Principal (or that we otherwise receive) when you apply for or receive a product or service used primarily for personal, family or household purposes. We may collect additional information depending on the nature of your relationship with Principal or if you interact with us through our website or other digital technologies. Details about how we protect and use this additional information, including information about your privacy rights under California law such as the California Consumer Privacy Act, are available online at www.principal.com/privacy-policies.

If you do not have access to www.principal.com/privacy-policies, please contact us at 1-800-986-3343 to have a copy mailed to you.

EE11865PFI-03 | 01/2020


	Statements of Assets and Liabilities
	Principal Exchange-Traded Funds
	December 31, 2021 (unaudited)

										Principal
							Principal			International
			Principal				Healthcare			Adaptive
			Active High				Innovators			Multi-Factor
			Yield ETF ^(a)				ETF ^(b)			ETF
Investment in securities — at cost		$	248,600,520			$	111,319,498		$	130,863,262
Investment in affiliated funds — at cost			$	847,958		$	4,668,883		$	—
Foreign currency — at cost			$	—		$	—		$	21,548
Assets
Investment in securities — at value		$	248,815,820		^(c)	$	90,022,419	^(c)	$	131,852,862
Investment in affiliated funds — at value				847,958			4,668,883			—
Foreign currency — at value				—			—			21,710
Cash				29,780			—			—
Receivables:
Dividends				13,384			5			126,155
Interest				3,592,514			—			—
Securities lending income				230			4,093			—
Investment securities sold				906,632			853,357			6
	Total Assets		254,206,318				95,548,757			132,000,733

Liabilities
Accrued management and investment advisory fees				85,657			37,038			28,372
Accrued income distribution				1,064,065			861,124			675,974
Payables:
Investment securities purchased				7,494,454			—			—
Collateral obligation on securities loaned — at value				847,958			4,668,883			—
	Total Liabilities			9,492,134			5,567,045			704,346
Net Assets Applicable to Outstanding Shares		$	244,714,184			$	89,981,712		$	131,296,387

Net Assets Consist of:
Capital shares and additional paid-in-capital		$	234,804,680			$	105,824,344		$	131,309,161
Total distributable earnings (accumulated loss)				9,909,504			(15,842,632	)		(12,774	)
	Total Net Assets	$	244,714,184			$	89,981,712		$	131,296,387

Net Asset Value Per Share:
Net assets		$	244,714,184			$	89,981,712		$	131,296,387
Shares issued and outstanding			11,800,000		^(d)		1,900,001			5,200,001
Net asset value per share			$	20.74	^(d)	$	47.36		$	25.25

^(a)	Effective September 1, 2021, Principal Active Income ETF changed its name to Principal Active High Yield ETF.
^(b)	Effective October 29, 2021, Principal Healthcare Innovators Index ETF changed its name to Principal Healthcare Innovators ETF.
^(c)	Includes fair market value of securities loaned, see 'Securities Lending' in Notes to Financial Statements.
^(d)	Reflects a 2 to 1 stock split effective after the close of trading on August 30, 2021; see Notes to Financial Statements.

See accompanying notes.


Statements of Assets and Liabilities
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

		Principal
		Investment
		Grade			Principal
		Corporate			Millennials			Principal
		Active ETF			ETF ^(a)			Quality ETF
Investment in securities — at cost	$	485,151,400		$	112,781,750		$	91,299,366
Investment in affiliated funds — at cost	$	1,601,613		$	2,317,867		$	—
Assets
Investment in securities — at value	$	486,475,333	^(b)	$	104,092,879	^(b)	$	96,797,640
Investment in affiliated funds — at value		1,601,613			2,317,867			—
Deposits with counterparty		643,400			—			—
Receivables:
Dividends		86			35,506			45,926
Interest		4,025,795			—			—
Securities lending income		232			737			—
Fund shares sold		—			5,802,687			—
Investment securities sold		—			1,989,896			173,123
Variation margin on financial derivative instruments		29,475			—			—
Total Assets		492,775,934			114,239,572			97,016,689

Liabilities
Accrued management and investment advisory fees		84,278			39,453			13,065
Accrued income distribution		1,283,773			2,542,964			274,755
Payables:
Investment securities purchased		—			5,309,117			—
Collateral obligation on securities loaned — at value		1,601,613			2,317,867			—
Total Liabilities		2,969,664			10,209,401			287,820
Net Assets Applicable to Outstanding Shares	$	489,806,270		$	104,030,171		$	96,728,869

Net Assets Consist of:
Capital shares and additional paid-in-capital	$	490,448,044		$	110,505,395		$	85,320,836
Total distributable earnings (accumulated loss)		(641,774	)		(6,475,224	)		11,408,033
Total Net Assets	$	489,806,270		$	104,030,171		$	96,728,869

Net Asset Value Per Share:
Net assets	$	489,806,270		$	104,030,171		$	96,728,869
Shares issued and outstanding		18,650,001			1,800,001			1,600,001
Net asset value per share	$	26.26		$	57.79		$	60.46

^(a)	Effective October 29, 2021, Principal Millennials Index ETF changed its name to Principal Millennials ETF.
^(b)	Includes fair market value of securities loaned, see 'Securities Lending' in Notes to Financial Statements.

See accompanying notes.


Statements of Assets and Liabilities
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

					Principal
		Principal			Spectrum
		Spectrum			Tax-		Principal
		Preferred			Advantaged		Ultra-Short
		Securities			Dividend		Active
		Active ETF			Active ETF		Income ETF
Investment in securities — at cost	$	442,439,793		$	22,849,322	$	8,596,100
Investment in affiliated funds — at cost	$	7,334,728		$	—	$	4,170
Assets
Investment in securities — at value	$	449,262,550	^(a)	$	23,944,824	$	8,568,142	^(a)
Investment in affiliated funds — at value		7,334,728			—		4,170
Deposits with counterparty		—			14,955		—
Receivables:
Dividends		234			17,623		4
Interest		3,985,004			199,338		19,776
Securities lending income		3,429			—		1
Total Assets		460,585,945			24,176,740		8,592,093

Liabilities
Accrued management and investment advisory fees		218,119			13,050		1,398
Accrued income distribution		1,418,868			99,452		8,000
Payables:
Investment securities purchased		235,948			—		—
Collateral obligation on securities loaned — at value		7,334,728			—		4,170
Total Liabilities		9,207,663			112,502		13,568
Net Assets Applicable to Outstanding Shares	$	451,378,282		$	24,064,238	$	8,578,525

Net Assets Consist of:
Capital shares and additional paid-in-capital	$	451,078,429		$	23,199,193	$	8,800,419
Total distributable earnings (accumulated loss)		299,853			865,045		(221,894	)
Total Net Assets	$	451,378,282		$	24,064,238	$	8,578,525

Net Asset Value Per Share:
Net assets	$	451,378,282		$	24,064,238	$	8,578,525
Shares issued and outstanding		22,350,005			1,150,001		350,001
Net asset value per share	$	20.20		$	20.93	$	24.51

^(a)Includes fair market value of securities loaned, see 'Securities Lending' in Notes to Financial Statements.

See accompanying notes.


	Statements of Assets and Liabilities
	Principal Exchange-Traded Funds
	December 31, 2021 (unaudited)

			Principal U.S.					Principal U.S.
			Large-Cap					Small-Cap
			Adaptive			Principal U.S.		Adaptive
			Multi-Factor			Mega-Cap		Multi-Factor
				ETF		ETF		ETF
Investment in securities — at cost		$	123,771,997		$	1,495,299,872	$	6,216,933
Assets
Investment in securities — at value		$	131,911,411		$	1,866,341,022	$	6,660,494
Receivables:
Dividends				82,840		1,294,478		7,466
Fund shares sold				2,901,273		—		—
Investment securities sold				180,760		6,634,807		44,249
Expense reimbursement from Advisor				—		51,313		—
	Total Assets		135,076,284			1,874,321,620		6,712,209

Liabilities
Accrued management and investment advisory fees				18,080		256,564		1,124
Accrued income distribution				421,620		8,364,176		50,000
Payables:
Investment securities purchased				2,895,939		—		—
	Total Liabilities			3,335,639		8,620,740		51,124
Net Assets Applicable to Outstanding Shares		$	131,740,645		$	1,865,700,880	$	6,661,085

Net Assets Consist of:
Capital shares and additional paid-in-capital		$	119,455,849		$	1,307,382,814	$	6,262,759
Total distributable earnings (accumulated loss)			12,284,796			558,318,066		398,326
	Total Net Assets	$	131,740,645		$	1,865,700,880	$	6,661,085

Net Asset Value Per Share:
Net assets		$	131,740,645		$	1,865,700,880	$	6,661,085
Shares issued and outstanding				4,550,001		42,100,001		250,001
Net asset value per share			$	28.95	$	44.32	$	26.64

See accompanying notes.


Statements of Assets and Liabilities
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

		Principal U.S.
		Small-Cap
		Multi-Factor				Principal
		ETF				Value ETF
Investment in securities — at cost	$	1,183,213,260			$	79,917,211
Investment in affiliated funds — at cost	$	10,127,850			$	—
Assets
Investment in securities — at value	$	1,238,741,207		^(a)	$	82,092,053
Investment in affiliated funds — at value		10,127,850				—
Receivables:
Dividends			1,190,513			139,963
Securities lending income			8,170			11
Investment securities sold			5,544,861			527,986
Total Assets		1,255,612,601				82,760,013

Liabilities
Accrued management and investment advisory fees			447,280			9,749
Accrued income distribution			7,734,239			609,773
Collateral obligation on securities loaned — at value		10,127,850				—
Total Liabilities		18,309,369				619,522
Net Assets Applicable to Outstanding Shares	$	1,237,303,232			$	82,140,491

Net Assets Consist of:
Capital shares and additional paid-in-capital	$	1,081,277,085			$	78,128,944
Total distributable earnings (accumulated loss)		156,026,147				4,011,547
Total Net Assets	$	1,237,303,232			$	82,140,491

Net Asset Value Per Share:
Net assets	$	1,237,303,232			$	82,140,491
Shares issued and outstanding		26,100,001				1,850,001
Net asset value per share		$	47.41		$	44.40

^(a)Includes fair market value of securities loaned, see 'Securities Lending' in Notes to Financial Statements.

See accompanying notes.


Statements of Operations
Principal Exchange-Traded Funds
Six Months Ended December 31, 2021 (unaudited)

					Principal			Principal
		Principal			Healthcare			International
		Active High			Innovators			Adaptive Multi-
		Yield ETF ^(a)			ETF ^(b)			Factor ETF
Net Investment Income (Loss)
Income:
Dividend	$	180,941		$	31,578		$	1,210,226
Withholding tax		(719	)		—			(115,551	)
Interest		4,993,710			—			—
Securities lending — net		2,880			31,254			—
Total Income		5,176,812			62,832			1,094,675

Expenses:
Management and investment advisory fees		509,111			293,536			110,792
Total Expenses		509,111			293,536			110,792
Net Investment Income (Loss)		4,667,701			(230,704	)		983,883

Net Realized and Unrealized Gain (Loss) on Investments and Foreign Currency:
Net realized gain (loss) from:
Investment transactions		6,572,508			(1,709,600	)		(1,569,884	)
In-kind redemptions		18,690,957			11,483,281			677,163
Foreign currency transactions		(478	)		—			(7,290	)
Change in unrealized appreciation (depreciation) of:
Investments		(25,072,094	)		(42,533,785	)		2,015,194
Foreign currency transactions		247			—			1,150
Net Realized and Unrealized Gain (Loss) on Investments and Foreign Currency		191,140			(32,760,104	)		1,116,333
Net Increase (Decrease) in Net Assets Resulting from Operations	$	4,858,841		$	(32,990,808	)	$	2,100,216

^(a)	Effective September 1, 2021, Principal Active Income ETF changed its name to Principal Active High Yield ETF.
^(b)	Effective October 29, 2021, Principal Healthcare Innovators Index ETF changed its name to Principal Healthcare Innovators ETF.

See accompanying notes.


Statements of Operations
Principal Exchange-Traded Funds
Six Months Ended December 31, 2021 (unaudited)

		Principal
		Investment
		Grade			Principal
		Corporate			Millennials			Principal
		Active ETF			ETF ^(a)			Quality ETF
Net Investment Income (Loss)
Income:
Dividend	$	708		$	3,124,642		$	534,516
Withholding tax		—			(408,015	)		—
Interest		6,250,277			—			—
Securities lending — net		5,175			154,186			—
Total Income		6,256,160			2,870,813			534,516

Expenses:
Management and investment advisory fees		472,802			238,823			67,314
Total Expenses		472,802			238,823			67,314
Net Investment Income (Loss)		5,783,358			2,631,990			467,202

Net Realized and Unrealized Gain (Loss) on Investments, Foreign Currency and Futures:
Net realized gain (loss) from:
Investment transactions		1,724,414			41,750			3,344
In-kind redemptions		—			5,105,168			7,449,209
Foreign currency transactions		—			(3,472	)		—
Futures contracts		453,652			—			—
Change in unrealized appreciation (depreciation) of:
Investments		(6,996,446	)		(19,962,462	)		3,123,274
Futures contracts		(21,855	)		—			—
Foreign currency transactions		—			(445	)		—
Net Realized and Unrealized Gain (Loss) on Investments, Foreign Currency and
Futures		(4,840,235	)		(14,819,461	)		10,575,827
Net Increase (Decrease) in Net Assets Resulting from Operations	$	943,123		$	(12,187,471	)	$	11,043,029

^(a)Effective October 29, 2021, Principal Millennials Index ETF changed its name to Principal Millennials ETF.

See accompanying notes.


Statements of Operations
Principal Exchange-Traded Funds
Six Months Ended December 31, 2021 (unaudited)

					Principal
		Principal			Spectrum
		Spectrum			Tax-			Principal
		Preferred			Advantaged			Ultra-Short
		Securities			Dividend			Active
		Active ETF			Active ETF			Income ETF
Net Investment Income (Loss)
Income:
Dividend	$	1,148		$	74,559		$	31
Interest		7,426,831			461,865			24,451
Securities lending — net		19,472			—			90
Total Income		7,447,451			536,424			24,572

Expenses:
Management and investment advisory fees		1,141,908			71,861			7,912
Total Expenses		1,141,908			71,861			7,912
Net Investment Income (Loss)		6,305,543			464,563			16,660

Net Realized and Unrealized Gain (Loss) on Investments and Futures:
Net realized gain (loss) from:
Investment transactions		551,714			28,679			322
Futures contracts		—			(11,778	)		—
Written options					13,924
Change in unrealized appreciation (depreciation) of:
Investments		(6,769,145	)		(469,569	)		(39,375	)
Net Realized and Unrealized Gain (Loss) on Investments		(6,217,431	)		(438,744	)		(39,053	)
Net Increase (Decrease) in Net Assets Resulting from Operations	$	88,112		$	25,819		$	(22,393	)

See accompanying notes.


Statements of Operations
Principal Exchange-Traded Funds
Six Months Ended December 31, 2021 (unaudited)

	Principal U.S.							Principal U.S.
		Large-Cap						Small-Cap
		Adaptive			Principal U.S.			Adaptive
		Multi-Factor			Mega-Cap			Multi-Factor
		ETF			ETF			ETF
Net Investment Income (Loss)
Income:
Dividend	$	729,220		$	17,250,907		$	72,035
Withholding tax		(102	)		—			(62	)
Total Income		729,118			17,250,907			71,973

Expenses:
Management and investment advisory fees		82,432			1,549,433			6,228
Total Gross Expenses		82,432			1,549,433			6,228
Less: Reimbursement from Advisor		—			(309,887	)		—
Total Net Expenses		82,432			1,239,546			6,228
Net Investment Income (Loss)		646,686			16,011,361			65,745

Net Realized and Unrealized Gain (Loss) on Investments:
Net realized gain (loss) from:
Investment transactions		(795,716	)		32,206,008			(13,745	)
In-kind redemptions		4,939,114			220,013,534			—
Change in unrealized appreciation (depreciation) of:
Investments		7,766,450			(19,503,795	)		311,897
Net Realized and Unrealized Gain (Loss) on Investments		11,909,848			232,715,747			298,152
Net Increase (Decrease) in Net Assets Resulting from Operations	$	12,556,534		$	248,727,108		$	363,897

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Active High Yield ETF ^(a)
		Period ended			Year ended
		December 31, 2021			June 30, 2021
Operations
Net investment income (loss)	$	4,667,701		$	9,199,173
Net realized gain (loss) on investments and foreign currency		25,262,987			(6,479,099	)
Change in unrealized appreciation (depreciation) of investments and foreign currency		(25,071,847	)		42,205,061
Net Increase (Decrease) in Net Assets Resulting from Operations		4,858,841			44,925,135

Dividends to Shareholders
From net investment income and net realized gain on investments		(6,251,383	)		(9,881,656	)
Total Dividends		(6,251,383	)		(9,881,656	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		13,664,114			(72,696,915	)
Total Increase (Decrease) in Net Assets		12,271,572			(37,653,436	)

Net Assets
Beginning of period		232,442,612			270,096,048
End of period	$	244,714,184		$	232,442,612

Capital Share Transactions
Dollars:
Sold	$	71,762,801		$	2,059,299
Redeemed		(58,098,687	)		(74,756,214	)
Net Increase (Decrease)	$	13,664,114		$	(72,696,915	)
Shares: ^(b)
Sold		2,050,000			100,000
Redeemed		(1,400,000	)		(3,900,000	)
Net Increase (Decrease)		650,000			(3,800,000	)

(a)	Effective September 1, 2021, Principal Active Income ETF changed its name to Principal Active High Yield ETF.
(b)	Reflects a 2 to 1 stock split effective after the close of trading on August 30, 2021; see Notes to Financial Statements.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

	Principal Healthcare Innovators ETF ^(a)
		Period ended		Year ended
	December 31, 2021			June 30, 2021
Operations
Net investment income (loss)	$	(230,704	)	$	(372,510	)
Net realized gain (loss) on investments		9,773,681			28,979,751
Change in unrealized appreciation (depreciation) of investments		(42,533,785	)		6,955,733
Net Increase (Decrease) in Net Assets Resulting from Operations		(32,990,808	)		35,562,974

Dividends to Shareholders
From net investment income and net realized gain on investments		(861,124	)		(527,787	)
Total Dividends		(861,124	)		(527,787	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		(52,363,718	)		45,823,914
Total Increase (Decrease) in Net Assets		(86,215,650	)		80,859,101

Net Assets
Beginning of period		176,197,362			95,338,261
End of period	$	89,981,712		$	176,197,362

Capital Share Transactions
Dollars:
Sold	$	2,777,910		$	111,095,936
Redeemed		(55,141,628	)		(65,272,022	)
Net Increase (Decrease)	$	(52,363,718	)	$	45,823,914
Shares:
Sold		50,000			1,900,000
Redeemed		(1,050,000	)		(1,150,000	)
Net Increase (Decrease)		(1,000,000	)		750,000

(a) Effective October 29, 2021, Principal Healthcare Innovators Index ETF changed its name to Principal Healthcare Innovators ETF.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal International Adaptive Multi-
		Factor ETF
		Period ended		Period ended
		December 31, 2021		June 30, 2021 ^(a)
Operations
Net investment income (loss)	$	983,883		$	67,312
Net realized gain (loss) on investments and foreign currency		(900,011	)		13,912
Change in unrealized appreciation (depreciation) of investments and foreign currency		2,016,344			(1,026,037	)
Net Increase (Decrease) in Net Assets Resulting from Operations		2,100,216			(944,813	)

Dividends to Shareholders
From net investment income and net realized gain on investments		(1,153,177	)		—
Total Dividends		(1,153,177	)		—

Capital Share Transactions
Net increase (decrease) in capital share transactions		83,231,311			48,062,850
Total Increase (Decrease) in Net Assets		84,178,350			47,118,037

Net Assets
Beginning of period		47,118,037			—
End of period	$	131,296,387		$	47,118,037

Capital Share Transactions
Dollars:
Sold	$	93,195,278		$	48,062,850
Redeemed		(9,963,967	)		—
Net Increase (Decrease)	$	83,231,311		$	48,062,850
Shares:
Sold		3,700,000			1,900,001
Redeemed		(400,000	)		—
Net Increase (Decrease)		3,300,000			1,900,001

^(a)Period from May 26, 2021, date operations commenced, through June 30, 2021.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Investment Grade Corporate Active
		ETF
		Period ended			Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	5,783,358		$	7,616,986
Net realized gain (loss) on investments and futures		2,178,066			3,895,398
Change in unrealized appreciation (depreciation) of investments and futures		(7,018,301	)		403,989
Net Increase (Decrease) in Net Assets Resulting from Operations		943,123			11,916,373

Dividends to Shareholders
From net investment income and net realized gain on investments		(9,710,687	)		(14,392,204	)
Total Dividends		(9,710,687	)		(14,392,204	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		17,302,572			373,054,558
Total Increase (Decrease) in Net Assets		8,535,008			370,578,727

Net Assets
Beginning of period		481,271,262			110,692,535
End of period	$	489,806,270		$	481,271,262

Capital Share Transactions
Dollars:
Sold	$	17,302,572		$	383,550,803
Redeemed		—			(10,496,245	)
Net Increase (Decrease)	$	17,302,572		$	373,054,558
Shares:
Sold		650,000			14,250,000
Redeemed		—			(400,000	)
Net Increase (Decrease)		650,000			13,850,000

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Millennials ETF ^(a)
		Period ended		Year ended
	December 31, 2021			June 30, 2021
Operations
Net investment income (loss)	$	2,631,990		$	331,354
Net realized gain (loss) on investments and foreign currency		5,143,446			21,712,308
Change in unrealized appreciation (depreciation) of investments and foreign currency		(19,962,907	)		7,404,266
Net Increase (Decrease) in Net Assets Resulting from Operations		(12,187,471	)		29,447,928

Dividends to Shareholders
From net investment income and net realized gain on investments		(2,713,066	)		(481,261	)
Total Dividends		(2,713,066	)		(481,261	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		(7,468,588	)		71,724,249
Total Increase (Decrease) in Net Assets		(22,369,125	)		100,690,916

Net Assets
Beginning of period		126,399,296			25,708,380
End of period	$	104,030,171		$	126,399,296

Capital Share Transactions
Dollars:
Sold	$	30,366,003		$	147,097,949
Redeemed		(37,834,591	)		(75,373,700	)
Net Increase (Decrease)	$	(7,468,588	)	$	71,724,249
Shares:
Sold		500,000			2,550,000
Redeemed		(600,000	)		(1,250,000	)
Net Increase (Decrease)		(100,000	)		1,300,000

(a) Effective October 29, 2021, Principal Millennials Index ETF changed its name to Principal Millennials ETF.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Quality ETF
		Period ended		Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	467,202		$	380,155
Net realized gain (loss) on investments		7,452,553			7,418,259
Change in unrealized appreciation (depreciation) of investments		3,123,274			1,633,115
Net Increase (Decrease) in Net Assets Resulting from Operations		11,043,029			9,431,529

Dividends to Shareholders
From net investment income and net realized gain on investments		(614,556	)		(296,923	)
Total Dividends		(614,556	)		(296,923	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		27,814,769			31,399,812
Total Increase (Decrease) in Net Assets		38,243,242			40,534,418

Net Assets
Beginning of period		58,485,627			17,951,209
End of period	$	96,728,869		$	58,485,627

Capital Share Transactions
Dollars:
Sold	$	106,111,513		$	83,793,358
Redeemed		(78,296,744	)		(52,393,546	)
Net Increase (Decrease)	$	27,814,769		$	31,399,812
Shares:
Sold		1,900,000			1,700,000
Redeemed		(1,400,000	)		(1,050,000	)
Net Increase (Decrease)		500,000			650,000

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Spectrum Preferred Securities
		Active ETF
		Period ended		Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	6,305,543		$	8,156,646
Net realized gain (loss) on investments		551,714			550,789
Change in unrealized appreciation (depreciation) of investments		(6,769,145	)		13,134,839
Net Increase (Decrease) in Net Assets Resulting from Operations		88,112			21,842,274

Dividends to Shareholders
From net investment income and net realized gain on investments		(9,470,707	)		(9,608,037	)
Total Dividends		(9,470,707	)		(9,608,037	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		97,427,743			211,103,817
Total Increase (Decrease) in Net Assets		88,045,148			223,338,054

Net Assets
Beginning of period		363,333,134			139,995,080
End of period	$	451,378,282		$	363,333,134

Capital Share Transactions
Dollars:
Sold	$	97,427,743		$	211,103,817
Redeemed		—			—
Net Increase (Decrease)	$	97,427,743		$	211,103,817
Shares:
Sold		4,750,000			10,350,000
Redeemed		—			—
Net Increase (Decrease)		4,750,000			10,350,000

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Spectrum Tax-Advantaged
		Dividend Active ETF
		Period ended			Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	464,563		$	919,696
Net realized gain (loss) on investments		30,825			129,559
Change in unrealized appreciation (depreciation) of investments		(469,569	)		1,712,911
Net Increase (Decrease) in Net Assets Resulting from Operations		25,819			2,762,166

Dividends to Shareholders
From net investment income and net realized gain on investments		(738,053	)		(1,062,462	)
Total Dividends		(738,053	)		(1,062,462	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		2,129,041			1,000,132
Total Increase (Decrease) in Net Assets		1,416,807			2,699,836

Net Assets
Beginning of period		22,647,431			19,947,595
End of period	$	24,064,238		$	22,647,431

Capital Share Transactions
Dollars:
Sold	$	2,129,041		$	1,000,132
Redeemed		—			—
Net Increase (Decrease)	$	2,129,041		$	1,000,132
Shares:
Sold		100,000			50,000
Redeemed		—			—
Net Increase (Decrease)		100,000			50,000

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Ultra-Short Active
		Income ETF
		Period ended		Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	16,660		$	89,020
Net realized gain (loss) on investments		322			13,955
Change in unrealized appreciation (depreciation) of investments		(39,375	)		(32,874	)
Net Increase (Decrease) in Net Assets Resulting from Operations		(22,393	)		70,101

Dividends to Shareholders
From net investment income and net realized gain on investments		(56,101	)		(215,987	)
Total Dividends		(56,101	)		(215,987	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		—			(3,706,573	)
Total Increase (Decrease) in Net Assets		(78,494	)		(3,852,459	)

Net Assets
Beginning of period		8,657,019			12,509,478
End of period	$	8,578,525		$	8,657,019

Capital Share Transactions
Dollars:
Sold	$	—		$	1,238,181
Redeemed		—			(4,944,754	)
Net Increase (Decrease)	$	—		$	(3,706,573	)
Shares:
Sold		—			50,000
Redeemed		—			(200,000	)
Net Increase (Decrease)		—			(150,000	)

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal U.S. Large-Cap Adaptive Multi-
		Factor ETF
		Period ended			Period ended
		December 31, 2021		June 30, 2021 ^(a)
Operations
Net investment income (loss)	$	646,686		$	15,311
Net realized gain (loss) on investments		4,143,398			110
Change in unrealized appreciation (depreciation) of investments		7,766,450			372,964
Net Increase (Decrease) in Net Assets Resulting from Operations		12,556,534			388,385

Dividends to Shareholders
From net investment income and net realized gain on investments		(660,123	)		—
Total Dividends		(660,123	)		—

Capital Share Transactions
Net increase (decrease) in capital share transactions		90,002,261			29,453,588
Total Increase (Decrease) in Net Assets		101,898,672			29,841,973

Net Assets
Beginning of period		29,841,973			—
End of period	$	131,740,645		$	29,841,973

Capital Share Transactions
Dollars:
Sold	$	138,799,895		$	29,453,588
Redeemed		(48,797,634	)		—
Net Increase (Decrease)	$	90,002,261		$	29,453,588
Shares:
Sold		5,150,000			1,150,001
Redeemed		(1,750,000	)		—
Net Increase (Decrease)		3,400,000			1,150,001

^(a)Period from May 19, 2021, date operations commenced, through June 30, 2021.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal U.S. Mega-Cap ETF
		Period ended			Year ended
		December 31, 2021			June 30, 2021
Operations
Net investment income (loss)	$	16,011,361		$	28,827,265
Net realized gain (loss) on investments		252,219,542			192,160,118
Change in unrealized appreciation (depreciation) of investments		(19,503,795	)		284,619,935
Net Increase (Decrease) in Net Assets Resulting from Operations		248,727,108			505,607,318

Dividends to Shareholders
From net investment income and net realized gain on investments		(24,965,735	)		(27,303,682	)
Total Dividends		(24,965,735	)		(27,303,682	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		(316,124,669	)		(25,285,343	)
Total Increase (Decrease) in Net Assets		(92,363,296	)		453,018,293

Net Assets
Beginning of period		1,958,064,176			1,505,045,883
End of period	$	1,865,700,880		$	1,958,064,176

Capital Share Transactions
Dollars:
Sold	$	407,861,839		$	526,851,840
Redeemed		(723,986,508	)		(552,137,183	)
Net Increase (Decrease)	$	(316,124,669	)	$	(25,285,343	)
Shares:
Sold		9,600,000			14,150,000
Redeemed		(16,850,000	)		(14,900,000	)
Net Increase (Decrease)		(7,250,000	)		(750,000	)

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal U.S. Small-Cap Adaptive Multi-
		Factor ETF
		Period ended		Period ended
		December 31, 2021		June 30, 2021 ^(a)
Operations
Net investment income (loss)	$	65,745		$	6,980
Net realized gain (loss) on investments		(13,745	)		1,295
Change in unrealized appreciation (depreciation) of investments		311,897			131,664
Net Increase (Decrease) in Net Assets Resulting from Operations		363,897			139,939

Dividends to Shareholders
From net investment income and net realized gain on investments		(105,510	)		—
Total Dividends		(105,510	)		—

Capital Share Transactions
Net increase (decrease) in capital share transactions		—			6,262,759
Total Increase (Decrease) in Net Assets		258,387			6,402,698

Net Assets
Beginning of period		6,402,698			—
End of period	$	6,661,085		$	6,402,698

Capital Share Transactions
Dollars:
Sold	$	—		$	6,262,759
Redeemed		—			—
Net Increase (Decrease)	$	—		$	6,262,759
Shares:
Sold		—			250,001
Redeemed		—			—
Net Increase (Decrease)		—			250,001

(a) Period from May 19, 2021, date operations commenced, through June 30, 2021.

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal U.S. Small-Cap Multi-Factor ETF
		Period ended			Year ended
		December 31, 2021			June 30, 2021
Operations
Net investment income (loss)	$	14,021,758		$	13,278,051
Net realized gain (loss) on investments		185,204,436			186,577,277
Change in unrealized appreciation (depreciation) of investments		(168,080,184	)		264,338,863
Net Increase (Decrease) in Net Assets Resulting from Operations		31,146,010			464,194,191

Dividends to Shareholders
From net investment income and net realized gain on investments		(17,349,751	)		(10,376,768	)
Total Dividends		(17,349,751	)		(10,376,768	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		(404,496,326	)		845,880,659
Total Increase (Decrease) in Net Assets		(390,700,067	)		1,299,698,082

Net Assets
Beginning of period		1,628,003,299			328,305,217
End of period	$	1,237,303,232		$	1,628,003,299

Capital Share Transactions
Dollars:
Sold	$	424,307,185		$	1,451,694,258
Redeemed		(828,803,511	)		(605,813,599	)
Net Increase (Decrease)	$	(404,496,326	)	$	845,880,659
Shares:
Sold		9,050,000			36,050,000
Redeemed		(17,650,000	)		(13,350,000	)
Net Increase (Decrease)		(8,600,000	)		22,700,000

See accompanying notes.


Statement of Changes in Net Assets
Principal Exchange-Traded Funds
(unaudited)

		Principal Value ETF
		Period ended			Year ended
		December 31, 2021		June 30, 2021
Operations
Net investment income (loss)	$	1,069,700		$	826,275
Net realized gain (loss) on investments		4,042,509			7,607,296
Change in unrealized appreciation (depreciation) of investments		(622,242	)		1,803,600
Net Increase (Decrease) in Net Assets Resulting from Operations		4,489,967			10,237,171

Dividends to Shareholders
From net investment income and net realized gain on investments		(1,428,275	)		(700,888	)
Total Dividends		(1,428,275	)		(700,888	)

Capital Share Transactions
Net increase (decrease) in capital share transactions		34,580,463			3,055,086
Total Increase (Decrease) in Net Assets		37,642,155			12,591,369

Net Assets
Beginning of period		44,498,336			31,906,967
End of period	$	82,140,491		$	44,498,336

Capital Share Transactions
Dollars:
Sold	$	64,496,194		$	38,529,990
Redeemed		(29,915,731	)		(35,474,904	)
Net Increase (Decrease)	$	34,580,463		$	3,055,086
Shares:
Sold		1,500,000			950,000
Redeemed		(700,000	)		(1,050,000	)
Net Increase (Decrease)		800,000			(100,000	)

See accompanying notes.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

1. Organization

The Principal Exchange-Traded Funds (the “Trust”) is a statutory trust organized under the laws of the State of Delaware in 2013 and is authorized to have multiple series or portfolios. The Trust is an open-end management investment company, registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Trust currently consists of fourteen series, Principal Active High Yield ETF, Principal Healthcare Innovators ETF, Principal International Adaptive Multi-Factor ETF, Principal Investment Grade Corporate Active ETF, Principal Millennials ETF, Principal Quality ETF, Principal Spectrum Preferred Securities Active ETF, Principal Spectrum Tax-Advantaged Dividend Active ETF, Principal Ultra-Short Active Income ETF, Principal U.S. Large-Cap Adaptive Multi-Factor ETF, Principal U.S. Mega-Cap ETF, Principal U.S. Small-Cap Adaptive Multi-Factor ETF, Principal U.S. Small-Cap Multi-Factor ETF and Principal Value ETF (collectively, the “Funds” and individually, a “Fund”). The Funds are “diversified”, and as such, the Funds' investments are required to meet certain diversification requirements under the 1940 Act. The shares of the Funds are referred to herein as “Shares”.

Each of the Funds is an investment company and applies specialized accounting and reporting under Accounting Standards Codification Topic 946, Financial Services - Investment Companies. The Funds have not provided financial support and are not contractually required to provide financial support to any investee.

The Trust issues and redeems Shares at net asset value (“NAV”) only with Authorized Participants (“APs”) and only in aggregations of 50,000 Shares with the exception of Principal International Adaptive Multi-Factor ETF which is issued and redeemed in aggregations of 100,000 shares (each a “Creation Unit” or multiples thereof “Creation Unit Aggregations”), which is subject to change. The Trust issues and redeems Creation Unit Aggregations in exchange for portfolio securities and/or cash, plus a fixed and/or variable transaction fee.

Shares trade on exchanges at market prices that may be below, at, or above NAV. Shares are listed on the respective exchanges as listed below:


Fund	Exchange
Principal Active High Yield ETF	NYSE Arca
Principal Healthcare Innovators ETF	The Nasdaq Stock Market LLC
Principal International Adaptive Multi-Factor ETF	Cboe BZX Exchange, Inc.
Principal Investment Grade Corporate Active ETF	NYSE Arca
Principal Millennials ETF	The Nasdaq Stock Market LLC
Principal Quality ETF	The Nasdaq Stock Market LLC
Principal Spectrum Preferred Securities Active ETF	NYSE Arca
Principal Spectrum Tax-Advantaged Dividend Active ETF	NYSE Arca
Principal Ultra-Short Active Income ETF	NYSE Arca
Principal U.S. Large-Cap Adaptive Multi-Factor ETF	Cboe BZX Exchange, Inc.
Principal U.S. Mega-Cap ETF	The Nasdaq Stock Market LLC
Principal U.S. Small-Cap Adaptive Multi-Factor ETF	Cboe BZX Exchange, Inc.
Principal U.S. Small-Cap Multi-Factor ETF	The Nasdaq Stock Market LLC
Principal Value ETF	The Nasdaq Stock Market LLC

Principal U.S. Large-Cap Adaptive Multi-Factor ETF and Principal U.S. Small-Cap Adaptive Multi-Factor ETF initial investments and commencement of operations was May 19, 2021. Principal International Adaptive Multi-Factor ETF initial investment and commencement of operations was May 26, 2021.

Effective September 1, 2021, Principal Active Income ETF changed its name to Principal Active High Yield ETF. In addition to the name change, the Trust's Board of Trustees authorized a 2 for 1 stock split effective after the close of trading on August 30, 2021. The stock split has been retroactively reflected on the Statement of Changes in Net Assets and Financial Highlights.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

1. Organization (continued)

Effective October 29, 2021, the following Funds changed their names as shown below:


Previous Name	New Name
Principal Healthcare Innovators Index ETF	Principal Healthcare Innovators ETF
Principal Millennials Index ETF	Principal Millennials ETF

2. Significant Accounting Policies

The preparation of financial statements in conformity with U.S. Generally Accepted Accounting Principles (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The following summarizes the significant accounting policies of the Funds:

Security Valuation. The Funds may invest in series of Principal Funds, Inc. and other investment funds, which may include money market funds and other registered open-end investment companies. Investments in registered open-end investment companies are valued at the respective fund's closing NAV per share on the day of valuation.

The Funds value securities for which market quotations are readily available at fair value, which is determined using the last reported sale price. If no sales are reported, as is regularly the case for some securities traded over-the-counter, securities are valued using the last reported bid price or an evaluated bid price provided by a pricing service. Pricing services use modeling techniques that incorporate security characteristics such as current quotations by broker/dealers, coupon, maturity, quality, type of issue, trading characteristics, other yield and risk factors and other market conditions to determine an evaluated bid price. When reliable market quotations are not considered to be readily available, which may be the case, for example, with respect to restricted securities, certain debt securities, preferred stocks, and foreign securities, the investments are valued at their fair value as determined in good faith by the Principal Global Investors, LLC (“the Advisor”) under procedures established and periodically reviewed by the Fund's Board of Trustees.

The value of foreign securities used in computing the NAV per share is generally determined as of the close of the foreign exchange where the security is principally traded. Events that occur after the close of the applicable foreign market or exchange but prior to the calculation of the Fund’s NAV are reflected in the Fund’s NAV and these securities are valued at fair value. Many factors, provided by independent pricing services, are reviewed in the course of making a good faith determination of a security's fair value including, but not limited to, price movements in American Depository Receipts (“ADRs”), futures contracts, industry indices, general indices, and foreign currencies.

To the extent the Funds invest in foreign securities listed on foreign exchanges which trade on days on which the Funds do not determine NAV, for example, weekends and other customary national U.S. holidays, the Fund’s NAV could be significantly affected on days when shares are not able to be issued or redeemed by APs.

Certain securities issued by companies in emerging market countries may have more than one quoted valuation at any given point in time, sometimes referred to as a “local” price and a “premium” price. The premium price is often a negotiated price, which may not consistently represent a price at which a specific transaction can be effected. It is the policy of the Funds to value such securities at prices at which it is expected those shares may be sold, and the Advisor, or any sub-advisor, is authorized to make such determinations subject to such oversight by the Trust's Board of Trustees, as may occasionally be necessary.

Currency Translation. Foreign holdings are translated to U.S. dollars using the exchange rate at the daily close of the New York Stock Exchange. The identified cost of the Funds’ holdings is translated at approximate rates prevailing when acquired. Income and expense amounts are translated at approximate rates prevailing when received or paid, with daily accruals of such amounts reported at approximate rates prevailing at the date of valuation. Since the carrying amount of the foreign securities is determined based on the exchange rate and market values at the close of the period, it is not practicable to isolate that portion of the results of operations arising as a result of changes in the foreign exchange rates from the fluctuations arising from changes in the market prices of securities during the period.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

2. Significant Accounting Policies (continued)

Net realized foreign exchange gains or losses arise from sales of foreign currencies, currency gains or losses realized between trade and settlement dates on security transactions, and the difference between the amount of dividends, interest income, interest expense, and foreign withholding taxes recorded on the books and the U.S. dollar equivalent of the amounts actually received or paid. Net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies arise from changes in the exchange rate relating to assets and liabilities, other than investments in securities, purchased and held in non-U.S. denominated currencies.

The following Funds held securities denominated in foreign currencies that exceeded 5% of net assets of the respective Fund as of December 31, 2021:


Principal International Adaptive Multi-Factor ETF
Australian Dollar	6.13	%
British Pound Sterling	11.19	%
Canadian Dollar	13.44	%
Euro	25.73	%
Japanese Yen	20.24	%
Swiss Franc	10.01	%
Principal Millennials ETF
Euro	12.65	%
Japanese Yen	5.50	%
Korean Won	7.89	%

Income and Investment Transactions. The Funds record investment transactions on a trade date basis. Trade date for senior floating rate interests purchased in the primary market is considered the date on which the loan allocations are determined. Trade date for senior floating rate interests purchased in the secondary market is the date on which the transaction is entered into. The identified cost basis has been used in determining the net realized gain or loss from investment transactions and unrealized appreciation or depreciation of investments. The Funds record dividend income on the ex-dividend date, except dividend income from foreign securities whereby the ex-dividend date has passed; such dividends are recorded as soon as the Funds are informed of the ex-dividend date. Interest income is recognized on an accrual basis. Discounts and premiums on securities are accreted/amortized, respectively, on the level yield method over the expected lives of the respective securities. Callable debt securities purchased at a premium are amortized to the earliest call date and to the callable amount, if other than par.

Capital Share Transactions. Capital shares are issued and redeemed by the Funds only in a Creation Unit or Creation Unit Aggregations. Except when aggregated into at least a Creation Unit, Shares are not redeemable.

The consideration for the purchase of a Creation Unit or Creation Unit Aggregations of a Fund generally consists of a basket of cash and/or securities that the Fund specifies each business day. To offset transfer and other transaction costs associated with the issuance and redemption of Creation Unit Aggregations, APs are subject to standard creation and redemption transaction fees.

Expenses. For all Funds, a unitary investment management and advisory fee is charged. The Advisor covers all operating expenses through the investment management and advisory fee with the exception of 12b-1 fees, brokerage commissions and other expenses connected to the execution of portfolio transactions, interest expense, taxes, acquired fund fees and expenses, litigation expenses and other extraordinary expenses, if applicable.

Dividends to Shareholders. Dividends to shareholders of the Funds are recorded on the ex-dividend date. Dividends to shareholders from net investment income and net realized gain from investments and foreign currency transactions are determined in accordance with federal tax regulations, which may differ from U.S. GAAP. These differences are primarily due to differing treatments for amortization of premiums and discounts, futures contracts, net operating losses, sales of passive foreign investment companies, partnership investments, foreign currency transactions, losses deferred due to wash sales, tax straddles, mortgage-backed securities, certain preferred securities, redemptions-in-kind, real estate investment trusts (“REITs”), utilization of earnings and profits distributed to shareholders on redemption of Shares, and limitations imposed by Sections 381-384 of the Internal Revenue Code (“IRC”). Permanent

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

2. Significant Accounting Policies (continued)

book and tax basis differences are reclassified within the capital accounts based on federal tax-basis treatment; temporary differences do not require reclassification. To the extent dividends exceed current and accumulated earnings and profits for federal income tax purposes, they are reported as return of capital distributions.

Federal Income Taxes. No provision for federal income taxes is considered necessary because the Funds each intend to qualify as a “regulated investment company” under the IRC and they intend to distribute each year substantially all of their net investment income and realized capital gains to shareholders.

Management evaluates tax positions taken or expected to be taken in the course of preparing the Funds' tax returns to determine whether it is “more likely than not” that each tax position would be sustained upon examination by a taxing authority based on the technical merits of their position. Tax positions not deemed to meet the “more likely than not” threshold would be recorded as a tax benefit or expense in the current year. During the period ended December 31, 2021, the Funds did not record any such tax benefit or expense in the accompanying financial statements. The statute of limitations remains open for the last three years, once a return is filed. No examinations are in progress at this time.

Foreign Taxes. Certain Funds are subject to foreign income taxes imposed by certain countries in which they invest. Foreign income taxes are accrued by the Funds as a reduction of income. These amounts are shown as withholding tax on the Statements of Operations.

Recent Accounting Pronouncements. In March 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-04, Reference Rate Reform (Topic 848); Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform. The guidance is applicable to contracts referencing London Inter-Bank Offered Rate (“LIBOR”) or another reference rate that is expected to be discontinued due to reference rate reform. The ASU is effective as of March 12, 2020 and generally can be applied through December 31, 2022. Management is evaluating the impact of the ASU over the period of time the ASU is effective.

3. Operating Policies

Contingent Convertible Securities (“CoCos”). As footnoted in the Schedules of Investments, certain of the Funds invest in contingent convertible securities. CoCos are hybrid debt securities that may convert into equity or have their principal written down upon the occurrence of certain “triggers”. Although a contingent convertible security's equity conversion and principal write-down features are tailored to the particular issuing banking institution and its regulatory requirements, triggers are generally linked to regulatory capital thresholds or regulatory actions calling into question such institution's continued viability as a going-concern. CoCos may have no stated maturity and fully discretionary coupons, which means coupon payments can be canceled at the issuing banking institution's discretion or at the request of the relevant regulatory authority without causing a default. To provide the appropriate regulatory capital treatment, CoCos are usually issued in the form of subordinated debt instruments that rank junior to the claims of holders of more senior obligations in the event of the issuer's liquidation. If CoCos are converted into equity securities due to a trigger event, holders will be further subordinated. The future value of CoCos is unpredictable and is influenced by many factors including, without limitation: the creditworthiness of the issuer and/or fluctuations in such issuer's applicable capital ratios; supply and demand for CoCos; general market conditions and available liquidity; and economic, financial and political events that affect the issuer, its particular market or the financial markets in general. Due to these features, CoCos may have substantially greater risk than other securities in times of financial stress. Because of the uncertainty regarding whether a conversion event will occur, it may be difficult to predict when, if at all, a contingent convertible security will be converted to equity, and a fund may suffer losses as a result. If the trigger level is breached, the issuer's decision to write down, write off or convert a contingent convertible security may result in the fund's complete loss on an investment in CoCos with no chance of recovery even if the issuer remains in existence.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

3. Operating Policies (continued)

Cross Trades. The Funds may engage in cross trades. A cross trade is a purchase or sale transaction between affiliated portfolios executed directly or through an intermediary. Mutual funds and other managed portfolios may be considered affiliated if they have a common investment advisor, so a fund may be considered affiliated with any portfolio for which the fund's sub-advisor acts as an investment advisor. Such transactions are permissible provided that the conditions of Rule 17a-7 under the 1940 Act are satisfied. For the period ended December 31, 2021, the Funds did not engage in cross trades.

Deposits with Counterparty. Cash pledged as collateral is reflected as an asset on the Statements of Assets and Liabilities as deposits with counterparty. There are a variety of security types which require varying levels of pledged collateral. Customer account agreements govern cleared derivatives transactions such as futures contracts. Such transactions require posting of initial margin as determined by each relevant clearing agency which is segregated in an account at a futures commission merchant (“FCM”) registered with the Commodity Futures Trading Commission. As of December 31,2021, deposits with counterparty for Principal Investment Grade Corporate Active ETF and Principal Spectrum Tax-Advantaged Dividend Active ETF were $643,400 and $14,955.

Futures Contracts. The Funds are subject to equity price risk, interest rate risk, and foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The Funds may enter into futures contracts to hedge against changes in, or to gain exposure to, change in the value of equities, interest rates and foreign currencies. Initial margin deposits are made by cash deposits or segregation of specific securities as may be required by the exchange on which the transaction was conducted. Pursuant to the contracts, typically a Fund agrees to receive from or pay to the broker, an amount of cash equal to the daily fluctuation in the value of the contract. Such receipts or payments are known as “variation margin” and are recorded by the Funds as variation margin receivable or payable on financial derivative instruments. For those contracts where daily variation margin payments are not received from or paid to the broker, the cumulative unrealized gains or losses are included in variation margin receivable or payable on financial derivative instruments. Futures contracts are marked to market daily at the closing settlement price or in the absence of such a price, the most recent quoted bid price. If there are no quotations available, the security is valued at the last available closing settlement price. During the period the futures contracts are open, daily changes in the fair value of the contracts are recognized as unrealized gains or losses. These unrealized gains or losses are included as a component of net unrealized appreciation (depreciation) of investments on the Statements of Assets and Liabilities. When the contracts are closed, the Funds recognize a realized gain or loss equal to the difference between the proceeds from, or cost of, the closing transaction and the Fund’s cost basis in the contract. There is minimal counterparty credit risk to the Funds because futures are exchange traded and the exchange’s clearinghouse, as counterparty to all exchange traded futures, guarantees the futures against default.

Long and short U.S. Treasury futures contracts are used to obtain interest rate exposure in order to manage duration of the Principal Investment Grade Corporate Active ETF. The notional values of the futures contracts will vary in accordance with changing duration of this Fund.

Illiquid Securities. Illiquid securities generally cannot be sold or disposed of in the ordinary course of business (within seven calendar days) at approximately the value at which each of the Funds has valued the investments. This may have an adverse effect on each of the Funds’ ability to dispose of particular illiquid securities at fair value and may limit each of the Funds’ ability to obtain accurate market quotations for purposes of valuing the securities.

Indemnification. In a normal course of business, the Funds enter into contracts that contain a variety of indemnifications. The Funds’ maximum exposure under these arrangements is unknown as this would involve potential future claims against the Funds that have not yet occurred. Based on management's experience, the risk of loss would be remote.

Restricted Securities. Certain of the Funds may invest in securities that are subject to legal or contractual restrictions on resale. These securities generally may be resold in transactions exempt from registration or to the public if the securities are registered. Disposal of these securities may involve time-consuming negotiations and expense, and prompt sale at an acceptable price may be difficult.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

3. Operating Policies (continued)

Securities Lending. As footnoted in the Schedules of Investments, certain of the Funds may lend portfolio securities to approved brokerage firms to earn additional income. The Funds receive collateral, in the form of cash, against the loaned securities. During the period of the loan, the borrower must maintain collateral in an amount not less than 102% of the market value of the domestic and foreign fixed income loaned securities and 105% of the market value of the foreign equity loaned securities. The market value of the loaned securities is determined at the close of business of the Funds and any additional required collateral is delivered to the Funds on the next business day. The cash collateral received is usually invested in a SEC-registered money market mutual fund and the Funds could realize a loss on such investments. Further, the Funds could experience a delay in recovering their securities and possible loss of income or value if the borrower fails to return them. Securities lending income, net of related fees, is shown on the Statements of Operations.

Senior Floating Rate Interests. The Fund may invest in senior floating rate interests (bank loans). Senior floating rate interests hold the most senior position in the capital structure of a business entity (the “Borrower”), are typically secured by specific collateral and have a claim on the assets and/or stock of the Borrower that is senior to that held by subordinated debtholders and stockholders of the Borrower. Senior floating rate interests are typically structured and administered by a financial institution that acts as the agent of the lenders participating in the senior floating rate interest. Borrowers of senior floating rate interests are typically rated below investment grade, which means they are more likely to default than investment-grade loans. A default could lead to non-payment of income which would result in a reduction of income to the Fund and there can be no assurance that the liquidation of any collateral would satisfy the Borrower’s obligation in the event of non-payment of scheduled interest or principal payments, or that such collateral could be readily liquidated.

Senior floating rate interests pay interest at rates which are periodically reset by reference to a base lending rate plus a spread. These base lending rates are generally the prime rate offered by a designated U.S. bank or the LIBOR rate.

Senior floating rate interests generally are subject to mandatory and/or optional prepayment. Because of these mandatory prepayment conditions and because there may be significant economic incentives for the Borrower to repay, prepayments of senior floating rate interests may occur. As a result, the actual remaining maturity of senior floating rate interests may be substantially less than stated maturities shown in the Schedule of Investments.

In connection with the senior floating rate interests, the Fund may also enter into unfunded loan commitments. All or a portion of the loan commitments may be unfunded. The Fund is obligated to fund these commitments at the Borrower’s discretion. Therefore, the Fund must have funds sufficient to cover its contractual obligation. Unfunded loan commitments are marked to market daily and the unrealized gain or loss is shown as a separate line item called unrealized gain or loss on unfunded commitments on the statement of assets and liabilities and included in the net change in unrealized appreciation/(depreciation) of investments on the statements of operations, as applicable. As of period end, the unfunded loan commitments are categorized as Level 2 within the disclosure hierarchy. As of December 31, 2021, there were no unfunded loan commitments.

Underlying Funds. An underlying fund may experience relatively large redemptions or purchases as the investee fund periodically reallocates or rebalances its assets. These transactions may accelerate the realization of taxable income if sales of portfolio securities result in gains and could increase transaction costs.

The Advisor is the advisor to Principal Funds, Inc., Principal Variable Contracts Funds, Inc., affiliates of the Advisor, and other asset allocation programs. The Advisor is committed to minimizing the potential impact of underlying fund risk to the extent consistent with pursuing the investment objectives of the investee funds which it manages. Each may face conflicts of interest in fulfilling its responsibilities to all such funds.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

3. Operating Policies (continued)

As of December 31, 2021, series of Principal Funds, Inc. and Principal Variable Contracts Funds, Inc. owned the following percentages, in aggregate, of the outstanding Shares of the Funds listed below:


	Total Percentage of
Fund	Outstanding Shares Owned
Principal Active High Yield ETF	80.46	%
Principal Investment Grade Corporate Active ETF	93.57
Principal U.S. Mega-Cap ETF	83.25
Principal U.S. Small-Cap Multi-Factor ETF	93.68

U.S. Government Agencies or Government-Sponsored Enterprises. Certain of the Funds may invest in U.S. Government agencies or government-sponsored enterprises. U.S. Government securities are obligations of, and in certain cases, guaranteed by, the U.S. Government or its agencies. The U.S. Government does not guarantee the NAV of the Funds’ Shares. Some U.S. Government securities such as treasury bills, notes and bonds, and securities guaranteed by the Government National Mortgage Association (“GNMA”) are supported by the full faith and credit of the U.S. Government. Other securities, such as those of the Federal Home Loan Bank, are supported by the right of the issuer to borrow from the U.S. Department of the Treasury. Still other securities, such as those of the Federal National Mortgage Association (“FNMA”), are supported by the discretionary authority of the U.S. Government to purchase the agency’s obligations.

Government related guarantors (those not backed by the full faith and credit of the U.S. Government) include FNMA and Federal Home Loan Mortgage Corporation (“FHLMC”). FNMA is a government sponsored corporation, the common stock of which is owned entirely by private stockholders. FNMA purchases conventional residential mortgages from a list of approved seller/servicers which include state and federally chartered savings and loan associations, mutual savings banks, commercial banks, credit unions, and mortgage bankers. Pass-through securities issued by FNMA are guaranteed as to the timely payment of principal and interest by FNMA, but are not backed by the full faith and credit of the U.S. Government. FHLMC issues participation certificates, which are pass-through securities, each representing an undivided interest in a pool of residential mortgages. FHLMC guarantees the timely payment of interest and ultimate collection of principal, but participation certificates are not backed by the full faith and credit of the U.S. Government.

Derivatives. The following tables provide information about where on the Statements of Assets and Liabilities and Statements of Operations information about derivatives can be found:


	Asset Derivatives		Liability Derivatives
	December 31, 2021		December 31, 2021

	Statement of Assets and		Statement of Assets and
Derivatives not accounted for as hedging instruments	Liabilities Location	Fair Value	Liabilities Location		Fair Value
Principal Investment Grade Corporate Active ETF
Interest rate contracts	Receivables, Total		Payables, Total
	distributable earnings		distributable earnings
	(accumulated loss)	$ —*	(accumulated loss)	$	(111,634	)*

* Includes cumulative unrealized appreciation (depreciation) of futures contracts as shown in the Schedule of Investments. Only the portion of the unrealized appreciation (depreciation) not yet cash settled is shown in the Statements of Assets and Liabilities as variation margin.


Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)



3. Operating Policies (continued)

		Net Realized Gain or				Net Change in Unrealized
		(Loss) on Derivatives				Appreciation
	Location of Gain or (Loss) on		Recognized in			(Depreciation) of
	Derivatives Recognized in		Statement of			Derivatives Recognized in
Derivatives not accounted for as hedging instruments	Statement of Operations		Operations			Statement of Operations
Principal Investment Grade Corporate Active ETF
Interest rate contracts	Net realized gain (loss) from
	Futures contracts/Net change
in unrealized appreciation/
(depreciation) of Futures
	contracts	$	453,652		$	(21,855	)

Principal Spectrum Tax-Advantaged Dividend Active ETF
Interest rate contracts	Net realized gain (loss) from
Investment transactions,
	Futures contracts and Options
	/Change in unrealized
	appreciation (depreciation) of	$	(45	)	$	—
	Investments, Futures contracts
	and Options

The following table includes a summary of the monthly average outstanding notional by derivative instrument type for the period ended December 31, 2021:


			Average Notional or
Contract Type	Derivative Type		Number of Contracts
Principal Investment Grade Corporate Active ETF
Interest rate contracts	Futures — Short	$	60,963,461

Principal Spectrum Tax-Advantaged Dividend Active ETF
Interest rate contracts	Purchased options		3
	Written options		3

4. Fair Valuation

Fair value is defined as the price that the Funds would receive upon selling a security or transferring a liability in a timely transaction to an independent buyer in the principal or most advantageous market of the security at the measurement date. In determining fair value, the Funds may use one or more of the following approaches: market, income and/or cost. A hierarchy for inputs is used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available.

Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Funds. Unobservable inputs are inputs that reflect the Fund’s own estimates about the estimates market participants would use in pricing the asset or liability developed based on the best information available in the circumstances.

The three-tier hierarchy of inputs is summarized in the three broad levels listed below.

Level 1 — Quoted prices are available in active markets for identical securities as of the reporting date. Investments which are generally included in this category include listed equities and listed derivatives.

Level 2 — Other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.). Investments which are generally included in this category include certain corporate bonds, senior floating rate interests, over-the-counter (“OTC”) derivatives, mortgage-backed securities and municipal bonds.

Level 3 — Significant unobservable inputs (including the Funds' assumptions in determining the fair value of investments). Investments which are generally included in this category include certain corporate bonds and certain common stocks.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

4. Fair Valuation (continued)

The availability of observable inputs can vary from security to security and is affected by a wide variety of factors, including, for example, the type of security, whether the security is new and not yet established in the market place, and other characteristics particular to the transaction. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Funds in determining fair value is greatest for instruments categorized in Level 3.

In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

Fair value is a market based measure considered from the perspective of a market participant who holds the asset rather than an entity specific measure. Therefore, even when market assumptions are not readily available, the Funds’ own assumptions are set to reflect those that market participants would use in pricing the asset or liability at the measurement date. The Funds use prices and inputs that are current as of the measurement date, to the extent available.

Investments which are included in the Level 3 category may be valued using quoted prices from brokers and dealers participating in the market for these investments. These investments are classified as Level 3 investments due to the lack of market transparency and market corroboration to support these quoted prices.

Valuation models may be used as the pricing source for other investments classified as Level 3. Valuation models rely on one or more significant unobservable inputs such as prepayment rates, probability of default, or loss severity in the event of default. Significant increases in any of those inputs in isolation would result in a significantly lower fair value measurement.

The fair values of these entities are dependent on economic, political and other considerations. The values of the underlying investee entities may be affected by significant changes in the economic conditions, changes in government policies, and other factors (e.g., natural disasters, pandemics, accidents, conflicts, etc.).

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those instruments.

During the period there were no significant purchases, sales, or transfers into or out of Level 3.

The following is a summary of the inputs used as of December 31, 2021, in valuing the Funds' securities carried at fair value:


				Level 2 —
				Other		Level 3 —
		Level 1 —		Significant		Significant
		Quoted		Observable		Unobservable
Fund		Prices		Inputs		Inputs		Totals (Level 1,2,3)

Principal Active High Yield ETF
Common Stocks*	$	2,064,161	$	— $			— $	2,064,161
Bonds*		—		216,847,714			—	216,847,714
Senior Floating Rate Interests*		—		21,401,924			—	21,401,924
Investment Companies		9,349,979		—			—	9,349,979
Total investments in securities	$	11,414,140	$	238,249,638	$		— $	249,663,778

Principal Healthcare Innovators ETF
Common Stocks*	$	89,836,056	$	— $			— $	89,836,056
Investment Companies		4,855,246		—			—	4,855,246
Total investments in securities	$	94,691,302	$	— $			— $	94,691,302


Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)



4. Fair Valuation (continued)

				Level 2 —
				Other		Level 3 —
		Level 1 —		Significant		Significant
		Quoted		Observable		Unobservable
Fund		Prices		Inputs		Inputs		Totals (Level 1,2,3)

Principal International Adaptive Multi-Factor ETF
Common Stocks*
Basic Materials	$	8,530,029	$	— $			— $	8,530,029
Communications		8,089,493		—			—	8,089,493
Consumer, Cyclical		17,247,739		—			—	17,247,739
Consumer, Non-cyclical		30,440,310		—			—	30,440,310
Diversified		232,664		—			—	232,664
Energy		3,136,210		—			—	3,136,210
Financial		30,340,004		63,817			—	30,403,821
Industrial		17,760,648		94,793			—	17,855,441
Technology		9,428,101		—			—	9,428,101
Utilities		5,240,767		—			—	5,240,767
Preferred Stocks*		320,980		—			—	320,980
Investment Companies		927,307		—			—	927,307
Total investments in securities	$	131,694,252	$	158,610	$		— $	131,852,862

Principal Investment Grade Corporate Active ETF
Bonds*	$	— $		482,353,183	$		— $	482,353,183
Investment Companies		5,723,763		—			—	5,723,763
Total investments in securities	$	5,723,763	$	482,353,183	$		— $	488,076,946
Derivatives
Liabilities
Interest rate contracts
Futures	$	(111,634	) $	— $			— $	(111,634	)

Principal Millennials ETF
Common Stocks*	$	103,313,440	$	— $			— $	103,313,440
Investment Companies		3,097,306		—			—	3,097,306
Total investments in securities	$	106,410,746	$	— $			— $	106,410,746

Principal Quality ETF
Common Stocks*	$	96,527,314	$	— $			— $	96,527,314
Investment Companies		270,326		—			—	270,326
Total investments in securities	$	96,797,640	$	— $			— $	96,797,640

Principal Spectrum Preferred Securities Active ETF
Bonds*	$	— $		437,462,705	$		— $	437,462,705
Investment Companies		19,134,573		—			—	19,134,573
Total investments in securities	$	19,134,573	$	437,462,705	$		— $	456,597,278

Principal Spectrum Tax-Advantaged Dividend Active ETF
Preferred Stocks*	$	2,978,397	$	— $			— $	2,978,397
Bonds*		—		20,811,607			—	20,811,607
Investment Companies		154,820		—			—	154,820
Total investments in securities	$	3,133,217	$	20,811,607	$		— $	23,944,824

Principal Ultra-Short Active Income ETF
Bonds*	$	— $		8,086,931	$		— $	8,086,931
U.S. Government & Government
Agency Obligations*		—		199,984			—	199,984
Investment Companies		285,397		—			—	285,397
Total investments in securities	$	285,397	$	8,286,915	$		— $	8,572,312

Principal U.S. Large-Cap Adaptive Multi-Factor ETF
Common Stocks*	$	131,396,617	$	— $			— $	131,396,617
Investment Companies		514,794		—			—	514,794
Total investments in securities	$	131,911,411	$	— $			— $	131,911,411

Principal U.S. Mega-Cap ETF
Common Stocks*	$	1,862,074,458	$	— $			— $	1,862,074,458
Investment Companies		4,266,564		—			—	4,266,564
Total investments in securities	$	1,866,341,022	$	— $			— $	1,866,341,022


Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)



4. Fair Valuation (continued)

				Level 2 —
				Other	Level 3 —
		Level 1 —		Significant	Significant
		Quoted		Observable	Unobservable
Fund		Prices		Inputs	Inputs		Totals (Level 1,2,3)

Principal U.S. Small-Cap Adaptive Multi-Factor ETF
Common Stocks*	$	6,644,495	$	— $		— $	6,644,495
Investment Companies		15,999		—		—	15,999
Total investments in securities	$	6,660,494	$	— $		— $	6,660,494

Principal U.S. Small-Cap Multi-Factor ETF
Common Stocks*	$	1,233,473,213	$	— $		— $	1,233,473,213
Investment Companies		15,395,844		—		—	15,395,844
Total investments in securities	$	1,248,869,057	$	— $		— $	1,248,869,057

Principal Value ETF
Common Stocks*	$	81,818,381	$	— $		— $	81,818,381
Investment Companies		273,672		—		—	273,672
Total investments in securities	$	82,092,053	$	— $		— $	82,092,053

*	For additional detail regarding sector classifications, please see the Schedules of Investments.
5.	Management Agreement and Transactions with Affiliates

Management Services. The Funds have agreed to pay management and investment advisory fees to the Advisor computed at an annual percentage rate of each of the Funds' average daily net assets. A portion of the management fee is paid by the Advisor to the sub-advisor of the Funds, which is also an affiliate of the Advisor. The management fee schedule for the Funds is as follows:


	First		Next		Next		Over
Fund	$500 Million		$500 Million		$500 Million		$1.5 Billion
Principal Healthcare Innovators ETF	0.42	%	0.40	%	0.38	%	0.37	%
Principal Millennials ETF	0.45		0.43		0.41		0.40

Fund							All Assets
Principal Active High Yield ETF							0.39	%*
Principal International Adaptive Multi-Factor ETF							0.24
Principal Investment Grade Corporate Active ETF							0.19
Principal Quality ETF							0.15
Principal Spectrum Preferred Securities Active ETF							0.55
Principal Spectrum Tax-Advantaged Dividend Active ETF							0.60
Principal Ultra-Short Active Income ETF							0.18
Principal U.S. Large-Cap Adaptive Multi-Factor ETF							0.15
Principal U.S. Mega-Cap ETF							0.15
Principal U.S. Small-Cap Adaptive Multi-Factor ETF							0.19
Principal U.S. Small-Cap Multi-Factor ETF							0.38
Principal Value ETF							0.15
* Prior to September 1, 2021, the management fee was 0.49%.

The Advisor has contractually agreed to limit the expenses (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, tax reclaim recovery expenses, and other extraordinary expenses) for certain of the Funds. The reductions and reimbursements are in amounts that maintain total operating expenses at or below certain limits.

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

5. Management Agreement and Transactions with Affiliates (continued)

The limit is expressed as a percentage of average daily net assets attributable to each Fund on an annualized basis during the reporting period. The expenses borne by the Advisor are subject to reimbursement by the Fund through the fiscal year end, provided no reimbursement will be made if it would result in the Fund exceeding the total operating expense limit. Any amount outstanding at the end of the period are shown as an expense reimbursement from Advisor or expense reimbursement to Advisor on the Statements of Assets and Liabilities. The expense limit for Principal U.S. Mega-Cap ETF is 0.12% through October 31, 2022.

Affiliated Ownership. At December 31, 2021, Principal Financial Services, Inc., Principal Funds, Inc., and Principal Variable Contracts Funds, Inc. (each an affiliate of the Advisor) owned Shares of the Funds as follows:


Fund	Shares
Principal Active High Yield ETF	9,494,200
Principal International Adaptive Multi-Factor ETF	390,001
Principal Investment Grade Corporate Active ETF	17,450,000
Principal Spectrum Tax-Advantaged Dividend Active ETF	995,521
Principal Ultra-Short Active Income ETF	199,681
Principal U.S. Large-Cap Adaptive Multi-Factor ETF	198,571
Principal U.S. Mega-Cap ETF	35,050,000
Principal U.S. Small-Cap Adaptive Multi-Factor ETF	200,965
Principal U.S. Small-Cap Multi-Factor ETF	24,450,000

Affiliated Brokerage Commissions. With respect to Principal Spectrum Tax-Advantaged Dividend Active ETF, $248 of brokerage commissions were paid to SAMI Brokerage LLC, a member of the Principal Financial Group. The other Funds did not pay brokerage commissions to any member of the Principal Financial Group during the period ended December 31, 2021.

6. Investment Transactions

For the period ended December 31, 2021, the cost of investment securities purchased and proceeds from investment securities sold (not including short-term investments and in-kind transactions) by the Funds were as follows:


		Non-U.S. Government				U.S. Government
Fund		Purchases		Sales		Purchases		Sales
Principal Active High Yield ETF	$	270,364,742	$	205,187,908	$	—	$	—
Principal Healthcare Innovators ETF		34,728,454		35,743,564		—		—
Principal International Adaptive Multi-Factor ETF		40,839,319		29,769,802		—		—
Principal Investment Grade Corporate Active ETF		123,945,795		112,130,226		—		—
Principal Millennials ETF		7,407,698		7,976,072		—		—
Principal Quality ETF		196,375		349,761		—		—
Principal Spectrum Preferred Securities Active ETF		78,370,634		12,094,490		—		—
Principal Spectrum Tax-Advantaged Dividend Active ETF		508,643		322,197		—		—
Principal Ultra-Short Active Income ETF		3,717,965		2,774,116		—		—
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		38,380,416		38,316,738		—		—
Principal U.S. Mega-Cap ETF		220,693,294		225,620,738		—		—
Principal U.S. Small-Cap Adaptive Multi-Factor ETF		2,719,076		2,744,313		—		—
Principal U.S. Small-Cap Multi-Factor ETF		506,914,962		507,628,721		—		—
Principal Value ETF		1,231,138		1,688,264		—		—

For the period ended December 31, 2021, in-kind transactions were as follows:


Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)


7. Federal Tax Information

Fund		Purchases		Sales
Principal Active High Yield ETF	$	10,921,581	$	57,639,903
Principal Healthcare Innovators ETF		2,778,151		55,147,594
Principal International Adaptive Multi-Factor ETF		81,561,771		9,526,463
Principal Investment Grade Corporate Active ETF		16,289,109		—
Principal Millennials ETF		27,938,128		35,328,764
Principal Quality ETF		106,083,308		78,270,451
Principal Spectrum Preferred Securities Active ETF		26,631,448		—
Principal Spectrum Tax-Advantaged Dividend Active ETF		1,940,785		—
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		135,627,856		45,930,003
Principal U.S. Mega-Cap ETF		407,732,001		726,593,827
Principal U.S. Small-Cap Multi-Factor ETF		421,813,647		828,119,640
Principal Value ETF		64,486,566		29,924,001

Unsettled in-kind purchases and sales at the end of the period are included in investment securities purchased and investment securities sold, respectively, on the Statements of Assets and Liabilities.

Distributions to Shareholders. The federal income tax character of distributions paid for the periods ended June 30, 2021, and December 31, 2021 was as follows:


		Ordinary Income				Long-Term Capital Gain*
		Period ended		Period ended		Period ended	Period ended
Fund		December 31, 2021		June 30, 2021		December 31, 2021	June 30, 2021
Principal Active High Yield ETF	$	6,251,383	$	9,881,656	$	— $	—
Principal Healthcare Innovators ETF		861,124		527,787		—	—
Principal International Adaptive Multi-Factor ETF		1,153,177		—		—	—
Principal Investment Grade Corporate Active ETF		9,076,520		10,618,462		634,167	3,773,742
Principal Millennials ETF		2,713,066		481,261		—	—
Principal Quality ETF		614,556		296,923		—	—
Principal Spectrum Preferred Securities Active ETF		9,470,707		9,608,037		—	—
Principal Spectrum Tax-Advantaged Dividend Active ETF		707,569		1,062,462		30,484	—
Principal Ultra-Short Active Income ETF		56,101		215,987		—	—
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		660,123		—		—	—
Principal U.S. Mega-Cap ETF		24,965,735		27,303,682		—	—
Principal U.S. Small-Cap Adaptive Multi-Factor ETF		105,510		—		—	—
Principal U.S. Small-Cap Multi-Factor ETF		17,349,751		10,376,768		—	—
Principal Value ETF		1,428,275		700,888		—	—

* The Funds designate these distributions as long-term capital gain dividends per IRC Sec. 852(b)(3)(C) in the 20-percent group (which may be taxed at a 20-percent rate, a 15-percent rate or a 0-percent rate, depending on the shareholder’s taxable income).

For U.S. federal income tax purposes, short-term capital gain distributions are considered ordinary income distributions.

Distributable Earnings. As of June 30, 2021, the components of distributable earnings (accumulated loss) on a federal income tax basis were:


Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)


7. Federal Tax Information (continued)

				Late Year
				Ordinary and
	Undistributed	Undistributed	Unrealized	Post Oct
	Ordinary	Long-Term	Appreciation/	Capital Loss		Capital Loss
Fund	Income	Capital Gains	(Depreciation)	Deferrals		Carryforward
Principal Active High Yield ETF	$831,649	$—	$24,849,782	$—	$	(14,379,385)
Principal Healthcare Innovators ETF	861,124	—	19,384,511	(1,381,846)		(854,489)
Principal International Adaptive Multi-Factor ETF	75,711	—	(1,035,524)	—		—
Principal Investment Grade Corporate Active ETF	1,067,183	65,131	6,993,476	—		—
Principal Millennials ETF	65,272	—	11,188,422	—		(2,828,381)
Principal Quality ETF	142,898	—	2,374,987	—		(1,538,325)
Principal Spectrum Preferred Securities Active ETF	1,381,160	—	10,176,459	—		(1,875,171)
Principal Spectrum Tax-Advantaged Dividend Active ETF	149,815	—	1,427,464	—		—
Principal Ultra-Short Active Income ETF	9,140	—	(26,912)	—		(125,628)
Principal U.S. Large-Cap Adaptive Multi-Factor ETF	15,441	247	372,697	—		—
Principal U.S. Mega-Cap ETF	8,465,068	—	389,916,580	—		(63,824,955)
Principal U.S. Small-Cap Adaptive Multi-Factor ETF	8,240	35	131,664	—		—
Principal U.S. Small-Cap Multi-Factor ETF	4,414,408	—	223,375,303	—		(85,559,823)
Principal Value ETF	340,273	—	2,791,996	—		(2,182,414)

Capital Loss Carryforwards. For federal income tax purposes, capital loss carryforwards are losses that can be used to offset future capital gains of the Fund. As of June 30, 2021, the Funds had approximate net capital loss carryforwards as follows:


		No Expiration		No Expiration			Annual
Fund		Short-Term		Long-Term		Total	Limitations*
Principal Active High Yield ETF	$	5,508,508	$	8,870,877	$	14,379,385	$ 1,874,152
Principal Healthcare Innovators ETF		—		854,489		854,489	—
Principal International Adaptive Multi-Factor ETF		—		—		—	—
Principal Investment Grade Corporate Active ETF		—		—		—	—
Principal Millennials ETF		2,819,136		9,245		2,828,381	—
Principal Quality ETF		1,157,520		380,805		1,538,325	294,429
Principal Spectrum Preferred Securities Active ETF		957,946		917,225		1,875,171	—
Principal Spectrum Tax-Advantaged Dividend Active ETF		—		—		—	—
Principal Ultra-Short Active Income ETF		71,425		54,203		125,628	—
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		—		—		—	—
Principal U.S. Mega-Cap ETF		57,299,653		6,525,302		63,824,955	—
Principal U.S. Small-Cap Adaptive Multi-Factor ETF		—		—		—	—
Principal U.S. Small-Cap Multi-Factor ETF		56,960,496		28,599,327		85,559,823	—
Principal Value ETF		869,689		1,312,725		2,182,414	230,798

* In accordance with IRC Sections 381-384, a portion of certain Funds’ losses have been subjected to an annual limitation.

All of these capital losses were generated in taxable years beginning after the enactment date of the Regulated Investment Company Modernization Act of 2010 on December 22, 2010, and will be carried forward with no expiration and with the character of the loss retained.

For the year ended June 30, 2021, the Funds utilized capital loss carryforwards as follows:


Fund		Utilized
Principal Healthcare Innovators ETF	$	2,985,702
Principal Spectrum Tax-Advantaged Dividend Active ETF		5,892
Principal U.S. Mega-Cap ETF		16,646,055

Notes to Financial Statements
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

7. Federal Tax Information (continued)

Late-Year Losses. A regulated investment company may elect to treat any portion of its qualified late-year loss as arising on the first day of the next taxable year. Qualified late-year losses are certain capital and ordinary losses which occur during the portion of the Fund’s taxable year subsequent to October 31 and December 31, respectively.

For the taxable year ended June 30, 2021, the Funds intend to defer late-year capital and ordinary losses as follows:


Fund		Late Year Ordinary Loss		Post October Loss Capital Loss
Principal Healthcare Innovators ETF	$	—	$	(1,381,846	)

Reclassification of Capital Accounts. The Funds may record reclassifications in their capital accounts. These reclassifications have no impact on the total net assets of the Funds. The reclassifications are a result of permanent differences between U.S. GAAP and tax accounting. Adjustments are made to reflect the impact these items have on current and future distributions to shareholders. Therefore, the source of the Funds’ distributions may be shown in the accompanying Statement of Changes in Net Assets as from net investment income and net realized gains on investments or from tax return of capital depending on the type of book and tax differences that exist. For the period ended June 30, 2021, the Funds recorded reclassifications as follows:


		Total
		Distributable Earnings
Fund		(Accumulated Loss)			Paid In Capital
Principal Active High Yield ETF	$	(268,856	)	$	268,856
Principal Healthcare Innovators ETF		(26,764,189	)		26,764,189
Principal International Adaptive Multi-Factor ETF		(15,000	)		15,000
Principal Investment Grade Corporate Active ETF		(1,023,845	)		1,023,845
Principal Millennials ETF		(22,957,641	)		22,957,641
Principal Quality ETF		(7,315,778	)		7,315,778
Principal Spectrum Preferred Securities Active ETF		(757,854	)		757,854
Principal Spectrum Tax-Advantaged Dividend Active ETF		—			—
Principal Ultra-Short Active Income ETF		(3,091	)		3,091
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		—			—
Principal U.S. Mega-Cap ETF		(175,651,470	)		175,651,470
Principal U.S. Small-Cap Adaptive Multi-Factor ETF		—			—
Principal U.S. Small-Cap Multi-Factor ETF		(208,573,293	)		208,573,293
Principal Value ETF		(7,817,645	)		7,817,645

Federal Income Tax Basis. As of June 30, 2021, the net federal income tax unrealized appreciation (depreciation) and federal tax cost of investments held by each Fund were as follows:


										Cost for
							Net Unrealized			Federal
		Unrealized		Unrealized			Appreciation			Income Tax
Fund		Appreciation		Depreciation			(Depreciation)			Purposes
Principal Active High Yield ETF	$	27,746,110	$	(2,896,082	)	$	24,850,028		$	209,215,515
Principal Healthcare Innovators ETF		32,133,352		(12,748,841	)		19,384,511			163,391,512
Principal International Adaptive Multi-Factor ETF		284,101		(1,319,182	)		(1,035,081	)		48,109,836
Principal Investment Grade Corporate Active ETF		8,896,060		(1,902,584	)		6,993,476			473,764,748
Principal Millennials ETF		13,595,959		(2,407,370	)		11,188,589			120,014,188
Principal Quality ETF		2,915,066		(540,078	)		2,374,988			56,082,189
Principal Spectrum Preferred Securities Active ETF		11,030,241		(853,781	)		10,176,460			359,885,216
Principal Spectrum Tax-Advantaged Dividend Active ETF		1,430,511		(3,048	)		1,427,463			21,025,470
Principal Ultra-Short Active Income ETF		9,124		(36,036	)		(26,912	)		8,664,026
Principal U.S. Large-Cap Adaptive Multi-Factor ETF		666,512		(293,815	)		372,697			29,514,328


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 0.84%		Shares Held		Value

REITs — 0.84%
CBL & Associates Properties Inc ^(a)		66,159	$	2,064,161
TOTAL COMMON STOCKS			$	2,064,161
		Principal
BONDS — 88.61%		Amount		Value

Aerospace & Defense — 1.78%
Bombardier, Inc.
7.13%, 06/15/2026 ^(b)	$	848,000	$	879,723
Triumph Group, Inc.
7.75%, 08/15/2025 ^(c)		3,312,000		3,287,160
8.88%, 06/01/2024 ^(b)		185,000		201,776
			$	4,368,659

Airlines — 0.12%
United Airlines Pass-Through Trust
3.65%, 07/07/2027		288,587		285,375

Auto Manufacturers — 1.98%
Ford Motor Co.
3.25%, 02/12/2032		1,497,000		1,532,928
Ford Motor Credit Co. LLC
3.38%, 11/13/2025		1,889,000		1,962,520
4.39%, 01/08/2026		217,000		233,818
4.54%, 08/01/2026		1,037,000		1,126,441
			$	4,855,707

Auto Parts & Equipment — 1.52%
Tenneco, Inc.
7.88%, 01/15/2029 ^(b)		3,445,000		3,720,600

Banks — 1.43%
Deutsche Bank AG
(5-year Treasury Constant Maturity Rate + 4.52%),
6.00%, 10/30/2025 ^(d),(e),(f)		3,360,000		3,490,200

Chemicals — 3.81%
Consolidated Energy Finance SA
5.63%, 10/15/2028 ^(b)		3,560,000		3,479,900
Kobe U.S. Midco 2, Inc.
9.25%, PIK 10.00%; 11/01/2026 ^(b),(g)		943,000		963,039
Olympus Water U.S. Holding Corp.
6.25%, 10/01/2029 ^(b)		2,470,000		2,408,250
Tronox, Inc.
4.63%, 03/15/2029 ^(b)		2,470,000		2,466,912
			$	9,318,101

Commercial Services — 4.01%
Ahern Rentals, Inc.
7.38%, 05/15/2023 ^(b)		1,665,000		1,583,831
Albion Financing 1 SARL/Aggreko Holdings, Inc.
6.13%, 10/15/2026 ^(b)		2,048,000		2,068,480
Garda World Security Corp.
6.00%, 06/01/2029 ^(b)		366,000		349,530
9.50%, 11/01/2027 ^(b)		2,395,000		2,582,253
WASH Multifamily Acquisition, Inc.
5.75%, 04/15/2026 ^(b)		3,079,000		3,235,875
			$	9,819,969

Construction Materials — 2.63%
Patrick Industries, Inc.
4.75%, 05/01/2029 ^(b)		838,000		833,810
7.50%, 10/15/2027 ^(b)		1,523,000		1,621,995

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Construction Materials (continued)
SRM Escrow Issuer LLC
6.00%, 11/01/2028 ^(b)	$	3,718,000	$	3,969,151
			$	6,424,956

Diversified Financial Services — 5.89%
AerCap Holdings NV
(5-year Treasury Constant Maturity Rate + 4.54%),
5.88%, 10/10/2079 ^(d)		3,485,000		3,606,975
Coinbase Global, Inc.
3.63%, 10/01/2031 ^(b),(c)		591,000		543,720
Credit Acceptance Corp.
6.63%, 03/15/2026		3,392,000		3,530,529
Global Aircraft Leasing Co. Ltd.
6.50%, PIK 7.25%; 09/15/2024 ^(b),(g)		3,481,789		3,359,926
OneMain Finance Corp.
4.00%, 09/15/2030		2,425,000		2,384,697
6.63%, 01/15/2028		872,000		976,640
			$	14,402,487

Electric — 2.05%
Clearway Energy Operating LLC
4.75%, 03/15/2028 ^(b)		1,095,000		1,151,119
GenOn Energy, Inc.
0.00%, 10/15/2049 ^(a),(h),(i)		3,100,000		—
Vistra Corp.
(5-year Treasury Constant Maturity Rate + 5.74%),
7.00%, 12/15/2026 ^(b),(d),(e)		1,560,000		1,580,108
Vistra Operations Co. LLC
4.38%, 05/01/2029 ^(b)		2,285,000		2,288,725
			$	5,019,952

Engineering & Construction — 1.59%
MasTec, Inc.
4.50%, 08/15/2028 ^(b)		3,738,000		3,882,847

Entertainment — 6.41%
Boyne USA, Inc.
4.75%, 05/15/2029 ^(b)		2,295,000		2,363,850
Caesars Entertainment, Inc.
6.25%, 07/01/2025 ^(b)		406,000		426,148
8.13%, 07/01/2027 ^(b)		1,869,000		2,069,805
CCM Merger, Inc.
6.38%, 05/01/2026 ^(b)		3,470,000		3,613,138
International Game Technology PLC
5.25%, 01/15/2029 ^(b)		2,133,000		2,260,020
Lions Gate Capital Holdings LLC
5.50%, 04/15/2029 ^(b)		1,546,000		1,573,055
Peninsula Pacific Entertainment LLC/Peninsula Pacific Entertainment Finance, Inc.
8.50%, 11/15/2027 ^(b)		3,136,000		3,386,880
			$	15,692,896

Food — 5.45%
Albertsons Cos., Inc./Safeway, Inc./New Albertsons LP/Albertsons LLC
4.63%, 01/15/2027 ^(b)		722,000		757,696
Chobani LLC/Chobani Finance Corp, Inc.
7.50%, 04/15/2025 ^(b)		2,861,000		2,945,256
Fresh Market, Inc.
9.75%, 05/01/2023 ^(b)		2,315,000		2,381,556
Kraft Heinz Foods Co.
3.75%, 04/01/2030		3,297,000		3,558,865

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Food (continued)
Pilgrim's Pride Corp.
3.50%, 03/01/2032 ^(b)	$	3,002,000	$	3,032,020
4.25%, 04/15/2031 ^(b)		624,000		655,200
			$	13,330,593

Forest Products & Paper — 1.01%
Mercer International, Inc.
5.13%, 02/01/2029		2,410,000		2,461,502

Healthcare — Services — 5.40%
Acadia Healthcare Co., Inc.
5.00%, 04/15/2029 ^(b)		3,214,000		3,302,385
Centene Corp.
2.50%, 03/01/2031		531,000		516,936
3.38%, 02/15/2030		1,929,000		1,964,474
CHS/Community Health Systems, Inc.
6.00%, 01/15/2029 ^(b)		3,438,000		3,665,768
LifePoint Health, Inc.
5.38%, 01/15/2029 ^(b)		3,792,000		3,773,040
			$	13,222,603

Home Builders — 2.19%
Empire Communities Corp.
7.00%, 12/15/2025 ^(b)		2,315,000		2,396,025
Forestar Group, Inc.
3.85%, 05/15/2026 ^(b)		566,000		567,415
5.00%, 03/01/2028 ^(b)		2,335,000		2,396,294
			$	5,359,734

Insurance — 0.80%
Acrisure LLC/Acrisure Finance, Inc.
4.25%, 02/15/2029 ^(b)		431,000		419,148
7.00%, 11/15/2025 ^(b)		1,546,000		1,544,871
			$	1,964,019

Investment Companies — 1.01%
Compass Group Diversified Holdings LLC
5.25%, 04/15/2029 ^(b)		2,352,000		2,463,720

Iron & Steel — 0.97%
TMS International Corp.
6.25%, 04/15/2029 ^(b)		2,380,000		2,368,100

Leisure Time — 2.00%
Life Time, Inc.
5.75%, 01/15/2026 ^(b)		2,395,000		2,478,825
NCL Corp. Ltd.
10.25%, 02/01/2026 ^(b)		65,000		75,604
12.25%, 05/15/2024 ^(b)		1,087,000		1,288,095
NCL Finance Ltd.
6.13%, 03/15/2028 ^(b)		1,070,000		1,053,950
			$	4,896,474

Media — 6.26%
DIRECTV Holdings LLC/DIRECTV Financing Co., Inc.
5.88%, 08/15/2027 ^(b)		3,550,000		3,634,171
DISH DBS Corp.
5.13%, 06/01/2029		469,000		426,790
5.25%, 12/01/2026 ^(b)		674,284		684,928
5.88%, 11/15/2024		1,240,000		1,273,802
7.38%, 07/01/2028		2,072,000		2,097,900
Scripps Escrow II, Inc.
5.38%, 01/15/2031 ^(b)		983,000		998,974

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Media (continued)
Sirius XM Radio, Inc.
3.13%, 09/01/2026 ^(b)	$	2,305,000	$	2,305,668
UPC Holding BV
5.50%, 01/15/2028 ^(b)		1,606,000		1,666,225
Ziggo BV
5.50%, 01/15/2027 ^(b)		2,172,000		2,231,730
			$	15,320,188

Mining — 4.69%
Copper Mountain Mining Corp.
8.00%, 04/09/2026 ^(b)		2,130,600		2,229,247
First Quantum Minerals Ltd.
6.88%, 10/15/2027 ^(b)		3,090,000		3,325,612
Novelis Corp.
3.88%, 08/15/2031 ^(b)		3,054,000		3,034,913
Taseko Mines Ltd.
7.00%, 02/15/2026 ^(b)		2,769,000		2,879,760
			$	11,469,532

Oil & Gas — 6.68%
Aethon United BR LP/Aethon United Finance Corp.
8.25%, 02/15/2026 ^(b)		3,292,000		3,536,267
Antero Resources Corp.
7.63%, 02/01/2029 ^(b)		2,813,000		3,122,430
Ascent Resources Utica Holdings LLC/ARU Finance Corp.
5.88%, 06/30/2029 ^(b)		526,000		506,112
7.00%, 11/01/2026 ^(b)		2,403,000		2,436,041
Oasis Petroleum, Inc.
6.38%, 06/01/2026 ^(b)		3,520,000		3,687,200
Occidental Petroleum Corp.
3.40%, 04/15/2026		918,000		941,574
4.40%, 04/15/2046		218,000		223,450
6.13%, 01/01/2031		318,000		386,370
6.63%, 09/01/2030		1,220,000		1,509,750
			$	16,349,194

Packaging & Containers — 0.66%
LABL, Inc.
5.88%, 11/01/2028 ^(b)		257,000		264,871
8.25%, 11/01/2029 ^(b)		1,352,000		1,359,503
			$	1,624,374

Pharmaceuticals — 0.83%
Jazz Securities DAC
4.38%, 01/15/2029 ^(b)		1,974,000		2,043,959

Pipelines — 6.06%
Antero Midstream Partners LP/Antero Midstream Finance Corp.
5.38%, 06/15/2029 ^(b)		2,265,000		2,389,609
5.75%, 03/01/2027 ^(b)		1,433,000		1,484,946
CNX Midstream Partners LP
4.75%, 04/15/2030 ^(b)		3,667,000		3,653,249
Crestwood Midstream Partners LP/Crestwood Midstream Finance Corp.
5.63%, 05/01/2027 ^(b)		3,550,000		3,616,562
Targa Resources Partners LP/Targa Resources Partners Finance Corp.
4.88%, 02/01/2031		3,402,000		3,694,402
			$	14,838,768

REITs — 2.26%
CBL & Associates HoldCo II LLC
10.00%, 11/15/2029		1,735,616		1,739,955

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

REITs (continued)
CBL & Associates LP
0.00%, 12/15/2026 ^(a),(h),(i)	$	6,000,000	$	—
Ladder Capital Finance Holdings LLLP/Ladder Capital Finance Corp.
4.75%, 06/15/2029 ^(b)		3,698,000		3,790,450
			$	5,530,405

Retail — 5.73%
At Home Group, Inc.
4.88%, 07/15/2028 ^(b)		1,956,000		1,926,660
Bath & Body Works, Inc.
5.25%, 02/01/2028		386,000		426,530
6.63%, 10/01/2030 ^(b)		1,090,000		1,234,425
9.38%, 07/01/2025 ^(b)		416,000		507,520
BCPE Ulysses Intermediate, Inc.
7.75%, PIK 7.75%; 04/01/2027 ^(b),(g)		2,846,000		2,810,425
Dave & Buster's, Inc.
7.63%, 11/01/2025 ^(b)		1,755,000		1,871,269
Golden Nugget, Inc.
6.75%, 10/15/2024 ^(b)		1,200,000		1,200,000
LSF9 Atlantis Holdings LLC/Victra Finance Corp.
7.75%, 02/15/2026 ^(b)		2,360,000		2,386,361
Park River Holdings, Inc.
5.63%, 02/01/2029 ^(b)		1,736,000		1,657,880
			$	14,021,070

Telecommunications — 1.46%
DKT Finance ApS
9.38%, 06/17/2023 ^(b)		3,548,000		3,583,480

Transportation — 1.93%
Navios Maritime Holdings, Inc./Navios Maritime Finance II US, Inc.
7.38%, 01/15/2022 ^(b)		1,076,000		1,067,930
11.25%, 08/15/2022 ^(b)		1,296,000		1,289,520
Watco Cos LLC/Watco Finance Corp.
6.50%, 06/15/2027 ^(b)		2,270,000		2,360,800
			$	4,718,250
TOTAL BONDS			$	216,847,714
		Principal
SENIOR FLOATING RATE INTERESTS — 8.75%		Amount		Value

Airlines — 2.35%
AAdvantage Loyalty IP Ltd., 2021 Term Loan
(3-month USD LIBOR + 4.75%),
5.50%, 04/20/2028	$	3,355,000	$	3,470,613
United Airlines, Inc., 2021 Term Loan B
(3-month USD LIBOR + 3.75%),
4.50%, 04/21/2028		2,278,521		2,281,620
			$	5,752,233

Entertainment — 1.07%
Lions Gate Capital Holdings LLC, 2018 Term Loan B
(1-month USD LIBOR + 2.25%),
2.35%, 03/24/2025		1,757,039		1,740,207
The Enterprise Development Authority, Term Loan B
0.00%, 02/28/2028 ^(j)		877,215		875,390
			$	2,615,597

See accompanying notes.


Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

		Principal
SENIOR FLOATING RATE INTERESTS (continued)		Amount		Value

Forest Products & Paper — 1.40%
Pixelle Specialty Solutions LLC, Term Loan B
(1-month USD LIBOR + 6.50%),
7.50%, 10/31/2024	$	3,445,000	$	3,424,709

Insurance — 1.61%
Acrisure LLC, 2020 Term Loan B
(3-month USD LIBOR + 3.50%),
3.72%, 02/15/2027		422,848		417,563
Asurion LLC, 2021 2nd Lien Term Loan B3
(1-month USD LIBOR + 5.25%),
5.35%, 01/31/2028		3,505,000		3,513,763
			$	3,931,326

Lodging — 0.49%
Golden Nugget, Inc., 2017 Incremental Term Loan B
(3-month USD LIBOR + 2.50%),
3.25%, 10/04/2023		1,211,224		1,202,685

Packaging & Containers — 1.11%
Valcour Packaging LLC, 2021 1st Lien Term Loan
(3-month USD LIBOR + 3.75%),
4.25%, 10/04/2028		1,600,000		1,598,000
Valcour Packaging LLC, 2021 2nd Lien Term Loan
(3-month USD LIBOR + 7.00%),
7.50%, 10/04/2029		1,125,000		1,119,375
			$	2,717,375

Pharmaceuticals — 0.62%
Jazz Financing Lux SARL, USD Term Loan
0.00%, 05/05/2028 ^(j)		1,518,859		1,523,704

Retail — 0.10%
At Home Group, Inc. Term Loan B
0.00%, 07/23/2028 ^(j)		234,413		234,295
TOTAL SENIOR FLOATING RATE INTERESTS			$	21,401,924
INVESTMENT COMPANIES — 3.82%		Shares Held		Value

Money Market Funds — 3.82%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(k),(l),(m)}		847,958	$	847,958
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(m)		8,502,021		8,502,021
TOTAL INVESTMENT COMPANIES			$	9,349,979
Total Investments			$	249,663,778
Other Assets and Liabilities — (2.02)%				(4,949,594	)
Total Net Assets — 100.00%			$	244,714,184

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $173,208,131 or 70.78% of net assets.
^(c)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $830,737 or 0.34% of net assets.
^(d)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or floating rate in the future.
^(e)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
(f)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities totaled $3,490,200 or 1.43% of net assets.
^(g)	Payment in kind; the issuer has the option of paying additional securities in lieu of cash.

See accompanying notes.

Schedule of Investments
Principal Active High Yield ETF
December 31, 2021 (unaudited)

^(h)	The value of these investments was determined using significant unobservable inputs, in good faith by the Advisor, under procedures established and periodically reviewed by the Board of Trustees.
(i)	Security is defaulted.
(j)	This Senior Floating Rate Interest will settle after December 31, 2021, at which time the interest rate will be determined.
^(k)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
(l)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $847,958 or 0.35% of net assets.
^(m)	Current yield shown is as of period end.


Portfolio Summary (unaudited)
Sector					Percent
Consumer, Cyclical					23.96	%
Consumer, Non-cyclical					16.32	%
Financial					13.83	%
Energy					12.74	%
Basic Materials					11.87	%
Industrial					9.70	%
Communications					7.73	%
Money Market Funds					3.82	%
Utilities					2.05	%
Other Assets and Liabilities					(2.02	)%
TOTAL NET ASSETS					100.00	%

			June 30, 2021		Purchases		Sales		December 31, 2021
Affiliated Securities			Value		Cost		Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	3,145,675	$	18,397,284		20,695,001	$	847,958
		$	3,145,675	$	18,397,284		20,695,001	$	847,958

							Realized Gain
					Realized		from		Change in
					Gain/Loss on		Capital Gain		Unrealized
			Income ^(a)		Investments		Distributions		Gain/Loss
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$	—		—	$	—
		$	—	$	—		—	$	—

^(a)	Amount excludes earnings from securities lending collateral.

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.84%	Shares Held		Value

Biotechnology — 46.49%
2seventy bio, Inc. ^(a)	2,691	$	68,970
9 Meters Biopharma, Inc. ^(a)	30,491		29,842
ACADIA Pharmaceuticals, Inc. ^(a)	19,113		446,097
ADMA Biologics, Inc. ^(a)	15,888		22,402
Adverum Biotechnologies, Inc. ^(a)	11,743		20,668
Agenus, Inc. ^(a)	27,901		89,841
Akero Therapeutics, Inc. ^(a)	4,170		88,195
Albireo Pharma, Inc. ^(a)	2,307		53,730
Aldeyra Therapeutics, Inc. ^(a)	6,925		27,700
Allakos, Inc. ^(a)	6,583		64,448
Allogene Therapeutics, Inc. ^(a)	17,017		253,894
Alnylam Pharmaceuticals, Inc. ^(a)	14,282		2,421,942
Altimmune, Inc. ^(a),(b)	4,755		43,556
ALX Oncology Holdings, Inc. ^(a)	4,831		103,818
Alzamend Neuro, Inc. ^(a),(b)	10,400		19,760
Amicus Therapeutics, Inc. ^(a)	32,033		369,981
AnaptysBio, Inc. ^(a)	3,287		114,223
Anavex Life Sciences Corp. ^(a),(b)	9,057		157,048
Annovis Bio, Inc. ^(a)	965		16,965
Apellis Pharmaceuticals, Inc. ^(a)	10,453		494,218
Applied Molecular Transport, Inc. ^(a)	4,601		64,322
Arcturus Therapeutics Holdings, Inc. ^(a)	3,148		116,507
Arcus Biosciences, Inc. ^(a)	8,580		347,233
Arcutis Biotherapeutics, Inc. ^(a)	6,010		124,647
Ardelyx, Inc. ^(a)	12,338		13,572
Arena Pharmaceuticals, Inc. ^(a)	7,291		677,626
Arrowhead Pharmaceuticals, Inc. ^(a)	12,529		830,673
Atara Biotherapeutics, Inc. ^(a)	10,146		159,901
Atea Pharmaceuticals, Inc. ^(a)	9,907		88,569
Atossa Therapeutics, Inc. ^(a)	15,156		24,250
Atreca, Inc., Class A ^(a),(b)	3,609		10,935
Avid Bioservices, Inc. ^(a)	7,341		214,210
Avidity Biosciences, Inc. ^(a)	5,468		129,974
Axsome Therapeutics, Inc. ^(a),(b)	4,509		170,350
Beam Therapeutics, Inc. ^(a)	7,919		631,065
Berkeley Lights, Inc. ^(a)	8,033		146,040
BioAtla, Inc. ^(a)	3,862		75,811
BioCryst Pharmaceuticals, Inc. ^(a)	21,413		296,570
Biohaven Pharmaceutical Holding Co. Ltd. ^(a)	7,860		1,083,187
BioMarin Pharmaceutical, Inc. ^(a)	22,037		1,946,969
Bluebird Bio, Inc. ^(a)	8,086		80,779
Blueprint Medicines Corp. ^(a)	7,039		753,947
Bridgebio Pharma, Inc. ^(a),(b)	18,225		303,993
Brooklyn ImmunoTherapeutics, Inc. ^(a)	6,194		25,829
C4 Therapeutics Inc ^(a)	5,799		186,728
Cara Therapeutics, Inc. ^(a)	5,998		73,056
Cardiff Oncology, Inc. ^(a)	4,730		28,427
Cassava Sciences, Inc. ^(a),(b)	4,791		209,367
CEL-SCI Corp. ^(a),(b)	5,147		36,544
Celldex Therapeutics, Inc. ^(a)	5,562		214,916
Century Therapeutics, Inc. ^(a)	6,509		103,233
Cerevel Therapeutics Holdings, Inc. ^(a)	17,406		564,303
Certara Inc ^(a)	18,324		520,768
ChemoCentryx, Inc. ^(a)	8,370		304,752
ChromaDex Corp. ^(a)	8,160		30,518
Clearside Biomedical, Inc. ^(a)	7,118		19,574
Cortexyme, Inc. ^(a),(b)	3,557		44,889
CRISPR Therapeutics AG ^(a),(b)	9,159		694,069
Cullinan Oncology, Inc. ^(a),(b)	5,214		80,452
Curis, Inc. ^(a)	10,965		52,193
CytomX Therapeutics, Inc. ^(a)	7,800		33,774
Deciphera Pharmaceuticals, Inc. ^(a)	6,951		67,911
Denali Therapeutics, Inc. ^(a)	14,610		651,606

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Biotechnology (continued)
Dynavax Technologies Corp. ^(a)	13,733	$	193,223
Editas Medicine, Inc. ^(a)	8,171		216,940
Epizyme, Inc. ^(a)	12,238		30,595
Esperion Therapeutics, Inc. ^(a),(b)	3,383		16,915
Evolus, Inc. ^(a)	6,533		42,530
Fate Therapeutics, Inc. ^(a)	11,436		669,120
FibroGen, Inc. ^(a)	11,088		156,341
Forma Therapeutics Holdings, Inc. ^(a)	5,668		80,599
Forte Biosciences, Inc. ^(a),(b)	1,680		3,595
Generation Bio Co. ^(a)	6,799		48,137
Global Blood Therapeutics, Inc. ^(a)	7,476		218,823
Gossamer Bio, Inc. ^(a)	9,095		102,864
Guardant Health, Inc. ^(a)	12,172		1,217,443
Homology Medicines, Inc. ^(a)	6,834		24,876
Humanigen, Inc. ^(a)	7,108		26,442
iBio, Inc. ^(a)	26,076		14,316
IGM Biosciences, Inc. ^(a)	3,075		90,190
ImmunityBio, Inc. ^(a),(b)	46,816		284,641
ImmunoGen, Inc. ^(a)	24,227		179,764
Immunome, Inc. ^(a)	1,407		18,235
Immunovant, Inc. ^(a)	13,768		117,303
Impel Neuropharma, Inc. ^(a),(b)	2,334		20,142
Infinity Pharmaceuticals, Inc. ^(a)	10,619		23,893
Inmune Bio, Inc. ^(a)	2,122		21,644
Innoviva, Inc. ^(a)	8,315		143,434
Inovio Pharmaceuticals, Inc. ^(a)	25,179		125,643
Insmed, Inc. ^(a)	13,850		377,274
Intercept Pharmaceuticals, Inc. ^(a),(b)	3,971		64,688
Intra-Cellular Therapies, Inc. ^(a)	9,776		511,676
Ionis Pharmaceuticals, Inc. ^(a)	16,967		516,306
Iovance Biotherapeutics, Inc. ^(a)	18,631		355,666
iTeos Therapeutics, Inc. ^(a)	4,214		196,204
IVERIC bio, Inc. ^(a)	12,446		208,097
Janux Therapeutics, Inc. ^(a)	4,982		98,295
Karuna Therapeutics, Inc. ^(a)	3,517		460,727
Karyopharm Therapeutics, Inc. ^(a)	9,036		58,101
Keros Therapeutics, Inc. ^(a)	2,794		163,477
Kiniksa Pharmaceuticals Ltd., Class A ^(a)	3,902		45,927
Kodiak Sciences, Inc. ^(a)	6,183		524,195
Krystal Biotech, Inc. ^(a)	2,653		185,577
Kymera Therapeutics, Inc. ^(a)	6,134		389,448
Lexicon Pharmaceuticals, Inc. ^(a)	17,295		68,142
MacroGenics, Inc. ^(a)	7,317		117,438
Mersana Therapeutics, Inc. ^(a)	8,590		53,430
Mirati Therapeutics, Inc. ^(a)	6,202		909,771
Mustang Bio, Inc. ^(a)	10,835		17,986
Myriad Genetics, Inc. ^(a)	9,345		257,922
Nektar Therapeutics ^(a)	22,003		297,261
NeoGenomics, Inc. ^(a)	14,755		503,441
NGM Biopharmaceuticals, Inc. ^(a)	9,254		163,888
Nkarta, Inc. ^(a)	3,934		60,387
Novavax, Inc. ^(a),(b)	8,949		1,280,333
NRX Pharmaceuticals, Inc. ^(a),(b)	5,818		27,810
Nurix Therapeutics, Inc. ^(a)	5,319		153,985
Nuvation Bio, Inc. ^(a),(b)	25,942		220,507
Olema Pharmaceuticals, Inc. ^(a)	4,729		44,263
Omeros Corp. ^(a),(b)	7,476		48,071
PDS Biotechnology Corp. ^(a)	3,404		27,572
Pieris Pharmaceuticals, Inc. ^(a)	7,983		30,176
Precigen, Inc. ^(a)	24,731		91,752
Precision BioSciences, Inc. ^(a)	7,136		52,806
Prelude Therapeutics, Inc. ^(a)	4,266		53,112
Prothena Corp. PLC ^(a)	5,395		266,513

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Biotechnology (continued)
Provention Bio, Inc. ^(a),(b)	7,588	$	42,645
PTC Therapeutics, Inc. ^(a)	8,465		337,161
Radius Health, Inc. ^(a)	5,660		39,167
RAPT Therapeutics, Inc. ^(a)	3,525		129,473
Recursion Pharmaceuticals Inc, Class A ^(a)	19,033		326,035
REGENXBIO, Inc. ^(a)	5,105		166,933
Relay Therapeutics, Inc. ^(a)	11,139		342,079
Replimune Group, Inc. ^(a)	5,594		151,597
REVOLUTION Medicines, Inc. ^(a)	8,805		221,622
Rigel Pharmaceuticals, Inc. ^(a)	20,450		54,192
Rocket Pharmaceuticals, Inc. ^(a)	7,617		166,279
Rubius Therapeutics, Inc. ^(a)	10,749		104,050
Sage Therapeutics, Inc. ^(a)	7,040		299,482
Sana Biotechnology, Inc. ^(a)	22,579		349,523
Sangamo Therapeutics, Inc. ^(a)	17,395		130,462
Scholar Rock Holding Corp. ^(a)	4,122		102,390
Seagen, Inc. ^(a)	18,282		2,826,397
Seelos Therapeutics, Inc. ^(a)	12,247		19,963
Seer, Inc. ^(a),(b)	6,797		155,040
Selecta Biosciences, Inc. ^(a)	13,772		44,897
Sema4 Holdings Corp. ^(a),(b)	28,751		128,229
Sesen Bio, Inc. ^(a)	23,459		19,119
Silverback Therapeutics, Inc. ^(a)	4,196		27,945
Sorrento Therapeutics, Inc. ^(a)	35,683		165,926
SpringWorks Therapeutics, Inc. ^(a)	5,875		364,132
Stoke Therapeutics, Inc. ^(a)	4,397		105,484
Surface Oncology, Inc. ^(a)	5,443		26,018
Sutro Biopharma, Inc. ^(a)	5,520		82,138
Syndax Pharmaceuticals, Inc. ^(a)	5,818		127,356
TCR2 Therapeutics, Inc. ^(a)	4,574		21,315
TG Therapeutics, Inc. ^(a)	17,096		324,824
Theravance Biopharma, Inc. ^(a)	8,794		97,174
TransMedics Group, Inc. ^(a)	3,312		63,458
Travere Therapeutics, Inc. ^(a)	7,267		225,568
Turning Point Therapeutics, Inc. ^(a)	5,915		282,145
Twist Bioscience Corp. ^(a)	5,866		453,970
Tyme Technologies, Inc. ^(a),(b)	20,612		12,431
Ultragenyx Pharmaceutical, Inc. ^(a)	8,097		680,877
Vaxart, Inc. ^(a)	14,702		92,182
Veracyte, Inc. ^(a)	8,484		349,541
Verastem, Inc. ^(a)	21,639		44,360
Vericel Corp. ^(a)	5,585		219,490
Verve Therapeutics, Inc. ^(a),(b)	5,740		211,634
Viking Therapeutics, Inc. ^(a)	9,358		43,047
Vir Biotechnology, Inc. ^(a)	15,656		655,517
Xencor, Inc. ^(a)	6,987		280,318
Xeris Biopharma Holdings, Inc. ^(a),(b)	7,963		23,332
Y-mAbs Therapeutics, Inc. ^(a)	5,219		84,600
Zentalis Pharmaceuticals, Inc. ^(a)	5,360		450,562
ZIOPHARM Oncology, Inc. ^(a)	25,802		28,124
		$	41,831,412

Chemicals — 0.27%
Codexis, Inc. ^(a)	7,741		242,061

Commercial Services — 0.88%
HealthEquity, Inc. ^(a)	9,933		439,436
Multiplan Corp. ^(a)	79,992		354,365
		$	793,801

Electronics — 0.04%
Fluidigm Corp. ^(a)	9,117		35,739

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Engineering & Construction — 0.09%
908 Devices, Inc. ^(a)	3,307	$	85,552

Healthcare — Products — 21.50%
10X Genomics, Inc., Class A ^(a)	10,888		1,621,876
ABIOMED, Inc ^(a)	5,453		1,958,554
Acutus Medical, Inc. ^(a)	3,340		11,389
Adaptive Biotechnologies Corp. ^(a)	16,913		474,579
Alphatec Holdings, Inc. ^(a)	11,986		137,000
AngioDynamics, Inc. ^(a)	4,602		126,923
Asensus Surgical, Inc. ^(a),(b)	28,046		31,131
AtriCure, Inc. ^(a)	5,514		383,388
Avanos Medical, Inc. ^(a)	5,759		199,665
Axonics, Inc. ^(a)	5,519		309,064
BioLife Solutions, Inc. ^(a)	4,877		181,766
Bionano Genomics, Inc. ^(a),(b)	33,411		99,899
Butterfly Network, Inc. ^(a)	20,052		134,148
Cardiovascular Systems, Inc. ^(a)	4,812		90,369
CareDx, Inc. ^(a)	6,304		286,706
Castle Biosciences, Inc. ^(a)	3,013		129,167
Cerus Corp. ^(a)	20,545		139,911
ClearPoint Neuro, Inc. ^(a)	2,678		30,047
CryoLife, Inc. ^(a)	4,703		95,706
Cutera, Inc. ^(a)	2,147		88,714
DermTech, Inc. ^(a)	3,545		56,011
Eargo, Inc. ^(a)	4,688		23,909
Exact Sciences Corp. ^(a)	20,661		1,608,046
Glaukos Corp. ^(a)	5,574		247,709
Haemonetics Corp ^(a)	6,109		324,021
Inogen, Inc. ^(a)	2,706		92,004
Inspire Medical Systems, Inc. ^(a)	3,257		749,305
Insulet Corp. ^(a)	8,277		2,202,261
iRhythm Technologies, Inc. ^(a)	3,533		415,799
Lantheus Holdings, Inc. ^(a)	8,090		233,720
Lucira Health, Inc. ^(a)	4,630		39,864
Merit Medical Systems, Inc. ^(a)	6,762		421,273
MiMedx Group, Inc. ^(a)	13,395		80,906
NanoString Technologies, Inc. ^(a)	5,445		229,942
Natera, Inc. ^(a)	11,271		1,052,599
Nautilus Biotechnology, Inc. ^(a)	14,853		76,939
Nevro Corp. ^(a)	4,190		339,683
Novocure Ltd. ^(a)	12,456		935,196
OraSure Technologies, Inc. ^(a)	8,616		74,873
OrthoPediatrics Corp. ^(a)	2,350		140,671
Pacific Biosciences of California, Inc. ^(a)	23,922		489,444
PAVmed, Inc. ^(a)	10,146		24,959
Progenity, Inc. ^(a)	9,507		19,870
Pulmonx Corp. ^(a),(b)	4,388		140,723
Quanterix Corp. ^(a)	4,374		185,458
Quantum-Si, Inc. ^(a),(b)	13,939		109,700
Shockwave Medical, Inc. ^(a)	4,224		753,266
SI-BONE, Inc. ^(a)	3,979		88,374
Sientra, Inc. ^(a)	6,946		25,492
Silk Road Medical, Inc. ^(a)	4,155		177,045
SmileDirectClub, Inc. ^(a),(b)	14,226		33,431
Surgalign Holdings, Inc. ^(a)	16,685		11,953
T2 Biosystems, Inc. ^(a)	19,851		10,247
Tandem Diabetes Care, Inc. ^(a)	7,576		1,140,340
Varex Imaging Corp. ^(a)	4,718		148,853
ViewRay, Inc. ^(a)	19,671		108,387
		$	19,342,275

Healthcare — Services — 12.71%
23andMe Holding Co., Class A ^(a)	11,129		74,119

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Healthcare — Services (continued)
Accolade, Inc. ^(a)	7,910	$	208,507
agilon health, Inc. ^(a)	46,974		1,268,298
American Well Corp., Class A ^(a)	25,216		152,305
ATI Physical Therapy, Inc. ^(a),(b)	23,535		79,784
Brookdale Senior Living, Inc. ^(a)	22,409		115,630
Cano Health, Inc. ^(a)	20,722		184,633
CareMax, Inc. ^(a)	9,707		74,550
Centene Corp. ^(a)	49,821		4,105,250
Clover Health Investments Corp. ^(a)	28,230		105,016
Invitae Corp. ^(a)	25,832		394,455
LifeStance Health Group, Inc. ^(a)	44,963		428,048
MEDNAX, Inc. ^(a)	10,334		281,188
Neuronetics, Inc. ^(a)	3,146		14,031
Oak Street Health, Inc. ^(a),(b)	28,937		958,972
Ontrak, Inc. ^(a)	2,237		14,071
OPKO Health, Inc. ^(a),(b)	81,857		393,732
Personalis, Inc. ^(a)	5,318		75,888
Surgery Partners, Inc. ^(a)	9,910		529,293
Teladoc Health, Inc. ^(a)	19,140		1,757,435
Tivity Health, Inc. ^(a)	5,939		157,027
Vapotherm, Inc. ^(a),(b)	3,108		64,367
		$	11,436,599

Pharmaceuticals — 15.01%
Aclaris Therapeutics, Inc. ^(a)	7,325		106,505
Adamis Pharmaceuticals Corp. ^(a),(b)	17,822		10,782
AdaptHealth Corp. ^(a)	15,732		384,805
Aerie Pharmaceuticals, Inc. ^(a)	5,655		39,698
Agios Pharmaceuticals, Inc. ^(a)	7,061		232,095
Akebia Therapeutics, Inc. ^(a)	20,888		47,207
Alector, Inc. ^(a)	9,681		199,913
Alkermes PLC ^(a)	19,195		446,476
Amneal Pharmaceuticals, Inc. ^(a)	17,870		85,597
Arvinas, Inc. ^(a)	5,855		480,930
Athenex, Inc. ^(a)	13,085		17,796
Bioxcel Therapeutics, Inc. ^(a)	3,347		68,044
Chimerix, Inc. ^(a)	10,325		66,390
Citius Pharmaceuticals, Inc. ^(a),(b)	17,470		26,904
Clovis Oncology, Inc. ^(a),(b)	14,174		38,411
Coherus Biosciences, Inc. ^(a)	9,153		146,082
Cytokinetics, Inc. ^(a)	10,035		457,395
Elanco Animal Health, Inc. ^(a)	56,836		1,613,006
Enanta Pharmaceuticals, Inc. ^(a)	2,424		181,267
Fulcrum Therapeutics, Inc. ^(a),(b)	4,823		85,319
G1 Therapeutics, Inc. ^(a),(b)	5,064		51,703
Galectin Therapeutics, Inc. ^(a)	7,097		14,691
Gritstone bio, Inc. ^(a)	5,920		76,131
Harmony Biosciences Holdings, Inc. ^(a)	6,825		291,018
Heron Therapeutics, Inc. ^(a)	12,196		111,349
Heska Corp. ^(a)	1,273		232,310
Ideaya Biosciences, Inc. ^(a)	4,595		108,626
Intellia Therapeutics, Inc. ^(a)	8,831		1,044,177
Jaguar Health, Inc. ^(a)	5,482		5,701
Kala Pharmaceuticals, Inc. ^(a),(b)	7,779		9,413
KalVista Pharmaceuticals, Inc. ^(a)	2,922		38,658
Kura Oncology, Inc. ^(a)	7,931		111,034
Lyell Immunopharma, Inc. ^(a)	28,651		221,759
Madrigal Pharmaceuticals, Inc. ^(a)	1,985		168,209
MannKind Corp. ^(a),(b)	29,886		130,602
Marinus Pharmaceuticals, Inc. ^(a)	4,394		52,201
Morphic Holding, Inc. ^(a)	4,357		206,435
Ocugen, Inc. ^(a),(b)	23,789		108,240
Ocular Therapeutix, Inc. ^(a)	9,168		63,901

See accompanying notes.


Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Pharmaceuticals (continued)
Option Care Health, Inc. ^(a)	21,454	$	610,152
Oramed Pharmaceuticals, Inc. ^(a)	3,894		55,606
ORIC Pharmaceuticals, Inc. ^(a)	4,705		69,163
Outlook Therapeutics, Inc. ^(a)	20,985		28,540
Passage Bio, Inc. ^(a)	6,473		41,103
Perrigo Co. PLC	15,952		620,533
PetIQ, Inc. ^(a)	3,461		78,599
PLx Pharma, Inc. ^(a),(b)	3,220		25,792
PMV Pharmaceuticals, Inc. ^(a)	5,419		125,179
Protagonist Therapeutics, Inc. ^(a)	5,694		194,735
Reata Pharmaceuticals, Inc., Class A ^(a)	3,767		99,336
Relmada Therapeutics Inc ^(a)	2,084		46,952
Revance Therapeutics, Inc. ^(a)	8,601		140,368
Rhythm Pharmaceuticals, Inc. ^(a)	6,008		59,960
Sarepta Therapeutics, Inc. ^(a)	9,595		864,030
Senseonics Holdings, Inc. ^(a),(b)	53,293		142,292
Seres Therapeutics, Inc. ^(a)	10,982		91,480
Spectrum Pharmaceuticals, Inc. ^(a)	19,641		24,944
Syros Pharmaceuticals, Inc. ^(a)	7,411		24,160
TherapeuticsMD, Inc. ^(a)	50,725		18,033
Tonix Pharmaceuticals Holding Corp. ^(a)	42,793		15,307
uniQure NV ^(a)	5,520		114,485
Vaxcyte, Inc. ^(a)	6,245		148,568
Viatris, Inc.	145,312		1,966,071
Zogenix, Inc. ^(a)	6,687		108,664
Zynerba Pharmaceuticals, Inc. ^(a)	4,937		14,219
		$	13,509,051

Retail — 0.15%
OptimizeRx Corp. ^(a)	2,110		131,052

Software — 2.70%
1Life Healthcare, Inc. ^(a)	21,789		382,833
Evolent Health, Inc., Class A ^(a)	10,450		289,152
Health Catalyst, Inc. ^(a)	5,580		221,080
Hims & Hers Health, Inc. ^(a)	23,324		152,772
Outset Medical, Inc. ^(a)	5,545		255,569
Phreesia, Inc. ^(a)	6,087		253,584
Privia Health Group, Inc. ^(a)	12,656		327,411
Sharecare, Inc. ^(a)	39,960		179,420
Signify Health, Inc., Class A ^(a),(b)	20,110		285,964
Tabula Rasa HealthCare, Inc. ^(a)	2,989		44,834
Talkspace, Inc. ^(a),(b)	18,221		35,895
		$	2,428,514
TOTAL COMMON STOCKS		$	89,836,056
INVESTMENT COMPANIES — 5.39%	Shares Held		Value

Money Market Funds — 5.39%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(c),(d),(e)}	4,668,883	$	4,668,883
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)	186,363		186,363
TOTAL INVESTMENT COMPANIES		$	4,855,246
Total Investments		$	94,691,302
Other Assets and Liabilities — (5.23)%			(4,709,590	)

Total Net Assets — 100.00%		$	89,981,712

^(a)	Non-income producing security.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $4,398,397 or 4.89% of net assets.
^(c)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $4,668,883 or 5.19% of net assets.

See accompanying notes.

Schedule of Investments
Principal Healthcare Innovators ETF
December 31, 2021 (unaudited)

^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.


Portfolio Summary (unaudited)
Sector					Percent
Consumer, Non-cyclical					96.59		%
Money Market Funds					5.39		%
Technology					2.70		%
Basic Materials					0.27		%
Consumer, Cyclical					0.15		%
Industrial					0.13		%
Other Assets and Liabilities					(5.23		)%
TOTAL NET ASSETS					100.00		%

			June 30, 2021		Purchases				Sales		December 31, 2021
Affiliated Securities			Value		Cost				Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	6,534,128	$	32,319,809			$	34,185,054	$	4,668,883
		$	6,534,128	$	32,319,809			$	34,185,054	$	4,668,883

									Realized Gain
					Realized				from		Change in
					Gain/Loss on				Capital Gain		Unrealized
			Income ^(a)		Investments				Distributions		Gain/Loss
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—		$	—		$	—	$	—
		$	—		$	—		$	—	$	—

^(a)	Amount excludes earnings from securities lending collateral.

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.47%	Shares Held		Value

Advertising — 0.25%
Hakuhodo DY Holdings, Inc.	5,700	$	94,942
Publicis Groupe SA	2,179		146,863
WPP PLC	5,748		87,099
		$	328,904

Aerospace & Defense — 0.70%
Airbus SE ^(a)	3,021		386,452
BAE Systems PLC	28,270		210,380
CAE, Inc. ^(a)	2,254		56,860
Elbit Systems Ltd.	807		139,910
Rolls-Royce Holdings PLC ^(a)	42,939		71,418
Thales SA	639		54,417
		$	919,437

Agriculture — 0.68%
British American Tobacco PLC	13,037		482,360
Imperial Brands PLC	3,849		84,217
Japan Tobacco, Inc.	11,800		238,246
Swedish Match AB	10,621		84,651
		$	889,474

Airlines — 0.08%
Air Canada ^(a)	2,738		45,736
Singapore Airlines Ltd. ^(a)	14,800		54,803
		$	100,539

Apparel — 1.90%
adidas AG	507		146,152
Burberry Group PLC	2,440		60,026
Gildan Activewear, Inc.	1,598		67,750
Hermes International	305		533,365
LVMH Moet Hennessy Louis Vuitton SE	1,876		1,552,745
Puma SE	1,148		140,502
		$	2,500,540

Auto Manufacturers — 2.64%
Bayerische Motoren Werke AG	1,102		111,022
Bayerische Motoren Werke AG	1,368		114,162
Daimler AG	4,477		344,511
Daimler Truck Holding AG ^(a)	2,195		80,693
Ferrari NV	1,059		274,290
Honda Motor Co. Ltd.	11,100		311,684
Isuzu Motors Ltd.	10,300		128,134
Mazda Motor Corp. ^(a)	12,500		96,171
Porsche Automobil Holding SE	768		72,957
Renault SA ^(a)	1,676		58,284
Stellantis NV	6,417		121,904
Suzuki Motor Corp.	4,300		165,563
Toyota Motor Corp.	71,600		1,310,561
Volkswagen AG	405		119,146
Volvo AB, Class B	4,713		109,347
Volvo AB, Class A	2,205		51,878
		$	3,470,307

Auto Parts & Equipment — 1.08%
Aisin Corp.	3,200		122,681
Cie Generale des Etablissements Michelin SCA	1,466		240,592
Denso Corp.	4,200		347,925
Magna International, Inc.	2,263		183,104
NGK Insulators Ltd.	8,000		135,200
Stanley Electric Co. Ltd.	4,200		105,119
Sumitomo Electric Industries Ltd.	10,400		135,572

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Auto Parts & Equipment (continued)
Toyota Industries Corp.	1,900	$	151,795
		$	1,421,988

Banks — 10.76%
ABN AMRO Bank NV ^(b)	4,193		61,658
Australia & New Zealand Banking Group Ltd.	18,678		373,838
Banco Bilbao Vizcaya Argentaria SA	20,441		122,178
Banco Santander SA	47,660		159,554
Bank Hapoalim BM	17,097		176,527
Bank Leumi Le-Israel BM	26,518		285,314
Bank of Montreal	5,834		628,114
Bank of Nova Scotia	10,566		748,002
Banque Cantonale Vaudoise	1,448		112,509
Barclays PLC	103,042		260,814
BNP Paribas SA	2,992		207,006
BOC Hong Kong Holdings Ltd.	30,000		98,300
Canadian Imperial Bank of Commerce	4,288		499,834
Chiba Bank Ltd.	19,900		114,006
Commonwealth Bank of Australia	10,232		751,873
Credit Agricole SA	5,614		80,214
DBS Group Holdings Ltd.	18,900		458,054
Deutsche Bank AG ^(a)	7,810		97,969
DNB Bank ASA	3,928		90,098
Erste Group Bank AG	1,603		75,464
FinecoBank Banca Fineco SpA	11,878		208,729
Hang Seng Bank Ltd.	5,495		100,562
HSBC Holdings PLC	50,150		304,546
ING Groep NV	11,163		155,584
Intesa Sanpaolo SpA	49,366		127,806
Israel Discount Bank Ltd., Class A	24,601		165,697
Japan Post Bank Co. Ltd.	14,900		136,656
KBC Group NV	1,042		89,519
Lloyds Banking Group PLC	217,010		140,405
Macquarie Group Ltd.	2,433		363,585
Mediobanca Banca di Credito Finanziario SpA	11,761		135,372
Mitsubishi UFJ Financial Group, Inc.	81,800		444,378
Mizrahi Tefahot Bank Ltd.	5,203		200,827
Mizuho Financial Group, Inc.	1,600		20,350
National Australia Bank Ltd.	20,879		438,095
National Bank of Canada	4,256		324,478
Natwest Group PLC	26,908		82,203
Nordea Bank Abp	23,445		286,699
Oversea-Chinese Banking Corp. Ltd.	28,300		239,403
Raiffeisen Bank International AG	2,050		60,402
Resona Holdings, Inc.	40,500		157,522
Royal Bank of Canada	11,097		1,177,732
Skandinaviska Enskilda Banken AB, Class A	21,087		293,685
Societe Generale SA	3,126		107,498
Standard Chartered PLC	12,973		78,737
Sumitomo Mitsui Financial Group, Inc.	2,800		95,978
Svenska Handelsbanken AB, Class A	16,158		174,988
Swedbank AB	9,302		187,457
Toronto-Dominion Bank	14,600		1,119,339
UBS Group AG	33,718		607,605
UniCredit SpA	7,829		120,722
United Overseas Bank Ltd.	11,200		223,568
Westpac Banking Corp.	23,051		358,056
		$	14,129,509

Beverages — 1.85%
Asahi Group Holdings Ltd.	4,900		190,582
Carlsberg AS, Class B	1,082		187,096
Coca-Cola Europacific Partners PLC	1,209		67,619

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Beverages (continued)
Coca-Cola HBC AG	3,341	$	115,542
Davide Campari-Milano NV	5,509		80,627
Diageo PLC	18,779		1,025,883
Endeavour Group Ltd.	15,438		75,703
Heineken Holding NV	973		89,895
Heineken NV	1,252		140,915
JDE Peet's NV	3,491		107,709
Pernod Ricard SA	829		199,617
Remy Cointreau SA	364		88,685
Treasury Wine Estates Ltd.	6,566		59,140
		$	2,429,013

Biotechnology — 0.49%
CSL Ltd.	2,590		547,820
Genmab A/S ^(a)	226		90,994
		$	638,814

Chemicals — 3.39%
Air Liquide SA	2,829		493,815
Akzo Nobel NV	1,026		112,722
Arkema SA	1,036		146,079
Asahi Kasei Corp.	15,000		140,963
Brenntag SE	1,799		162,993
Chr Hansen Holding A/S	1,631		128,691
Clariant AG	6,090		126,986
Croda International PLC	2,108		288,752
EMS-Chemie Holding AG	79		88,520
Evonik Industries AG	2,399		77,759
Fuchs Petrolub SE	2,378		108,078
Givaudan SA	64		336,576
ICL Group Ltd.	7,773		75,031
Koninklijke DSM NV	742		167,264
Mitsubishi Gas Chemical Co., Inc.	5,000		84,674
Mitsui Chemicals, Inc.	3,600		96,705
Nippon Sanso Holdings Corp.	4,200		91,755
Nissan Chemical Corp.	2,300		133,565
Nitto Denko Corp.	2,000		154,568
Novozymes A/S, Class B	2,300		189,154
Nutrien Ltd.	1,926		144,768
Shin-Etsu Chemical Co. Ltd.	2,400		415,613
Solvay SA	513		59,690
Sumitomo Chemical Co. Ltd.	23,500		110,728
Symrise AG	1,324		196,411
Tosoh Corp.	5,600		83,053
Umicore SA	2,266		92,229
Yara International ASA	2,954		149,267
		$	4,456,409

Commercial Services — 2.83%
Adyen NV ^(a),(b)	107		281,586
Afterpay Ltd. ^(a)	912		55,079
Ashtead Group PLC	4,811		386,939
Brambles Ltd.	11,216		86,743
Bureau Veritas SA	6,361		211,321
Experian PLC	6,550		322,004
Intertek Group PLC	2,138		162,926
Nuvei Corp. ^(a),(b)	490		31,764
Persol Holdings Co. Ltd.	4,700		136,469
Randstad NV	890		60,836
Recruit Holdings Co. Ltd.	9,200		557,615
RELX PLC	12,433		404,225
Rentokil Initial PLC	20,729		163,857
Ritchie Bros Auctioneers, Inc.	862		52,751

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Commercial Services (continued)
Secom Co. Ltd.	2,400	$	166,621
Securitas AB, Class B	4,614		63,648
SGS SA	61		203,981
Sohgo Security Services Co. Ltd.	2,400		95,349
Toppan Printing Co. Ltd.	7,700		144,321
Transurban Group	13,179		132,511
		$	3,720,546

Computers — 1.81%
Bechtle AG	716		51,306
Capgemini SE	1,716		421,015
CGI, Inc. ^(a)	2,102		185,864
Check Point Software Technologies Ltd. ^(a)	1,385		161,436
Computershare Ltd.	11,012		160,236
CyberArk Software Ltd. ^(a)	352		60,995
Fujitsu Ltd.	200		34,304
Itochu Techno-Solutions Corp.	3,000		96,497
Logitech International SA	1,562		131,789
NEC Corp.	3,500		161,566
Nomura Research Institute Ltd.	4,800		205,929
NTT Data Corp.	7,900		169,359
Otsuka Corp.	2,400		114,544
SCSK Corp.	4,700		93,526
Teleperformance	727		324,454
		$	2,372,820

Construction Materials — 2.30%
AGC, Inc.	2,900		138,407
Cie de Saint-Gobain	5,455		384,245
CRH PLC	2,486		131,666
Daikin Industries Ltd.	1,700		385,578
Geberit AG	432		353,299
HeidelbergCement AG	1,713		116,079
Holcim Ltd.	2,605		132,966
Investment AB Latour, Class B	3,172		129,426
James Hardie Industries PLC	3,995		160,733
Kingspan Group PLC	681		81,408
Nibe Industrier AB	11,875		179,711
Rinnai Corp.	900		81,214
ROCKWOOL International A/S, Class B	211		92,384
Sika AG	1,369		571,218
Xinyi Glass Holdings Ltd.	34,000		85,027
		$	3,023,361

Distribution/Wholesale — 1.67%
Bunzl PLC	4,463		174,280
Ferguson PLC	2,504		444,166
ITOCHU Corp.	11,500		351,708
Marubeni Corp.	19,400		188,806
Mitsubishi Corp.	10,800		342,881
Mitsui & Co. Ltd.	14,100		333,838
Toromont Industries Ltd.	2,271		205,314
Toyota Tsusho Corp.	3,300		152,047
		$	2,193,040

Diversified Financial Services — 2.70%
Acom Co. Ltd.	30,400		87,476
Amundi SA ^(b)	1,429		118,033
ASX Ltd.	2,547		172,150
Brookfield Asset Management, Inc., Class A	6,788		409,926
Daiwa Securities Group, Inc.	21,600		121,811
Deutsche Boerse AG	1,485		248,698

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services (continued)
EQT AB	3,113	$	169,840
Futu Holdings Ltd. ^(a)	1,108		47,976
Hargreaves Lansdown PLC	2,847		52,216
Hong Kong Exchanges & Clearing Ltd.	3,100		181,049
IGM Financial, Inc.	4,609		166,222
Julius Baer Group Ltd.	2,214		148,653
Magellan Financial Group Ltd.	1,764		27,259
Mitsubishi HC Capital, Inc.	24,000		118,717
Onex Corp.	2,600		204,062
ORIX Corp.	12,100		246,933
Partners Group Holding AG	235		390,076
SBI Holdings, Inc.	4,600		125,367
Schroders PLC	2,203		106,155
Singapore Exchange Ltd.	17,200		118,700
St. James's Place PLC	3,148		71,734
TMX Group Ltd.	1,217		123,389
Tokyo Century Corp.	1,739		84,357
		$	3,540,799

Electric — 2.96%
Algonquin Power & Utilities Corp.	9,473		136,821
Atco Ltd., Class I	2,060		69,538
AusNet Services Ltd.	25,621		47,906
Canadian Utilities Ltd., Class A	2,476		71,817
Chubu Electric Power Co., Inc.	12,900		135,919
CLP Holdings Ltd.	10,876		109,840
E.ON SE	18,354		254,764
EDP Renovaveis SA	2,289		57,072
Electricite de France SA	4,497		52,888
Elia Group SA	945		124,480
Emera, Inc.	3,347		167,277
Endesa SA	3,631		83,505
Enel SpA	29,089		233,348
Engie SA	9,218		136,578
Fortis, Inc.	2,533		122,210
Fortum Oyj	5,484		168,513
HK Electric Investments & HK Electric Investments Ltd.	66,000		64,751
Hydro One Ltd. ^(b)	5,604		145,798
Iberdrola SA	21,411		253,758
Mercury NZ Ltd.	11,296		47,348
Meridian Energy Ltd.	13,733		45,618
National Grid PLC	14,209		203,827
Northland Power, Inc.	4,039		121,175
Power Assets Holdings Ltd.	14,500		90,375
Red Electrica Corp. SA	6,886		149,150
RWE AG	3,300		134,202
SSE PLC	13,483		300,941
Terna SpA	19,536		158,228
Uniper SE	1,626		77,380
Verbund AG	1,079		121,493
		$	3,886,520

Electrical Components & Equipment — 1.46%
ABB Ltd.	15,685		600,753
Legrand SA	3,091		362,115
Prysmian SpA	2,242		84,514
Schneider Electric SE	4,440		871,775
		$	1,919,157

Electronics — 1.69%
Assa Abloy AB, Class B	8,012		244,894
Halma PLC	5,940		257,283
Hoya Corp.	2,500		371,859

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Electronics (continued)
Ibiden Co. Ltd.	2,500	$	148,657
Murata Manufacturing Co. Ltd.	3,800		302,500
Nidec Corp.	3,000		352,604
Sartorius AG	231		156,534
Shimadzu Corp.	3,143		132,654
TDK Corp.	4,800		187,360
Venture Corp. Ltd.	5,140		69,838
		$	2,224,183

Energy — Alternate Sources — 0.07%
Vestas Wind Systems A/S	3,023		92,559

Engineering & Construction — 0.66%
Bouygues SA	3,445		123,508
CK Infrastructure Holdings Ltd.	20,500		130,531
Infrastrutture Wireless Italiane SpA ^(b)	6,018		73,174
Kajima Corp.	9,400		107,949
Keppel Corp. Ltd.	19,100		72,568
Singapore Technologies Engineering Ltd.	24,700		68,917
Skanska AB, Class B	2,377		61,607
Sydney Airport ^(a)	10,209		64,471
WSP Global, Inc.	1,139		165,346
		$	868,071

Entertainment — 0.69%
Aristocrat Leisure Ltd.	4,877		154,598
Entain PLC ^(a)	5,151		117,341
Evolution AB ^(b)	1,179		167,817
Genting Singapore Ltd.	123,100		70,794
La Francaise des Jeux SAEM ^(b)	3,320		147,186
Tabcorp Holdings Ltd.	33,225		121,348
Universal Music Group NV	4,284		120,860
		$	899,944

Environmental Control — 0.05%
GFL Environmental, Inc.	1,552		58,684

Food — 4.99%
Barry Callebaut AG	33		80,255
Chocoladefabriken Lindt & Spruengli AG	14		194,052
Chocoladefabriken Lindt & Spruengli AG	1		134,109
Coles Group Ltd.	8,374		109,300
Danone SA	2,609		162,151
Empire Co. Ltd.	4,091		124,643
Etablissements Franz Colruyt NV	2,027		85,986
George Weston Ltd.	1,886		218,665
HelloFresh SE ^(a)	1,501		115,418
ICA Gruppen AB	2,607		154,178
J Sainsbury PLC	14,545		54,298
Jeronimo Martins SGPS SA	6,007		137,463
Kerry Group PLC, Class A	1,460		188,245
Kesko Oyj, Class B	5,640		188,396
Kobe Bussan Co. Ltd.	2,800		108,441
Koninklijke Ahold Delhaize NV	4,574		156,928
Loblaw Cos. Ltd.	3,351		274,554
Metro, Inc.	3,297		175,465
Mowi ASA	2,513		59,554
Nestle SA	19,500		2,727,261
NH Foods Ltd.	2,414		86,881
Nisshin Seifun Group, Inc.	5,500		79,275
Orkla ASA	14,404		144,522
Saputo, Inc.	3,021		68,065
Seven & i Holdings Co. Ltd.	600		26,372

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Food (continued)
Tesco PLC	37,468	$	147,022
Toyo Suisan Kaisha Ltd.	2,200		93,237
Wilmar International Ltd.	24,600		75,574
Woolworths Group Ltd.	13,661		377,784
		$	6,548,094

Forest Products & Paper — 0.46%
Mondi PLC	2,738		67,672
Oji Holdings Corp.	25,400		122,992
Smurfit Kappa Group PLC	1,309		72,190
Svenska Cellulosa AB SCA, Class B	9,274		164,980
UPM-Kymmene Oyj	3,004		114,435
West Fraser Timber Co. Ltd.	692		66,019
		$	608,288

Gas — 0.57%
AltaGas Ltd.	9,197		198,561
Enagas SA	3,274		76,040
Hong Kong & China Gas Co. Ltd.	67,250		104,702
Naturgy Energy Group SA	2,372		77,316
Osaka Gas Co. Ltd.	8,000		132,209
Snam SpA	26,561		160,270
		$	749,098

Hand/Machine Tools — 0.47%
Fuji Electric Co. Ltd.	2,800		152,864
Schindler Holding AG	533		143,604
Schindler Holding AG	450		120,698
Techtronic Industries Co. Ltd.	10,000		199,037
		$	616,203

Healthcare — Products — 2.06%
Alcon, Inc.	1,541		136,546
Carl Zeiss Meditec AG	640		134,689
Cochlear Ltd.	370		58,178
Coloplast A/S, Class B	1,144		201,582
Demant A/S ^(a)	1,945		99,780
DiaSorin SpA	224		42,704
EssilorLuxottica SA	2,621		558,726
Fisher & Paykel Healthcare Corp. Ltd.	2,913		65,360
Koninklijke Philips NV	3,728		139,065
Olympus Corp.	11,300		260,274
QIAGEN NV ^(a)	2,901		161,803
Sartorius Stedim Biotech	250		137,303
Siemens Healthineers AG ^(b)	3,984		298,545
Smith & Nephew PLC	4,015		70,295
Sonova Holding AG	430		168,848
Straumann Holding AG	83		176,439
		$	2,710,137

Healthcare — Services — 0.98%
BioMerieux	405		57,590
Eurofins Scientific SE	1,140		141,210
Fresenius Medical Care AG & Co. KGaA	1,379		89,709
Fresenius SE & Co. KGaA	2,349		94,671
Lonza Group AG	480		401,194
Medibank Pvt Ltd.	74,695		182,054
Orpea SA	449		45,036
Ramsay Health Care Ltd.	1,654		86,041
Sonic Healthcare Ltd.	5,451		184,929
		$	1,282,434

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Holding Companies — Diversified — 0.18%
CK Hutchison Holdings Ltd.	16,000	$	103,212
Jardine Matheson Holdings Ltd.	1,371		75,419
Swire Pacific Ltd., Class A	9,500		54,033
		$	232,664

Home Builders — 0.50%
Barratt Developments PLC	6,820		69,049
Daiwa House Industry Co. Ltd.	5,900		169,670
Iida Group Holdings Co. Ltd.	3,600		83,749
Persimmon PLC	1,845		71,323
Sekisui House Ltd.	9,100		195,322
Taylor Wimpey PLC	27,002		64,143
		$	653,256

Home Furnishings — 1.28%
Electrolux AB, Class B	2,176		52,858
GN Store Nord AS	790		49,743
Panasonic Corp.	20,600		226,541
Rational AG	54		55,356
SEB SA	800		124,688
Sharp Corp.	7,200		82,685
Sony Group Corp.	8,600		1,082,196
		$	1,674,067

Household Products — 1.50%
Beiersdorf AG	765		78,717
Essity AB, Class B	3,537		115,627
L'Oreal SA	2,019		958,414
Unilever PLC	15,271		815,537
		$	1,968,295

Household Products/Wares — 0.36%
Henkel AG & Co. KGaA	965		75,477
Reckitt Benckiser Group PLC	4,624		396,934
		$	472,411

Insurance — 5.16%
Admiral Group PLC	4,371		186,780
Aegon NV	13,068		65,359
AIA Group Ltd.	38,000		383,043
Allianz SE	1,380		326,245
Assicurazioni Generali SpA	10,140		215,072
Aviva PLC	16,145		89,685
AXA SA	12,954		386,180
Baloise Holding AG	513		83,942
CNP Assurances	3,178		78,695
Dai-ichi Life Holdings, Inc.	10,200		206,208
Direct Line Insurance Group PLC	18,445		69,656
Fairfax Financial Holdings Ltd.	547		269,074
Gjensidige Forsikring ASA	5,279		128,280
Great-West Lifeco, Inc.	6,709		201,331
Hannover Rueck SE	840		159,852
iA Financial Corp., Inc.	2,089		119,532
Intact Financial Corp.	2,306		299,737
Japan Post Holdings Co. Ltd.	22,700		176,974
Legal & General Group PLC	23,733		95,568
M&G PLC	21,420		57,841
Manulife Financial Corp.	12,468		237,641
Muenchener Rueckversicherungs-Gesellschaft AG in Muenchen	433		128,419
NN Group NV	3,257		176,542
Phoenix Group Holdings PLC	8,426		74,498
Power Corp. of Canada	8,259		272,917

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Insurance (continued)
Prudential PLC	7,673	$	132,367
QBE Insurance Group Ltd.	8,385		69,241
Sampo Oyj, Class A	2,509		125,857
SCOR SE	1,752		54,733
Sompo Holdings, Inc.	4,500		190,085
Sun Life Financial, Inc.	4,756		264,730
Suncorp Group Ltd.	7,616		61,339
Swiss Life Holding AG	356		218,398
Swiss Re AG	1,493		147,891
T&D Holdings, Inc.	8,800		112,611
Tokio Marine Holdings, Inc.	6,200		344,522
Tryg A/S	5,859		144,859
Zurich Insurance Group AG	950		417,449
		$	6,773,153

Internet — 1.64%
Auto Trader Group PLC ^(b)	9,564		95,796
CyberAgent, Inc.	7,900		131,449
M3, Inc.	3,100		156,118
Prosus NV	2,385		199,657
Scout24 SE ^(b)	1,023		71,535
Sea Ltd. ^(a)	272		60,849
SEEK Ltd.	5,237		124,898
Shopify, Inc., Class A ^(a)	770		1,060,201
Trend Micro, Inc. ^(a)	2,900		161,097
ZOZO, Inc.	3,000		93,628
		$	2,155,228

Investment Companies — 1.35%
Eurazeo SE	1,029		89,972
EXOR NV	764		68,680
Groupe Bruxelles Lambert SA	820		91,639
Industrivarden AB, Class A	5,381		171,740
Industrivarden AB, Class C	5,644		177,449
Investor AB, Class B	18,648		470,008
Kinnevik AB, Class B ^(a)	3,241		115,760
L E Lundbergforetagen AB, Class B	2,166		121,769
Melrose Industries PLC	26,916		58,255
Sofina SA	453		222,800
Washington H Soul Pattinson & Co. Ltd.	4,012		86,430
Wendel SE	830		99,598
		$	1,774,100

Iron & Steel — 0.53%
ArcelorMittal SA	2,936		94,079
BlueScope Steel Ltd.	7,495		113,967
Evraz PLC	12,846		104,604
Fortescue Metals Group Ltd.	7,049		98,519
Nippon Steel Corp.	10,300		168,204
voestalpine AG	3,248		118,331
		$	697,704

Leisure Time — 0.08%
Yamaha Motor Co. Ltd.	4,600		110,331

Lodging — 0.09%
City Developments Ltd.	12,200		61,652
Whitbread PLC ^(a)	1,399		56,714
		$	118,366

Machinery — Construction & Mining — 0.77%
Epiroc AB, Class A	6,713		170,273
Epiroc AB, Class B	6,282		133,271

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Machinery — Construction & Mining (continued)
Hitachi Ltd.	6,600	$	357,455
Mitsubishi Electric Corp.	18,300		232,031
Sandvik AB	3,967		110,894
		$	1,003,924

Machinery — Diversified — 2.21%
Atlas Copco AB, Class A	4,738		328,129
Atlas Copco AB, Class B	3,686		217,092
CNH Industrial NV	4,700		91,341
FANUC Corp.	1,300		275,528
GEA Group AG	1,669		91,379
Hexagon AB, Class B	21,750		345,764
Husqvarna AB, Class B	4,099		65,707
Keyence Corp.	1,300		816,865
KION Group AG	569		62,500
Kone Oyj, Class B	2,946		211,437
Nabtesco Corp.	2,700		79,923
SMC Corp.	100		67,452
Spirax-Sarco Engineering PLC	1,149		249,614
		$	2,902,731

Media — 1.01%
Bollore SA	29,470		165,074
Informa PLC ^(a)	8,968		62,708
Pearson PLC	6,181		51,302
Quebecor, Inc., Class B	4,959		111,925
Shaw Communications, Inc., Class B	4,890		148,407
Thomson Reuters Corp.	2,432		290,832
Vivendi SE	9,636		130,440
Wolters Kluwer NV	3,092		364,697
		$	1,325,385

Metal Fabrication & Hardware — 0.09%
SKF AB, Class B	2,448		58,110
Tenaris SA	5,465		57,304
		$	115,414

Mining — 2.11%
Agnico Eagle Mines Ltd.	1,361		72,292
Anglo American PLC	7,669		313,072
Antofagasta PLC	5,963		108,033
B2Gold Corp.	14,089		55,467
BHP Group Ltd.	7,435		224,487
BHP Group PLC	11,883		353,773
Boliden AB	1,822		70,572
Cameco Corp.	2,963		64,603
First Quantum Minerals Ltd.	7,190		172,055
Franco-Nevada Corp.	738		102,064
Glencore PLC	30,268		153,614
Ivanhoe Mines Ltd., Class A ^(a)	8,087		65,977
Kinross Gold Corp.	10,370		60,173
Kirkland Lake Gold Ltd.	1,549		64,914
Lundin Mining Corp.	7,099		55,447
Newcrest Mining Ltd.	4,031		71,794
Norsk Hydro ASA	16,706		131,879
Northern Star Resources Ltd.	8,380		57,372
Pan American Silver Corp.	2,130		53,143
Rio Tinto Ltd.	1,322		96,288
Rio Tinto PLC	2,891		191,429
Sumitomo Metal Mining Co. Ltd.	3,800		143,702
Wheaton Precious Metals Corp.	1,992		85,478
		$	2,767,628

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Miscellaneous Manufacture — 0.46%
Alfa Laval AB	1,790	$	72,185
Knorr-Bremse AG	1,196		118,327
Siemens AG	2,383		414,227
		$	604,739

Office & Business Equipment — 0.49%
Canon, Inc.	11,200		272,722
FUJIFILM Holdings Corp.	3,600		266,831
Seiko Epson Corp.	6,100		109,825
		$	649,378

Oil & Gas — 1.45%
Canadian Natural Resources Ltd.	3,789		160,103
Cenovus Energy, Inc.	7,503		91,997
DCC PLC	1,608		131,679
ENEOS Holdings, Inc.	37,900		141,775
Eni SpA	8,656		120,426
Idemitsu Kosan Co. Ltd.	5,400		137,875
Imperial Oil Ltd.	2,068		74,582
Inpex Corp.	16,800		146,341
Lundin Energy AB	3,305		118,686
OMV AG	1,043		59,313
Parkland Corp.	1,820		50,027
Repsol SA	6,552		77,847
Royal Dutch Shell PLC, Class B	9,682		212,617
Royal Dutch Shell PLC, Class A	10,480		230,056
Suncor Energy, Inc.	5,395		134,987
TotalEnergies SE	395		20,070
		$	1,908,381

Packaging & Containers — 0.15%
CCL Industries, Inc., Class B	3,700		198,404

Pharmaceuticals — 7.45%
Amplifon SpA	2,099		113,392
Astellas Pharma, Inc.	200		3,252
AstraZeneca PLC	10,453		1,227,820
Bausch Health Cos., Inc. ^(a)	2,187		60,409
Chugai Pharmaceutical Co. Ltd.	7,400		240,276
Daiichi Sankyo Co. Ltd.	11,900		302,595
GlaxoSmithKline PLC	28,771		625,658
Grifols SA	2,176		41,806
Hikma Pharmaceuticals PLC	3,901		117,168
Ipsen SA	498		45,641
Medipal Holdings Corp.	6,600		123,646
Merck KGaA	1,497		386,884
Nippon Shinyaku Co. Ltd.	1,600		111,414
Novartis AG	13,432		1,183,408
Novo Nordisk A/S, Class B	11,366		1,278,926
Ono Pharmaceutical Co. Ltd.	5,600		139,038
Orion Oyj, Class B	2,940		122,239
Otsuka Holdings Co. Ltd.	5,000		181,214
Recordati Industria Chimica e Farmaceutica SpA	2,160		138,942
Roche Holding AG	4,751		1,976,629
Roche Holding AG	392		175,867
Sanofi	6,357		641,093
Sumitomo Dainippon Pharma Co. Ltd.	6,840		78,788
Takeda Pharmaceutical Co. Ltd.	10,800		294,528
UCB SA	1,492		170,459
		$	9,781,092

Pipelines — 0.87%
APA Group	12,456		91,167

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Pipelines (continued)
Enbridge, Inc.	17,390	$	679,268
Keyera Corp.	2,257		50,905
Koninklijke Vopak NV	1,627		57,052
Pembina Pipeline Corp.	2,653		80,474
TC Energy Corp.	3,793		176,404
		$	1,135,270

Private Equity — 0.13%
3i Group PLC	8,676		170,162

Real Estate — 1.55%
Aroundtown SA	8,245		49,938
Azrieli Group Ltd.	567		54,166
CK Asset Holdings Ltd.	28,500		179,643
Daito Trust Construction Co. Ltd.	1,300		148,839
Fastighets AB Balder, Class B ^(a)	1,743		125,726
FirstService Corp.	1,025		201,443
Henderson Land Development Co. Ltd.	20,000		85,155
Hongkong Land Holdings Ltd.	15,988		83,138
Hulic Co. Ltd.	8,700		82,591
LEG Immobilien SE	1,009		140,951
New World Development Co. Ltd.	19,000		75,171
Nomura Real Estate Holdings, Inc.	4,000		92,046
REA Group Ltd.	913		111,355
Sino Land Co. Ltd.	54,000		67,244
Sun Hung Kai Properties Ltd.	8,500		103,122
Swire Properties Ltd.	25,800		64,653
Swiss Prime Site AG	790		77,726
UOL Group Ltd.	12,600		66,291
Vonovia SE	4,056		223,961
		$	2,033,159

REITs — 1.51%
Ascendas Real Estate Investment Trust	34,300		75,085
British Land Co. PLC	8,233		59,174
Canadian Apartment Properties REIT	3,459		163,960
CapitaLand Integrated Commercial Trust	50,717		76,775
Covivio	614		50,471
Dexus	17,438		141,080
Goodman Group	13,859		267,203
GPT Group	14,949		58,949
Klepierre SA	2,376		56,401
Land Securities Group PLC	6,113		64,241
Link REIT	21,600		190,167
Mapletree Commercial Trust	43,000		63,817
Mapletree Logistics Trust	78,300		110,396
Mirvac Group	27,609		58,453
RioCan Real Estate Investment Trust	6,595		119,601
Segro PLC	16,304		317,011
Stockland	16,765		51,717
Unibail-Rodamco-Westfield ^(a)	785		55,071
Unibail-Rodamco-Westfield ^(a)	48		3,367
		$	1,982,939

Retail — 2.84%
Alimentation Couche-Tard, Inc.	6,602		276,617
Canadian Tire Corp. Ltd., Class A	1,384		198,516
Chow Tai Fook Jewellery Group Ltd.	51,800		93,136
Cie Financiere Richemont SA	1,472		221,236
Cosmos Pharmaceutical Corp.	500		73,590
Dollarama, Inc.	3,543		177,325
Domino's Pizza Enterprises Ltd.	975		83,726
Fast Retailing Co. Ltd.	500		283,883

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
JD Sports Fashion PLC	38,286	$	112,868
Kingfisher PLC	26,907		123,209
Lawson, Inc.	2,400		113,709
McDonald's Holdings Co. Japan Ltd.	2,700		119,473
Moncler SpA	2,163		157,654
Next PLC	671		74,021
Nitori Holdings Co. Ltd.	1,000		149,744
Pan Pacific International Holdings Corp.	8,600		118,649
Pandora A/S	1,049		130,947
Reece Ltd.	3,749		73,727
Restaurant Brands International, Inc.	2,899		175,780
Swatch Group AG	1,224		71,799
Swatch Group AG	291		89,101
Tsuruha Holdings, Inc.	900		86,377
Welcia Holdings Co. Ltd.	3,400		106,111
Wesfarmers Ltd.	11,124		479,931
Yamada Holdings Co. Ltd.	21,200		72,430
Zalando SE ^(a),(b)	848		68,682
		$	3,732,241

Semiconductors — 2.91%
Advantest Corp.	2,400		227,419
ASM International NV	395		174,801
ASML Holding NV	2,838		2,283,392
Infineon Technologies AG	7,243		336,113
STMicroelectronics NV	4,622		228,219
Tokyo Electron Ltd.	1,000		576,198
		$	3,826,142

Shipbuilding — 0.05%
Wartsila Oyj Abp	4,559		64,154

Software — 1.97%
BlackBerry Ltd. ^(a)	5,453		50,954
Capcom Co. Ltd.	4,000		94,167
Constellation Software, Inc.	222		411,890
Dassault Systemes SE	6,932		412,835
Koei Tecmo Holdings Co. Ltd.	2,100		82,609
Konami Holdings Corp.	2,100		100,774
Lightspeed Commerce, Inc. ^(a)	590		23,825
Nemetschek SE	500		64,211
Open Text Corp.	3,191		151,459
Oracle Corp.	1,200		91,176
Sage Group PLC	8,605		99,305
SAP SE	3,616		514,190
Sinch AB ^(a),(b)	6,034		76,859
Temenos AG	423		58,515
TIS, Inc.	4,000		119,099
Ubisoft Entertainment SA ^(a)	826		40,503
WiseTech Global Ltd.	2,767		117,929
Xero Ltd. ^(a)	675		69,461
		$	2,579,761

Telecommunications — 3.26%
BCE, Inc.	2,363		122,937
BT Group PLC	38,877		89,220
Deutsche Telekom AG	20,588		382,063
Elisa Oyj	2,227		137,218
Hikari Tsushin, Inc.	500		76,980
HKT Trust & HKT Ltd.	52,000		69,889
KDDI Corp.	11,000		321,499
Koninklijke KPN NV	67,406		209,505
Nice Ltd. ^(a)	271		82,957

See accompanying notes.


Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Telecommunications (continued)
Nippon Telegraph & Telephone Corp.	11,600	$	317,656
Nokia Oyj ^(a)	18,962		120,333
Orange SA	10,788		115,612
Proximus SADP	5,695		111,131
Rogers Communications, Inc., Class B	2,245		106,895
Singapore Telecommunications Ltd.	54,400		93,654
SoftBank Corp.	25,400		321,171
SoftBank Group Corp.	8,100		382,643
Spark New Zealand Ltd.	22,610		69,995
Swisscom AG	173		97,702
Tele2 AB, Class B	8,954		127,926
Telecom Italia SpA	118,821		58,737
Telecom Italia SpA	106,352		50,588
Telefonaktiebolaget LM Ericsson, Class B	9,499		104,901
Telefonica Deutschland Holding AG	23,517		65,355
Telefonica SA	20,666		90,631
Telenor ASA	9,086		142,998
Telia Co. AB	21,115		82,731
Telstra Corp. Ltd.	55,603		169,097
TELUS Corp.	6,707		157,952
		$	4,279,976

Toys, Games & Hobbies — 0.28%
Nintendo Co. Ltd.	800		373,120

Transportation — 2.54%
AP Moller - Maersk A/S, Class A	42		140,042
AP Moller - Maersk A/S, Class B	52		186,680
Aurizon Holdings Ltd.	45,557		115,676
Canadian National Railway Co.	4,241		520,943
Canadian Pacific Railway Ltd.	4,723		339,696
Deutsche Post AG	8,773		564,725
DSV PANALPINA A/S	1,910		446,648
Kuehne + Nagel International AG	745		240,702
MTR Corp. Ltd.	14,500		77,822
Nippon Express Co. Ltd. ^(a)	1,600		94,793
Nippon Yusen KK	1,900		144,693
Poste Italiane SpA ^(b)	9,896		130,016
SG Holdings Co. Ltd.	5,000		117,056
SITC International Holdings Co. Ltd.	27,000		97,646
Yamato Holdings Co. Ltd.	5,100		119,841
		$	3,336,979

Water — 0.46%
Severn Trent PLC	2,239		89,312
Suez SA	8,659		195,292
United Utilities Group PLC	14,964		220,572
Veolia Environnement SA	2,722		99,973
		$	605,149
TOTAL COMMON STOCKS		$	130,604,575
PREFERRED STOCKS — 0.24%	Shares Held		Value

Auto Manufacturers — 0.17%
Volkswagen AG
2.84%, 09/09/2023	1,142	$	230,754

Household Products/Wares — 0.07%
Henkel AG & Co. KGaA
1.98%, 08/07/2022	1,114		90,226
TOTAL PREFERRED STOCKS		$	320,980

See accompanying notes.

Schedule of Investments
Principal International Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)


INVESTMENT COMPANIES — 0.71%	Shares Held		Value
Money Market Fund — 0.71%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(c)	927,307	$	927,307
TOTAL INVESTMENT COMPANIES		$	927,307
Total Investments		$	131,852,862
Other Assets and Liabilities — (0.42)%			(556,475	)
Total Net Assets — 100.00%		$	131,296,387

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $1,768,449 or 1.35% of net assets.
^(c)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Location	Percent
Japan	20.24	%
Canada	13.39	%
Switzerland	10.39	%
United Kingdom	9.98	%
France	9.32	%
Germany	6.24	%
Australia	6.22	%
Netherlands	4.51	%
Sweden	4.32	%
Denmark	2.64	%
Hong Kong	2.30	%
Italy	2.04	%
Singapore	1.57	%
Finland	1.17	%
Israel	1.07	%
Spain	0.91	%
Ireland	0.83	%
Belgium	0.80	%
United States	0.75	%
Norway	0.64	%
Austria	0.33	%
Luxembourg	0.26	%
New Zealand	0.23	%
Portugal	0.10	%
Jordan	0.09	%
Chile	0.08	%
Other Assets and Liabilities	(0.42	)%
TOTAL NET ASSETS	100.00	%

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS — 98.48%		Amount		Value

Advertising — 0.18%
Omnicom Group, Inc.
2.60%, 08/01/2031	$	876,000	$	887,675

Aerospace & Defense — 3.19%
Boeing Co.
2.20%, 02/04/2026		5,455,000		5,453,700
2.70%, 02/01/2027		3,058,000		3,109,345
2.80%, 03/01/2024		366,000		376,046
3.25%, 02/01/2028		1,416,000		1,475,457
3.50%, 03/01/2039		416,000		422,091
4.88%, 05/01/2025		401,000		438,722
5.71%, 05/01/2040		2,712,000		3,483,313
5.81%, 05/01/2050		656,000		888,307
			$	15,646,981

Agriculture — 2.21%
Altria Group, Inc.
2.35%, 05/06/2025		1,155,000		1,182,113
3.40%, 02/04/2041		1,028,000		948,264
5.80%, 02/14/2039		411,000		494,014
5.95%, 02/14/2049		120,000		149,752
BAT Capital Corp.
2.26%, 03/25/2028		3,022,000		2,944,743
3.22%, 08/15/2024		1,887,000		1,961,242
3.56%, 08/15/2027		2,885,000		3,025,790
Reynolds American, Inc.
5.85%, 08/15/2045		95,000		115,429
			$	10,821,347

Airlines — 2.57%
United Airlines 2012-1 Class A Pass Through Trust
4.15%, 10/11/2025		804,991		834,505
Delta Air Lines, Inc./SkyMiles IP Ltd.
4.50%, 10/20/2025 ^(a)		3,441,583		3,617,143
4.75%, 10/20/2028 ^(a)		2,307,359		2,519,593
JetBlue 2019-1 Class AA Pass Through Trust
2.75%, 11/15/2033		270,736		272,586
Southwest Airlines Co.
5.13%, 06/15/2027		1,391,000		1,590,223
5.25%, 05/04/2025		1,802,000		2,001,451
United Airlines 2014-2 Class A Pass Through Trust
3.75%, 03/03/2028		582,662		608,628
United Airlines 2016-2 Class A Pass Through Trust
3.10%, 04/07/2030		908,412		898,676
United Airlines 2019-2 Class AA Pass Through Trust
2.70%, 11/01/2033		253,542		251,329
			$	12,594,134

Auto Manufacturers — 1.42%
General Motors Co.
5.00%, 10/01/2028		3,105,000		3,560,749
6.25%, 10/02/2043		1,189,000		1,627,075
General Motors Financial Co., Inc.
2.70%, 06/10/2031		1,755,000		1,748,741
			$	6,936,565

Banks — 21.04%
Australia & New Zealand Banking Group Ltd.
(5-year Treasury Constant Maturity Rate + 1.70%),
2.57%, 11/25/2035 ^(a),(b)		1,061,000		1,015,924
Banco Santander SA
2.75%, 12/03/2030		1,800,000		1,761,412

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Bank of America Corp.
(6-month Secured Overnight Financing Rate + 1.06%),
2.09%, 06/14/2029 ^(b)	$	2,623,000	$	2,604,563
(5-year Treasury Constant Maturity Rate + 1.20%),
2.48%, 09/21/2036 ^(b)		2,512,000		2,433,298
(6-month Secured Overnight Financing Rate + 1.21%),
2.57%, 10/20/2032 ^(b)		1,494,000		1,501,177
(6-month Secured Overnight Financing Rate + 1.93%),
2.68%, 06/19/2041 ^(b)		877,000		844,173
(6-month Secured Overnight Financing Rate + 1.88%),
2.83%, 10/24/2051 ^(b)		3,480,000		3,416,649
(3-month USD LIBOR + 1.19%),
2.88%, 10/22/2030 ^(b)		667,000		688,709
(6-month Secured Overnight Financing Rate + 1.56%),
2.97%, 07/21/2052 ^(b)		253,000		253,752
4.25%, 10/22/2026		4,942,000		5,453,013
Barclays PLC
(1-year Treasury Constant Maturity Rate + 1.30%),
3.33%, 11/24/2042 ^(b)		636,712		647,931
4.84%, 05/09/2028		5,631,000		6,202,983
BPCE SA
(6-month Secured Overnight Financing Rate + 1.95%),
3.58%, 10/19/2042 ^(a),(b)		1,874,000		1,914,467
Citigroup, Inc.
(6-month Secured Overnight Financing Rate + 1.38%),
2.90%, 11/03/2042 ^(b)		1,134,000		1,122,806
(3-month USD LIBOR + 1.15%),
3.52%, 10/27/2028 ^(b)		415,000		445,163
Credit Suisse Group AG
(6-month Secured Overnight Financing Rate + 0.98%),
1.31%, 02/02/2027 ^(a),(b)		3,253,000		3,142,925
(6-month Secured Overnight Financing Rate + 1.73%),
3.09%, 05/14/2032 ^(a),(b)		2,098,000		2,134,823
(5-year Treasury Constant Maturity Rate + 4.89%),
5.25%, 02/11/2027 ^{(a),(b),(c),(d)}		4,107,000		4,240,478
Deutsche Bank AG
(6-month US International Swaps and Derivative Association + 2.55%),
4.88%, 12/01/2032 ^(b)		1,755,000		1,896,222
First Republic Bank
4.63%, 02/13/2047		3,356,000		4,156,992
Goldman Sachs Group, Inc.
(6-month Secured Overnight Financing Rate + 0.91%),
1.95%, 10/21/2027 ^(b)		1,289,000		1,283,329
3.85%, 01/26/2027		2,616,000		2,811,604
HSBC Holdings PLC
(6-month Secured Overnight Financing Rate + 1.29%),
1.59%, 05/24/2027 ^(b)		6,279,000		6,140,447
(6-month Secured Overnight Financing Rate + 1.73%),
2.01%, 09/22/2028 ^(b)		538,000		526,646
JPMorgan Chase & Co.
(6-month Secured Overnight Financing Rate + 0.70%),
1.04%, 02/04/2027 ^(b)		7,014,000		6,788,509
(6-month Secured Overnight Financing Rate + 2.46%),
3.11%, 04/22/2041 ^(b)		112,000		115,993
(3-month USD LIBOR + 1.38%),
3.96%, 11/15/2048 ^(b)		588,000		689,625
5.50%, 10/15/2040		783,000		1,065,111
Macquarie Bank Ltd.
(5-year Treasury Constant Maturity Rate + 1.70%),
3.05%, 03/03/2036 ^(a),(b)		1,381,000		1,361,426

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Macquarie Group Ltd.
(6-month Secured Overnight Financing Rate + 0.91%),
1.63%, 09/23/2027 ^(a),(b)	$	527,000	$	516,374
(6-month Secured Overnight Financing Rate + 1.44%),
2.69%, 06/23/2032 ^(a),(b)		517,000		515,626
Morgan Stanley
(6-month Secured Overnight Financing Rate + 0.88%),
1.59%, 05/04/2027 ^(b)		1,556,000		1,540,661
(6-month Secured Overnight Financing Rate + 1.36%),
2.48%, 09/16/2036 ^(b)		2,547,000		2,452,633
(6-month Secured Overnight Financing Rate + 1.43%),
2.80%, 01/25/2052 ^(b)		2,235,000		2,192,982
(3-month USD LIBOR + 1.34%),
3.59%, 07/22/2028 ^(b)		3,690,000		3,978,159
5.00%, 11/24/2025		1,842,000		2,062,004
National Australia Bank Ltd.
2.33%, 08/21/2030 ^(a)		2,385,000		2,284,787
Natwest Group PLC
(5-year Treasury Constant Maturity Rate + 2.35%),
3.03%, 11/28/2035 ^(b)		1,264,000		1,247,175
(1-year Treasury Constant Maturity Rate + 2.55%),
3.07%, 05/22/2028 ^(b)		711,000		739,504
(3-month USD LIBOR + 1.91%),
5.08%, 01/27/2030 ^(b)		1,955,000		2,267,386
(5-year Treasury Constant Maturity Rate + 5.63%),
6.00%, 12/29/2025 ^(b),(c),(d)		1,332,000		1,457,634
Standard Chartered PLC
(3-month USD LIBOR + 1.21%),
2.82%, 01/30/2026 ^(a),(b)		2,290,000		2,347,449
(5-year Treasury Constant Maturity Rate + 2.30%),
3.27%, 02/18/2036 ^(a),(b)		1,867,000		1,842,224
(5-year Treasury Constant Maturity Rate + 5.66%),
6.00%, 07/26/2025 ^{(a),(b),(c),(d),(e)}		1,596,000		1,701,735
Sumitomo Mitsui Financial Group, Inc.
1.90%, 09/17/2028		1,263,000		1,238,155
Wells Fargo & Co.
(6-month Secured Overnight Financing Rate + 2.10%),
2.39%, 06/02/2028 ^(b)		4,813,000		4,891,591
(6-month Secured Overnight Financing Rate + 2.53%),
3.07%, 04/30/2041 ^(b)		453,000		464,563
4.40%, 06/14/2046		355,000		420,728
4.90%, 11/17/2045		388,000		487,926
Westpac Banking Corp.
(5-year Treasury Constant Maturity Rate + 1.53%),
3.02%, 11/18/2036 ^(b)		856,000		845,818
(5-year Treasury Constant Maturity Rate + 2.00%),
4.11%, 07/24/2034 ^(b)		855,000		922,714
			$	103,077,978

Beverages — 2.37%
Anheuser-Busch Cos. LLC/Anheuser-Busch InBev Worldwide, Inc.
3.65%, 02/01/2026		1,270,000		1,363,541
4.90%, 02/01/2046		1,630,000		2,060,214
Anheuser-Busch InBev Worldwide, Inc.
4.38%, 04/15/2038		4,394,000		5,145,619
4.60%, 04/15/2048		426,000		520,929
5.45%, 01/23/2039		1,002,000		1,311,374
Constellation Brands, Inc.
2.88%, 05/01/2030		147,000		150,858

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Beverages (continued)
JDE Peet's NV
1.38%, 01/15/2027 ^(a)	$	1,118,000	$	1,079,671
			$	11,632,206

Biotechnology — 0.39%
Amgen, Inc.
3.00%, 01/15/2052		1,089,000		1,056,651
Gilead Sciences, Inc.
4.50%, 02/01/2045		687,000		837,511
			$	1,894,162

Building Materials — 0.47%
Masco Corp.
1.50%, 02/15/2028		2,359,000		2,283,314

Chemicals — 0.71%
DuPont de Nemours, Inc.
5.32%, 11/15/2038		1,116,000		1,438,000
International Flavors & Fragrances, Inc.
1.23%, 10/01/2025 ^(a)		627,000		613,151
1.83%, 10/15/2027 ^(a)		799,000		784,416
Westlake Chemical Corp.
2.88%, 08/15/2041		661,000		643,065
			$	3,478,632

Commercial Services — 1.06%
CoStar Group, Inc.
2.80%, 07/15/2030 ^(a)		5,201,000		5,202,229

Computers — 0.57%
Apple, Inc.
2.65%, 05/11/2050		356,000		349,995
Dell International LLC/EMC Corp.
3.38%, 12/15/2041 ^(a)		722,000		713,799
4.90%, 10/01/2026		1,197,000		1,348,209
8.35%, 07/15/2046		228,000		379,052
			$	2,791,055

Diversified Financial Services — 7.54%
AerCap Ireland Capital DAC/AerCap Global Aviation Trust
2.45%, 10/29/2026		1,169,000		1,178,586
3.00%, 10/29/2028		3,297,000		3,343,606
3.15%, 02/15/2024		5,123,000		5,283,852
3.40%, 10/29/2033		2,078,000		2,115,641
3.85%, 10/29/2041		1,037,790		1,081,002
Air Lease Corp.
2.88%, 01/15/2026		1,209,000		1,247,011
Ally Financial, Inc.
5.75%, 11/20/2025		1,408,000		1,587,984
8.00%, 11/01/2031		3,631,000		5,139,932
Aviation Capital Group LLC
1.95%, 01/30/2026 ^(a)		3,593,000		3,504,528
Avolon Holdings Funding Ltd.
2.75%, 02/21/2028 ^(a)		1,016,000		996,911
4.25%, 04/15/2026 ^(a)		3,117,000		3,303,069
4.38%, 05/01/2026 ^(a)		1,284,000		1,375,239
5.50%, 01/15/2026 ^(a)		991,000		1,095,173
Blackstone Holdings Finance Co. LLC
2.85%, 08/05/2051 ^(a)		1,246,342		1,213,094
Brookfield Finance, Inc.
2.72%, 04/15/2031		973,000		981,599

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Diversified Financial Services (continued)
Brookfield Finance, Inc. (continued)
3.45%, 04/15/2050	$	978,000	$	1,018,282
4.85%, 03/29/2029		1,391,000		1,603,739
Synchrony Financial
3.95%, 12/01/2027		786,000		844,022
			$	36,913,270

Electric — 7.46%
American Electric Power Co., Inc.
1.00%, 11/01/2025		1,839,000		1,798,246
American Transmission Systems, Inc.
2.65%, 01/15/2032 ^(a)		649,000		655,028
Commonwealth Edison Co.
4.00%, 03/01/2049		1,817,000		2,155,988
Dominion Energy, Inc.
4.25%, 06/01/2028		518,000		577,295
DTE Energy Co.
3.40%, 06/15/2029		1,452,000		1,532,357
Duke Energy Florida LLC
3.80%, 07/15/2028		266,000		293,094
Duke Energy Ohio, Inc.
4.30%, 02/01/2049		837,000		1,004,361
Entergy Corp.
1.90%, 06/15/2028		972,000		952,397
Evergy, Inc.
2.90%, 09/15/2029		978,000		1,001,048
Georgia Power Co.
3.25%, 03/15/2051		504,000		505,488
3.70%, 01/30/2050		120,000		127,581
NextEra Energy Capital Holdings, Inc.
1.88%, 01/15/2027		822,000		826,874
2.44%, 01/15/2032		411,000		411,918
3.50%, 04/01/2029		692,000		742,267
NRG Energy, Inc.
2.00%, 12/02/2025 ^(a)		1,911,000		1,923,119
2.45%, 12/02/2027 ^(a)		722,000		715,400
4.45%, 06/15/2029 ^(a)		965,588		1,050,394
Pacific Gas & Electric Co.
1.70%, 11/15/2023		2,238,000		2,243,780
1.75%, 06/16/2022		1,100,000		1,100,004
2.95%, 03/01/2026		2,485,000		2,526,503
3.50%, 06/15/2025		1,303,000		1,352,913
4.50%, 07/01/2040		2,005,391		2,088,419
Public Service Co. of Colorado
4.05%, 09/15/2049		695,000		823,896
Southern California Edison Co.
4.88%, 03/01/2049		1,153,000		1,407,551
Southern Co.
1.75%, 03/15/2028		1,042,000		1,014,419
(3-month USD LIBOR + 3.63%),
5.50%, 03/15/2057 ^(b)		2,504,000		2,509,801
Southern Power Co.
0.90%, 01/15/2026		1,515,000		1,464,004
Tampa Electric Co.
3.63%, 06/15/2050		431,000		478,766
Tucson Electric Power Co.
4.85%, 12/01/2048		473,000		609,525
Virginia Electric & Power Co.
3.80%, 04/01/2028		1,359,000		1,487,369

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Electric (continued)
WEC Energy Group, Inc.
1.38%, 10/15/2027	$	1,225,000	$	1,181,091
			$	36,560,896

Food — 1.86%
JBS USA LUX SA/JBS USA Food Co./JBS USA Finance, Inc.
3.00%, 05/15/2032 ^(a)		887,385		887,385
3.75%, 12/01/2031 ^(a)		1,184,000		1,201,760
Kraft Heinz Foods Co.
3.88%, 05/15/2027		1,118,000		1,207,599
Mars, Inc.
2.38%, 07/16/2040 ^(a)		669,000		636,902
Pilgrim's Pride Corp.
3.50%, 03/01/2032 ^(a)		1,584,000		1,599,840
Sysco Corp.
3.15%, 12/14/2051		1,020,736		1,004,688
6.60%, 04/01/2050		1,644,000		2,553,914
			$	9,092,088

Gas — 1.29%
CenterPoint Energy Resources Corp.
1.75%, 10/01/2030		2,218,000		2,100,729
NiSource, Inc.
0.95%, 08/15/2025		1,837,000		1,788,072
Piedmont Natural Gas Co., Inc.
3.50%, 06/01/2029		1,501,000		1,602,478
Southern California Gas Co.
2.55%, 02/01/2030		819,000		839,782
			$	6,331,061

Healthcare — Products — 1.30%
Boston Scientific Corp.
2.65%, 06/01/2030		4,362,000		4,446,667
Medtronic, Inc.
4.63%, 03/15/2045		39,000		51,076
PerkinElmer, Inc.
1.90%, 09/15/2028		1,008,000		984,078
2.25%, 09/15/2031		907,000		881,924
			$	6,363,745

Healthcare — Services — 1.23%
Centene Corp.
2.45%, 07/15/2028		1,785,000		1,758,225
3.38%, 02/15/2030		356,000		362,547
HCA, Inc.
5.63%, 09/01/2028		1,234,000		1,441,917
Roche Holdings, Inc.
1.93%, 12/13/2028 ^(a)		1,329,000		1,337,063
UnitedHealth Group, Inc.
2.75%, 05/15/2040		1,090,000		1,106,545
			$	6,006,297

Home Builders — 0.99%
Lennar Corp.
4.75%, 05/30/2025		3,487,000		3,814,970
Toll Brothers Finance Corp.
4.35%, 02/15/2028		964,000		1,055,580
			$	4,870,550

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Insurance — 6.04%
AIA Group Ltd.
3.20%, 09/16/2040 ^(a)	$	1,430,000	$	1,468,761
American International Group, Inc.
4.50%, 07/16/2044		845,000		1,040,660
AmFam Holdings, Inc.
3.83%, 03/11/2051 ^(a)		639,000		705,291
Athene Global Funding
1.45%, 01/08/2026 ^(a)		1,556,000		1,528,323
2.50%, 03/24/2028 ^(a)		2,678,000		2,693,149
2.55%, 11/19/2030 ^(a)		1,471,000		1,446,085
Athene Holding Ltd.
3.45%, 05/15/2052		842,000		845,697
4.13%, 01/12/2028		633,000		692,304
Enstar Group Ltd.
3.10%, 09/01/2031 ^(e)		3,291,000		3,225,885
Equitable Financial Life Global Funding
1.80%, 03/08/2028 ^(a)		1,053,000		1,035,471
Equitable Holdings, Inc.
5.00%, 04/20/2048		1,364,000		1,703,589
Everest Reinsurance Holdings, Inc.
3.13%, 10/15/2052		1,123,000		1,093,140
Markel Corp.
4.30%, 11/01/2047		1,643,000		1,902,862
Marsh & McLennan Cos., Inc.
2.90%, 12/15/2051		735,000		733,513
Massachusetts Mutual Life Insurance Co.
3.38%, 04/15/2050 ^(a)		251,000		264,691
New York Life Insurance Co.
3.75%, 05/15/2050 ^(a)		1,472,000		1,675,258
Swiss Re Finance Luxembourg SA
(5-year Treasury Constant Maturity Rate + 3.58%),
5.00%, 04/02/2049 ^(a),(b)		1,000,000		1,118,750
XLIT Ltd.
4.45%, 03/31/2025		3,505,000		3,799,322
5.50%, 03/31/2045		1,902,000		2,603,130
			$	29,575,881

Internet — 1.73%
Amazon.com, Inc.
2.70%, 06/03/2060		602,000		580,090
3.10%, 05/12/2051		758,000		809,258
eBay, Inc.
3.65%, 05/10/2051		2,103,000		2,286,934
Expedia Group, Inc.
3.80%, 02/15/2028		2,277,000		2,434,452
4.63%, 08/01/2027		1,210,000		1,347,419
Netflix, Inc.
4.88%, 04/15/2028		882,000		1,005,480
			$	8,463,633

Iron & Steel — 0.23%
Nucor Corp.
2.70%, 06/01/2030		231,000		238,108
Vale Overseas Ltd.
3.75%, 07/08/2030		874,000		904,599
			$	1,142,707

Lodging — 0.20%
Hyatt Hotels Corp.
1.80%, 10/01/2024		978,000		978,871

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Media — 4.27%
Charter Communications Operating LLC/Charter Communications Operating
Capital
2.30%, 02/01/2032	$	1,765,000	$	1,675,395
3.90%, 06/01/2052		878,000		880,429
3.95%, 06/30/2062		745,000		717,718
4.80%, 03/01/2050		440,000		492,639
Comcast Corp.
2.89%, 11/01/2051 ^(a)		498,000		482,057
3.75%, 04/01/2040		617,000		690,748
3.97%, 11/01/2047		2,714,000		3,124,758
Discovery Communications LLC
4.00%, 09/15/2055		757,000		799,748
Fox Corp.
4.71%, 01/25/2029		1,835,000		2,094,465
Time Warner Cable LLC
5.50%, 09/01/2041		1,838,000		2,228,412
5.88%, 11/15/2040		1,611,000		2,010,387
ViacomCBS, Inc.
2.90%, 01/15/2027		4,547,000		4,734,919
5.25%, 04/01/2044		788,000		986,503
			$	20,918,178

Mining — 1.38%
Newmont Corp.
2.25%, 10/01/2030		2,231,000		2,199,586
Teck Resources Ltd.
3.90%, 07/15/2030		889,000		955,103
5.40%, 02/01/2043		1,529,000		1,864,437
Yamana Gold, Inc.
2.63%, 08/15/2031 ^(a)		1,795,000		1,722,856
			$	6,741,982

Miscellaneous Manufacture — 0.74%
GE Capital International Funding Unlimited Co.
4.42%, 11/15/2035		3,021,000		3,605,141

Oil & Gas — 2.32%
BP Capital Markets America, Inc.
3.00%, 02/24/2050		713,000		701,890
3.59%, 04/14/2027		1,626,000		1,755,911
4.23%, 11/06/2028		25,000		28,218
Canadian Natural Resources Ltd.
4.95%, 06/01/2047		396,000		485,922
Chevron Corp.
2.00%, 05/11/2027		744,000		755,135
Devon Energy Corp.
4.50%, 01/15/2030		1,596,000		1,713,457
Exxon Mobil Corp.
3.00%, 08/16/2039		1,134,000		1,147,363
Marathon Oil Corp.
4.40%, 07/15/2027		1,717,000		1,880,766
6.60%, 10/01/2037		56,000		73,169
Pioneer Natural Resources Co.
0.75%, 01/15/2024		1,058,000		1,043,654
Shell International Finance BV
3.13%, 11/07/2049		1,722,000		1,771,920
			$	11,357,405

Packaging & Containers — 0.21%
WRKCo, Inc.
3.00%, 06/15/2033		979,000		1,006,722

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Pharmaceuticals — 5.55%
AbbVie, Inc.
4.25%, 11/21/2049	$	2,210,000	$	2,656,801
Bayer US Finance II LLC
3.38%, 07/15/2024 ^(a)		316,000		328,811
4.38%, 12/15/2028 ^(a)		1,513,000		1,689,930
4.63%, 06/25/2038 ^(a)		1,412,000		1,648,737
Becton Dickinson and Co.
3.70%, 06/06/2027		1,496,000		1,630,300
4.67%, 06/06/2047		1,034,000		1,303,699
4.69%, 12/15/2044		1,615,000		2,033,421
Bristol-Myers Squibb Co.
4.13%, 06/15/2039		1,556,000		1,840,519
4.25%, 10/26/2049		441,000		544,973
Cigna Corp.
4.38%, 10/15/2028		2,908,000		3,304,944
CVS Health Corp.
4.78%, 03/25/2038		1,263,000		1,537,385
5.05%, 03/25/2048		4,727,000		6,180,259
Merck & Co., Inc.
2.75%, 12/10/2051		556,000		550,159
Viatris, Inc.
2.30%, 06/22/2027		236,000		237,376
Zoetis, Inc.
3.90%, 08/20/2028		1,520,000		1,686,510
			$	27,173,824

Pipelines — 3.02%
Eastern Gas Transmission & Storage, Inc.
3.00%, 11/15/2029 ^(a)		235,000		242,500
Enbridge, Inc.
2.50%, 08/01/2033		1,616,000		1,586,007
Energy Transfer LP
3.75%, 05/15/2030		3,101,000		3,285,993
5.15%, 03/15/2045		1,600,000		1,808,117
6.25%, 04/15/2049		386,000		504,217
Enterprise Products Operating LLC
3.30%, 02/15/2053		812,000		807,607
4.20%, 01/31/2050		1,885,000		2,113,070
Kinder Morgan, Inc.
3.60%, 02/15/2051		1,033,000		1,038,857
MPLX LP
4.00%, 03/15/2028		995,000		1,078,242
ONEOK, Inc.
4.45%, 09/01/2049		603,000		666,261
Sabine Pass Liquefaction LLC
5.00%, 03/15/2027		1,480,000		1,662,300
5.75%, 05/15/2024		9,000		9,788
			$	14,802,959

Private Equity — 0.43%
KKR Group Finance Co. VIII LLC
3.50%, 08/25/2050 ^(a)		1,421,000		1,486,988
KKR Group Finance Co. X LLC
3.25%, 12/15/2051 ^(a)		620,000		617,849
			$	2,104,837

REITs — 3.22%
Alexandria Real Estate Equities, Inc.
4.70%, 07/01/2030		396,000		463,293
American Campus Communities Operating Partnership LP
2.25%, 01/15/2029		1,674,000		1,655,688

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

REITs (continued)
American Homes 4 Rent LP
3.38%, 07/15/2051	$	1,457,000	$	1,462,649
Invitation Homes Operating Partnership LP
2.00%, 08/15/2031		2,496,000		2,350,469
Realty Income Corp.
3.10%, 12/15/2029		1,886,070		2,002,516
Simon Property Group LP
1.75%, 02/01/2028		1,255,000		1,230,745
Spirit Realty LP
3.20%, 01/15/2027 ^(e)		4,370,000		4,567,889
3.20%, 02/15/2031		784,000		810,244
VICI Properties LP/VICI Note Co., Inc.
4.13%, 08/15/2030 ^(a)		1,178,000		1,245,735
			$	15,789,228

Retail — 0.24%
Home Depot, Inc.
3.30%, 04/15/2040		642,000		696,041
McDonald's Corp.
4.88%, 12/09/2045		370,000		475,360
			$	1,171,401

Semiconductors — 3.19%
Broadcom, Inc.
3.14%, 11/15/2035 ^(a)		654,000		657,897
3.42%, 04/15/2033 ^(a)		2,593,000		2,718,247
4.11%, 09/15/2028		537,000		588,713
KLA Corp.
3.30%, 03/01/2050		671,000		716,938
Lam Research Corp.
4.88%, 03/15/2049		329,000		446,582
Micron Technology, Inc.
3.37%, 11/01/2041		2,226,000		2,285,813
4.19%, 02/15/2027		2,223,000		2,434,429
NVIDIA Corp.
3.50%, 04/01/2040		2,162,000		2,429,671
3.50%, 04/01/2050		1,022,000		1,165,052
NXP BV/NXP Funding LLC/NXP USA, Inc.
2.70%, 05/01/2025 ^(a)		100,000		103,308
3.15%, 05/01/2027 ^(a)		1,095,000		1,151,528
QUALCOMM, Inc.
4.30%, 05/20/2047		733,000		917,852
			$	15,616,030

Software — 2.37%
Activision Blizzard, Inc.
4.50%, 06/15/2047		482,000		578,085
Fiserv, Inc.
4.40%, 07/01/2049		1,756,000		2,092,005
Oracle Corp.
2.80%, 04/01/2027		1,842,000		1,899,074
4.00%, 07/15/2046		2,396,000		2,486,861
VMware, Inc.
1.80%, 08/15/2028		1,129,000		1,098,691
4.50%, 05/15/2025		2,277,000		2,479,506
4.65%, 05/15/2027		877,000		986,295
			$	11,620,517

Telecommunications — 4.30%
AT&T, Inc.
3.50%, 06/01/2041		3,243,000		3,332,973

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Telecommunications (continued)
AT&T, Inc. (continued)
3.50%, 09/15/2053	$	5,017,000	$	5,061,626
3.55%, 09/15/2055		1,880,000		1,886,822
4.50%, 03/09/2048		1,012,000		1,179,845
T-Mobile USA, Inc.
2.05%, 02/15/2028		1,792,000		1,778,752
Verizon Communications, Inc.
2.36%, 03/15/2032 ^(a)		2,938,000		2,894,865
2.65%, 11/20/2040		4,819,000		4,579,097
Vodafone Group PLC
(5-year Treasury Constant Maturity Rate + 2.45%),
3.25%, 06/04/2081 ^(b)		354,000		347,090
			$	21,061,070

Transportation — 0.78%
Burlington Northern Santa Fe LLC
4.38%, 09/01/2042		421,000		511,581
FedEx Corp.
4.10%, 02/01/2045		1,871,000		2,094,684
Union Pacific Corp.
2.95%, 03/10/2052		1,193,000		1,207,090
			$	3,813,355

Trucking & Leasing — 0.20%
SMBC Aviation Capital Finance DAC
1.90%, 10/15/2026 ^(a)		993,000		983,413

Water — 0.21%
Essential Utilities, Inc.
2.40%, 05/01/2031		1,048,000		1,041,844
TOTAL BONDS			$	482,353,183
INVESTMENT COMPANIES — 1.17%		Shares Held		Value

Money Market Funds — 1.17%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(f),(g),(h),(i)}		1,601,613	$	1,601,613
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ⁽ⁱ⁾		4,122,150		4,122,150
TOTAL INVESTMENT COMPANIES			$	5,723,763
Total Investments			$	488,076,946
Other Assets and Liabilities — 0.35%				1,729,324

Total Net Assets — 100.00%			$	489,806,270

^(a)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $88,953,645 or 18.16% of net assets.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or floating rate in the future.
^(c)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(d)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities totaled $7,399,847 or 1.51% of net assets.
^(e)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $1,568,573 or 0.32% of net assets.
(f)	Non-income producing security.
^(g)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $1,601,613 or 0.33% of net assets.
^(h)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.

See accompanying notes.


Schedule of Investments
Principal Investment Grade Corporate Active ETF
December 31, 2021 (unaudited)

(i) Current yield shown is as of period end.

Portfolio Summary (unaudited)
Sector					Percent
Financial					38.28		%
Consumer, Non-cyclical					15.96		%
Communications					10.48		%
Utilities						8.97	%
Technology						6.13	%
Industrial						5.58	%
Consumer, Cyclical						5.42	%
Energy						5.34	%
Basic Materials						2.32	%
Money Market Funds						1.17	%
Other Assets and Liabilities						0.35	%
TOTAL NET ASSETS					100.00		%

			June 30, 2021		Purchases				Sales			December 31, 2021
Affiliated Securities			Value		Cost				Proceeds			Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	2,138,163	$	19,805,668			$	20,342,218		$	1,601,613
		$	2,138,163	$	19,805,668			$	20,342,218		$	1,601,613

									Realized Gain
					Realized				from			Change in
					Gain/Loss on				Capital Gain			Unrealized
			Income ^(a)		Investments				Distributions			Gain/Loss
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—	$		—		$		—	$	—
		$	—	$		—		$		—	$	—

^(a)Amount excludes earnings from securities lending collateral.

Futures Contracts

											Value and Unrealized
Description and Expiration Date			Type	Contracts		Notional Amount				Appreciation/(Depreciation)
U.S. 5 Year Notes; March 2022			Short		390	$		47,180,860		$		(9,909	)
U.S. 10 Year Notes; March 2022			Short		128			16,700,000				(62,593	)
U.S. Treasury Ultra 10-Year Notes;
March 2022			Short		37			5,418,188				(39,132	)
Total										$		(111,634	)

See accompanying notes.


Schedule of Investments
Principal Millennials ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.31%	Shares Held		Value

Apparel — 2.76%
Carter's, Inc.	2,309	$	233,717
Columbia Sportswear Co.	1,949		189,911
Deckers Outdoor Corp. ^(a)	621		227,478
Fila Holdings Corp.	7,382		222,624
Hanesbrands, Inc.	10,468		175,025
SMCP SA ^(a),(b)	40,913		341,660
Urban Outfitters, Inc. ^(a)	43,564		1,279,039
Yue Yuen Industrial Holdings Ltd. ^(a)	123,500		206,532
		$	2,875,986

Beverages — 1.57%
Brown-Forman Corp., Class B	5,835		425,138
Constellation Brands, Inc., Class A	1,741		436,939
Monster Beverage Corp. ^(a)	4,484		430,643
Treasury Wine Estates Ltd.	37,422		337,063
		$	1,629,783

Building Materials — 0.67%
Fortune Brands Home & Security, Inc.	2,144		229,194
Masco Corp.	6,632		465,699
		$	694,893

Commercial Services — 3.76%
Adyen NV ^(a),(b)	962		2,531,640
China Yuhua Education Corp. Ltd. ^(b)	378,000		135,250
Global Payments, Inc.	2,038		275,497
GMO Payment Gateway, Inc.	2,300		286,925
GXO Logistics, Inc. ^(a)	1,668		151,504
PayPal Holdings, Inc. ^(a)	1,682		317,192
PROG Holdings, Inc.	4,744		214,002
		$	3,912,010

Computers — 0.56%
Apple, Inc.	3,260		578,878

Diversified Financial Services — 3.68%
Discover Financial Services	22,785		2,633,035
LexinFintech Holdings Ltd., ADR ^(a)	159,419		615,357
Rocket Cos., Inc., Class A ^(c)	8,919		124,866
XP, Inc., Class A ^(a)	15,729		452,051
		$	3,825,309

Electronics — 0.59%
Garmin Ltd.	4,507		613,718

Engineering & Construction — 0.21%
HomeServe PLC	18,489		218,851

Entertainment — 5.08%
CTS Eventim AG & Co. KGaA ^(a)	27,754		2,033,642
DraftKings, Inc., Class A ^(a)	17,501		480,752
Universal Music Group NV	98,111		2,767,910
		$	5,282,304

Food — 3.15%
Albertsons Cos., Inc., Class A	10,770		325,146
Kroger Co.	60,138		2,721,846
Sprouts Farmers Market, Inc. ^(a)	7,735		229,575
		$	3,276,567

Home Builders — 0.72%
DR Horton, Inc.	4,459		483,579

See accompanying notes.


Schedule of Investments
Principal Millennials ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Home Builders (continued)
Toll Brothers, Inc.	3,621	$	262,124
		$	745,703

Home Furnishings — 4.82%
Sleep Number Corp. ^(a)	11,271		863,359
Sony Group Corp.	30,900		3,888,355
Tempur Sealy International, Inc.	5,618		264,214
		$	5,015,928

Internet — 31.32%
AfreecaTV Co. Ltd.	32,989		5,625,127
Alibaba Group Holding Ltd., ADR ^(a)	2,687		319,189
Alphabet, Inc., Class C ^(a)	1,047		3,029,589
Amazon.com, Inc. ^(a)	130		433,464
ASOS PLC ^(a)	4,024		130,230
Baidu, Inc., ADR ^(a)	2,797		416,166
eBay, Inc.	6,484		431,186
Expedia Group, Inc. ^(a)	6,272		1,133,476
Farfetch Ltd., Class A ^(a)	30,358		1,014,868
Hello Group, Inc.	164,017		1,472,873
IAC/InterActiveCorp ^(a)	4,975		650,282
JOYY, Inc.	25,771		1,170,777
Kakao Corp. ^(a)	6,374		603,218
Kogan.com Ltd. ^(c)	33,328		213,865
Meta Platforms, Inc., Class A ^(a)	7,347		2,471,163
Naspers Ltd., Class N	8,979		1,392,914
NCSoft Corp.	724		391,615
Netflix, Inc. ^(a)	761		458,457
Overstock.com, Inc. ^(a)	3,098		182,813
Pinduoduo, Inc., ADR ^(a)	16,021		934,024
Pinterest, Inc., Class A ^(a)	19,396		705,045
Rakuten Group, Inc. ^(a)	49,700		498,599
RealReal, Inc. ^(a)	9,099		105,639
Revolve Group, Inc. ^(a)	36,108		2,023,492
Roku, Inc. ^(a)	4,416		1,007,731
Shutterstock, Inc.	2,307		255,800
Snap, Inc., Class A ^(a)	27,544		1,295,394
Temple & Webster Group Ltd. ^(a)	42,536		332,990
Tencent Holdings Ltd.	7,500		439,369
Tencent Music Entertainment Group, ADR ^(a)	117,662		805,985
Trip.com Group Ltd., ADR ^(a)	40,607		999,744
Vimeo, Inc. ^(a)	8,325		149,517
Wayfair, Inc., Class A ^(a),(c)	5,141		976,636
Weibo Corp. ^(a)	6,072		188,111
ZOZO, Inc.	10,300		321,455
		$	32,580,803

Leisure Time — 1.73%
Camping World Holdings, Inc., Class A ^(c)	44,581		1,801,072

Media — 4.79%
Comcast Corp., Class A	7,546		379,790
Fox Corp., Class B	5,882		201,576
Sirius XM Holdings, Inc.	67,057		425,812
ViacomCBS, Inc., Class B	47,919		1,446,196
Vivendi SE	97,884		1,325,032
Walt Disney Co. ^(a)	7,803		1,208,607
		$	4,987,013

Real Estate — 0.64%
REA Group Ltd.	5,506		671,547

See accompanying notes.


Schedule of Investments
Principal Millennials ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

REITs — 4.19%
American Homes 4 Rent, Class A	6,161	$	268,681
AvalonBay Communities, Inc.	2,155		544,331
Duke Realty Corp.	9,501		623,646
EastGroup Properties, Inc.	1,379		314,205
Essex Property Trust, Inc.	1,463		515,313
Invitation Homes, Inc.	12,444		564,211
Prologis, Inc.	3,759		632,865
Segro PLC	46,022		894,840
		$	4,358,092

Retail — 17.31%
Academy Sports & Outdoors, Inc. ^(a)	7,611		334,123
Bath & Body Works, Inc.	6,421		448,122
Bed Bath & Beyond, Inc. ^(a)	36,867		537,521
Dick's Sporting Goods, Inc.	2,810		323,122
Domino's Pizza, Inc.	1,082		610,605
Foot Locker, Inc.	3,661		159,729
Hennes & Mauritz AB, Class B	95,240		1,876,933
Hibbett, Inc.	2,981		214,423
Home Depot, Inc.	7,091		2,942,836
Industria de Diseno Textil SA	65,881		2,139,907
JD Sports Fashion PLC	129,843		382,781
Kingfisher PLC	67,104		307,273
Li Ning Co. Ltd.	91,771		1,004,502
Lowe's Cos., Inc.	2,093		540,999
Lululemon Athletica, Inc. ^(a)	1,296		507,319
Mr Price Group Ltd.	23,229		290,818
Pandora A/S	2,862		357,265
Pets at Home Group PLC	51,746		325,690
Qurate Retail, Inc., Series A	19,703		149,743
Signet Jewelers Ltd.	27,838		2,422,741
Truworths International Ltd.	94,015		308,270
Victoria's Secret & Co. ^(a)	2,220		123,299
Williams-Sonoma, Inc.	2,211		373,946
Zalando SE ^(a),(b)	16,384		1,326,987
		$	18,008,954

Semiconductors — 0.49%
Samsung Electronics Co. Ltd.	7,790		513,108

Software — 5.40%
Activision Blizzard, Inc.	23,241		1,546,224
Bilibili, Inc., ADR ^(a),(c)	20,035		929,624
Electronic Arts, Inc.	2,929		386,335
Fiserv, Inc. ^(a)	3,327		345,309
Microsoft Corp.	1,689		568,045
NetEase, Inc., ADR	5,753		585,540
Netmarble Corp. ^(b)	2,432		255,731
Pearl Abyss Corp. ^(a)	5,151		599,271
Take-Two Interactive Software, Inc. ^(a)	2,245		398,981
		$	5,615,060

Telecommunications — 1.69%
AT&T, Inc.	71,433		1,757,252

Textiles — 0.36%
Mohawk Industries, Inc. ^(a)	2,060		375,291

Toys, Games & Hobbies — 1.94%
Funko, Inc., Class A ^(a)	82,378		1,548,707
Nintendo Co. Ltd.	1,000		466,400
		$	2,015,107

See accompanying notes.


Schedule of Investments
Principal Millennials ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Transportation — 1.88%
Deutsche Post AG	10,828	$	697,007
FedEx Corp.	1,437		371,666
United Parcel Service, Inc., Class B	2,340		501,555
XPO Logistics, Inc. ^(a)	1,668		129,153
Yamato Holdings Co. Ltd.	11,100		260,830
		$	1,960,211
TOTAL COMMON STOCKS		$	103,313,440
INVESTMENT COMPANIES — 2.98%	Shares Held		Value
Money Market Funds — 2.98%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(d),(e),(f)}	2,317,867	$	2,317,867
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)	779,439		779,439
TOTAL INVESTMENT COMPANIES		$	3,097,306
Total Investments		$	106,410,746
Other Assets and Liabilities — (2.29)%			(2,380,575	)
Total Net Assets — 100.00%		$	104,030,171

^(a)	Non-income producing security.
^(b)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $4,591,268 or 4.41% of net assets.
^(c)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $2,229,283 or 2.14% of net assets.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.
(f)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $2,317,867 or 2.23% of net assets.


Portfolio Summary (unaudited)

Sector	Percent
Communications	37.80	%
Consumer, Cyclical	34.72	%
Financial	8.51	%
Consumer, Non-cyclical	8.48	%
Technology	6.45	%
Industrial	3.35	%
Money Market Funds	2.98	%
Other Assets and Liabilities	(2.29	)%
TOTAL NET ASSETS	100.00	%

See accompanying notes.


Schedule of Investments
Principal Quality ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.79%	Shares Held		Value

Aerospace & Defense — 1.56%
Lockheed Martin Corp.	2,272	$	807,492
Northrop Grumman Corp.	1,803		697,887
		$	1,505,379

Agriculture — 0.85%
Altria Group, Inc.	12,071		572,045
Philip Morris International, Inc.	2,684		254,980
		$	827,025

Beverages — 2.29%
Brown-Forman Corp., Class B	7,458		543,390
Coca-Cola Co.	4,603		272,543
Keurig Dr Pepper, Inc.	7,386		272,248
Monster Beverage Corp. ^(a)	8,567		822,775
PepsiCo, Inc.	1,741		302,429
		$	2,213,385

Biotechnology — 2.32%
Amgen, Inc.	996		224,070
Bio-Rad Laboratories, Inc., Class A ^(a)	382		288,628
Regeneron Pharmaceuticals, Inc. ^(a)	1,160		732,563
Seagen, Inc. ^(a)	1,463		226,180
Vertex Pharmaceuticals, Inc. ^(a)	3,532		775,627
		$	2,247,068

Chemicals — 2.48%
FMC Corp.	5,176		568,791
RPM International, Inc.	6,603		666,903
Sherwin-Williams Co.	3,306		1,164,241
		$	2,399,935

Commercial Services — 5.88%
Automatic Data Processing, Inc.	1,295		319,321
Booz Allen Hamilton Holding Corp.	9,733		825,261
Gartner, Inc. ^(a)	1,252		418,569
MarketAxess Holdings, Inc.	1,347		553,981
Moody's Corp.	2,721		1,062,768
PayPal Holdings, Inc. ^(a)	865		163,122
Rollins, Inc.	15,860		542,570
S&P Global, Inc.	1,598		754,144
Verisk Analytics, Inc.	4,564		1,043,924
		$	5,683,660

Computers — 3.98%
Accenture PLC, Class A	2,982		1,236,188
Apple, Inc.	6,200		1,100,934
EPAM Systems, Inc. ^(a)	602		402,407
Fortinet, Inc. ^(a)	3,102		1,114,859
		$	3,854,388

Distribution/Wholesale — 2.74%
Fastenal Co.	16,200		1,037,772
LKQ Corp.	5,723		343,552
Pool Corp.	2,241		1,268,406
		$	2,649,730

Diversified Financial Services — 3.26%
BlackRock, Inc.	757		693,079
Intercontinental Exchange, Inc.	2,045		279,695
Mastercard, Inc., Class A	638		229,246
Nasdaq, Inc.	3,804		798,878
T Rowe Price Group, Inc.	4,690		922,241

See accompanying notes.


Schedule of Investments
Principal Quality ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services (continued)
Visa, Inc., Class A	1,058	$	229,279
		$	3,152,418

Electric — 2.16%
CMS Energy Corp.	9,723		632,481
Evergy, Inc.	4,210		288,848
Eversource Energy	2,841		258,474
Southern Co.	3,972		272,400
WEC Energy Group, Inc.	6,522		633,091
		$	2,085,294

Electrical Components & Equipment — 0.54%
AMETEK, Inc.	1,915		281,581
Generac Holdings, Inc. ^(a)	677		238,250
		$	519,831

Electronics — 4.48%
Agilent Technologies, Inc.	4,278		682,983
Amphenol Corp., Class A	4,187		366,195
Garmin Ltd.	4,213		573,684
Honeywell International, Inc.	1,092		227,693
Keysight Technologies, Inc. ^(a)	1,596		329,590
Mettler-Toledo International, Inc. ^(a)	672		1,140,525
Waters Corp. ^(a)	2,730		1,017,198
		$	4,337,868

Engineering & Construction — 0.28%
Jacobs Engineering Group, Inc.	1,954		272,055

Environmental Control — 0.36%
Republic Services, Inc.	2,528		352,530

Food — 2.76%
Campbell Soup Co.	4,956		215,388
General Mills, Inc.	13,667		920,882
Hershey Co.	5,158		997,918
J M Smucker Co.	2,014		273,542
McCormick & Co., Inc.	2,681		259,011
		$	2,666,741

Healthcare — Products — 9.43%
Abbott Laboratories	4,392		618,130
Bio-Techne Corp.	614		317,647
Danaher Corp.	3,421		1,125,543
Edwards Lifesciences Corp. ^(a)	2,715		351,728
Hologic, Inc. ^(a)	7,301		558,964
IDEXX Laboratories, Inc. ^(a)	1,441		948,841
Masimo Corp. ^(a)	897		262,624
PerkinElmer, Inc.	5,964		1,199,122
ResMed, Inc.	3,899		1,015,611
STERIS PLC	3,007		731,934
Thermo Fisher Scientific, Inc.	1,666		1,111,622
West Pharmaceutical Services, Inc.	1,870		877,049
		$	9,118,815

Healthcare — Services — 3.68%
Charles River Laboratories International, Inc. ^(a)	1,826		688,001
Humana, Inc.	591		274,141
Laboratory Corp. of America Holdings ^(a)	2,186		686,863
Quest Diagnostics, Inc.	6,500		1,124,565
UnitedHealth Group, Inc.	1,573		789,866
		$	3,563,436

See accompanying notes.


Schedule of Investments
Principal Quality ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Home Builders — 0.66%
DR Horton, Inc.	2,938	$	318,626
Lennar Corp., Class A	2,717		315,607
		$	634,233

Household Products — 1.91%
Colgate-Palmolive Co.	9,994		852,888
Procter & Gamble Co.	6,081		994,730
		$	1,847,618

Household Products/Wares — 2.65%
Avery Dennison Corp.	1,282		277,643
Church & Dwight Co., Inc.	9,545		978,363
Clorox Co.	4,154		724,291
Kimberly-Clark Corp.	4,095		585,257
		$	2,565,554

Housewares — 0.59%
Scotts Miracle-Gro Co.	3,521		566,881
Insurance — 5.31%
Allstate Corp.	2,112		248,477
Aon PLC	3,296		990,646
Arthur J Gallagher & Co.	6,276		1,064,849
Brown & Brown, Inc.	11,463		805,619
Marsh & McLennan Cos., Inc.	6,522		1,133,654
Progressive Corp.	8,745		897,674
		$	5,140,919

Internet — 2.53%
Alphabet, Inc., Class A ^(a)	259		750,333
eBay, Inc.	13,320		885,780
Etsy, Inc. ^(a)	1,023		223,976
Netflix, Inc. ^(a)	968		583,162
		$	2,443,251

Machinery — Diversified — 1.69%
Graco, Inc.	7,588		611,744
IDEX Corp.	1,153		272,477
Rockwell Automation, Inc.	2,148		749,330
		$	1,633,551

Media — 1.24%
FactSet Research Systems, Inc.	2,466		1,198,501
Miscellaneous Manufacture — 1.07%
3M Co.	4,288		761,677
Illinois Tool Works, Inc.	1,117		275,676
		$	1,037,353

Pharmaceuticals — 3.88%
AbbVie, Inc.	2,089		282,850
Becton Dickinson & Co.	2,177		547,472
Cigna Corp.	2,502		574,534
Eli Lilly & Co.	2,562		707,676
Johnson & Johnson	4,744		811,556
Zoetis, Inc.	3,389		827,018
		$	3,751,106

REITs — 2.65%
Alexandria Real Estate Equities, Inc.	1,409		314,151
American Tower Corp.	2,432		711,360
Crown Castle International Corp.	3,354		700,114

See accompanying notes.


Schedule of Investments
Principal Quality ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

REITs (continued)
Public Storage	2,243	$	840,138
		$	2,565,763

Retail — 9.79%
AutoZone, Inc. ^(a)	451		945,472
Costco Wholesale Corp.	2,270		1,288,679
Dollar General Corp.	3,977		937,896
Domino's Pizza, Inc.	644		363,429
Home Depot, Inc.	2,909		1,207,264
Lowe's Cos., Inc.	4,702		1,215,373
O'Reilly Automotive, Inc. ^(a)	1,679		1,185,760
Target Corp.	4,094		947,515
Tractor Supply Co.	4,730		1,128,578
Walmart, Inc.	1,730		250,314
		$	9,470,280

Semiconductors — 2.15%
KLA Corp.	1,679		722,155
Monolithic Power Systems, Inc.	1,395		688,195
Teradyne, Inc.	4,091		669,001
		$	2,079,351

Software — 11.31%
Activision Blizzard, Inc.	5,500		365,915
Adobe, Inc. ^(a)	1,632		925,442
Akamai Technologies, Inc. ^(a)	2,342		274,108
Autodesk, Inc. ^(a)	810		227,764
Broadridge Financial Solutions, Inc.	5,275		964,375
Cerner Corp.	10,876		1,010,054
Citrix Systems, Inc.	1,691		159,952
Fair Isaac Corp. ^(a)	1,150		498,720
Intuit, Inc.	1,345		865,131
Jack Henry & Associates, Inc.	3,546		592,146
Microsoft Corp.	3,231		1,086,650
Oracle Corp.	11,655		1,016,433
Paychex, Inc.	5,740		783,510
PTC, Inc. ^(a)	1,652		200,140
Synopsys, Inc. ^(a)	3,051		1,124,293
Tyler Technologies, Inc. ^(a)	479		257,678
Veeva Systems, Inc., Class A ^(a)	1,862		475,704
Zoom Video Communications, Inc., Class A ^(a)	601		110,530
		$	10,938,545

Telecommunications — 0.77%
Cisco Systems, Inc.	11,720		742,696

Transportation — 1.52%
Expeditors International of Washington, Inc.	8,183		1,098,895
Old Dominion Freight Line, Inc.	1,046		374,866
		$	1,473,761

Water — 1.02%
American Water Works Co., Inc.	3,708		700,293
Essential Utilities, Inc.	5,366		288,100
		$	988,393
TOTAL COMMON STOCKS		$	96,527,314

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS — 96.92%		Amount		Value

Banks — 40.60%
Bank of America Corp.
(3-month USD LIBOR + 4.55%),
6.30%, 03/10/2026 ^(a),(b)	$	818,000	$	920,250
Bank of Montreal
(5-year Treasury Constant Maturity Rate + 2.98%),
4.80%, 08/25/2024 ^(a),(b),(c)		3,750,000		3,909,375
Bank of New York Mellon Corp.
(5-year Treasury Constant Maturity Rate + 3.35%),
3.70%, 03/20/2026 ^(a),(b)		16,077,000		16,438,732
(5-year Treasury Constant Maturity Rate + 2.63%),
3.75%, 12/20/2026 ^(a),(b)		4,878,000		4,895,414
(5-year Treasury Constant Maturity Rate + 4.36%),
4.70%, 09/20/2025 ^(a),(b)		786,000		838,466
Bank of Nova Scotia
(5-year Treasury Constant Maturity Rate + 4.55%),
4.90%, 06/04/2025 ^(a),(b)		5,227,000		5,601,057
BNP Paribas SA
(3-month USD LIBOR + 1.29%),
7.20%, 06/25/2037 ^{(a),(b),(c),(d)}		2,300,000		2,297,125
Citigroup, Inc.
(5-year Treasury Constant Maturity Rate + 3.42%),
3.88%, 02/18/2026 ^(a),(b)		7,325,000		7,325,000
(5-year Treasury Constant Maturity Rate + 3.60%),
4.00%, 12/10/2025 ^(a),(b)		9,860,000		9,933,950
(3-month USD LIBOR + 3.91%),
5.95%, 05/15/2025 ^(a),(b)		4,095,000		4,381,650
Citizens Financial Group, Inc.
(5-year Treasury Constant Maturity Rate + 3.22%),
4.00%, 10/06/2026 ^(a),(b)		2,699,000		2,699,000
(5-year Treasury Constant Maturity Rate + 5.31%),
5.65%, 10/06/2025 ^(a),(b),(c)		3,263,000		3,568,906
(3-month USD LIBOR + 3.16%),
6.38%, 04/06/2024 ^(a),(b)		3,008,000		3,139,600
Comerica, Inc.
(5-year Treasury Constant Maturity Rate + 5.29%),
5.63%, 07/01/2025 ^(a),(b)		655,000		713,950
Fifth Third Bancorp
(5-year Treasury Constant Maturity Rate + 4.22%),
4.50%, 09/30/2025 ^(a),(b),(c)		1,066,000		1,128,628
Goldman Sachs Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.92%),
3.65%, 08/10/2026 ^(a),(b)		2,095,000		2,074,050
(5-year Treasury Constant Maturity Rate + 2.97%),
3.80%, 05/10/2026 ^(a),(b)		1,448,000		1,440,760
(5-year Treasury Constant Maturity Rate + 2.95%),
4.13%, 11/10/2026 ^(a),(b)		5,500,000		5,590,406
(5-year Treasury Constant Maturity Rate + 3.62%),
5.50%, 08/10/2024 ^(a),(b)		6,136,000		6,473,480
HSBC Capital Funding Dollar 1 LP
(3-month USD LIBOR + 4.98%),
10.18%, 06/30/2030 ^(a),(b)		5,924,000		9,685,740
Huntington Bancshares, Inc.
(7-year Treasury Constant Maturity Rate + 4.05%),
4.45%, 10/15/2027 ^(a),(b)		2,271,000		2,398,744
(10-year Treasury Constant Maturity Rate + 4.95%),
5.63%, 07/15/2030 ^(a),(b)		7,376,000		8,417,860
JPMorgan Chase & Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.65%, 06/01/2026 ^(a),(b)		8,380,000		8,359,050
(3-month USD LIBOR + 3.30%),
6.00%, 08/01/2023 ^(a),(b)		4,512,000		4,703,760

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
JPMorgan Chase & Co. (continued)
(3-month USD LIBOR + 3.78%),
6.75%, 02/01/2024 ^(a),(b)	$	5,314,000	$	5,759,712
KeyCorp
(3-month USD LIBOR + 3.61%),
5.00%, 09/15/2026 ^(a),(b)		1,229,000		1,328,856
Lloyds Bank PLC
(3-month USD LIBOR + 11.76%),
12.00%, 12/16/2024 ^{(a),(b),(c),(d)}		4,559,000		4,612,340
M&T Bank Corp.
(5-year Treasury Constant Maturity Rate + 2.68%),
3.50%, 09/01/2026 ^(a),(b)		4,172,000		4,087,726
PNC Financial Services Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.60%),
3.40%, 09/15/2026 ^(a),(b)		2,820,000		2,775,557
SVB Financial Group
(5-year Treasury Constant Maturity Rate + 3.20%),
4.00%, 05/15/2026 ^(a),(b)		2,402,000		2,414,010
(10-year Treasury Constant Maturity Rate + 3.06%),
4.10%, 02/15/2031 ^(a),(b)		537,000		531,093
(5-year Treasury Constant Maturity Rate + 3.07%),
4.25%, 11/15/2026 ^(a),(b)		5,275,000		5,348,850
Truist Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.00%),
4.80%, 09/01/2024 ^(a),(b)		8,184,000		8,531,820
(5-year Treasury Constant Maturity Rate + 4.61%),
4.95%, 09/01/2025 ^(a),(b)		1,830,000		1,963,392
U.S. Bancorp
(5-year Treasury Constant Maturity Rate + 2.54%),
3.70%, 01/15/2027 ^(a),(b)		9,588,000		9,586,082
Wells Fargo & Co.
(5-year Treasury Constant Maturity Rate + 3.45%),
3.90%, 03/15/2026 ^(a),(b)		12,879,000		13,233,173
(3-month USD LIBOR + 3.99%),
5.88%, 06/15/2025 ^(a),(b)		5,627,000		6,147,498
			$	183,255,062

Diversified Financial Services — 10.67%
Ally Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.87%),
4.70%, 05/15/2026 ^(a),(b)		5,399,000		5,601,463
(7-year Treasury Constant Maturity Rate + 3.48%),
4.70%, 05/15/2028 ^(a),(b)		1,087,000		1,120,480
American Express Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.55%, 09/15/2026 ^(a),(b)		12,203,000		12,224,355
Capital One Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.16%),
3.95%, 09/01/2026 ^(a),(b)		5,157,000		5,182,785
Charles Schwab Corp.
(5-year Treasury Constant Maturity Rate + 3.17%),
4.00%, 06/01/2026 ^(a),(b)		11,049,000		11,269,980
(5-year Treasury Constant Maturity Rate + 4.97%),
5.38%, 06/01/2025 ^(a),(b)		4,912,000		5,354,080
Discover Financial Services
(5-year Treasury Constant Maturity Rate + 5.78%),
6.13%, 06/23/2025 ^(a),(b)		6,713,000		7,401,082
			$	48,154,225

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Electric — 11.46%
American Electric Power Co., Inc.
(5-year Treasury Constant Maturity Rate + 2.68%),
3.88%, 02/15/2062 ^(b)	$	3,692,000	$	3,748,059
CMS Energy Corp.
(5-year Treasury Constant Maturity Rate + 2.90%),
3.75%, 12/01/2050 ^(b)		3,552,000		3,489,840
(5-year Treasury Constant Maturity Rate + 4.12%),
4.75%, 06/01/2050 ^(b)		3,153,000		3,428,888
Dominion Energy, Inc.
(5-year Treasury Constant Maturity Rate + 2.99%),
4.65%, 12/15/2024 ^(a),(b)		14,607,000		15,227,797
Duke Energy Corp.
(5-year Treasury Constant Maturity Rate + 2.32%),
3.25%, 01/15/2082 ^(b)		3,310,000		3,226,253
(5-year Treasury Constant Maturity Rate + 3.39%),
4.88%, 09/16/2024 ^(a),(b)		9,924,000		10,296,150
Emera, Inc.
(3-month USD LIBOR + 5.44%),
6.75%, 06/15/2076 ^(b)		7,359,000		8,462,850
Southern Co.
(5-year Treasury Constant Maturity Rate + 2.92%),
3.75%, 09/15/2051 ^(b)		937,000		937,000
(5-year Treasury Constant Maturity Rate + 3.73%),
4.00%, 01/15/2051 ^(b)		2,862,000		2,926,395
			$	51,743,232

Gas — 1.47%
NiSource, Inc.
(5-year Treasury Constant Maturity Rate + 2.84%),
5.65%, 06/15/2023 ^(a),(b)		6,438,000		6,615,045

Hand/Machine Tools — 0.93%
Stanley Black & Decker, Inc.
(5-year Treasury Constant Maturity Rate + 2.66%),
4.00%, 03/15/2060 ^(b)		4,095,000		4,207,039

Insurance — 23.21%
Allstate Corp.
(3-month USD LIBOR + 2.94%),
5.75%, 08/15/2053 ^(b)		4,095,000		4,258,800
American International Group, Inc.
(3-month USD LIBOR + 2.87%),
5.75%, 04/01/2048 ^(b)		1,706,000		1,914,985
Argentum Netherlands BV for Swiss Re Ltd.
(3-month USD LIBOR + 3.78%),
5.63%, 08/15/2052 ^(b)		5,600,000		6,293,000
Argentum Netherlands BV for Zurich Insurance Co. Ltd.
(5-year Treasury Constant Maturity Rate + 3.27%),
5.13%, 06/01/2048 ^(b)		4,000,000		4,450,000
AXA SA
(3-month USD LIBOR + 2.26%),
6.38%, 12/14/2036 ^(a),(b),(d)		5,431,000		7,496,138
Cloverie PLC for Zurich Insurance Co. Ltd.
(3-month USD LIBOR + 4.92%),
5.63%, 06/24/2046 ^(b)		5,600,000		6,244,000
Equitable Holdings, Inc.
(5-year Treasury Constant Maturity Rate + 4.74%),
4.95%, 09/15/2025 ^(a),(b)		4,191,000		4,390,072
Liberty Mutual Group, Inc.
(5-year Treasury Constant Maturity Rate + 3.32%),
4.13%, 12/15/2051 ^(b),(d)		3,289,000		3,280,777

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Insurance (continued)
Meiji Yasuda Life Insurance Co.
(5-year Swap rate + 4.23%),
5.20%, 10/20/2045 ^(b),(d)	$	4,095,000	$	4,499,116
MetLife, Inc.
(5-year Treasury Constant Maturity Rate + 3.58%),
3.85%, 09/15/2025 ^(a),(b)		7,842,000		7,998,840
9.25%, 04/08/2068 ^(d)		5,971,000		8,839,700
Nippon Life Insurance Co.
(5-year Treasury Constant Maturity Rate + 2.65%),
2.75%, 01/21/2051 ^(b),(d)		5,379,000		5,271,420
(5-year Treasury Constant Maturity Rate + 2.60%),
2.90%, 09/16/2051 ^(b),(d)		3,070,000		3,035,882
Prudential Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.04%),
3.70%, 10/01/2050 ^(b)		10,745,000		10,869,510
(3-month USD LIBOR + 3.92%),
5.63%, 06/15/2043 ^(b)		6,396,000		6,655,091
Sumitomo Life Insurance Co.
(5-year Treasury Constant Maturity Rate + 2.75%),
3.38%, 04/15/2081 ^(b),(d)		4,958,000		5,181,110
(3-month USD LIBOR + 4.44%),
6.50%, 09/20/2073 ^(b),(d)		8,221,000		8,868,404
Voya Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.36%),
6.13%, 09/15/2023 ^(a),(b),(c)		4,095,000		4,256,630
Zurich Finance Ireland Designated Activity Co.
(5-year Treasury Constant Maturity Rate + 2.78%),
3.00%, 04/19/2051 ^(b)		1,000,000		970,966
			$	104,774,441

Oil & Gas — 1.31%
BP Capital Markets PLC
(5-year Treasury Constant Maturity Rate + 4.04%),
4.38%, 06/22/2025 ^(a),(b)		5,650,000		5,904,250

Pipelines — 5.10%
Enbridge, Inc.
(5-year Treasury Constant Maturity Rate + 5.31%),
5.75%, 07/15/2080 ^(b)		2,370,000		2,630,700
(3-month USD LIBOR + 3.89%),
6.00%, 01/15/2077 ^(b)		6,136,000		6,590,932
Enterprise Products Operating LLC
(3-month USD LIBOR + 3.03%),
5.25%, 08/16/2077 ^(b)		4,095,000		4,180,665
Transcanada Trust
(6-month Secured Overnight Financing Rate + 4.41%),
5.50%, 09/15/2079 ^(b)		8,995,000		9,602,162
			$	23,004,459

REITs — 0.88%
Scentre Group Trust 2
(5-year Treasury Constant Maturity Rate + 4.38%),
4.75%, 09/24/2080 ^(b),(d)		1,157,000		1,210,511
(5-year Treasury Constant Maturity Rate + 4.69%),
5.13%, 09/24/2080 ^(b),(d)		2,582,000		2,765,968
			$	3,976,479

Telecommunications — 1.29%
Vodafone Group PLC
(5-year Swap rate + 4.87%),
7.00%, 04/04/2079 ^(b)		4,819,000		5,828,473

See accompanying notes.


Schedule of Investments
Principal Spectrum Preferred Securities Active ETF
December 31, 2021 (unaudited)

	Principal
BONDS (continued)	Amount		Value
TOTAL BONDS		$	437,462,705
INVESTMENT COMPANIES — 4.24%	Shares Held		Value
Money Market Funds — 4.24%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(e),(f),(g),(h)}	7,334,728	$	7,334,728
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(h)	11,799,845		11,799,845
TOTAL INVESTMENT COMPANIES		$	19,134,573
Total Investments		$	456,597,278
Other Assets and Liabilities — (1.16%)			(5,218,996	)
Total Net Assets — 100.00%		$	451,378,282

^(a)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or floating rate in the future.
^(c)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $7,187,579 or 1.59% of net assets.
^(d)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $57,358,491 or 12.71% of net assets.
^(e)	Non-income producing security.
(f)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $7,334,728 or 1.62% of net assets.
^(g)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(h)	Current yield shown is as of period end.


Portfolio Summary (unaudited)
Sector					Percent
Financial					75.36	%
Utilities					12.93	%
Energy					6.41	%
Money Market Funds					4.24	%
Communications					1.29	%
Industrial					0.93	%
Other Assets and Liabilities					(1.16	)%
TOTAL NET ASSETS					100.00	%

			June 30, 2021		Purchases				Sales			December 31, 2021
Affiliated Securities			Value		Cost				Proceeds			Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	10,355,640	$	33,766,495			$	36,787,407		$	7,334,728
		$	10,355,640	$	33,766,495			$	36,787,407		$	7,334,728

									Realized Gain
					Realized				from			Change in
					Gain/Loss on				Capital Gain			Unrealized
			Income ^(a)		Investments				Distributions			Gain/Loss
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—		$		—		$	—	$	—
		$	—		$		—		$	—	$	—

^(a)	Amount excludes earnings from securities lending collateral.

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
December 31, 2021 (unaudited)

PREFERRED STOCKS — 12.38%		Shares Held		Value

Banks — 5.32%
Associated Banc-Corp.; Series F
5.63%, 09/15/2025 ^(a)		2,070		56,842
Bank of America Corp.; Series NN
4.38%, 11/03/2025 ^(a)		4,380		112,040
Fulton Financial Corp.; Series A
5.13%, 01/15/2026 ^(a)		9,200		241,500
JPMorgan Chase & Co.; Series DD
5.75%, 12/01/2023 ^(a)		1,261		33,896
JPMorgan Chase & Co.; Series EE
6.00%, 03/01/2024 ^(a)		1,642		44,745
Morgan Stanley; Series I
(3-month USD LIBOR + 3.71%),
6.38%, 10/15/2024 ^(a)		17,030		480,246
Synovus Financial Corp.; Series E
(5-year Treasury Constant Maturity Rate + 4.13%),
5.88%, 07/01/2024 ^(a)		11,500		310,500
			$	1,279,769

Insurance — 4.11%
Allstate Corp.; Series H
5.10%, 10/15/2024 ^(a)		11,500		311,880
American International Group, Inc.; Series A
5.85%, 03/15/2024 ^(a)		8,019		217,235
MetLife, Inc.; Series F
4.75%, 03/15/2025 ^(a)		17,250		460,230
			$	989,345

Telecommunications — 2.95%
AT&T, Inc.; Series A
5.00%, 02/18/2025 ^(a)		11,381		305,011
AT&T, Inc.; Series C
4.75%, 12/12/2024 ^(a)		15,395		404,272
			$	709,283
TOTAL PREFERRED STOCKS			$	2,978,397
		Principal
BONDS — 86.48%		Amount		Value

Banks — 70.64%
Bank of America Corp.
(3-month USD LIBOR + 3.90%),
6.10%, 03/17/2025 ^(a),(b)	$	230,000	$	249,263
(3-month USD LIBOR + 4.55%),
6.30%, 03/10/2026 ^(a),(b)		575,000		646,875
Bank of New York Mellon Corp.
(5-year Treasury Constant Maturity Rate + 3.35%),
3.70%, 03/20/2026 ^(a),(b)		230,000		235,175
(5-year Treasury Constant Maturity Rate + 4.36%),
4.70%, 09/20/2025 ^(a),(b)		575,000		613,381
Bank of Nova Scotia
(5-year Treasury Constant Maturity Rate + 4.55%),
4.90%, 06/04/2025 ^(a),(b)		575,000		616,149
Citigroup, Inc.
(5-year Treasury Constant Maturity Rate + 3.42%),
3.88%, 02/18/2026 ^(a),(b)		335,000		335,000
Citizens Financial Group, Inc.
(5-year Treasury Constant Maturity Rate + 5.31%),
5.65%, 10/06/2025 ^(a),(b)		575,000		628,906
Comerica, Inc.
(5-year Treasury Constant Maturity Rate + 5.29%),
5.63%, 07/01/2025 ^(a),(b)		575,000		626,750

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Banks (continued)
Credit Agricole SA
(5-year Swap rate + 4.90%),
7.88%, 01/23/2024 ^(a),(b),(c)	$	861,000	$	941,719
Credit Suisse Group AG
(5-year Treasury Constant Maturity Rate + 4.82%),
6.38%, 08/21/2026 ^{(a),(b),(c),(d)}		384,000		413,875
(5-year Swap rate + 5.11%),
7.13%, 07/29/2022 ^(a),(b),(c)		500,000		512,500
Fifth Third Bancorp
(5-year Treasury Constant Maturity Rate + 4.22%),
4.50%, 09/30/2025 ^(a),(b)		548,000		580,195
Goldman Sachs Group, Inc.
(5-year Treasury Constant Maturity Rate + 2.97%),
3.80%, 05/10/2026 ^(a),(b)		438,000		435,810
HSBC Holdings PLC
(5-year Swap rate + 4.37%),
6.38%, 03/30/2025 ^(a),(b),(c)		861,000		929,260
Huntington Bancshares, Inc.
(10-year Treasury Constant Maturity Rate + 4.95%),
5.63%, 07/15/2030 ^(a),(b)		575,000		656,219
ING Groep NV
(5-year Treasury Constant Maturity Rate + 4.34%),
5.75%, 11/16/2026 ^(a),(b),(c)		861,000		926,651
JPMorgan Chase & Co.
(5-year Treasury Constant Maturity Rate + 2.85%),
3.65%, 06/01/2026 ^(a),(b)		110,000		109,725
Lloyds Banking Group PLC
(5-year Swap rate + 4.50%),
7.50%, 09/27/2025 ^(a),(b),(c)		861,000		973,114
M&T Bank Corp.
(3-month USD LIBOR + 3.52%),
5.13%, 11/01/2026 ^(a),(b)		247,000		264,450
Natwest Group PLC
(5-year Swap rate + 5.72%),
8.00%, 08/10/2025 ^(a),(b),(c)		861,000		999,836
Nordea Bank Abp
(5-year Treasury Constant Maturity Rate + 4.11%),
6.63%, 03/26/2026 ^{(a),(b),(c),(d)}		861,000		978,311
Societe Generale SA
(5-year Swap rate + 4.98%),
7.88%, 12/18/2023 ^(a),(b),(c)		824,000		901,250
Standard Chartered PLC
(5-year Swap rate + 6.30%),
7.50%, 04/02/2022 ^(a),(b),(c)		824,000		835,330
SVB Financial Group
(5-year Treasury Constant Maturity Rate + 3.20%),
4.00%, 05/15/2026 ^(a),(b)		110,000		110,550
Truist Financial Corp.
(5-year Treasury Constant Maturity Rate + 4.61%),
4.95%, 09/01/2025 ^(a),(b)		575,000		616,913
U.S. Bancorp
(5-year Treasury Constant Maturity Rate + 2.54%),
3.70%, 01/15/2027 ^(a),(b)		209,000		208,958
UBS Group AG
(5-year Swap rate + 4.34%),
7.00%, 01/31/2024 ^(a),(b),(c)		861,000		928,373
Wells Fargo & Co.
(5-year Treasury Constant Maturity Rate + 3.45%),
3.90%, 03/15/2026 ^(a),(b)		328,000		337,020
(3-month USD LIBOR + 3.99%),
5.88%, 06/15/2025 ^(a),(b)		355,000		387,838
			$	16,999,396

See accompanying notes.


Schedule of Investments
Principal Spectrum Tax-Advantaged Dividend Active ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Diversified Financial Services — 8.45%
Ally Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.87%),
4.70%, 05/15/2026 ^(a),(b)	$	220,000	$	228,250
Capital One Financial Corp.
(5-year Treasury Constant Maturity Rate + 3.16%),
3.95%, 09/01/2026 ^(a),(b)		209,000		210,045
Charles Schwab Corp.
(5-year Treasury Constant Maturity Rate + 3.17%),
4.00%, 06/01/2026 ^(a),(b)		328,000		334,560
(5-year Treasury Constant Maturity Rate + 4.97%),
5.38%, 06/01/2025 ^(a),(b)		575,000		626,750
Discover Financial Services
(5-year Treasury Constant Maturity Rate + 5.78%),
6.13%, 06/23/2025 ^(a),(b)		575,000		633,937
			$	2,033,542

Electric — 4.47%
Dominion Energy, Inc.
(5-year Treasury Constant Maturity Rate + 2.99%),
4.65%, 12/15/2024 ^(a),(b)		460,000		479,550
Duke Energy Corp.
(5-year Treasury Constant Maturity Rate + 3.39%),
4.88%, 09/16/2024 ^(a),(b)		575,000		596,563
			$	1,076,113

Insurance — 2.92%
MetLife, Inc.
(5-year Treasury Constant Maturity Rate + 3.58%),
3.85%, 09/15/2025 ^(a),(b)		220,000		224,400
Voya Financial, Inc.
(5-year Treasury Constant Maturity Rate + 3.36%),
6.13%, 09/15/2023 ^(a),(b)		460,000		478,156
			$	702,556
TOTAL BONDS			$	20,811,607
INVESTMENT COMPANIES — 0.64%		Shares Held		Value

Money Market Fund — 0.64%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)		154,820	$	154,820
TOTAL INVESTMENT COMPANIES			$	154,820
Total Investments			$	23,944,824
Other Assets and Liabilities — 0.50%				119,414

Total Net Assets — 100.00%			$	24,064,238

^(a)	Perpetual security. Perpetual securities pay an indefinite stream of interest, but they may be called by the issuer at an earlier date. Date shown, if any, reflects the next call date or final legal maturity date. Rate shown is as of period end.
^(b)	Rate shown is as of period end. The rate may be a variable or floating rate or a fixed rate which may convert to a variable or floating rate in the future.
^(c)	Security is a contingent convertible security, ("CoCo"). CoCo's are hybrid debt securities that may convert to equity or have their principal written down upon occurrence of certain "triggers". At the end of the period, the value of these securities totaled $9,340,219 or 38.81% of net assets.
^(d)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $1,392,186 or 5.79% of net assets.
^(e)	Current yield shown is as of period end.

See accompanying notes.


Schedule of Investments
Principal Ultra-Short Active Income ETF
December 31, 2021 (unaudited)

		Principal
BONDS — 94.27%		Amount		Value

Asset-Backed Securities — 18.20%
AmeriCredit Automobile Receivables Trust 2021-1
0.28%, 06/18/2024	$	111,888	$	111,856
CPS Auto Receivables Trust 2021-B
0.37%, 03/17/2025 ^(a)		52,130		52,095
CPS Auto Receivables Trust 2021-C
0.33%, 07/15/2024 ^(a)		134,925		134,842
GreatAmerica Leasing Receivables Funding LLC
0.27%, 06/15/2023 ^(a)		45,578		45,528
JFIN CLO 2017-II Ltd.
(3-month USD LIBOR +0.99%),
1.20%, 09/20/2029 ^(a)		250,000		249,869
Madison Park Funding Ltd.2015-18A
(3-month USD LIBOR + 0.94%),
1.06%, 10/21/2030 ^(a)		250,000		249,819
Navient Private Education Loan Trust 2018-BA
1.69%, 05/15/2069 ^(a)		114,124		114,198
Navient Private Education Refi Loan Trust 2021-F
1.11%, 02/18/2070 ^(a)		96,325		94,687
Santander Drive Auto Receivables Trust 2021-1
0.29%, 11/15/2023		4,351		4,351
SMB Private Education Loan Trust 2015-B
(1-month USD LIBOR + 1.20%),
1.31%, 07/15/2027 ^(a)		22,718		22,739
Trafigura Securitisation Finance PLC
(1-month USD LIBOR + 0.53%),
0.64%, 01/15/2025 ^(a)		250,000		249,306
Westlake Automobile Receivables Trust 2020-2A
0.93%, 02/15/2024 ^(a)		55,977		56,033
World Omni Auto Receivables Trust 2021-A
0.17%, 02/15/2024		26,159		26,149
World Omni Select Auto Trust 2021-A
0.29%, 02/18/2025		150,000		149,584
			$	1,561,056

Banks — 27.26%
Bank of New York Mellon Corp.
(3-month Secured Overnight Financing Rate + 0.26%),
0.31%, 04/26/2024		250,000		249,877
Citigroup, Inc.
(3-month USD LIBOR + 1.43%),
1.60%, 09/01/2023		250,000		251,870
Fifth Third Bancorp
2.60%, 06/15/2022		279,000		281,171
Goldman Sachs Group, Inc.
(3-month Secured Overnight Financing Rate + 0.54%),
0.59%, 11/17/2023		250,000		250,023
Morgan Stanley
(3-month Secured Overnight Financing Rate + 0.70%),
0.75%, 01/20/2023		200,000		200,031
MUFG Union Bank NA
(3-month Secured Overnight Financing Rate + 0.71%),
0.76%, 12/09/2022		300,000		301,306
Royal Bank of Canada
(3-month Secured Overnight Financing Rate + 0.36%),
0.41%, 07/29/2024		250,000		250,130
Toronto-Dominion Bank
(3-month Secured Overnight Financing Rate + 0.24%),
0.29%, 01/06/2023		200,000		200,118
Truist Bank
2.45%, 08/01/2022 ^(b)		350,000		353,564
			$	2,338,090

See accompanying notes.

101


Schedule of Investments
Principal Ultra-Short Active Income ETF
December 31, 2021 (unaudited)

		Principal
BONDS (continued)		Amount		Value

Beverages — 2.28%
JDE Peet's NV
0.80%, 09/24/2024 ^(a)	$	200,000	$	195,968

Biotechnology — 2.18%
Gilead Sciences, Inc.
0.75%, 09/29/2023		188,000		187,208

Chemicals — 2.35%
Westlake Chemical Corp.
3.60%, 07/15/2022		200,000		201,637

Diversified Financial Services — 1.75%
AerCap Ireland Capital DAC/AerCap Global Aviation Trust
(3-month Secured Overnight Financing Rate + 0.68%),
0.73%, 09/29/2023		150,000		150,026

Electric — 8.12%
Black Hills Corp.
1.04%, 08/23/2024		250,000		246,876
Dominion Energy, Inc.
(3-month USD LIBOR + 0.53%),
0.73%, 09/15/2023		150,000		149,866
Florida Power & Light Co.
(3-month Secured Overnight Financing Rate + 0.25%),
0.30%, 05/10/2023		100,000		99,711
NextEra Energy Capital Holdings, Inc.
(6-month Secured Overnight Financing Rate + 0.40%),
0.45%, 11/03/2023		200,000		200,024
			$	696,477

Food — 2.87%
Nestle Holdings, Inc.
0.61%, 09/14/2024 ^(a)		250,000		246,418

Healthcare — Products — 2.89%
PerkinElmer, Inc.
0.55%, 09/15/2023		250,000		247,881

Healthcare — Services — 2.90%
Humana, Inc.
0.65%, 08/03/2023		250,000		248,702

Household Products/Wares — 2.87%
Avery Dennison Corp.
0.85%, 08/15/2024		250,000		246,341

Insurance — 2.92%
Metropolitan Life Global Funding I
0.90%, 06/08/2023 ^(a)		250,000		250,683

Miscellaneous Manufacture — 2.93%
Siemens Financieringsmaatschappij NV
(3-month Secured Overnight Financing Rate + 0.43%),
0.48%, 03/11/2024 ^(a)		250,000		251,009

Oil & Gas — 4.77%
Suncor Energy, Inc.
2.80%, 05/15/2023		400,000		409,212

Pipelines — 3.07%
ONEOK Partners LP
5.00%, 09/15/2023		250,000		263,270

Telecommunications — 6.91%
AT&T, Inc.
2.63%, 12/01/2022		221,000		223,777

See accompanying notes.

102


Schedule of Investments
Principal Ultra-Short Active Income ETF
December 31, 2021 (unaudited)

			Principal
BONDS (continued)			Amount		Value
Telecommunications (continued)
NTT Finance Corp.
0.37%, 03/03/2023 ^(a)		$	200,000	$	199,168
Sprint Spectrum Co. LLC/Sprint Spectrum Co. II LLC/Sprint Spectrum Co. III
LLC
4.74%, 09/20/2029 ^(a)			162,500		170,008
				$	592,953
TOTAL BONDS				$	8,086,931
U.S. GOVERNMENT & GOVERNMENT AGENCY OBLIGATIONS —			Principal
2.33	%		Amount		Value
Sovereign — 2.33%
U.S. Treasury Bill
0.04%, 03/10/2022 ^(c)		$	200,000	$	199,984
TOTAL U.S. GOVERNMENT & GOVERNMENT AGENCY OBLIGATIONS				$	199,984
INVESTMENT COMPANIES — 3.33%			Shares Held		Value
Money Market Funds — 3.33%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(d),(e),(f),(g)}			4,170	$	4,170
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(g)			281,227		281,227
TOTAL INVESTMENT COMPANIES				$	285,397
Total Investments				$	8,572,312
Other Assets and Liabilities — 0.07%					6,213
Total Net Assets — 100.00%				$	8,578,525

^(a)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities totaled $2,582,370 or 30.10% of net assets.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $4,081 or 0.05% of net assets.
^(c)	Discount Rate.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $4,170 or less than 0.05% of net assets.
(f)	Non-income producing security.
^(g)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Financial	31.93	%
Consumer, Non-cyclical	16.00	%
Asset-Backed Securities	18.20	%
Utilities	8.12	%
Energy	7.84	%
Communications	6.91	%
Money Market Funds	3.33	%
Industrial	2.92	%
Basic Materials	2.35	%
Government	2.33	%
Other Assets and Liabilities	0.07	%
TOTAL NET ASSETS	100.00	%

See accompanying notes.

103


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.74%	Shares Held		Value

Advertising — 0.17%
Interpublic Group of Cos., Inc.	3,852	$	144,258
Omnicom Group, Inc.	1,130		82,795
		$	227,053

Aerospace & Defense — 0.87%
General Dynamics Corp.	1,690		352,314
Howmet Aerospace, Inc.	2,511		79,925
L3Harris Technologies, Inc.	569		121,334
Lockheed Martin Corp.	900		319,869
Northrop Grumman Corp.	687		265,917
		$	1,139,359

Agriculture — 0.53%
Altria Group, Inc.	6,587		312,158
Archer-Daniels-Midland Co.	1,845		124,704
Philip Morris International, Inc.	2,682		254,790
		$	691,652

Airlines — 0.05%
American Airlines Group, Inc. ^(a)	3,871		69,523

Apparel — 0.77%
NIKE, Inc., Class B	3,223		537,177
PVH Corp.	687		73,269
Ralph Lauren Corp.	634		75,357
Tapestry, Inc.	3,479		141,247
Under Armour, Inc., Class A ^(a)	3,354		71,071
Under Armour, Inc., Class C ^(a)	6,740		121,590
		$	1,019,711

Auto Manufacturers — 2.70%
Cummins, Inc.	845		184,328
Ford Motor Co.	8,762		181,987
General Motors Co. ^(a)	5,094		298,661
PACCAR, Inc.	1,284		113,326
Tesla, Inc. ^(a)	2,634		2,783,559
		$	3,561,861

Auto Parts & Equipment — 0.09%
Aptiv PLC ^(a)	702		115,795

Banks — 4.20%
Bank of America Corp.	10,199		453,754
Bank of New York Mellon Corp.	2,086		121,155
Citigroup, Inc.	2,923		176,520
Citizens Financial Group, Inc.	1,928		91,098
Comerica, Inc.	1,010		87,870
Fifth Third Bancorp	4,236		184,478
First Republic Bank	951		196,391
Goldman Sachs Group, Inc.	947		362,275
Huntington Bancshares, Inc.	5,932		91,472
JPMorgan Chase & Co.	9,734		1,541,379
KeyCorp	7,513		173,776
Morgan Stanley	3,965		389,204
Northern Trust Corp.	822		98,319
PNC Financial Services Group, Inc.	768		153,999
Regions Financial Corp.	7,660		166,988
State Street Corp.	1,127		104,811
SVB Financial Group ^(a)	304		206,185
Truist Financial Corp.	4,664		273,077
U.S. Bancorp	4,607		258,775
Wells Fargo & Co.	5,400		259,092

See accompanying notes.

105


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks (continued)
Zions Bancorp NA	2,315	$	146,215
		$	5,536,833

Beverages — 1.45%
Brown-Forman Corp., Class B	2,137		155,702
Coca-Cola Co.	10,968		649,415
Constellation Brands, Inc., Class A	933		234,155
Monster Beverage Corp. ^(a)	2,117		203,317
PepsiCo, Inc.	3,865		671,389
		$	1,913,978

Biotechnology — 1.16%
Amgen, Inc.	1,833		412,370
Bio-Rad Laboratories, Inc., Class A ^(a)	193		145,825
Corteva, Inc.	2,319		109,642
Gilead Sciences, Inc.	2,562		186,027
Illumina, Inc. ^(a)	302		114,893
Moderna, Inc. ^(a)	1,142		290,045
Regeneron Pharmaceuticals, Inc. ^(a)	416		262,713
		$	1,521,515

Building Materials — 0.74%
Carrier Global Corp.	3,894		211,211
Fortune Brands Home & Security, Inc.	681		72,799
Johnson Controls International PLC	3,435		279,300
Martin Marietta Materials, Inc.	454		199,996
Masco Corp.	1,505		105,681
Vulcan Materials Co.	499		103,582
		$	972,569

Chemicals — 1.27%
Air Products & Chemicals, Inc.	545		165,822
Albemarle Corp.	400		93,508
Celanese Corp.	445		74,787
Ecolab, Inc.	619		145,211
FMC Corp.	876		96,264
Linde PLC	1,546		535,581
Mosaic Co.	2,280		89,581
PPG Industries, Inc.	776		133,813
Sherwin-Williams Co.	954		335,960
		$	1,670,527

Commercial Services — 2.68%
Automatic Data Processing, Inc.	2,323		572,805
Cintas Corp.	497		220,255
Equifax, Inc.	674		197,340
FleetCor Technologies, Inc. ^(a)	271		60,661
Gartner, Inc. ^(a)	525		175,518
Global Payments, Inc.	600		81,108
IHS Markit Ltd.	2,774		368,720
MarketAxess Holdings, Inc.	151		62,102
Moody's Corp.	688		268,719
Nielsen Holdings PLC	3,765		77,220
PayPal Holdings, Inc. ^(a)	2,908		548,391
Quanta Services, Inc.	705		80,835
Robert Half International, Inc.	781		87,097
Rollins, Inc.	1,566		53,573
S&P Global, Inc.	804		379,432
United Rentals, Inc. ^(a)	261		86,728
Verisk Analytics, Inc.	931		212,948
		$	3,533,452

See accompanying notes.

106


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Computers — 8.71%
Accenture PLC, Class A	2,617	$	1,084,877
Apple, Inc.	50,839		9,027,481
Cognizant Technology Solutions Corp., Class A	2,716		240,964
DXC Technology Co. ^(a)	2,174		69,981
Fortinet, Inc. ^(a)	644		231,454
Hewlett Packard Enterprise Co.	6,333		99,871
HP, Inc.	3,602		135,687
International Business Machines Corp.	1,654		221,074
Kyndryl Holdings, Inc. ^(a)	324		5,864
Leidos Holdings, Inc.	690		61,341
NetApp, Inc.	960		88,310
Seagate Technology Holdings PLC	1,002		113,206
Western Digital Corp. ^(a)	1,483		96,707
		$	11,476,817

Distribution/Wholesale — 0.74%
Copart, Inc. ^(a)	1,290		195,590
Fastenal Co.	3,491		223,634
LKQ Corp.	2,809		168,624
Pool Corp.	327		185,082
WW Grainger, Inc.	397		205,741
		$	978,671

Diversified Financial Services — 3.80%
American Express Co.	1,933		316,239
Ameriprise Financial, Inc.	364		109,804
BlackRock, Inc.	675		618,003
Capital One Financial Corp.	1,583		229,677
Cboe Global Markets, Inc.	654		85,282
Charles Schwab Corp.	4,510		379,291
CME Group, Inc.	810		185,053
Discover Financial Services	1,495		172,762
Franklin Resources, Inc.	2,438		81,649
Intercontinental Exchange, Inc.	2,261		309,237
Invesco Ltd.	3,062		70,487
Mastercard, Inc., Class A	1,142		410,343
Nasdaq, Inc.	1,318		276,793
Raymond James Financial, Inc.	1,656		166,262
Synchrony Financial	3,484		161,623
T Rowe Price Group, Inc.	1,604		315,411
Visa, Inc., Class A	4,821		1,044,759
Western Union Co.	3,872		69,076
		$	5,001,751

Electric — 2.67%
Alliant Energy Corp.	1,510		92,820
Ameren Corp.	1,130		100,581
American Electric Power Co., Inc.	1,466		130,430
CenterPoint Energy, Inc.	6,798		189,732
CMS Energy Corp.	2,589		168,415
Consolidated Edison, Inc.	1,380		117,742
Dominion Energy, Inc.	1,960		153,978
DTE Energy Co.	847		101,250
Duke Energy Corp.	1,687		176,966
Edison International	1,664		113,568
Entergy Corp.	917		103,300
Evergy, Inc.	3,681		252,553
Eversource Energy	1,258		114,453
Exelon Corp.	4,940		285,334
FirstEnergy Corp.	4,915		204,415
NextEra Energy, Inc.	3,361		313,783

See accompanying notes.

107


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Electric (continued)
NRG Energy, Inc.	1,830	$	78,836
Pinnacle West Capital Corp.	1,071		75,602
PPL Corp.	3,354		100,821
Public Service Enterprise Group, Inc.	1,767		117,912
Sempra Energy	938		124,079
Southern Co.	2,425		166,307
WEC Energy Group, Inc.	1,148		111,436
Xcel Energy, Inc.	1,771		119,897
		$	3,514,210

Electrical Components & Equipment — 0.54%
AMETEK, Inc.	1,431		210,414
Emerson Electric Co.	3,852		358,121
Generac Holdings, Inc. ^(a)	386		135,841
		$	704,376

Electronics — 2.08%
Agilent Technologies, Inc.	2,045		326,484
Allegion PLC	1,045		138,400
Amphenol Corp., Class A	2,877		251,622
Fortive Corp.	1,382		105,433
Garmin Ltd.	1,576		214,604
Honeywell International, Inc.	1,198		249,795
Keysight Technologies, Inc. ^(a)	1,627		335,992
Mettler-Toledo International, Inc. ^(a)	194		329,259
TE Connectivity Ltd.	2,345		378,342
Trimble, Inc. ^(a)	1,805		157,378
Waters Corp. ^(a)	663		247,034
		$	2,734,343

Energy — Alternate Sources — 0.08%
Enphase Energy, Inc. ^(a)	561		102,629

Engineering & Construction — 0.19%
Jacobs Engineering Group, Inc.	1,797		250,196

Entertainment — 0.14%
Caesars Entertainment, Inc. ^(a)	815		76,227
Live Nation Entertainment, Inc. ^(a)	859		102,814
		$	179,041

Environmental Control — 0.41%
Pentair PLC	2,132		155,700
Republic Services, Inc.	810		112,954
Waste Management, Inc.	1,644		274,384
		$	543,038

Food — 1.25%
Campbell Soup Co.	1,864		81,009
Conagra Brands, Inc.	4,641		158,490
General Mills, Inc.	3,319		223,634
Hershey Co.	1,012		195,792
Hormel Foods Corp.	2,026		98,889
J M Smucker Co.	699		94,938
Kellogg Co.	1,404		90,446
Kraft Heinz Co.	2,727		97,899
Kroger Co.	2,348		106,271
McCormick & Co., Inc.	1,963		189,645
Mondelez International, Inc., Class A	2,917		193,426
Tyson Foods, Inc., Class A	1,266		110,345
		$	1,640,784

See accompanying notes.

108


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Forest Products & Paper — 0.12%
International Paper Co.	3,253	$	152,826
Sylvamo Corp. ^(a)	299		8,339
		$	161,165

Gas — 0.14%
Atmos Energy Corp.	937		98,169
NiSource, Inc.	3,319		91,638
		$	189,807

Hand/Machine Tools — 0.25%
Snap-on, Inc.	658		141,720
Stanley Black & Decker, Inc.	1,009		190,318
		$	332,038

Healthcare — Products — 4.26%
Abbott Laboratories	5,024		707,078
Align Technology, Inc. ^(a)	310		203,726
Baxter International, Inc.	1,483		127,301
Bio-Techne Corp.	161		83,292
Boston Scientific Corp. ^(a)	3,332		141,543
Cooper Cos., Inc.	384		160,873
Danaher Corp.	2,613		859,703
Edwards Lifesciences Corp. ^(a)	3,546		459,384
Hologic, Inc. ^(a)	897		68,674
IDEXX Laboratories, Inc. ^(a)	335		220,584
Intuitive Surgical, Inc. ^(a)	1,037		372,594
Medtronic PLC	2,246		232,349
PerkinElmer, Inc.	860		172,912
ResMed, Inc.	1,131		294,603
STERIS PLC	431		104,910
Stryker Corp.	1,183		316,358
Teleflex, Inc.	174		57,155
Thermo Fisher Scientific, Inc.	1,082		721,954
West Pharmaceutical Services, Inc.	649		304,387
		$	5,609,380

Healthcare — Services — 2.99%
Anthem, Inc.	779		361,098
Catalent, Inc. ^(a)	1,166		149,283
Charles River Laboratories International, Inc. ^(a)	575		216,648
DaVita, Inc. ^(a)	1,259		143,224
HCA Healthcare, Inc.	947		243,303
Humana, Inc.	331		153,538
IQVIA Holdings, Inc. ^(a)	1,317		371,578
Laboratory Corp. of America Holdings ^(a)	945		296,928
Quest Diagnostics, Inc.	1,054		182,353
UnitedHealth Group, Inc.	3,529		1,772,052
Universal Health Services, Inc., Class B	418		54,198
		$	3,944,203

Home Builders — 0.26%
DR Horton, Inc.	892		96,737
Lennar Corp., Class A	764		88,746
NVR, Inc. ^(a)	13		76,815
PulteGroup, Inc.	1,328		75,909
		$	338,207

Home Furnishings — 0.09%
Leggett & Platt, Inc.	1,231		50,668
Whirlpool Corp.	308		72,275
		$	122,943

See accompanying notes.

109


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Household Products — 1.43%
Colgate-Palmolive Co.	3,441	$	293,655
Estee Lauder Cos., Inc., Class A	1,316		487,183
Procter & Gamble Co.	6,740		1,102,529
		$	1,883,367

Household Products/Wares — 0.57%
Avery Dennison Corp.	1,123		243,208
Church & Dwight Co., Inc.	1,965		201,412
Clorox Co.	1,003		174,883
Kimberly-Clark Corp.	943		134,774
		$	754,277

Housewares — 0.05%
Newell Brands, Inc.	3,187		69,604

Insurance — 4.31%
Aflac, Inc.	5,541		323,539
Allstate Corp.	2,377		279,654
American International Group, Inc.	2,072		117,814
Aon PLC	1,348		405,155
Arthur J Gallagher & Co.	1,235		209,542
Assurant, Inc.	507		79,021
Berkshire Hathaway, Inc., Class B ^(a)	5,421		1,620,879
Brown & Brown, Inc.	2,584		181,604
Chubb Ltd.	2,465		476,509
Cincinnati Financial Corp.	1,317		150,046
Everest Re Group Ltd.	232		63,549
Globe Life, Inc.	1,537		144,048
Hartford Financial Services Group, Inc.	1,326		91,547
Lincoln National Corp.	1,178		80,410
Loews Corp.	1,485		85,774
Marsh & McLennan Cos., Inc.	1,883		327,303
MetLife, Inc.	1,814		113,357
Progressive Corp.	2,607		267,609
Prudential Financial, Inc.	1,038		112,353
Travelers Cos., Inc.	1,996		312,234
Willis Towers Watson PLC	340		80,747
WR Berkley Corp.	1,939		159,754
		$	5,682,448

Internet — 11.08%
Alphabet, Inc., Class A ^(a)	975		2,824,614
Alphabet, Inc., Class C ^(a)	911		2,636,060
Amazon.com, Inc. ^(a)	1,414		4,714,757
CDW Corp.	1,420		290,788
eBay, Inc.	1,556		103,474
Etsy, Inc. ^(a)	783		171,430
Expedia Group, Inc. ^(a)	547		98,854
F5 Networks, Inc. ^(a)	398		97,394
Meta Platforms, Inc., Class A ^(a)	7,741		2,603,685
Netflix, Inc. ^(a)	1,445		870,526
Twitter, Inc. ^(a)	1,787		77,234
VeriSign, Inc. ^(a)	435		110,412
		$	14,599,228

Iron & Steel — 0.08%
Nucor Corp.	964		110,041

Leisure Time — 0.10%
Carnival Corp. ^(a)	3,520		70,822
Norwegian Cruise Line Holdings Ltd. ^(a)	2,851		59,130
		$	129,952

See accompanying notes.

110


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Lodging — 0.07%
MGM Resorts International	1,908	$	85,631

Machinery — Diversified — 1.15%
Deere & Co.	885		303,458
Dover Corp.	1,148		208,477
IDEX Corp.	712		168,260
Ingersoll Rand, Inc.	1,662		102,828
Otis Worldwide Corp.	2,544		221,506
Rockwell Automation, Inc.	983		342,919
Xylem, Inc.	1,417		169,927
		$	1,517,375

Media — 0.66%
Charter Communications, Inc., Class A ^(a)	253		164,949
Comcast Corp., Class A	7,116		358,148
Fox Corp., Class A	1,628		60,073
Fox Corp., Class B	1,562		53,530
News Corp., Class A	3,215		71,727
ViacomCBS, Inc., Class B	1,852		55,893
Walt Disney Co. ^(a)	692		107,184
		$	871,504

Mining — 0.11%
Freeport-McMoRan, Inc.	3,537		147,599

Miscellaneous Manufacture — 1.23%
3M Co.	1,947		345,846
AO Smith Corp.	914		78,467
Eaton Corp. PLC	1,760		304,163
General Electric Co.	1,721		162,583
Illinois Tool Works, Inc.	1,188		293,198
Parker-Hannifin Corp.	304		96,708
Textron, Inc.	1,169		90,247
Trane Technologies PLC	1,263		255,164
		$	1,626,376

Office & Business Equipment — 0.14%
Zebra Technologies Corp. ^(a)	309		183,917

Oil & Gas — 1.03%
ConocoPhillips	2,362		170,489
Devon Energy Corp.	2,690		118,494
Diamondback Energy, Inc.	942		101,595
EOG Resources, Inc.	1,449		128,715
Exxon Mobil Corp.	5,289		323,634
Hess Corp.	1,173		86,837
Marathon Oil Corp.	6,106		100,261
Marathon Petroleum Corp.	1,717		109,871
Occidental Petroleum Corp.	3,293		95,464
Pioneer Natural Resources Co.	650		118,222
		$	1,353,582

Oil & Gas Services — 0.08%
Schlumberger NV	3,705		110,965

Packaging & Containers — 0.47%
Amcor PLC	13,468		161,751
Ball Corp.	2,001		192,636
Packaging Corp. of America	586		79,784
Sealed Air Corp.	2,707		182,641
		$	616,812

Pharmaceuticals — 4.09%
AbbVie, Inc.	5,091		689,321

See accompanying notes.

111


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Pharmaceuticals (continued)
AmerisourceBergen Corp.	746	$	99,136
Becton Dickinson & Co.	1,115		280,400
Bristol-Myers Squibb Co.	3,977		247,966
Cardinal Health, Inc.	1,263		65,032
Cigna Corp.	584		134,104
CVS Health Corp.	4,582		472,679
Eli Lilly & Co.	1,055		291,412
Johnson & Johnson	7,627		1,304,751
McKesson Corp.	532		132,239
Merck & Co., Inc.	4,190		321,122
Pfizer, Inc.	15,931		940,726
Zoetis, Inc.	1,648		402,161
		$	5,381,049

Pipelines — 0.07%
ONEOK, Inc.	1,610		94,604

Real Estate — 0.09%
CBRE Group, Inc., Class A ^(a)	1,038		112,633

REITs — 3.22%
Alexandria Real Estate Equities, Inc.	912		203,339
American Tower Corp.	1,434		419,445
AvalonBay Communities, Inc.	910		229,857
Crown Castle International Corp.	1,612		336,489
Digital Realty Trust, Inc.	796		140,789
Duke Realty Corp.	3,590		235,648
Equinix, Inc.	197		166,630
Equity Residential	1,147		103,803
Essex Property Trust, Inc.	267		94,045
Extra Space Storage, Inc.	1,484		336,467
Federal Realty Investment Trust	635		86,563
Healthpeak Properties, Inc.	2,652		95,711
Iron Mountain, Inc.	3,207		167,822
Kimco Realty Corp.	3,697		91,131
Mid-America Apartment Communities, Inc.	965		221,410
Orion Office REIT, Inc. ^(a)	172		3,211
Prologis, Inc.	1,480		249,173
Public Storage	1,102		412,765
Realty Income Corp.	1,506		107,815
Regency Centers Corp.	1,132		85,296
SBA Communications Corp.	327		127,210
Simon Property Group, Inc.	820		131,011
UDR, Inc.	1,525		91,485
Welltower, Inc.	1,202		103,096
		$	4,240,211

Retail — 5.01%
Advance Auto Parts, Inc.	406		97,391
AutoZone, Inc. ^(a)	116		243,181
Bath & Body Works, Inc.	1,263		88,145
Best Buy Co., Inc.	689		70,002
CarMax, Inc. ^(a)	507		66,027
Chipotle Mexican Grill, Inc. ^(a)	119		208,042
Costco Wholesale Corp.	1,835		1,041,729
Darden Restaurants, Inc.	554		83,455
Dollar General Corp.	1,071		252,574
Domino's Pizza, Inc.	313		176,635
Gap, Inc.	3,021		53,321
Genuine Parts Co.	1,281		179,596
Home Depot, Inc.	2,998		1,244,200
Lowe's Cos., Inc.	931		240,645
McDonald's Corp.	1,232		330,262
O'Reilly Automotive, Inc. ^(a)	343		242,237

See accompanying notes.

112


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
Starbucks Corp.	2,114	$	247,275
Target Corp.	2,362		546,661
Tractor Supply Co.	780		186,108
Ulta Beauty, Inc. ^(a)	413		170,296
Walmart, Inc.	4,045		585,271
Yum! Brands, Inc.	1,753		243,422
		$	6,596,475

Savings & Loans — 0.06%
People's United Financial, Inc.	4,502		80,226

Semiconductors — 5.00%
Advanced Micro Devices, Inc. ^(a)	3,465		498,613
Analog Devices, Inc.	1,707		300,039
Applied Materials, Inc.	2,603		409,608
Broadcom, Inc.	507		337,363
Intel Corp.	4,873		250,960
KLA Corp.	612		263,227
Lam Research Corp.	472		339,439
Microchip Technology, Inc.	1,352		117,705
Monolithic Power Systems, Inc.	322		158,852
NVIDIA Corp.	8,090		2,379,350
NXP Semiconductors NV	574		130,746
Qorvo, Inc. ^(a)	508		79,446
QUALCOMM, Inc.	1,472		269,185
Skyworks Solutions, Inc.	450		69,813
Teradyne, Inc.	1,313		214,715
Texas Instruments, Inc.	2,687		506,419
Xilinx, Inc.	1,227		260,161
		$	6,585,641

Shipbuilding — 0.10%
Huntington Ingalls Industries, Inc.	692		129,224

Software — 10.36%
Activision Blizzard, Inc.	1,423		94,672
Adobe, Inc. ^(a)	1,284		728,105
Akamai Technologies, Inc. ^(a)	1,451		169,825
ANSYS, Inc. ^(a)	233		93,461
Autodesk, Inc. ^(a)	444		124,848
Broadridge Financial Solutions, Inc.	958		175,142
Cadence Design Systems, Inc. ^(a)	1,259		234,615
Ceridian HCM Holding, Inc. ^(a)	731		76,360
Cerner Corp.	2,281		211,836
Electronic Arts, Inc.	891		117,523
Fidelity National Information Services, Inc.	1,345		146,807
Fiserv, Inc. ^(a)	1,382		143,438
Intuit, Inc.	735		472,767
Jack Henry & Associates, Inc.	868		144,947
Microsoft Corp.	24,327		8,181,657
MSCI, Inc.	552		338,205
Oracle Corp.	7,516		655,470
Paychex, Inc.	2,717		370,870
Paycom Software, Inc. ^(a)	316		131,200
PTC, Inc. ^(a)	651		78,869
Roper Technologies, Inc.	499		245,438
salesforce.com, Inc. ^(a)	1,125		285,896
Synopsys, Inc. ^(a)	666		245,421
Take-Two Interactive Software, Inc. ^(a)	457		81,218
Tyler Technologies, Inc. ^(a)	181		97,369
		$	13,645,959

See accompanying notes.

113


Schedule of Investments
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Telecommunications — 2.01%
Arista Networks, Inc. ^(a)	1,760	$	253,000
AT&T, Inc.	11,691		287,598
Cisco Systems, Inc.	17,078		1,082,233
Corning, Inc.	4,864		181,087
Juniper Networks, Inc.	2,816		100,559
Motorola Solutions, Inc.	951		258,387
T-Mobile US, Inc. ^(a)	1,270		147,295
Verizon Communications, Inc.	6,590		342,416
		$	2,652,575

Textiles — 0.06%
Mohawk Industries, Inc. ^(a)	418		76,151
Transportation — 1.56%
CH Robinson Worldwide, Inc.	937		100,849
CSX Corp.	5,132		192,963
Expeditors International of Washington, Inc.	1,322		177,531
FedEx Corp.	461		119,233
JB Hunt Transport Services, Inc.	877		179,259
Norfolk Southern Corp.	587		174,756
Old Dominion Freight Line, Inc.	925		331,501
Union Pacific Corp.	1,173		295,514
United Parcel Service, Inc., Class B	2,278		488,267
		$	2,059,873

Water — 0.15%
American Water Works Co., Inc.	1,069		201,891
TOTAL COMMON STOCKS		$	131,396,617
INVESTMENT COMPANIES — 0.39%	Shares Held		Value
Money Market Fund — 0.39%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	514,794	$	514,794
TOTAL INVESTMENT COMPANIES		$	514,794
Total Investments		$	131,911,411
Other Assets and Liabilities — (0.13)%			(170,766	)
Total Net Assets — 100.00%		$	131,740,645

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Technology	24.21	%
Consumer, Non-cyclical	20.59	%
Financial	15.68	%
Communications	13.93	%
Consumer, Cyclical	10.13	%
Industrial	9.40	%
Utilities	2.96	%
Basic Materials	1.58	%
Energy	1.26	%
Money Market Fund	0.39	%
Other Assets and Liabilities	(0.13	)%
TOTAL NET ASSETS	100.00	%

See accompanying notes.

114


Schedule of Investments
Principal U.S. Mega-Cap ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.80%	Shares Held		Value
Auto Manufacturers — 1.56%
Tesla, Inc. ^(a)	27,554	$	29,118,516
Banks — 4.37%
Bank of America Corp.	504,594		22,449,387
JPMorgan Chase & Co.	233,677		37,002,753
Wells Fargo & Co.	461,593		22,147,232
		$	81,599,372

Beverages — 6.74%
Coca-Cola Co.	1,049,852		62,161,737
PepsiCo, Inc.	366,250		63,621,287
		$	125,783,024

Commercial Services — 0.83%
PayPal Holdings, Inc. ^(a)	82,475		15,553,135
Computers — 9.32%
Accenture PLC, Class A	119,404		49,498,928
Apple, Inc.	700,443		124,377,664
		$	173,876,592

Diversified Financial Services — 4.12%
Mastercard, Inc., Class A	110,065		39,548,556
Visa, Inc., Class A	171,721		37,213,658
		$	76,762,214

Healthcare — Products — 7.04%
Abbott Laboratories	323,318		45,503,776
Danaher Corp.	125,428		41,267,066
Thermo Fisher Scientific, Inc.	66,847		44,602,992
		$	131,373,834

Healthcare — Services — 2.63%
UnitedHealth Group, Inc.	97,763		49,090,713
Household Products — 3.46%
Procter & Gamble Co.	394,055		64,459,517
Insurance — 3.23%
Berkshire Hathaway, Inc., Class B ^(a)	201,818		60,343,582
Internet — 7.45%
Alphabet, Inc., Class A ^(a)	14,323		41,494,304
Amazon.com, Inc. ^(a)	11,622		38,751,699
Meta Platforms, Inc., Class A ^(a)	62,709		21,092,172
Netflix, Inc. ^(a)	62,554		37,685,032
		$	139,023,207

Media — 3.72%
Comcast Corp., Class A	683,526		34,401,864
Walt Disney Co. ^(a)	226,150		35,028,373
		$	69,430,237

Oil & Gas — 2.52%
Chevron Corp.	211,219		24,786,550
Exxon Mobil Corp.	364,216		22,286,377
		$	47,072,927

Pharmaceuticals — 11.81%
AbbVie, Inc.	354,111		47,946,630
Eli Lilly & Co.	165,306		45,660,823
Johnson & Johnson	341,062		58,345,476
Merck & Co., Inc.	509,481		39,046,624

See accompanying notes.

115


Schedule of Investments
Principal U.S. Mega-Cap ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Pharmaceuticals (continued)
Pfizer, Inc.	495,365	$	29,251,303
		$	220,250,856

Retail — 8.24%
Costco Wholesale Corp.	85,006		48,257,906
Home Depot, Inc.	116,363		48,291,809
Walmart, Inc.	395,165		57,176,424
		$	153,726,139

Semiconductors — 6.41%
Broadcom, Inc.	78,783		52,422,996
Intel Corp.	717,817		36,967,575
NVIDIA Corp.	102,871		30,255,390
		$	119,645,961

Software — 8.44%
Adobe, Inc. ^(a)	66,514		37,717,429
Microsoft Corp.	135,481		45,564,970
Oracle Corp.	438,191		38,214,637
salesforce.com, Inc. ^(a)	141,136		35,866,892
		$	157,363,928

Telecommunications — 7.91%
AT&T, Inc.	2,038,763		50,153,570
Cisco Systems, Inc.	701,674		44,465,081
Verizon Communications, Inc.	1,019,670		52,982,053
		$	147,600,704
TOTAL COMMON STOCKS		$	1,862,074,458
INVESTMENT COMPANIES — 0.23%	Shares Held		Value
Money Market Fund — 0.23%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	4,266,564	$	4,266,564
TOTAL INVESTMENT COMPANIES		$	4,266,564
Total Investments		$	1,866,341,022
Other Assets and Liabilities — (0.03)%			(640,142	)
Total Net Assets — 100.00%		$	1,865,700,880

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Consumer, Non-cyclical	32.51	%
Technology	24.17	%
Communications	19.08	%
Financial	11.72	%
Consumer, Cyclical	9.80	%
Energy	2.52	%
Money Market Fund	0.23	%
Other Assets and Liabilities	(0.03	)%
TOTAL NET ASSETS	100.00	%

See accompanying notes.

116


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.75%	Shares Held		Value

Aerospace & Defense — 1.09%
AAR Corp. ^(a)	162	$	6,323
Aerojet Rocketdyne Holdings, Inc.	513		23,988
AeroVironment, Inc. ^(a)	81		5,025
Barnes Group, Inc.	223		10,390
Moog, Inc., Class A	128		10,364
National Presto Industries, Inc.	70		5,742
Park Aerospace Corp.	392		5,174
Triumph Group, Inc. ^(a)	297		5,503
		$	72,509

Agriculture — 0.71%
Andersons, Inc.	341		13,200
Fresh Del Monte Produce, Inc.	408		11,261
Universal Corp.	161		8,842
Vector Group Ltd.	1,211		13,902
		$	47,205

Apparel — 0.94%
Fossil Group, Inc. ^(a)	339		3,488
Kontoor Brands, Inc.	302		15,478
Oxford Industries, Inc.	131		13,299
Steven Madden Ltd.	440		20,447
Wolverine World Wide, Inc.	342		9,853
		$	62,565

Auto Manufacturers — 0.13%
Wabash National Corp.	437		8,530

Auto Parts & Equipment — 1.51%
Dorman Products, Inc. ^(a)	202		22,828
Gentherm, Inc. ^(a)	336		29,198
Methode Electronics, Inc.	499		24,536
Motorcar Parts of America, Inc. ^(a)	207		3,534
Standard Motor Products, Inc.	273		14,303
Titan International, Inc. ^(a)	543		5,951
		$	100,350

Banks — 14.71%
Allegiance Bancshares, Inc.	304		12,832
Ameris Bancorp	379		18,829
BancFirst Corp.	221		15,594
Bancorp, Inc. ^(a)	487		12,326
BankUnited, Inc.	502		21,240
Banner Corp.	254		15,410
Cadence Bank	537		15,997
Central Pacific Financial Corp.	375		10,564
City Holding Co.	173		14,150
Columbia Banking System, Inc.	226		7,395
Community Bank System, Inc.	349		25,994
Customers Bancorp, Inc. ^(a)	265		17,323
CVB Financial Corp.	962		20,596
Dime Community Bancshares, Inc.	337		11,849
Eagle Bancorp, Inc.	396		23,103
FB Financial Corp.	344		15,074
First BanCorp	1,299		17,900
First Bancorp/Southern Pines	451		20,620
First Commonwealth Financial Corp.	1,465		23,572
First Financial Bancorp	648		15,798
First Hawaiian, Inc.	710		19,404
First Midwest Bancorp, Inc.	1,324		27,116
Flagstar Bancorp, Inc.	542		25,984
Great Western Bancorp, Inc.	417		14,161
Hanmi Financial Corp.	470		11,130

See accompanying notes.

117


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks (continued)
Heritage Financial Corp.	482	$	11,780
Hilltop Holdings, Inc.	717		25,195
HomeStreet, Inc.	302		15,704
Hope Bancorp, Inc.	937		13,783
Independent Bank Corp.	248		20,219
Independent Bank Group, Inc.	389		28,066
Lakeland Financial Corp.	326		26,126
Meta Financial Group, Inc.	248		14,796
National Bank Holdings Corp., Class A	347		15,247
NBT Bancorp, Inc.	422		16,255
OFG Bancorp	465		12,350
Old National Bancorp	1,204		21,816
Park National Corp.	127		17,438
Preferred Bank	261		18,737
Renasant Corp.	677		25,692
S&T Bancorp, Inc.	385		12,135
Seacoast Banking Corp. of Florida	410		14,510
ServisFirst Bancshares, Inc.	441		37,459
Simmons First National Corp., Class A	1,042		30,822
Southside Bancshares, Inc.	361		15,097
Tompkins Financial Corp.	157		13,122
Triumph Bancorp, Inc. ^(a)	163		19,410
TrustCo Bank Corp.	202		6,729
Trustmark Corp.	526		17,074
United Community Banks, Inc.	898		32,274
Veritex Holdings, Inc.	605		24,067
Walker & Dunlop, Inc.	163		24,593
Westamerica BanCorp	261		15,068
		$	979,525

Beverages — 1.04%
Celsius Holdings, Inc. ^(a)	103		7,681
Coca-Cola Consolidated, Inc.	57		35,294
MGP Ingredients, Inc.	252		21,417
National Beverage Corp.	107		4,850
		$	69,242

Biotechnology — 0.47%
Innoviva, Inc. ^(a)	764		13,179
Myriad Genetics, Inc. ^(a)	236		6,513
Organogenesis Holdings, Inc. ^(a)	653		6,034
Vericel Corp. ^(a)	149		5,856
		$	31,582

Building Materials — 1.96%
AAON, Inc.	293		23,273
Apogee Enterprises, Inc.	135		6,500
Boise Cascade Co.	135		9,612
Gibraltar Industries, Inc. ^(a)	148		9,869
Griffon Corp.	232		6,607
Patrick Industries, Inc.	167		13,475
PGT Innovations, Inc. ^(a)	670		15,068
SPX Corp. ^(a)	197		11,757
UFP Industries, Inc.	375		34,504
		$	130,665

Chemicals — 3.06%
AdvanSix, Inc.	281		13,277
American Vanguard Corp.	381		6,245
Balchem Corp.	110		18,546
Ferro Corp. ^(a)	748		16,329
GCP Applied Technologies, Inc. ^(a)	345		10,923

See accompanying notes.

118


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Chemicals (continued)
Hawkins, Inc.	134	$	5,286
HB Fuller Co.	343		27,783
Innospec, Inc.	115		10,389
Koppers Holdings, Inc. ^(a)	150		4,695
Kraton Corp. ^(a)	137		6,346
Quaker Chemical Corp.	89		20,539
Rogers Corp. ^(a)	102		27,846
Stepan Co.	162		20,135
Trinseo PLC	134		7,030
Unifi, Inc. ^(a)	357		8,264
		$	203,633

Coal — 0.13%
CONSOL Energy, Inc. ^(a)	191		4,338
SunCoke Energy, Inc.	690		4,547
		$	8,885

Commercial Services — 4.34%
ABM Industries, Inc.	468		19,118
Adtalem Global Education, Inc. ^(a)	245		7,242
Alarm.com Holdings, Inc. ^(a)	294		24,934
AMN Healthcare Services, Inc. ^(a)	384		46,975
CorVel Corp. ^(a)	117		24,336
Cross Country Healthcare, Inc. ^(a)	220		6,107
Deluxe Corp.	171		5,491
EVERTEC, Inc.	428		21,392
Forrester Research, Inc. ^(a)	211		12,392
Green Dot Corp., Class A ^(a)	226		8,190
Heidrick & Struggles International, Inc.	270		11,807
Korn Ferry	486		36,805
Medifast, Inc.	38		7,958
Monro, Inc.	158		9,207
Perdoceo Education Corp. ^(a)	624		7,338
Rent-A-Center, Inc.	329		15,805
Resources Connection, Inc.	386		6,886
Strategic Education, Inc.	121		6,999
TrueBlue, Inc. ^(a)	188		5,202
Viad Corp. ^(a)	109		4,664
		$	288,848

Computers — 1.67%
3D Systems Corp. ^(a)	337		7,259
ExlService Holdings, Inc. ^(a)	293		42,418
Insight Enterprises, Inc. ^(a)	333		35,498
TTEC Holdings, Inc.	228		20,645
Unisys Corp. ^(a)	254		5,225
		$	111,045

Distribution/Wholesale — 0.58%
G-III Apparel Group Ltd. ^(a)	386		10,669
Resideo Technologies, Inc. ^(a)	785		20,434
Veritiv Corp. ^(a)	60		7,354
		$	38,457

Diversified Financial Services — 3.18%
B Riley Financial, Inc.	172		15,284
Blucora, Inc. ^(a)	302		5,231
Brightsphere Investment Group, Inc.	553		14,157
Encore Capital Group, Inc. ^(a)	291		18,074
Enova International, Inc. ^(a)	339		13,885
EZCORP, Inc., Class A ^(a)	760		5,601
Greenhill & Co., Inc.	259		4,644

See accompanying notes.

119


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services (continued)
Mr Cooper Group, Inc. ^(a)	797	$	33,163
Piper Sandler Cos.	166		29,633
PRA Group, Inc. ^(a)	397		19,933
StoneX Group, Inc. ^(a)	197		12,066
Virtus Investment Partners, Inc.	79		23,471
WisdomTree Investments, Inc.	750		4,590
World Acceptance Corp. ^(a)	48		11,781
		$	211,513

Electric — 0.36%
Avista Corp.	291		12,365
Unitil Corp.	246		11,313
		$	23,678

Electrical Components & Equipment — 0.77%
Encore Wire Corp.	245		35,059
Insteel Industries, Inc.	255		10,152
Powell Industries, Inc.	211		6,222
		$	51,433

Electronics — 2.63%
Advanced Energy Industries, Inc.	103		9,379
Badger Meter, Inc.	284		30,263
Benchmark Electronics, Inc.	260		7,046
Brady Corp., Class A	368		19,835
Comtech Telecommunications Corp.	174		4,122
FARO Technologies, Inc. ^(a)	114		7,982
Knowles Corp. ^(a)	476		11,115
Mesa Laboratories, Inc.	27		8,859
OSI Systems, Inc. ^(a)	87		8,108
Plexus Corp. ^(a)	211		20,233
Sanmina Corp. ^(a)	487		20,191
TTM Technologies, Inc. ^(a)	646		9,625
Vicor Corp. ^(a)	146		18,539
		$	175,297

Energy — Alternate Sources — 0.10%
Green Plains, Inc. ^(a)	200		6,952

Engineering & Construction — 1.74%
Arcosa, Inc.	212		11,172
Comfort Systems USA, Inc.	263		26,021
Exponent, Inc.	412		48,093
Granite Construction, Inc.	167		6,463
MYR Group, Inc. ^(a)	218		24,100
		$	115,849

Entertainment — 0.08%
Monarch Casino & Resort, Inc. ^(a)	75		5,546

Environmental Control — 0.10%
U.S. Ecology, Inc. ^(a)	216		6,899

Food — 1.34%
B&G Foods, Inc.	229		7,037
Cal-Maine Foods, Inc.	220		8,138
Calavo Growers, Inc.	163		6,911
Chefs' Warehouse, Inc. ^(a)	163		5,428
J & J Snack Foods Corp.	65		10,267
John B Sanfilippo & Son, Inc.	82		7,393
Simply Good Foods Co. ^(a)	585		24,319
TreeHouse Foods, Inc. ^(a)	260		10,538

See accompanying notes.

120


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Food (continued)
United Natural Foods, Inc. ^(a)	193	$	9,472
		$	89,503

Food Service — 0.17%
Healthcare Services Group, Inc.	647		11,510

Forest Products & Paper — 0.44%
Glatfelter Corp.	434		7,465
Mercer International, Inc.	703		8,429
Neenah, Inc.	144		6,664
Schweitzer-Mauduit International, Inc.	216		6,458
		$	29,016

Gas — 0.72%
Chesapeake Utilities Corp.	139		20,268
Northwest Natural Holding Co.	304		14,829
South Jersey Industries, Inc.	486		12,694
		$	47,791

Hand/Machine Tools — 0.37%
Franklin Electric Co., Inc.	262		24,775

Healthcare — Products — 3.27%
AngioDynamics, Inc. ^(a)	205		5,654
Avanos Medical, Inc. ^(a)	266		9,222
BioLife Solutions, Inc. ^(a)	121		4,510
Cardiovascular Systems, Inc. ^(a)	237		4,451
CONMED Corp.	262		37,141
Cutera, Inc. ^(a)	97		4,008
Hanger, Inc. ^(a)	305		5,530
Inogen, Inc. ^(a)	107		3,638
Integer Holdings Corp. ^(a)	225		19,258
Lantheus Holdings, Inc. ^(a)	243		7,020
LeMaitre Vascular, Inc.	323		16,224
Meridian Bioscience, Inc. ^(a)	254		5,182
Merit Medical Systems, Inc. ^(a)	461		28,720
Natus Medical, Inc. ^(a)	270		6,407
Omnicell, Inc. ^(a)	233		42,042
Orthofix Medical, Inc. ^(a)	168		5,223
Surmodics, Inc. ^(a)	118		5,682
Tactile Systems Technology, Inc. ^(a)	109		2,074
Varex Imaging Corp. ^(a)	191		6,026
		$	218,012

Healthcare — Services — 2.37%
Addus HomeCare Corp. ^(a)	164		15,336
Community Health Systems, Inc. ^(a)	524		6,974
Ensign Group, Inc.	325		27,287
Fulgent Genetics, Inc. ^(a)	148		14,887
Joint Corp. ^(a)	111		7,292
Magellan Health, Inc. ^(a)	106		10,069
MEDNAX, Inc. ^(a)	270		7,347
ModivCare, Inc. ^(a)	40		5,932
Pennant Group, Inc. ^(a)	155		3,577
RadNet, Inc. ^(a)	396		11,923
Select Medical Holdings Corp.	955		28,077
Tivity Health, Inc. ^(a)	548		14,489
U.S. Physical Therapy, Inc.	52		4,969
		$	158,159

Home Builders — 1.83%
Cavco Industries, Inc. ^(a)	68		21,600
Century Communities, Inc.	213		17,421

See accompanying notes.

121


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Home Builders (continued)
Installed Building Products, Inc.	72	$	10,060
LCI Industries	168		26,186
LGI Homes, Inc. ^(a)	60		9,269
M/I Homes, Inc. ^(a)	110		6,840
MDC Holdings, Inc.	173		9,659
Meritage Homes Corp. ^(a)	99		12,084
Winnebago Industries, Inc.	113		8,466
		$	121,585

Home Furnishings — 0.66%
Daktronics, Inc. ^(a)	964		4,868
Ethan Allen Interiors, Inc.	607		15,958
iRobot Corp. ^(a)	94		6,193
Sleep Number Corp. ^(a)	154		11,796
Universal Electronics, Inc. ^(a)	128		5,216
		$	44,031

Household Products — 0.99%
Edgewell Personal Care Co.	457		20,889
elf Beauty, Inc. ^(a)	480		15,941
Inter Parfums, Inc.	270		28,863
		$	65,693

Household Products/Wares — 0.96%
Central Garden & Pet Co. ^(a)	213		11,210
Central Garden & Pet Co., Class A ^(a)	363		17,370
Quanex Building Products Corp.	520		12,886
WD-40 Co.	93		22,751
		$	64,217

Insurance — 2.27%
Ambac Financial Group, Inc. ^(a)	455		7,303
American Equity Investment Life Holding Co.	270		10,508
AMERISAFE, Inc.	230		12,381
Assured Guaranty Ltd.	200		10,040
Employers Holdings, Inc.	329		13,614
HCI Group, Inc.	42		3,509
Horace Mann Educators Corp.	385		14,899
NMI Holdings, Inc., Class A ^(a)	736		16,082
ProAssurance Corp.	239		6,047
Safety Insurance Group, Inc.	166		14,115
Selectquote, Inc. ^(a)	474		4,294
SiriusPoint Ltd. ^(a)	722		5,870
Stewart Information Services Corp.	247		19,693
Universal Insurance Holdings, Inc.	757		12,869
		$	151,224

Internet — 1.69%
Cogent Communications Holdings, Inc.	167		12,221
ePlus, Inc. ^(a)	264		14,224
HealthStream, Inc. ^(a)	225		5,931
Liquidity Services, Inc. ^(a)	186		4,107
Perficient, Inc. ^(a)	292		37,753
QuinStreet, Inc. ^(a)	379		6,894
Shutterstock, Inc.	140		15,523
TechTarget, Inc. ^(a)	164		15,688
		$	112,341

Iron & Steel — 0.18%
Allegheny Technologies, Inc. ^(a)	425		6,770
Carpenter Technology Corp.	187		5,459
		$	12,229

See accompanying notes.

122


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Leisure Time — 0.13%
Vista Outdoor, Inc. ^(a)	185	$	8,523

Machinery — Diversified — 2.70%
Alamo Group, Inc.	95		13,982
Albany International Corp., Class A	238		21,051
Applied Industrial Technologies, Inc.	363		37,280
Chart Industries, Inc. ^(a)	81		12,919
DXP Enterprises, Inc. ^(a)	150		3,851
Ichor Holdings Ltd. ^(a)	253		11,646
Lindsay Corp.	97		14,744
SPX FLOW, Inc.	118		10,205
Tennant Co.	111		8,995
Watts Water Technologies, Inc., Class A	232		45,047
		$	179,720

Media — 0.64%
AMC Networks, Inc., Class A ^(a)	252		8,679
EW Scripps Co., Class A	595		11,513
Gannett Co., Inc. ^(a)	1,510		8,049
Scholastic Corp.	368		14,705
		$	42,946

Metal Fabrication & Hardware — 1.13%
AZZ, Inc.	263		14,541
Mueller Industries, Inc.	622		36,922
Olympic Steel, Inc.	161		3,784
Standex International Corp.	130		14,386
TimkenSteel Corp. ^(a)	328		5,412
		$	75,045

Mining — 0.39%
Arconic Corp. ^(a)	300		9,903
Kaiser Aluminum Corp.	59		5,542
Livent Corp. ^(a)	429		10,459
		$	25,904

Miscellaneous Manufacture — 2.59%
Enerpac Tool Group Corp.	350		7,098
EnPro Industries, Inc.	105		11,557
ESCO Technologies, Inc.	125		11,249
Fabrinet ^(a)	328		38,858
Federal Signal Corp.	464		20,110
Haynes International, Inc.	113		4,557
Hillenbrand, Inc.	709		36,861
Materion Corp.	201		18,480
Myers Industries, Inc.	558		11,165
Sturm Ruger & Co., Inc.	183		12,448
		$	172,383

Office Furnishings — 0.31%
HNI Corp.	236		9,924
Interface, Inc.	678		10,814
		$	20,738

Oil & Gas — 1.48%
Callon Petroleum Co. ^(a)	153		7,229
Civitas Resources, Inc.	131		6,415
Helmerich & Payne, Inc.	317		7,513
Laredo Petroleum, Inc. ^(a)	64		3,848
Matador Resources Co.	295		10,892
Nabors Industries Ltd. ^(a)	54		4,379
Par Pacific Holdings, Inc. ^(a)	294		4,848
Patterson-UTI Energy, Inc.	726		6,135

See accompanying notes.

123


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Oil & Gas (continued)
PDC Energy, Inc.	244	$	11,902
Range Resources Corp. ^(a)	641		11,429
Ranger Oil Corp., Class A ^(a)	174		4,684
SM Energy Co.	360		10,613
Southwestern Energy Co. ^(a)	1,918		8,938
		$	98,825

Oil & Gas Services — 0.16%
Oceaneering International, Inc. ^(a)	439		4,965
U.S. Silica Holdings, Inc. ^(a)	575		5,405
		$	10,370

Packaging & Containers — 0.21%
Matthews International Corp., Class A	215		7,884
O-I Glass, Inc. ^(a)	527		6,340
		$	14,224

Pharmaceuticals — 2.13%
Amphastar Pharmaceuticals, Inc. ^(a)	345		8,035
Corcept Therapeutics, Inc. ^(a)	485		9,603
Eagle Pharmaceuticals, Inc. ^(a)	115		5,856
Enanta Pharmaceuticals, Inc. ^(a)	129		9,647
Heska Corp. ^(a)	32		5,840
Owens & Minor, Inc.	479		20,836
Pacira BioSciences, Inc. ^(a)	329		19,796
Phibro Animal Health Corp., Class A	469		9,577
Prestige Consumer Healthcare, Inc. ^(a)	506		30,689
uniQure NV ^(a)	161		3,339
USANA Health Sciences, Inc. ^(a)	139		14,067
Vanda Pharmaceuticals, Inc. ^(a)	290		4,550
		$	141,835

Real Estate — 0.79%
Alexander & Baldwin, Inc.	657		16,484
Douglas Elliman, Inc.	606		6,963
Marcus & Millichap, Inc. ^(a)	182		9,366
RE/MAX Holdings, Inc., Class A	198		6,037
Realogy Holdings Corp. ^(a)	397		6,674
St. Joe Co.	138		7,183
		$	52,707

REITs — 8.71%
Acadia Realty Trust	319		6,964
Agree Realty Corp.	408		29,115
American Assets Trust, Inc.	250		9,382
Apollo Commercial Real Estate Finance, Inc.	1,553		20,437
Armada Hoffler Properties, Inc.	500		7,610
ARMOUR Residential REIT, Inc.	638		6,259
Brandywine Realty Trust	766		10,280
CareTrust REIT, Inc.	793		18,104
Centerspace	140		15,526
Community Healthcare Trust, Inc.	267		12,621
DiamondRock Hospitality Co. ^(a)	729		7,006
Easterly Government Properties, Inc.	741		16,984
Ellington Financial, Inc.	643		10,989
Essential Properties Realty Trust, Inc.	1,105		31,857
Four Corners Property Trust, Inc.	621		18,264
Franklin BSP Realty Trust, Inc.	306		4,572
GEO Group, Inc.	704		5,456
Getty Realty Corp.	255		8,183
Global Net Lease, Inc.	534		8,160
Granite Point Mortgage Trust, Inc.	691		8,092

See accompanying notes.

124


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

REITs (continued)
Independence Realty Trust, Inc.	834	$	21,542
Industrial Logistics Properties Trust	591		14,805
Innovative Industrial Properties, Inc.	57		14,986
iStar, Inc.	621		16,040
Kite Realty Group Trust	717		15,616
KKR Real Estate Finance Trust, Inc.	551		11,477
LTC Properties, Inc.	240		8,194
LXP Industrial Trust	1,036		16,182
New York Mortgage Trust, Inc.	3,488		12,975
NexPoint Residential Trust, Inc.	130		10,898
Office Properties Income Trust	301		7,477
PennyMac Mortgage Investment Trust	830		14,384
Ready Capital Corp.	778		12,160
Redwood Trust, Inc.	1,591		20,985
Retail Opportunity Investments Corp.	405		7,938
RPT Realty	401		5,365
Safehold, Inc.	158		12,616
Saul Centers, Inc.	236		12,513
SITE Centers Corp.	538		8,517
Tanger Factory Outlet Centers, Inc.	376		7,249
Two Harbors Investment Corp.	1,486		8,574
Uniti Group, Inc.	940		13,169
Universal Health Realty Income Trust	197		11,716
Urstadt Biddle Properties, Inc., Class A	544		11,587
Washington Real Estate Investment Trust	394		10,185
Whitestone REIT	978		9,907
Xenia Hotels & Resorts, Inc. ^(a)	385		6,972
		$	579,890

Retail — 5.46%
Abercrombie & Fitch Co., Class A ^(a)	395		13,758
America's Car-Mart, Inc. ^(a)	41		4,198
Asbury Automotive Group, Inc. ^(a)	103		17,791
Barnes & Noble Education, Inc. ^(a)	371		2,527
Bed Bath & Beyond, Inc. ^(a)	334		4,870
Big Lots, Inc.	137		6,172
Bloomin' Brands, Inc. ^(a)	556		11,665
Boot Barn Holdings, Inc. ^(a)	173		21,288
Buckle, Inc.	266		11,254
Caleres, Inc.	208		4,717
Cato Corp., Class A	228		3,913
Chico's FAS, Inc. ^(a)	890		4,788
Children's Place, Inc. ^(a)	124		9,832
Chuy's Holdings, Inc. ^(a)	146		4,398
Conn's, Inc. ^(a)	172		4,045
Dave & Buster's Entertainment, Inc. ^(a)	155		5,952
Designer Brands, Inc., Class A ^(a)	344		4,888
El Pollo Loco Holdings, Inc. ^(a)	560		7,946
Genesco, Inc. ^(a)	80		5,134
GMS, Inc. ^(a)	295		17,732
Group 1 Automotive, Inc.	99		19,327
Guess?, Inc.	446		10,561
Haverty Furniture Cos., Inc.	245		7,490
Hibbett, Inc.	140		10,070
La-Z-Boy, Inc.	437		15,868
Macy's, Inc.	713		18,666
MarineMax, Inc. ^(a)	212		12,517
Movado Group, Inc.	266		11,127
ODP Corp. ^(a)	168		6,599
PC Connection, Inc.	133		5,736
PetMed Express, Inc.	163		4,117
PriceSmart, Inc.	204		14,927
Ruth's Hospitality Group, Inc. ^(a)	441		8,776

See accompanying notes.

125


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
Sally Beauty Holdings, Inc. ^(a)	814	$	15,026
Shoe Carnival, Inc.	260		10,161
Signet Jewelers Ltd.	137		11,923
Sonic Automotive, Inc., Class A	100		4,945
Vera Bradley, Inc. ^(a)	396		3,370
Zumiez, Inc. ^(a)	122		5,855
		$	363,929

Savings & Loans — 3.34%
Axos Financial, Inc. ^(a)	563		31,477
Banc of California, Inc.	262		5,141
Berkshire Hills Bancorp, Inc.	441		12,538
Brookline Bancorp, Inc.	1,264		20,464
Capitol Federal Financial, Inc.	1,273		14,423
Investors Bancorp, Inc.	2,128		32,239
Northfield Bancorp, Inc.	948		15,320
Northwest Bancshares, Inc.	1,179		16,695
Pacific Premier Bancorp, Inc.	858		34,346
Provident Financial Services, Inc.	979		23,711
WSFS Financial Corp.	320		16,038
		$	222,392

Semiconductors — 3.70%
Axcelis Technologies, Inc. ^(a)	127		9,469
Cohu, Inc. ^(a)	381		14,512
CTS Corp.	399		14,651
Diodes, Inc. ^(a)	276		30,308
FormFactor, Inc. ^(a)	223		10,196
Kulicke & Soffa Industries, Inc.	326		19,736
MaxLinear, Inc. ^(a)	188		14,173
Onto Innovation, Inc. ^(a)	262		26,522
Photronics, Inc. ^(a)	843		15,891
Power Integrations, Inc.	277		25,731
Rambus, Inc. ^(a)	815		23,953
SMART Global Holdings, Inc. ^(a)	109		7,738
Ultra Clean Holdings, Inc. ^(a)	307		17,609
Veeco Instruments, Inc. ^(a)	571		16,256
		$	246,745

Software — 2.55%
8x8, Inc. ^(a)	334		5,598
Agilysys, Inc. ^(a)	97		4,312
Allscripts Healthcare Solutions, Inc. ^(a)	469		8,653
Apollo Medical Holdings, Inc. ^(a)	208		15,284
Bottomline Technologies DE, Inc. ^(a)	212		11,972
Computer Programs & Systems, Inc. ^(a)	170		4,981
CSG Systems International, Inc.	313		18,035
Digi International, Inc. ^(a)	217		5,332
Donnelley Financial Solutions, Inc. ^(a)	151		7,118
ManTech International Corp., Class A	227		16,555
NextGen Healthcare, Inc. ^(a)	796		14,161
Progress Software Corp.	362		17,474
Simulations Plus, Inc.	113		5,345
SPS Commerce, Inc. ^(a)	200		28,470
Xperi Holding Corp.	365		6,902
		$	170,192

Telecommunications — 1.32%
ADTRAN, Inc.	256		5,844
ATN International, Inc.	126		5,034
Extreme Networks, Inc. ^(a)	577		9,059
Harmonic, Inc. ^(a)	548		6,444

See accompanying notes.

126


Schedule of Investments
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Telecommunications (continued)
InterDigital, Inc.	143	$	10,243
NETGEAR, Inc. ^(a)	163		4,761
Plantronics, Inc. ^(a)	196		5,751
Shenandoah Telecommunications Co.	279		7,115
Viavi Solutions, Inc. ^(a)	858		15,118
Vonage Holdings Corp. ^(a)	903		18,773
		$	88,142

Textiles — 0.32%
UniFirst Corp.	100		21,040
Transportation — 1.82%
ArcBest Corp.	178		21,333
Atlas Air Worldwide Holdings, Inc. ^(a)	215		20,236
Forward Air Corp.	207		25,066
Heartland Express, Inc.	408		6,863
Hub Group, Inc., Class A ^(a)	151		12,720
Marten Transport Ltd.	780		13,385
Matson, Inc.	241		21,697
		$	121,300

Water — 1.31%
American States Water Co.	248		25,653
California Water Service Group	502		36,074
Middlesex Water Co.	213		25,624
		$	87,351
TOTAL COMMON STOCKS		$	6,644,495
INVESTMENT COMPANIES — 0.24%	Shares Held		Value
Money Market Fund — 0.24%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	15,999	$	15,999
TOTAL INVESTMENT COMPANIES		$	15,999
Total Investments		$	6,660,494
Other Assets and Liabilities — 0.01%			591
Total Net Assets — 100.00%		$	6,661,085

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Financial	32.99	%
Consumer, Non-cyclical	17.63	%
Industrial	17.12	%
Consumer, Cyclical	12.11	%
Technology	7.93	%
Basic Materials	4.06	%
Communications	3.65	%
Utilities	2.38	%
Energy	1.88	%
Money Market Fund	0.24	%
Other Assets and Liabilities	0.01	%
TOTAL NET ASSETS	100.00	%

See accompanying notes.

127


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.69%	Shares Held		Value

Aerospace & Defense — 0.15%
Barnes Group, Inc.	38,765	$	1,806,061

Agriculture — 0.20%
Alico, Inc.	5,822		215,589
Andersons, Inc.	11,147		431,500
Turning Point Brands, Inc.	12,712		480,259
Universal Corp.	15,806		868,066
Vector Group Ltd.	42,185		484,284
		$	2,479,698

Apparel — 1.23%
Kontoor Brands, Inc.	47,187		2,418,334
Levi Strauss & Co., Class A	217,127		5,434,689
Oxford Industries, Inc.	13,091		1,328,998
Steven Madden Ltd.	90,514		4,206,186
Wolverine World Wide, Inc.	62,378		1,797,110
		$	15,185,317

Auto Manufacturers — 0.04%
REV Group, Inc.	36,133		511,282

Auto Parts & Equipment — 1.06%
Dana, Inc.	86,747		1,979,567
Gentherm, Inc. ^(a)	14,460		1,256,574
Goodyear Tire & Rubber Co. ^(a)	268,439		5,723,119
Methode Electronics, Inc.	37,612		1,849,382
Shyft Group, Inc.	26,475		1,300,717
Standard Motor Products, Inc.	19,720		1,033,131
		$	13,142,490

Banks — 8.08%
1st Source Corp.	16,616		824,154
Ameris Bancorp	104,340		5,183,611
Bancorp, Inc. ^(a)	66,810		1,690,961
Byline Bancorp, Inc.	43,341		1,185,376
Camden National Corp.	12,600		606,816
Cathay General Bancorp	92,418		3,973,050
City Holding Co.	20,094		1,643,488
Community Trust Bancorp, Inc.	20,419		890,473
Customers Bancorp, Inc. ^(a)	42,085		2,751,097
CVB Financial Corp.	192,603		4,123,630
Eagle Bancorp, Inc.	33,580		1,959,057
Enterprise Financial Services Corp.	42,158		1,985,220
FB Financial Corp.	38,559		1,689,655
First Bancshares, Inc.	25,521		985,621
First Busey Corp.	48,212		1,307,510
First Financial Bancorp	114,508		2,791,705
First Financial Corp.	20,202		914,949
First Foundation, Inc.	45,843		1,139,657
First Merchants Corp.	53,059		2,222,642
First of Long Island Corp.	24,163		521,679
German American Bancorp, Inc.	12,436		484,755
Hanmi Financial Corp.	32,670		773,626
Hilltop Holdings, Inc.	167,779		5,895,754
Home BancShares, Inc.	179,133		4,361,889
Hope Bancorp, Inc.	209,777		3,085,820
Horizon Bancorp, Inc.	29,067		606,047
Independent Bank Corp.	29,069		693,877
Independent Bank Group, Inc.	39,673		2,862,407
Kearny Financial Corp.	113,584		1,504,988
Lakeland Bancorp, Inc.	71,525		1,358,260
Lakeland Financial Corp.	65,395		5,240,755
Merchants Bancorp	12,331		583,626

See accompanying notes.

128


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Banks (continued)
Meta Financial Group, Inc.	42,189	$	2,516,996
Metropolitan Bank Holding Corp. ^(a)	12,159		1,295,298
Midland States Bancorp, Inc.	23,608		585,242
Origin Bancorp, Inc.	14,977		642,813
Preferred Bank	16,209		1,163,644
Premier Financial Corp.	27,699		856,176
QCR Holdings, Inc.	19,091		1,069,096
Sandy Spring Bancorp, Inc.	41,555		1,997,964
ServisFirst Bancshares, Inc.	43,477		3,692,936
Simmons First National Corp., Class A	111,616		3,301,601
Stock Yards Bancorp, Inc.	18,034		1,152,012
Tompkins Financial Corp.	9,561		799,108
TriCo Bancshares	27,688		1,189,477
Triumph Bancorp, Inc. ^(a)	32,285		3,844,498
UMB Financial Corp.	65,725		6,974,080
Veritex Holdings, Inc.	52,626		2,093,462
Washington Trust Bancorp, Inc.	16,792		946,565
		$	99,963,123

Beverages — 0.17%
Coca-Cola Consolidated, Inc.	2,673		1,655,095
MGP Ingredients, Inc.	5,761		489,627
		$	2,144,722

Biotechnology — 2.79%
Agenus, Inc. ^(a)	336,256		1,082,744
AnaptysBio, Inc. ^(a)	18,413		639,852
ANI Pharmaceuticals, Inc. ^(a)	5,815		267,955
Avid Bioservices, Inc. ^(a)	47,428		1,383,949
Cara Therapeutics, Inc. ^(a)	126,613		1,542,146
Cardiff Oncology, Inc. ^(a)	75,577		454,218
Cassava Sciences, Inc. ^(a),(b)	134,241		5,866,332
Celldex Therapeutics, Inc. ^(a)	45,038		1,740,268
Clearside Biomedical, Inc. ^(a)	58,226		160,122
Curis, Inc. ^(a)	131,937		628,020
Dynavax Technologies Corp. ^(a)	164,978		2,321,240
EyePoint Pharmaceuticals, Inc. ^(a)	11,082		135,644
Harvard Bioscience, Inc. ^(a)	28,537		201,186
ImmunoGen, Inc. ^(a)	168,945		1,253,572
Innoviva, Inc. ^(a)	108,621		1,873,712
Intercept Pharmaceuticals, Inc. ^(a),(b)	90,840		1,479,784
Intra-Cellular Therapies, Inc. ^(a)	44,786		2,344,099
Lexicon Pharmaceuticals, Inc. ^(a)	53,494		210,766
Ligand Pharmaceuticals, Inc. ^(a)	18,295		2,825,846
Lineage Cell Therapeutics, Inc. ^(a)	68,065		166,759
Myriad Genetics, Inc. ^(a)	58,659		1,618,988
Oncternal Therapeutics, Inc. ^(a)	48,218		109,455
Organogenesis Holdings, Inc. ^(a)	80,008		739,274
Prothena Corp. PLC ^(a)	29,706		1,467,476
Puma Biotechnology, Inc. ^(a)	50,445		153,353
Radius Health, Inc. ^(a)	53,090		367,383
Selecta Biosciences, Inc. ^(a)	56,969		185,719
Surface Oncology, Inc. ^(a)	58,714		280,653
Sutro Biopharma, Inc. ^(a)	32,249		479,865
TransMedics Group, Inc. ^(a)	21,007		402,494
Verastem, Inc. ^(a)	223,573		458,325
Vericel Corp. ^(a)	37,492		1,473,436
VistaGen Therapeutics, Inc. ^(a)	118,931		231,915
		$	34,546,550

Building Materials — 1.02%
Apogee Enterprises, Inc.	25,039		1,205,628
Boise Cascade Co.	53,028		3,775,594

See accompanying notes.

129


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Building Materials (continued)
Griffon Corp.	32,890	$	936,707
Patrick Industries, Inc.	21,254		1,714,985
UFP Industries, Inc.	53,633		4,934,772
		$	12,567,686

Chemicals — 2.72%
AdvanSix, Inc.	28,740		1,357,965
Balchem Corp.	25,471		4,294,411
Cabot Corp.	57,869		3,252,238
HB Fuller Co.	62,895		5,094,495
Ingevity Corp. ^(a)	35,615		2,553,595
Koppers Holdings, Inc. ^(a)	15,274		478,076
Minerals Technologies, Inc.	27,571		2,016,819
NewMarket Corp.	11,032		3,780,887
Rogers Corp. ^(a)	14,653		4,000,269
Sensient Technologies Corp.	46,369		4,639,682
Trinseo PLC	42,733		2,241,773
		$	33,710,210

Coal — 0.21%
Alpha Metallurgical Resources, Inc. ^(a)	18,037		1,101,159
CONSOL Energy, Inc. ^(a)	34,077		773,889
SunCoke Energy, Inc.	105,848		697,538
		$	2,572,586

Commercial Services — 5.04%
ABM Industries, Inc.	107,206		4,379,365
AMN Healthcare Services, Inc. ^(a)	56,115		6,864,548
Brink's Co.	52,868		3,466,555
Carriage Services, Inc.	16,631		1,071,702
Cass Information Systems, Inc.	8,748		343,971
CBIZ, Inc. ^(a)	42,734		1,671,754
CorVel Corp. ^(a)	5,540		1,152,320
CRA International, Inc.	5,486		512,173
Deluxe Corp.	36,088		1,158,786
EVERTEC, Inc.	67,619		3,379,598
Franklin Covey Co. ^(a)	9,057		419,882
Graham Holdings Co., Class B	4,409		2,776,920
H&R Block, Inc.	276,079		6,504,421
Hackett Group, Inc.	24,604		505,120
Herc Holdings, Inc.	18,261		2,858,760
ICF International, Inc.	15,861		1,626,546
Information Services Group, Inc.	51,446		392,018
Insperity, Inc.	36,770		4,342,905
John Wiley & Sons, Inc., Class A	35,987		2,060,975
Kforce, Inc.	20,927		1,574,129
Korn Ferry	46,801		3,544,240
Medifast, Inc.	9,907		2,074,823
Monro, Inc.	15,735		916,878
Rent-A-Center, Inc.	52,828		2,537,857
Resources Connection, Inc.	23,320		416,029
Stride, Inc. ^(a)	37,764		1,258,674
Transcat, Inc. ^(a)	3,865		357,242
Triton International Ltd.	69,361		4,177,613
		$	62,345,804

Computers — 1.11%
ExlService Holdings, Inc. ^(a)	38,044		5,507,630
Insight Enterprises, Inc. ^(a)	59,435		6,335,771
Rimini Street, Inc. ^(a)	45,073		269,086
Super Micro Computer, Inc. ^(a)	35,541		1,562,027
		$	13,674,514

See accompanying notes.

130


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Distribution/Wholesale — 1.15%
A-Mark Precious Metals, Inc.	6,639	$	405,643
Avient Corp.	63,973		3,579,289
G-III Apparel Group Ltd. ^(a)	33,523		926,576
Leslie's Inc ^(a)	181,090		4,284,589
Resideo Technologies, Inc. ^(a)	100,727		2,621,924
ScanSource, Inc. ^(a)	11,111		389,774
Titan Machinery, Inc. ^(a)	21,982		740,574
Veritiv Corp. ^(a)	10,357		1,269,457
		$	14,217,826

Diversified Financial Services — 6.53%
Alliance Data Systems Corp.	82,547		5,495,154
Atlanticus Holdings Corp ^(a)	6,083		433,840
B Riley Financial, Inc.	70,949		6,304,528
Brightsphere Investment Group, Inc.	200,557		5,134,259
Columbia Financial, Inc. ^(a)	65,754		1,371,628
Cowen, Inc., Class A	114,667		4,139,479
Diamond Hill Investment Group, Inc.	4,248		825,089
Encore Capital Group, Inc. ^(a)	64,695		4,018,206
Enova International, Inc. ^(a)	52,087		2,133,484
Federated Hermes, Inc.	155,081		5,827,944
Houlihan Lokey, Inc.	88,502		9,161,727
Moelis & Co., Class A	116,758		7,298,543
Mr Cooper Group, Inc. ^(a)	197,822		8,231,373
Navient Corp.	415,974		8,826,968
Piper Sandler Cos.	19,668		3,510,935
Regional Management Corp.	12,568		722,157
StepStone Group Inc, Class A	68,043		2,828,548
Virtus Investment Partners, Inc.	10,855		3,225,020
World Acceptance Corp. ^(a)	5,418		1,329,740
		$	80,818,622

Electric — 0.91%
Avista Corp.	74,289		3,156,540
Otter Tail Corp.	27,177		1,940,981
Portland General Electric Co.	105,228		5,568,666
Unitil Corp.	13,270		610,287
		$	11,276,474

Electrical Components & Equipment — 0.55%
Encore Wire Corp.	19,512		2,792,167
Energizer Holdings, Inc.	84,123		3,373,332
Insteel Industries, Inc.	17,155		682,941
		$	6,848,440

Electronics — 2.64%
Advanced Energy Industries, Inc.	33,867		3,083,929
Atkore, Inc. ^(a)	46,645		5,186,458
Avnet, Inc.	171,716		7,079,851
Badger Meter, Inc.	20,987		2,236,375
Benchmark Electronics, Inc.	39,365		1,066,791
Comtech Telecommunications Corp.	22,065		522,720
Fluidigm Corp. ^(a)	68,075		266,854
Kimball Electronics, Inc. ^(a)	9,602		208,939
Napco Security Technologies, Inc. ^(a)	4,505		225,160
NVE Corp.	4,870		332,621
OSI Systems, Inc. ^(a)	28,736		2,678,195
Sanmina Corp. ^(a)	68,640		2,845,814
Vicor Corp. ^(a)	18,848		2,393,319
Vishay Intertechnology, Inc.	206,007		4,505,373
		$	32,632,399

See accompanying notes.

131


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Engineering & Construction — 1.07%
Arcosa, Inc.	67,209	$	3,541,914
Comfort Systems USA, Inc.	29,160		2,885,090
Granite Construction, Inc.	50,964		1,972,307
MYR Group, Inc. ^(a)	18,253		2,017,869
NV5 Global, Inc. ^(a)	10,122		1,398,051
Primoris Services Corp.	56,716		1,360,050
		$	13,175,281

Entertainment — 0.25%
RCI Hospitality Holdings, Inc.	3,321		258,640
Warner Music Group Corp., Class A	65,045		2,808,643
		$	3,067,283

Environmental Control — 0.66%
Casella Waste Systems Inc, Class A ^(a)	26,629		2,274,649
Centrus Energy Corp., Class A ^(a)	5,267		262,876
Energy Recovery, Inc. ^(a)	47,826		1,027,781
Evoqua Water Technologies Corp. ^(a)	98,577		4,608,475
		$	8,173,781

Food — 1.54%
B&G Foods, Inc.	78,750		2,419,987
Hain Celestial Group, Inc. ^(a)	62,678		2,670,710
Hostess Brands, Inc. ^(a)	103,746		2,118,493
Ingles Markets, Inc., Class A	7,382		637,362
John B Sanfilippo & Son, Inc.	5,398		486,684
Seaboard Corp.	88		346,281
Simply Good Foods Co. ^(a)	45,403		1,887,403
SpartanNash Co.	28,103		723,933
Sprouts Farmers Market, Inc. ^(a)	223,871		6,644,491
United Natural Foods, Inc. ^(a)	23,291		1,143,122
		$	19,078,466

Food Service — 0.21%
Healthcare Services Group, Inc.	147,318		2,620,787

Forest Products & Paper — 0.11%
Neenah, Inc.	15,621		722,940
Schweitzer-Mauduit International, Inc.	21,557		644,554
		$	1,367,494

Gas — 1.16%
Chesapeake Utilities Corp.	7,355		1,072,432
National Fuel Gas Co.	59,781		3,822,397
South Jersey Industries, Inc.	163,113		4,260,512
Southwest Gas Holdings, Inc.	74,956		5,250,668
		$	14,406,009

Hand/Machine Tools — 0.27%
Franklin Electric Co., Inc.	34,632		3,274,802

Healthcare — Products — 4.36%
Accuray, Inc. ^(a)	60,832		290,169
AngioDynamics, Inc. ^(a)	34,096		940,368
Apria, Inc. ^(a)	36,541		1,191,237
AtriCure, Inc. ^(a)	38,028		2,644,087
Atrion Corp.	1,239		873,371
Avanos Medical, Inc. ^(a)	62,316		2,160,496
AxoGen, Inc. ^(a)	16,726		156,723
Axonics, Inc. ^(a)	57,769		3,235,064
Bionano Genomics, Inc. ^(a),(b)	835,235		2,497,353
Castle Biosciences, Inc. ^(a)	16,384		702,382
Co-Diagnostics, Inc. ^(a)	74,833		668,259

See accompanying notes.

132


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Healthcare — Products (continued)
CONMED Corp.	40,485	$	5,739,154
Cutera, Inc. ^(a)	29,267		1,209,312
Eargo, Inc. ^(a)	236,311		1,205,186
ICU Medical, Inc. ^(a)	14,812		3,515,480
Inogen, Inc. ^(a)	19,285		655,690
Integer Holdings Corp. ^(a)	21,165		1,811,512
Invacare Corp. ^(a)	46,555		126,630
iRadimed Corp. ^(a)	4,120		190,385
Lantheus Holdings, Inc. ^(a)	61,678		1,781,877
LeMaitre Vascular, Inc.	22,906		1,150,568
Meridian Bioscience, Inc. ^(a)	34,538		704,575
Merit Medical Systems, Inc. ^(a)	39,635		2,469,260
Natus Medical, Inc. ^(a)	18,450		437,818
NuVasive, Inc. ^(a)	106,383		5,582,980
Orthofix Medical, Inc. ^(a)	14,829		461,034
OrthoPediatrics Corp. ^(a)	10,897		652,294
Patterson Cos., Inc.	168,155		4,935,349
Quanterix Corp. ^(a)	20,268		859,363
SI-BONE, Inc. ^(a)	40,667		903,214
Sientra, Inc. ^(a)	75,383		276,656
Silk Road Medical, Inc. ^(a)	24,287		1,034,869
Surmodics, Inc. ^(a)	5,573		268,340
T2 Biosystems, Inc. ^(a)	239,452		123,605
Treace Medical Concepts, Inc. ^(a)	17,523		326,629
Varex Imaging Corp. ^(a)	49,487		1,561,315
ViewRay, Inc. ^(a)	108,007		595,118
		$	53,937,722

Healthcare — Services — 1.70%
Agiliti, Inc. ^(a)	24,093		557,994
ATI Physical Therapy, Inc. ^(a),(b)	128,184		434,544
Aveanna Healthcare Holdings, Inc. ^(a)	67,222		497,443
Brookdale Senior Living, Inc. ^(a)	257,560		1,329,010
Community Health Systems, Inc. ^(a)	139,093		1,851,328
Ensign Group, Inc.	42,682		3,583,581
Innovage Holding Corp. ^(a)	62,166		310,830
Inotiv, Inc. ^(a)	5,020		211,191
Joint Corp. ^(a)	16,361		1,074,754
MEDNAX, Inc. ^(a)	68,581		1,866,089
ModivCare, Inc. ^(a)	8,529		1,264,765
National HealthCare Corp.	6,980		474,221
Neuronetics, Inc. ^(a)	32,011		142,769
OPKO Health, Inc. ^(a),(b)	371,410		1,786,482
Pennant Group, Inc. ^(a)	8,734		201,581
RadNet, Inc. ^(a)	33,912		1,021,090
Surgery Partners, Inc. ^(a)	41,850		2,235,208
Tivity Health, Inc. ^(a)	55,974		1,479,953
U.S. Physical Therapy, Inc.	6,763		646,205
		$	20,969,038

Home Builders — 1.31%
Century Communities, Inc.	37,104		3,034,736
Hovnanian Enterprises, Inc., Class A ^(a)	5,358		682,020
LCI Industries	13,894		2,165,658
Skyline Champion Corp. ^(a)	41,172		3,251,764
TRI Pointe Homes, Inc. ^(a)	130,664		3,644,219
Winnebago Industries, Inc.	46,013		3,447,294
		$	16,225,691

Home Furnishings — 0.88%
Ethan Allen Interiors, Inc.	28,458		748,161
Lovesac Co. ^(a)	18,174		1,204,209
Sonos, Inc. ^(a)	251,528		7,495,535

See accompanying notes.

133


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Home Furnishings (continued)
Universal Electronics, Inc. ^(a)	6,375	$	259,781
Vizio Holding Corp., Class A ^(a)	62,484		1,214,064
		$	10,921,750

Household Products — 0.28%
Edgewell Personal Care Co.	50,346		2,301,316
Inter Parfums, Inc.	10,654		1,138,912
		$	3,440,228

Household Products/Wares — 0.39%
ACCO Brands Corp.	28,766		237,607
Central Garden & Pet Co., Class A ^(a)	25,970		1,242,665
Quanex Building Products Corp.	30,878		765,157
Spectrum Brands Holdings, Inc.	25,153		2,558,563
		$	4,803,992

Insurance — 1.70%
Enstar Group Ltd. ^(a)	17,648		4,369,468
Mercury General Corp.	89,876		4,768,821
Radian Group, Inc.	358,165		7,568,026
Stewart Information Services Corp.	54,605		4,353,657
		$	21,059,972

Internet — 2.71%
Cargurus, Inc. ^(a)	135,715		4,565,453
ChannelAdvisor Corp. ^(a)	25,103		619,542
ePlus, Inc. ^(a)	20,682		1,114,346
HealthStream, Inc. ^(a)	20,526		541,065
Mimecast Ltd. ^(a)	129,025		10,266,519
Perficient, Inc. ^(a)	68,606		8,870,070
Revolve Group, Inc. ^(a)	54,024		3,027,505
Shutterstock, Inc.	40,509		4,491,638
		$	33,496,138

Investment Companies — 0.47%
Altus Midstream Co., Class A	6,583		403,604
Golub Capital BDC, Inc.	351,529		5,427,608
		$	5,831,212

Iron & Steel — 0.38%
Commercial Metals Co.	129,606		4,703,402

Leisure Time — 0.75%
Acushnet Holdings Corp.	30,282		1,607,368
Camping World Holdings, Inc., Class A	85,680		3,461,472
Clarus Corp.	23,055		639,085
OneWater Marine, Inc., Class A	5,322		324,482
Vista Outdoor, Inc. ^(a)	70,714		3,257,794
		$	9,290,201

Lodging — 0.01%
Full House Resorts, Inc. ^(a)	14,201		171,974

Machinery — Construction & Mining — 0.33%
Terex Corp.	93,232		4,097,546

Machinery — Diversified — 1.79%
Albany International Corp., Class A	21,585		1,909,193
Altra Industrial Motion Corp.	39,193		2,021,183
Applied Industrial Technologies, Inc.	23,753		2,439,433
Cactus, Inc., Class A	47,102		1,795,999
Ichor Holdings Ltd. ^(a)	33,612		1,547,160
Kadant, Inc.	4,560		1,050,989

See accompanying notes.

134


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Machinery — Diversified (continued)
Lindsay Corp.	10,090	$	1,533,680
Mueller Water Products, Inc., Class A	191,641		2,759,631
Tennant Co.	15,927		1,290,724
Watts Water Technologies, Inc., Class A	29,733		5,773,257
		$	22,121,249

Media — 0.65%
AMC Networks, Inc., Class A ^(a)	30,708		1,057,583
Entravision Communications Corp., Class A	45,268		306,917
EW Scripps Co., Class A	26,932		521,134
Gray Television, Inc.	57,841		1,166,075
Scholastic Corp.	16,476		658,381
Sinclair Broadcast Group, Inc., Class A	36,575		966,677
TEGNA, Inc.	123,736		2,296,540
WideOpenWest, Inc. ^(a)	51,705		1,112,692
		$	8,085,999

Metal Fabrication & Hardware — 0.71%
AZZ, Inc.	17,851		986,982
Helios Technologies, Inc.	15,704		1,651,590
Mueller Industries, Inc.	38,078		2,260,310
Standex International Corp.	13,773		1,524,120
Worthington Industries, Inc.	43,576		2,381,864
		$	8,804,866

Mining — 0.09%
Kaiser Aluminum Corp.	12,044		1,131,413

Miscellaneous Manufacture — 1.36%
American Outdoor Brands, Inc. ^(a)	12,864		256,380
EnPro Industries, Inc.	14,350		1,579,504
Federal Signal Corp.	40,633		1,761,034
Hillenbrand, Inc.	81,239		4,223,616
John Bean Technologies Corp.	27,757		4,262,365
Myers Industries, Inc.	26,705		534,367
Smith & Wesson Brands, Inc.	158,676		2,824,433
Sturm Ruger & Co., Inc.	21,199		1,441,956
		$	16,883,655

Office & Business Equipment — 0.74%
Xerox Holdings Corp.	406,919		9,212,646

Office Furnishings — 0.13%
HNI Corp.	25,893		1,088,801
Interface, Inc.	28,730		458,243
		$	1,547,044

Oil & Gas — 2.70%
Brigham Minerals, Inc., Class A	37,607		793,132
California Resources Corp.	92,426		3,947,514
Callon Petroleum Co. ^(a)	111,629		5,274,470
Civitas Resources, Inc.	66,380		3,250,629
Comstock Resources, Inc. ^(a)	216,511		1,751,574
Falcon Minerals Corp.	66,013		321,483
Matador Resources Co.	137,023		5,058,889
Oasis Petroleum, Inc.	33,471		4,217,011
PDC Energy, Inc.	85,633		4,177,178
SilverBow Resources, Inc. ^(a)	11,593		252,380
Transocean Ltd. ^(a)	1,600,630		4,417,739
		$	33,461,999

Oil & Gas Services — 0.66%
Archrock, Inc.	123,001		920,048

See accompanying notes.

135


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Oil & Gas Services (continued)
ChampionX Corp. ^(a)	148,858	$	3,008,420
Core Laboratories NV	81,709		1,822,928
Oceaneering International, Inc. ^(a)	79,009		893,592
Solaris Oilfield Infrastructure, Inc., Class A	28,928		189,478
TETRA Technologies, Inc. ^(a)	139,617		396,512
Weatherford International PLC ^(a)	31,993		886,846
		$	8,117,824

Packaging & Containers — 0.55%
Greif, Inc., Class A	25,209		1,521,867
Matthews International Corp., Class A	13,408		491,672
Silgan Holdings, Inc.	112,898		4,836,550
		$	6,850,089

Pharmaceuticals — 5.05%
Aclaris Therapeutics, Inc. ^(a)	38,080		553,683
Agios Pharmaceuticals, Inc. ^(a)	93,758		3,081,825
Akebia Therapeutics, Inc. ^(a)	216,469		489,220
Alkermes PLC ^(a)	231,185		5,377,363
Amneal Pharmaceuticals, Inc. ^(a)	103,319		494,898
Amphastar Pharmaceuticals, Inc. ^(a)	35,445		825,514
Anika Therapeutics, Inc. ^(a)	12,671		454,002
Antares Pharma, Inc. ^(a)	103,172		368,324
BioDelivery Sciences International, Inc. ^(a)	81,055		251,270
Catalyst Pharmaceuticals, Inc. ^(a)	118,680		803,464
Clovis Oncology, Inc. ^(a),(b)	406,069		1,100,447
Coherus Biosciences, Inc. ^(a)	75,333		1,202,315
Collegium Pharmaceutical, Inc. ^(a)	29,941		559,298
Cytokinetics, Inc. ^(a)	80,522		3,670,193
Eagle Pharmaceuticals, Inc. ^(a)	12,164		619,391
Endo International PLC ^(a)	423,748		1,593,292
Harrow Health, Inc. ^(a)	15,713		135,760
Heat Biologics, Inc. ^(a)	32,235		97,994
Heska Corp. ^(a)	6,367		1,161,914
Ideaya Biosciences, Inc. ^(a)	22,003		520,151
Ironwood Pharmaceuticals, Inc. ^(a)	334,708		3,902,695
Jaguar Health, Inc. ^(a),(b)	163,426		169,963
Jounce Therapeutics, Inc. ^(a)	27,817		232,272
MannKind Corp. ^(a)	284,637		1,243,864
Neogen Corp. ^(a)	62,797		2,851,612
Option Care Health, Inc. ^(a)	239,408		6,808,763
Owens & Minor, Inc.	127,370		5,540,595
Pacira BioSciences, Inc. ^(a)	58,013		3,490,642
Paratek Pharmaceuticals, Inc. ^(a),(b)	50,216		225,470
PetIQ, Inc. ^(a)	72,787		1,652,993
Phibro Animal Health Corp., Class A	17,418		355,676
Premier, Inc., Class A	153,133		6,304,486
Prestige Consumer Healthcare, Inc. ^(a)	44,809		2,717,666
SIGA Technologies, Inc. ^(a)	37,837		284,534
Supernus Pharmaceuticals, Inc. ^(a)	62,402		1,819,642
USANA Health Sciences, Inc. ^(a)	7,438		752,726
Vanda Pharmaceuticals, Inc. ^(a)	49,640		778,852
		$	62,492,769

Pipelines — 0.91%
Antero Midstream Corp.	596,754		5,776,579
Equitrans Midstream Corp.	526,967		5,448,839
		$	11,225,418

Private Equity — 0.06%
Victory Capital Holdings, Inc., Class A	18,789		686,362

See accompanying notes.

136


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Real Estate — 0.58%
Alexander & Baldwin, Inc.	54,910	$	1,377,692
Douglas Elliman, Inc.	21,093		242,564
Kennedy-Wilson Holdings, Inc.	100,013		2,388,310
Newmark Group, Inc., Class A	98,938		1,850,141
RE/MAX Holdings, Inc., Class A	29,515		899,912
RMR Group, Inc., Class A	11,980		415,466
		$	7,174,085

REITs — 6.60%
Ares Commercial Real Estate Corp.	116,881		1,699,450
Brandywine Realty Trust	428,278		5,747,491
Broadstone Net Lease, Inc.	234,663		5,824,336
CareTrust REIT, Inc.	142,754		3,259,074
Corporate Office Properties Trust	203,174		5,682,777
CTO Realty Growth, Inc.	7,595		466,485
Essential Properties Realty Trust, Inc.	158,970		4,583,105
GEO Group, Inc.	337,123		2,612,703
Getty Realty Corp.	47,081		1,510,829
Gladstone Commercial Corp.	49,443		1,274,146
Healthcare Realty Trust, Inc.	273,588		8,656,324
Industrial Logistics Properties Trust	74,746		1,872,387
KKR Real Estate Finance Trust, Inc.	197,429		4,112,446
LTC Properties, Inc.	85,666		2,924,637
National Health Investors, Inc.	85,010		4,885,525
National Storage Affiliates Trust	155,424		10,755,341
NexPoint Residential Trust, Inc.	21,646		1,814,584
One Liberty Properties, Inc.	13,401		472,787
PotlatchDeltic Corp.	87,541		5,271,719
Preferred Apartment Communities, Inc.	58,708		1,060,267
Retail Value, Inc.	24,140		154,979
Saul Centers, Inc.	6,055		321,036
Tanger Factory Outlet Centers, Inc.	125,651		2,422,551
UMH Properties, Inc.	40,097		1,095,851
Urban Edge Properties	139,417		2,648,923
Urstadt Biddle Properties, Inc., Class A	25,138		535,439
		$	81,665,192

Retail — 7.95%
Abercrombie & Fitch Co., Class A ^(a)	130,344		4,539,882
Academy Sports & Outdoors, Inc. ^(a)	203,579		8,937,118
Asbury Automotive Group, Inc. ^(a)	16,842		2,909,119
Bassett Furniture Industries, Inc.	7,465		125,188
Big 5 Sporting Goods Corp. ^(b)	76,697		1,458,010
BlueLinx Holdings, Inc. ^(a)	17,603		1,685,663
Boot Barn Holdings, Inc. ^(a)	33,382		4,107,655
Buckle, Inc.	50,389		2,131,959
Caleres, Inc.	37,068		840,702
Cato Corp., Class A	10,086		173,076
Citi Trends, Inc. ^(a)	15,730		1,490,418
Dillard's, Inc., Class A	23,247		5,695,980
Duluth Holdings, Inc., Class B ^(a)	22,468		341,064
Franchise Group, Inc.	20,500		1,069,280
Genesco, Inc. ^(a)	8,151		523,050
GMS, Inc. ^(a)	37,868		2,276,246
Group 1 Automotive, Inc.	13,087		2,554,844
Haverty Furniture Cos., Inc.	28,260		863,908
Hibbett, Inc.	37,505		2,697,735
Jack in the Box, Inc.	49,831		4,359,216
La-Z-Boy, Inc.	48,399		1,757,368
MarineMax, Inc. ^(a)	28,161		1,662,625
Movado Group, Inc.	11,670		488,156
MSC Industrial Direct Co., Inc., Class A	101,589		8,539,571
Murphy USA, Inc.	24,818		4,944,738

See accompanying notes.

137


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Retail (continued)
National Vision Holdings, Inc. ^(a)	83,374	$	4,001,118
Nu Skin Enterprises, Inc., Class A	42,786		2,171,390
OptimizeRx Corp. ^(a)	12,020		746,562
Papa John's International, Inc.	48,858		6,521,077
PC Connection, Inc.	11,015		475,077
PriceSmart, Inc.	13,805		1,010,112
Qurate Retail, Inc., Series A	541,124		4,112,542
Rush Enterprises, Inc., Class A	23,074		1,283,837
Sally Beauty Holdings, Inc. ^(a)	101,330		1,870,552
Shoe Carnival, Inc.	24,615		961,954
Signet Jewelers Ltd.	48,405		4,212,687
Sonic Automotive, Inc., Class A	26,653		1,317,991
Tilly's, Inc., Class A	27,893		449,356
Winmark Corp.	845		209,805
World Fuel Services Corp.	108,829		2,880,704
		$	98,397,335

Savings & Loans — 1.15%
Axos Financial, Inc. ^(a)	55,662		3,112,062
Flushing Financial Corp.	39,151		951,369
Hingham Institution For Savings	2,863		1,202,117
Northfield Bancorp, Inc.	74,334		1,201,238
OceanFirst Financial Corp.	63,255		1,404,261
Pacific Premier Bancorp, Inc.	86,306		3,454,829
Provident Financial Services, Inc.	80,777		1,956,419
Waterstone Financial, Inc.	40,636		888,303
		$	14,170,598

Semiconductors — 2.72%
Alpha & Omega Semiconductor Ltd. ^(a)	27,581		1,670,305
CMC Materials, Inc.	35,599		6,823,972
CTS Corp.	31,260		1,147,867
Diodes, Inc. ^(a)	39,183		4,302,685
EMCORE Corp. ^(a)	42,253		294,926
MACOM Technology Solutions Holdings, Inc. ^(a)	56,194		4,399,990
Onto Innovation, Inc. ^(a)	36,594		3,704,411
Semtech Corp. ^(a)	55,434		4,929,746
SMART Global Holdings, Inc. ^(a)	68,626		4,871,760
Veeco Instruments, Inc. ^(a)	51,327		1,461,280
		$	33,606,942

Software — 3.57%
Altair Engineering, Inc., Class A ^(a)	46,537		3,598,241
American Software, Inc., Class A	20,354		532,664
Blackbaud, Inc. ^(a)	51,406		4,060,046
Castlight Health, Inc., Class B ^(a)	118,117		181,900
Cerence, Inc. ^(a)	62,506		4,790,460
CommVault Systems, Inc. ^(a)	57,542		3,965,795
Computer Programs & Systems, Inc. ^(a)	16,022		469,445
Convey Health Solutions Holdings, Inc. ^(a)	18,369		153,565
CSG Systems International, Inc.	42,200		2,431,564
Donnelley Financial Solutions, Inc. ^(a)	22,320		1,052,165
Ebix, Inc.	26,443		803,867
Evolent Health, Inc., Class A ^(a)	75,161		2,079,705
Health Catalyst, Inc. ^(a)	67,938		2,691,704
Loyalty Ventures, Inc. ^(a)	32,985		991,859
NextGen Healthcare, Inc. ^(a)	52,275		929,972
Phreesia, Inc. ^(a)	49,604		2,066,503
Privia Health Group, Inc. ^(a)	50,021		1,294,043
Progress Software Corp.	45,775		2,209,559
Sciplay Corp., Class A ^(a)	50,104		690,433
Signify Health, Inc., Class A ^(a)	166,501		2,367,644
Simulations Plus, Inc. ^(b)	18,416		871,077

See accompanying notes.

138


Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Software (continued)
SPS Commerce, Inc. ^(a)	28,609	$	4,072,491
Xperi Holding Corp.	89,953		1,701,011
Zedge, Inc., Class B ^(a)	20,813		176,910
		$	44,182,623

Telecommunications — 2.70%
A10 Networks, Inc.	76,382		1,266,414
ADTRAN, Inc.	49,981		1,141,066
Aviat Networks, Inc. ^(a)	19,938		639,611
Calix, Inc. ^(a)	54,684		4,373,080
Cambium Networks Corp. ^(a)	25,705		658,819
Casa Systems, Inc. ^(a)	38,566		218,669
Clearfield, Inc. ^(a)	9,554		806,549
CommScope Holding Co., Inc. ^(a)	390,007		4,305,677
Consolidated Communications Holdings, Inc. ^(a)	54,657		408,834
Extreme Networks, Inc. ^(a)	120,719		1,895,288
IDT Corp., Class B ^(a)	21,457		947,541
InterDigital, Inc.	41,176		2,949,437
Ribbon Communications, Inc. ^(a)	68,826		416,397
Switch, Inc., Class A	258,097		7,391,898
Telephone & Data Systems, Inc.	161,970		3,263,696
ViaSat, Inc. ^(a)	59,740		2,660,820
		$	33,343,796

Toys, Games & Hobbies — 0.07%
Funko, Inc., Class A ^(a)	47,938		901,234

Transportation — 2.06%
ArcBest Corp.	29,196		3,499,140
Atlas Air Worldwide Holdings, Inc. ^(a)	63,508		5,977,373
Daseke, Inc. ^(a)	51,492		516,980
Dorian LPG Ltd.	44,785		568,322
Forward Air Corp.	25,977		3,145,555
International Seaways, Inc.	30,039		440,972
Matson, Inc.	44,754		4,029,203
Pangaea Logistics Solutions Ltd.	42,146		159,312
Ryder System, Inc.	87,197		7,187,649
		$	25,524,506

Water — 0.75%
American States Water Co.	34,285		3,546,440
California Water Service Group	34,938		2,510,645
Middlesex Water Co.	17,859		2,148,438
SJW Group	15,348		1,123,473
		$	9,328,996
TOTAL COMMON STOCKS		$	1,233,473,213
INVESTMENT COMPANIES — 1.24%	Shares Held		Value

Money Market Funds — 1.24%
Principal Government Money Market Fund — Institutional Class 0.00% ^{(a),(c),(d),(e)}	10,127,850	$	10,127,850
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(e)	5,267,994		5,267,994
TOTAL INVESTMENT COMPANIES		$	15,395,844
Total Investments		$	1,248,869,057
Other Assets and Liabilities — (0.93)%			(11,565,825	)

Total Net Assets — 100.00%		$	1,237,303,232

^(a)	Non-income producing security.
^(b)	Security or a portion of the security was on loan. At the end of the period, the value of these securities totaled $9,684,920 or 0.78% of net assets.

See accompanying notes.

139

Schedule of Investments
Principal U.S. Small-Cap Multi-Factor ETF
December 31, 2021 (unaudited)

^(c)	Security or a portion of the security was received as collateral for securities lending. At the end of the period, the value of these securities totaled $10,127,850 or 0.82% of net assets.
^(d)	Affiliated Security. Security is either an affiliate (and registered under the Investment Company Act of 1940) or an affiliate as defined by the Investment Company Act of 1940 (controls 5.00% or more of the outstanding voting shares of the security).
	Please see Affiliated Securities sub-schedule for transactional information.
^(e)	Current yield shown is as of period end.


Portfolio Summary (unaudited)
Sector					Percent
Financial					25.16		%
Consumer, Non-cyclical					21.52		%
Consumer, Cyclical					15.04		%
Industrial					13.15		%
Technology					8.14		%
Communications					6.06		%
Energy					4.48		%
Basic Materials					3.31		%
Utilities					2.83		%
Money Market Funds					1.24		%
Other Assets and Liabilities					(0.93		)%
TOTAL NET ASSETS					100.00		%

			June 30, 2021		Purchases				Sales		December 31, 2021
Affiliated Securities			Value		Cost				Proceeds		Value
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	16,551,960	$	131,023,237			$	137,447,347	$	10,127,850
		$	16,551,960	$	131,023,237			$	137,447,347	$	10,127,850

									Realized Gain
					Realized				from		Change in
					Gain/Loss on				Capital Gain		Unrealized
			Income ^(a)		Investments				Distributions		Gain/Loss
Principal Government Money
Market Fund — Institutional Class
0.00	%	$	—		$	—		$	—	$	—
		$	—		$	—		$	—	$	—

^(a)	Amount excludes earnings from securities lending collateral.

See accompanying notes.

140


Schedule of Investments
Principal Value ETF
December 31, 2021 (unaudited)

COMMON STOCKS — 99.61%	Shares Held		Value
Advertising — 1.93%
Interpublic Group of Cos., Inc.	42,406	$	1,588,105
Aerospace & Defense — 3.50%
General Dynamics Corp.	4,527		943,744
L3Harris Technologies, Inc.	2,535		540,563
Lockheed Martin Corp.	2,143		761,644
Northrop Grumman Corp.	1,628		630,150
		$	2,876,101

Agriculture — 2.80%
Altria Group, Inc.	48,471		2,297,041
Banks — 5.10%
Citigroup, Inc.	12,899		778,971
First Horizon Corp.	74,075		1,209,645
Regions Financial Corp.	47,552		1,036,633
State Street Corp.	12,526		1,164,918
		$	4,190,167

Biotechnology — 0.87%
Amgen, Inc.	3,175		714,280
Building Materials — 1.20%
Fortune Brands Home & Security, Inc.	3,410		364,529
Masco Corp.	4,768		334,809
Vulcan Materials Co.	1,402		291,027
		$	990,365

Chemicals — 3.11%
Celanese Corp.	3,533		593,756
Dow, Inc.	21,709		1,231,335
NewMarket Corp.	1,292		442,794
Sherwin-Williams Co.	820		288,771
		$	2,556,656

Commercial Services — 4.08%
Automatic Data Processing, Inc.	3,063		755,274
Booz Allen Hamilton Holding Corp.	4,725		400,633
ManpowerGroup, Inc.	6,818		663,596
Quanta Services, Inc.	1,104		126,584
Robert Half International, Inc.	7,188		801,606
Service Corp. International	8,526		605,261
		$	3,352,954

Computers — 3.57%
Apple, Inc.	1,277		226,757
Cognizant Technology Solutions Corp., Class A	3,696		327,909
Genpact Ltd.	5,956		316,145
HP, Inc.	25,857		974,033
NetApp, Inc.	11,812		1,086,586
		$	2,931,430

Construction Materials — 0.85%
Lennox International, Inc.	1,032		334,740
Owens Corning	3,999		361,909
		$	696,649

Distribution/Wholesale — 1.23%
Fastenal Co.	15,768		1,010,098
Diversified Financial Services — 6.07%
Ameriprise Financial, Inc.	2,439		735,749
Cboe Global Markets, Inc.	4,348		566,979
Jefferies Financial Group, Inc.	21,402		830,398

See accompanying notes.

141


Schedule of Investments
Principal Value ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value

Diversified Financial Services (continued)
Raymond James Financial, Inc.	5,098	$	511,839
Synchrony Financial	16,839		781,161
T Rowe Price Group, Inc.	3,793		745,855
Western Union Co.	45,388		809,722
		$	4,981,703

Electric — 1.17%
NRG Energy, Inc.	22,317		961,416

Electrical Components & Equipment — 0.23%
AMETEK, Inc.	1,290		189,682

Electronics — 1.28%
Allegion PLC	2,577		341,298
Hubbell, Inc.	3,425		713,325
		$	1,054,623

Environmental Control — 0.22%
Tetra Tech, Inc.	1,052		178,630

Food — 2.00%
Kroger Co.	17,071		772,634
Tyson Foods, Inc., Class A	9,964		868,462
		$	1,641,096

Gas — 1.40%
UGI Corp.	25,051		1,150,091

Hand/Machine Tools — 0.86%
Snap-on, Inc.	3,274		705,154

Healthcare — Services — 2.30%
Anthem, Inc.	996		461,686
Humana, Inc.	407		188,791
Quest Diagnostics, Inc.	4,084		706,573
UnitedHealth Group, Inc.	1,063		533,774
		$	1,890,824

Home Builders — 2.18%
DR Horton, Inc.	3,466		375,888
Lennar Corp., Class A	2,526		293,420
PulteGroup, Inc.	6,510		372,112
Thor Industries, Inc.	3,811		395,467
Toll Brothers, Inc.	4,844		350,657
		$	1,787,544

Home Furnishings — 1.03%
Whirlpool Corp.	3,602		845,245

Household Products/Wares — 0.65%
Clorox Co.	3,054		532,495

Housewares — 1.27%
Newell Brands, Inc.	47,702		1,041,812

Insurance — 16.19%
Aflac, Inc.	13,516		789,199
Alleghany Corp. ^(a)	978		652,903
Allstate Corp.	4,742		557,896
American Financial Group, Inc.	12,777		1,754,538
Assurant, Inc.	3,904		608,477
Essent Group Ltd.	9,205		419,104
Fidelity National Financial, Inc.	23,023		1,201,340
First American Financial Corp.	16,750		1,310,352
Hartford Financial Services Group, Inc.	13,348		921,546
Old Republic International Corp.	59,876		1,471,752

See accompanying notes.

142


Schedule of Investments
Principal Value ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Insurance (continued)
Primerica, Inc.	2,139	$	327,845
Progressive Corp.	8,004		821,611
Prudential Financial, Inc.	16,603		1,797,109
Travelers Cos., Inc.	4,238		662,950
		$	13,296,622

Internet — 0.94%
CDW Corp.	1,905		390,106
eBay, Inc.	5,719		380,313
		$	770,419

Iron & Steel — 0.80%
Reliance Steel & Aluminum Co.	4,055		657,802
Leisure Time — 1.22%
Brunswick Corp.	3,722		374,917
Polaris, Inc.	5,677		623,959
		$	998,876

Machinery — Construction & Mining — 0.47%
Oshkosh Corp.	3,449		388,737
Machinery — Diversified — 0.18%
AGCO Corp.	1,283		148,854
Media — 1.63%
Fox Corp., Class A	12,188		449,737
Nexstar Media Group, Inc., Class A	3,832		578,555
ViacomCBS, Inc., Class B	10,269		309,919
		$	1,338,211

Mining — 0.62%
Newmont Corp.	8,182		507,448
Miscellaneous Manufacture — 1.50%
AO Smith Corp.	7,662		657,783
Carlisle Cos., Inc.	2,316		574,646
		$	1,232,429

Oil & Gas — 1.25%
EOG Resources, Inc.	11,595		1,029,984
Packaging & Containers — 1.16%
Sealed Air Corp.	8,554		577,139
Silgan Holdings, Inc.	8,729		373,950
		$	951,089

Pharmaceuticals — 4.38%
Bristol-Myers Squibb Co.	15,348		956,948
Cardinal Health, Inc.	22,376		1,152,140
CVS Health Corp.	10,966		1,131,252
McKesson Corp.	1,438		357,444
		$	3,597,784

Pipelines — 3.68%
Equitrans Midstream Corp.	292,424		3,023,664
REITs — 3.47%
Essex Property Trust, Inc.	4,331		1,525,508
VICI Properties, Inc.	44,080		1,327,249
		$	2,852,757

Retail — 6.14%
Advance Auto Parts, Inc.	1,014		243,239

See accompanying notes.

143


Schedule of Investments
Principal Value ETF
December 31, 2021 (unaudited)

COMMON STOCKS (continued)	Shares Held		Value
Retail (continued)
Best Buy Co., Inc.	5,585	$	567,436
Dollar General Corp.	904		213,190
Home Depot, Inc.	2,229		925,057
Lowe's Cos., Inc.	2,231		576,669
Qurate Retail, Inc., Series A	194,427		1,477,645
Tractor Supply Co.	1,702		406,097
Williams-Sonoma, Inc.	3,749		634,069
		$	5,043,402

Semiconductors — 3.53%
Broadcom, Inc.	1,664		1,107,242
Entegris, Inc.	810		112,250
Intel Corp.	11,199		576,748
KLA Corp.	1,103		474,411
Texas Instruments, Inc.	3,348		630,998
		$	2,901,649

Shipbuilding — 0.82%
Huntington Ingalls Industries, Inc.	3,619		675,812
Software — 1.03%
Cerner Corp.	3,588		333,217
Oracle Corp.	5,890		513,667
		$	846,884

Telecommunications — 1.70%
Juniper Networks, Inc.	38,975		1,391,797
TOTAL COMMON STOCKS		$	81,818,381
INVESTMENT COMPANIES — 0.33%	Shares Held		Value
Money Market Fund — 0.33%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	273,672	$	273,672
TOTAL INVESTMENT COMPANIES		$	273,672
Total Investments		$	82,092,053
Other Assets and Liabilities — 0.06%			48,438
Total Net Assets — 100.00%		$	82,140,491

^(a)	Non-income producing security.
^(b)	Current yield shown is as of period end.


Portfolio Summary (unaudited)

Sector	Percent
Financial	30.83	%
Consumer, Non-cyclical	17.08	%
Consumer, Cyclical	13.06	%
Industrial	12.28	%
Technology	8.13	%
Communications	6.19	%
Energy	4.94	%
Basic Materials	4.53	%
Utilities	2.57	%
Money Market Fund	0.33	%
Other Assets and Liabilities	0.06	%
TOTAL NET ASSETS	100.00	%

See accompanying notes.

144


		Financial Highlights
	Principal Exchange-Traded Funds
		(unaudited)
Principal Active High Yield ETF ^(a)
For a share outstanding:
	Period ended				Year ended				Year ended		Year ended				Year ended					Year ended
	December 31, 2021 ^(b)				June 30, 2021		June 30, 2020				June 30, 2019				June 30, 2018					June 30, 2017

Net asset value, beginning of period	$	20.85	^(c)	$	18.07	^(c)		$	19.96	^(c)		$	20.14^(c)			$	20.66	^(c)	$	19.56	^(c)

Investment Operations:
Net investment income (loss) ^(d)		0.41			0.77	^(c)			0.94	^(c)			0.96	^(c)			0.89	^(c)		0.98	^(c)
Net realized and change in unrealized gain (loss)		0.16			2.82	^(c)			(1.86)	^(c)			(0.01)	^(c)			(0.25)	^(c)		1.11	^(c)
Total from investment operations		0.57			3.59	^(c)			(0.92)	^(c)			0.95	^(c)			0.64	^(c)		2.09	^(c)

Dividends to Shareholders from:
Net investment income		(0.68	)		(0.81)	^(c)			(0.97)	^(c)			(0.96)	^(c)			(0.94)	^(c)		(0.99)	^(c)
Net realized gains		—			^—(c)				^—(c)				(0.17)	^(c)			(0.22)	^(c)		^—(c)
Total dividends to stockholders		(0.68	)		(0.81)	^(c)			(0.97)	^(c)			(1.13)	^(c)			(1.16)	^(c)		(0.99)	^(c)

Net asset value, end of period	$	20.74		$	20.85	^(c)		$	18.07	^(c)			$ 19.96	^(c)		$	20.14	^(c)	$	20.66	^(c)
Total return		2.17	% ^(e)		20.25	%			(4.78)	%			4.95	%			3.10	%		10.92	%

Ratios/Supplemental Data:
Net assets, end of year (000s)	$	244,714		$	232,443			$	270,096			$	216,519		$		292,967	$		286,084
Ratio of expenses to average net assets		0.42%	^(f)		0.49	%			0.49	%			0.61	%			0.65	% ^(g)		0.77	% ^(g)
Ratio of gross expenses to average net assets		—% ^(h)			—% ^(h)				—% ^(h)				—%^(h)				0.68	%		0.80	%
Ratio of net investment income (loss) to average net assets		3.93%	^(f)		3.90	%			4.89	%			4.84	%			4.34	%		4.82	%
Portfolio turnover rate ⁽ⁱ⁾		90.6%			19.5	%			10.6	%			17.9	%			11.0	%		30.7	%

^(a)	Effective September 1, 2021, Principal Active Income ETF changed its name to Principal Active High Yield ETF.
^(b)	Six months ended December 31, 2021.
^(c)	Reflects a 2 to 1 stock split effective after the close of trading on August 30, 2021, see Notes to Financial Statements.
^(d)	Calculated on average shares outstanding during the period.
^(e)	Total return amounts have not been annualized.
(f)	Computed on an annualized basis.
^(g)	Includes reimbursement from Advisor.
^(h)	Ratio is not applicable as there was no reimbursement from Advisor in the year.
(i)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

146


		Financial Highlights
		Principal Exchange-Traded Funds
		(unaudited)
Principal Healthcare Innovators ETF ^(a)
For a share outstanding:
		Period ended		Year ended			Year ended				Year ended			Year ended			Period ended
		December 31, 2021 ^(b)		June 30, 2021			June 30, 2020				June 30, 2019			June 30, 2018			June 30, 2017 ^(c)

Net asset value, beginning of period	$	60.76		$	44.34		$	34.37		$	34.74		$	28.56		$	25.00

Investment Operations:
Net investment income (loss) ^(d)		(0.09	)		(0.15	)		(0.10	)		(0.13	)		(0.12	)		(0.08	)
Net realized and change in unrealized gain (loss)		(12.86	)		16.79			10.07			(0.24	)		6.35			3.64
Total from investment operations		(12.95	)		16.64			9.97			(0.37	)		6.23			3.56

Dividends to Shareholders from:
Net investment income		(0.45	)		—			—			—			—			—
Net realized gains		—			(0.22	)		—			—			(0.05	)		—
Total dividends to stockholders		(0.45	)		(0.22	)		—			—			(0.05	)		—

Net asset value, end of period	$	47.36		$	60.76		$	44.34		$	34.37		$	34.74		$	28.56
Total return		(21.30	)% ^(e)		37.51	%		29.01	%		(1.05	)%		21.83	%		14.24	% ^(e)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	89,982		$	176,197		$	95,338		$	56,713		$	52,104		$	7,140
Ratio of expenses to average net assets		0.42	% ^(f)		0.42	%		0.42	%		0.42	%		0.42	%		0.42	% ^(f)
Ratio of net investment loss to average net assets		(0.33	)% ^(f)		(0.27	)%		(0.29	)%		(0.39	)%		(0.38	)%		(0.32	)% ^(f)
Portfolio turnover rate ^(g)		25.7	%		45.8	%		36.1	%		34.5	%		33.6	%		18.2	% ^(f)

^(a)	Effective October 29, 2021, Principal Healthcare Innovators Index ETF changed its name to Principal Healthcare Innovators ETF.
^(b)	Six months ended December 31, 2021.
^(c)	Period from August 19, 2016, date operations commenced, through June 30, 2017.
^(d)	Calculated on average shares outstanding during the period.
^(e)	Total return amounts have not been annualized.
(f)	Computed on an annualized basis.
^(g)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

147


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)
Principal International Adaptive Multi-Factor ETF
For a share outstanding:
		Period ended			Period ended
		December 31, 2021 ^(a)			June 30, 2021 ^(b)

Net asset value, beginning of period	$	24.80		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.27			0.07
Net realized and change in unrealized gain (loss)		0.47			(0.27	)
Total from investment operations		0.74			(0.20	)

Dividends to Shareholders from:
Net investment income		(0.29	)		—
Total dividends to stockholders		(0.29	)		—

Net asset value, end of period	$	25.25		$	24.80
Total return ^(d)		3.01	%		(0.80	)%

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	131,296		$	47,118
Ratio of expenses to average net assets ^(e)		0.24	%		0.24	%
Ratio of net investment income (loss) to average net assets ^(e)		2.15	%		2.76	%
Portfolio turnover rate ^(f)		33.1	%		1.5	%

^(a)	Six months ended December 31, 2021.
^(b)	Period from May 26, 2021, date operations commenced, through June 30, 2021
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

148


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal Investment Grade Corporate Active ETF
For a share outstanding:
		Period ended			Year ended			Year ended			Year ended			Period ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020			June 30, 2019			June 30, 2018 ^(b)

Net asset value, beginning of period	$	26.74		$	26.67		$	26.20		$	24.59		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.32			0.62			0.88			0.95			0.19
Net realized and change in unrealized gain (loss)		(0.27	)		0.69			1.39			1.66			(0.52	)
Total from investment operations		0.05			1.31			2.27			2.61			(0.33	)

Dividends to Shareholders from:
Net investment income		(0.46	)		(0.79	)		(0.95	)		(0.98	)		(0.08	)
Net realized gains		(0.07	)		(0.45	)		(0.85	)		(0.02	)		—
Total dividends to stockholders		(0.53	)		(1.24	)		(1.80	)		(1.00	)		(0.08	)

Net asset value, end of period	$	26.26		$	26.74		$	26.67		$	26.20		$	24.59
Total return		0.20%	^(d)		4.90	%		8.98	%		10.95	%		(1.32)%	^(d)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	489,806		$	481,271		$	110,693		$	120,540		$	228,710
Ratio of expenses to average net assets		0.19%	^(e)		0.25	%		0.26	%		0.26	%		0.26%	^(e)
Ratio of net investment income (loss) to average net assets		2.35%	^(e)		2.30	%		3.37	%		3.86	%		3.83%	^(e)
Portfolio turnover rate ^(f)		23.4%			67.8	%		73.3	%		92.8	%		47.8%	^(e)

(a)	Six months ended December 31, 2021.
(b)	Period from April 18, 2018, date operations commenced, through June 30, 2018.
(c)	Calculated on average shares outstanding during the period.
(d)	Total return amounts have not been annualized.
(e)	Computed on an annualized basis.
(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

149


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)
Principal Millennials ETF ^(a)
For a share outstanding:
	Period ended				Year ended			Year ended			Year ended			Year ended			Period ended
	December 31, 2021 ^(b)				June 30, 2021			June 30, 2020			June 30, 2019			June 30, 2018			June 30, 2018^(c)

Net asset value, beginning of period	$	66.53		$	42.85		$	38.24		$	36.76		$	28.92		$	25.00

Investment Operations:
Net investment income (loss) ^(d)		1.58			0.27			0.34			0.17			0.23			0.17
Net realized and change in unrealized gain (loss)		(8.72	)		23.81			4.59			1.54			7.91			3.87
Total from investment operations		(7.14	)		24.08			4.93			1.71			8.14			4.04

Dividends to Shareholders from:
Net investment income		(1.60	)		(0.40	)		(0.32	)		(0.23	)		(0.23	)		(0.09	)
Net realized gains		—			—			—			—			(0.07	)		(0.03	)
Total dividends to stockholders		(1.60	)		(0.40	)		(0.32	)		(0.23	)		(0.30	)		(0.12	)

Net asset value, end of period	$	57.79		$	66.53		$	42.85		$	38.24		$	36.76		$	28.92
Total return		(10.72	)% ^(e)		56.45	%		12.96	%		4.70	%		28.31	%		16.23	% ^(e)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	104,030		$	126,399		$	25,708		$	21,031		$	20,217		$	7,230
Ratio of expenses to average net assets		0.45	% ^(f)		0.45	%		0.45	%		0.45	%		0.45	%		0.45	% ^(f)
Ratio of expenses to average net assets excluding interest
expense		—% ^(g)			—% ^(g)			—% ^(g)			—% ^(g)			0.45	%		—% ^(g)
Ratio of net investment income (loss) to average net assets		5.02	% ^(f)		0.46	%		0.88	%		0.47	%		0.66	%		0.71	% ^(f)
Portfolio turnover rate ^(h)		7.0	%		55.7	%		47.4	%		32.9	%		35.6	%		5.1	% ^(f)

^(a)	Effective October 29, 2021, Principal Millennials Index ETF changed its name to Principal Millennials ETF.
^(b)	Six months ended December 31, 2021.
^(c)	Period from August 19, 2016, date operations commenced, through June 30, 2017.
^(d)	Calculated on average shares outstanding during the period.
^(e)	Total return amounts have not been annualized.
(f)	Computed on an annualized basis.
^(g)	Ratio is not applicable as there was no interest expense in the period.
^(h)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

150


		Financial Highlights
	Principal Exchange-Traded Funds
		(unaudited)
Principal Quality ETF
For a share outstanding:
	Period ended				Year ended				Year ended			Year ended			Year ended		Year ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020				June 30, 2019		June 30, 2018				June 30, 2017

Net asset value, beginning of period	$	53.17			$	39.89		$	37.79		$	33.32		$	29.03		$	26.08

Investment Operations:
Net investment income (loss) ^(b)		0.30				0.57			0.51			0.46			0.39			0.34
Net realized and change in unrealized gain (loss)		7.40				13.22			1.00			4.48			4.20			3.06
Net realized gain due from reimbursement from
Advisor		—				—			1.13	^(c)		—			—			—
Total from investment operations		7.70				13.79			2.64			4.94			4.59			3.40

Dividends to Shareholders from:
Net investment income		(0.41	)			(0.51	)		(0.54	)		(0.47	)		(0.27	)		(0.39	)
Net realized gains		—				—			—			—			(0.03	)		(0.06	)
Total dividends to stockholders		(0.41	)			(0.51	)		(0.54	)		(0.47	)		(0.30	)		(0.45	)

Net asset value, end of period	$	60.46			$	53.17		$	39.89		$	37.79		$	33.32		$	29.03
Total return		14.53	% ^(d)			34.83	%		7.05% ^(c)			15.03	%		15.89	%		13.23	%

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	96,729		$	58,486			$	17,951		$	20,786		$	21,655		$	7,257
Ratio of expenses to average net assets		0.15	% ^(e)			0.15	%		0.29%	^(f)		0.29%	^(f)		0.29%	^(f)		0.40	%
Ratio of gross expenses to average net assets		—% ^(g)				—%	^(g)		0.34	%		0.40	%		0.40	%		—% ^(g)
Ratio of net investment income (loss) to average net assets		1.05	% ^(e)			1.22	%		1.32	%		1.32	%		1.22	%		1.26	%
Portfolio turnover rate ^(h)		0.2	%			45.1	%		103.7	%		40.4	%		63.5	%		2.0	%

^(a)	Six months ended December 31, 2021.
^(b)	Calculated on average shares outstanding during the period.
^(c)	During 2020, the Fund experienced a significant one-time gain as the result of a payment by the Advisor due to an operational error by a third party. If such payment had not been recognized, the total return amounts expressed herein would have been lower by 3.04%.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
(f)	Includes reimbursement from Advisor.
^(g)	Ratio is not applicable as there was no reimbursement from Advisor in the year.
^(h)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

151


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal Spectrum Preferred Securities Active ETF
For a share outstanding:
		Period ended			Year ended			Year ended			Year ended			Period ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020			June 30, 2019			June 30, 2018 ^(b)

Net asset value, beginning of period	$	20.64		$	19.31	^(c)	$	19.36	^(c)	$	18.89	^(c)	$	20.00	^(c)

Investment Operations:
Net investment income (loss) ^(d)		0.32			0.70			0.80	^(c)		0.68	^(c)		0.94	^(c)
Net realized and change in unrealized gain (loss)		(0.28	)		1.86			0.08	^(c)		0.77	^(c)		(1.18	) ^(c)
Total from investment operations		0.04			2.56			0.88	^(c)		1.45	^(c)		(0.24	) ^(c)

Dividends to Shareholders from:
Net investment income		(0.48	)		(1.23	)		(0.93	) ^(c)		(0.98	) ^(c)		(0.87	) ^(c)
Net realized gains		—			—			^—(c)			^—(c)			(0.00) ^(c),(e)
Total dividends to stockholders		(0.48	)		(1.23	)		(0.93	) ^(c)		(0.98	) ^(c)		(0.87	) ^(c)

Net asset value, end of period	$	20.20		$	20.64		$	19.31	^(c)	$	19.36	^(c)	$	18.89	^(c)
Total return		0.14	% ^(f)		11.58	%		4.60	%		7.99	%		(1.28	)% ^(f)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	451,378		$	363,333		$	139,995		$	67,750		$	51,949
Ratio of expenses to average net assets		0.55	% ^(g)		0.55	%		0.55	%		0.55	%		0.55	% ^(g)
Ratio of net investment income (loss) to average net assets		3.07	% ^(g)		3.43	%		4.10	%		3.65	%		4.93	% ^(g)
Portfolio turnover rate ^(h)		3.1	%		12.6	%		41.9	%		27.6	%		41.0	% ^(g)

^(a)	Six months ended December 31, 2021.
^(b)	Period from July 7, 2017, date operations commenced, through June 30, 2018.
^(c)	Reflects a 5 to 1 stock split effective after the close of trading on July 22, 2020; see Notes to Financial Statements.
^(d)	Calculated on average shares outstanding during the period.
^(e)	Reflects an amount rounding to less than one cent.
^(f)	Total return amounts have not been annualized.
^(g)	Computed on an annualized basis.
^(h)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

152


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal Spectrum Tax-Advantaged Dividend Active ETF
For a share outstanding:
	Period ended				Year ended			Period ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020 ^(b)

Net asset value, beginning of period	$	21.57		$	19.95		$	20.00

Investment Operations:
Net investment income (loss) ^(c)		0.42			0.88			0.03
Net realized and change in unrealized gain (loss)		(0.39	)		1.76			(0.08	)
Total from investment operations		0.03			2.64			(0.05	)

Dividends to Shareholders from:
Net investment income		(0.58	)		(0.98	)		—
Net realized gains		(0.09	)		(0.04	)		—
Total dividends to stockholders		(0.67	)		(1.02	)		—

Net asset value, end of period	$	20.93		$	21.57		$	19.95
Total return		0.10	% ^(d)		13.42	%		(0.26)	% ^(d)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	24,064		$	22,647		$	19,948
Ratio of expenses to average net assets		0.60	% ^(e)		0.60	%		0.60	% ^(e)
Ratio of net investment income (loss) to average net assets		3.92	% ^(e)		4.15	%		4.35	% ^(e)
Portfolio turnover rate		1.4	%		15.5	%		6.3	%

^(a)	Six months ended December 31, 2021.
^(b)	Period from June 16, 2020, date operations commenced, through June 30, 2020.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.

See accompanying notes.

153


	Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal Ultra-Short Active Income ETF
For a share outstanding:
		Period ended			Year ended			Year ended			Period ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020			June 30, 2019 ^(b)

Net asset value, beginning of period	$	24.73		$	25.02		$	25.09		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.05			0.18			0.55			0.12
Net realized and change in unrealized gain (loss)		(0.11	)		(0.04	)		0.07			0.04
Total from investment operations		(0.06	)		0.14			0.62			0.16

Dividends to Shareholders from:
Net investment income		(0.16	)		(0.43	)		(0.69	)		(0.07	)
Total dividends to stockholders		(0.16	)		(0.43	)		(0.69	)		(0.07	)

Net asset value, end of period	$	24.51		$	24.73		$	25.02		$	25.09
Total return		(0.26)%	^(d)		0.57	%		2.54	%		0.62%	^(d)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	8,579		$	8,657		$	12,509		$	12,543
Ratio of expenses to average net assets		0.18	% ^(e)		0.18	%		0.18	%		0.18%	^(e)
Ratio of net investment income (loss) to average net assets		0.38	% ^(e)		0.72	%		2.19	%		2.51%	^(e)
Portfolio turnover rate		34.0	%		88.1	%		32.7	%		0.0% ^(e),(f)

^(a)	Six months ended December 31, 2021.
^(b)	Period from April 24, 2019, date operations commenced, through June 30, 2019.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
^(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

154


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)
Principal U.S. Large-Cap Adaptive Multi-Factor ETF
For a share outstanding:
		Period ended			Period ended
		December 31, 2021 ^(a)			June 30, 2021 ^(b)

Net asset value, beginning of period	$	25.95		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.16			0.03
Net realized and change in unrealized gain (loss)		2.99			0.92
Total from investment operations		3.15			0.95

Dividends to Shareholders from:
Net investment income		(0.15	)		—
Total dividends to stockholders		(0.15	)		—

Net asset value, end of period	$	28.95		$	25.95
Total return ^(d)		12.18	%		3.80	%

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	131,741		$	29,842
Ratio of expenses to average net assets ^(e)		0.15	%		0.15	%
Ratio of net investment income (loss) to average net assets ^(e)		1.18	%		0.99	%
Portfolio turnover rate ^(f)		36.6	%		0.4	%

^(a)	Six months ended December 31, 2021.
^(b)	Period from May 19, 2021, date operations commenced, through June 30, 2021.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

155


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal U.S. Mega-Cap ETF
For a share outstanding:
		Period ended			Year ended			Year ended			Year ended			Period ended
	December 31, 2021^(a)				June 30, 2021			June 30, 2020			June 30, 2019			June 30, 2018 ^(b)

Net asset value, beginning of period	$	39.68		$	30.04		$	29.07		$	26.02		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.33			0.59			0.60			0.63			0.38
Net realized and change in unrealized gain (loss)		4.84			9.60			1.00			3.04			0.80
Total from investment operations		5.17			10.19			1.60			3.67			1.18

Dividends to Shareholders from:
Net investment income		(0.53	)		(0.55	)		(0.63	)		(0.62	)		(0.16	)
Total dividends to stockholders		(0.53	)		(0.55	)		(0.63	)		(0.62	)		(0.16	)

Net asset value, end of period	$	44.32		$	39.68		$	30.04		$	29.07		$	26.02
Total return		13.12	% ^(d)		34.25	%		5.62	%		14.32	%		4.73	% ^(d)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	1,865,701		$	1,958,064		$	1,505,046		$	1,618,941		$	1,666,525
Ratio of expenses to average net assets ^(e)		0.12	% ^(f)		0.12	%		0.12	%		0.12	%		0.12	% ^(f)
Ratio of gross expenses to average net assets		0.15	% ^(f)		0.15	%		0.15	%		0.15	%		0.15	% ^(f)
Ratio of net investment income (loss) to average net assets		1.56	% ^(f)		1.67	%		2.05	%		2.30	%		2.02	% ^(f)
Portfolio turnover rate ^(g)		11.1	%		42.9	%		42.9	%		27.0	%		39.8	% ^(f)

^(a)	Six months ended December 31, 2021.
^(b)	Period from October 11, 2017, date operations commenced, through June 30, 2018.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Includes reimbursement from Advisor.
(f)	Computed on an annualized basis.
^(g)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

156


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)
Principal U.S. Small-Cap Adaptive Multi-Factor ETF
For a share outstanding:
		Period ended			Period ended
		December 31, 2021 ^(a)			June 30, 2021 ^(b)

Net asset value, beginning of period	$	25.61		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.26			0.03
Net realized and change in unrealized gain (loss)		1.20			0.58
Total from investment operations		1.46			0.61

Dividends to Shareholders from:
Net investment income		(0.30	)		—
Net realized gains		(0.13	)		—
Total dividends to stockholders		(0.43	)		—

Net asset value, end of period	$	26.64		$	25.61
Total return ^(d)		5.72	%		2.44	%

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	6,661		$	6,403
Ratio of expenses to average net assets ^(e)		0.19	%		0.19	%
Ratio of net investment income (loss) to average net assets ^(e)		2.03	%		0.96	%
Portfolio turnover rate ^(f)		42.6	%		0.2	%

^(a)	Six months ended December 31, 2021.
^(b)	Period from May 19, 2021, date operations commenced, through June 30, 2021.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

157


		Financial Highlights
		Principal Exchange-Traded Funds
					(unaudited)
Principal U.S. Small-Cap Multi-Factor ETF
For a share outstanding:
		Period ended			Year ended			Year ended			Year ended			Year ended			Period ended
	December 31, 2021 ^(a)				June 30, 2021		June 30, 2020				June 30, 2019			June 30, 2018			June 30, 2017 ^(b)

Net asset value, beginning of period	$	46.92		$	27.36		$	31.43		$	33.45		$	28.84		$	25.00

Investment Operations:
Net investment income (loss) ^(c)		0.42			0.54			0.45			0.40			0.29			0.26
Net realized and change in unrealized gain
(loss)		0.64			19.51			(4.11	)		(2.03	)		4.64			3.75
Total from investment operations		1.06			20.05			(3.66	)		(1.63	)		4.93			4.01

Dividends to Shareholders from:
Net investment income		(0.57	)		(0.49	)		(0.41	)		(0.39	)		(0.30	)		(0.17	)
Net realized gains		—			—			—			—			(0.02	)		—
Total dividends to stockholders		(0.57	)		(0.49	)		(0.41	)		(0.39	)		(0.32	)		(0.17	)

Net asset value, end of period	$	47.41		$	46.92		$	27.36		$	31.43		$	33.45		$	28.84
Total return		2.29	% ^(d)		74.05	%		(11.71	)%		(4.84	)%		17.14	%		16.08	% ^(d)

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	1,237,303		$	1,628,003		$	328,305		$	355,200		$	351,176		$	275,466
Ratio of expenses to average net assets		0.38	% ^(e)		0.38	%		0.38	%		0.38	%		0.38	%		0.38	% ^(e)
Ratio of net investment income (loss) to average
net assets		1.78	% ^(e)		1.39	%		1.54	%		1.27	%		0.94	%		1.21	% ^(e)
Portfolio turnover rate ^(f)		33.4	% ^(e)		93.1	%		80.4	%		81.9	%		76.3	%		44.7	% ^(e)

^(a)	Six months ended December 31, 2021.
^(b)	Period from September 21, 2016, date operations commenced, through June 30, 2017.
^(c)	Calculated on average shares outstanding during the period.
^(d)	Total return amounts have not been annualized.
^(e)	Computed on an annualized basis.
(f)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

158


Financial Highlights
Principal Exchange-Traded Funds
(unaudited)

Principal Value ETF
For a share outstanding:
	Period ended				Year ended			Year ended			Year ended			Year ended			Year ended
	December 31, 2021 ^(a)				June 30, 2021			June 30, 2020			June 30, 2019			June 30, 2018			June 30, 2017

Net asset value, beginning of period	$	42.38		$	27.75		$	31.99		$	32.49		$	29.16		$	24.65

Investment Operations:
Net investment income (loss) ^(b)		0.79			1.16			0.87			0.71			0.61			0.54
Net realized and change in unrealized gain (loss)		2.30			14.52			(4.36	)		(0.51	)		3.21			4.67
Total from investment operations		3.09			15.68			(3.49	)		0.20			3.82			5.21

Dividends to Shareholders from:
Net investment income		(1.07	)		(1.05	)		(0.75	)		(0.70	)		(0.47	)		(0.67	)
Net realized gains		—			—			—			—			(0.02	)		(0.03	)
Total dividends to stockholders		(1.07	)		(1.05	)		(0.75	)		(0.70	)		(0.49	)		(0.70	)

Net asset value, end of period	$	44.40		$	42.38		$	27.75		$	31.99		$	32.49		$	29.16
Total return		7.41	% ^(c)		57.97	%		(11.09	)%		0.68	%		13.17	%		21.42	%

Ratios/Supplemental Data:
Net assets, end of period (000s)	$	82,140		$	44,498		$	31,907		$	14,395		$	14,622		$	7,290
Ratio of expenses to average net assets		0.15	% ^(d)		0.15	%		0.29	% ^(e)		0.29	% ^(e)		0.29	% ^(e)		0.40	%
Ratio of gross expenses to average net assets		—% ^(f)			—% ^(f)			0.32	%		0.40	%		0.40	%		—% ^(f)
Ratio of net investment income (loss) to average net assets		3.66	% ^(d)		3.31	%		2.95	%		2.26	%		1.90	%		1.98	%
Portfolio turnover rate ^(g)		2.1	%		44.8	%		47.6	%		49.2	%		55.5	%		3.0	%

^(a)	Six months ended December 31, 2021.
^(b)	Calculated on average shares outstanding during the period.
^(c)	Total return amounts have not been annualized.
^(d)	Computed on an annualized basis.
^(e)	Includes reimbursement from Advisor.
(f)	Ratio is not applicable as there was no reimbursement from Advisor in the period.
^(g)	Portfolio turnover rate excludes in-kind transactions.

See accompanying notes.

159

Shareholder Expense Example
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)

As a shareholder of Principal Exchange-Traded Funds, you incur two types of costs: (1) transaction costs, including brokerage commissions paid on purchases and sales of Fund shares and (2) ongoing costs, including management fees. This Example is intended to help you understand your ongoing costs (in dollars) of investing in Principal Exchange-Traded Funds and to compare these costs with the ongoing costs of investing in other exchange-traded funds.

The Examples are based on an investment of $1,000 invested at the beginning of the period and held for the entire period, July 1, 2021 through December 31, 2021, except as noted in the following table.

Actual Expenses

The first section of the table provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes

The second section of table provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other fund.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transaction costs, such as contingent deferred sales charges, redemption fees or exchange fees. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different fund. In addition, if these transaction costs were included, your costs would have been higher.


					Annualized		Expenses
				Ending	Expense		Paid During
		Beginning		Account	Ratio July 1,		Period July 1,
		Account		Value	2021 to			2021 to
		Value		December 31,	December 31,			December 31,
		July 1, 2021		2021	2021			2021	^(a)
Principal Active High Yield ETF
Actual Fund Return	$	1,000	$	1,021.70	0.42	%	$	2.19
Hypothetical 5% Annual Return		1,000		1,023.04	0.42			2.19

Principal Healthcare Innovators ETF
Actual Fund Return		1,000		787.00	0.42			1.94
Hypothetical 5% Annual Return		1,000		1,023.04	0.42			2.19

Principal International Adaptive Multi-Factor ETF
Actual Fund Return		1,000		1,030.10	0.24			1.23
Hypothetical 5% Annual Return		1,000		1,024.00	0.24			1.22

160


Shareholder Expense Example
Principal Exchange-Traded Funds
December 31, 2021 (unaudited)


					Annualized		Expenses
				Ending	Expense		Paid During
	Beginning			Account	Ratio July 1,		Period July 1,
	Account			Value	2021 to			2021 to
		Value		December 31,	December 31,			December 31,
	July 1, 2021			2021	2021			2021	^(a)
Principal Investment Grade Corporate Active ETF
Actual Fund Return	$	1,000	$	1,002.00	0.19	%	$	0.96
Hypothetical 5% Annual Return		1,000		1,024.25	0.19			0.97

Principal Millennials ETF
Actual Fund Return		1,000		892.80	0.45			2.19
Hypothetical 5% Annual Return		1,000		1,022.89	0.45			2.35

Principal Quality ETF
Actual Fund Return		1,000		1,145.30	0.15			0.81
Hypothetical 5% Annual Return		1,000		1,024.45	0.15			0.77

Principal Spectrum Preferred Securities Active ETF
Actual Fund Return		1,000		1,001.40	0.55			2.82
Hypothetical 5% Annual Return		1,000		1,022.38	0.55			2.85

Principal Spectrum Tax-Advantaged Dividend Active ETF
Actual Fund Return		1,000		1,001.00	0.60			3.08
Hypothetical 5% Annual Return		1,000		1,022.13	0.60			3.11

Principal Ultra-Short Active Income ETF
Actual Fund Return		1,000		997.40	0.18			0.91
Hypothetical 5% Annual Return		1,000		1,024.30	0.18			0.92

Principal U.S. Large-Cap Adaptive Multi-Factor ETF
Actual Fund Return		1,000		1,121.80	0.15			0.80
Hypothetical 5% Annual Return		1,000		1,024.45	0.15			0.77

Principal U.S. Mega-Cap ETF
Actual Fund Return		1,000		1,131.20	0.12			0.64
Hypothetical 5% Annual Return		1,000		1,024.60	0.12			0.61

Principal U.S. Small-Cap Adaptive Multi-Factor ETF
Actual Fund Return		1,000		1,057.20	0.19			0.99
Hypothetical 5% Annual Return		1,000		1,024.25	0.19			0.97

Principal U.S. Small-Cap Multi-Factor ETF
Actual Fund Return		1,000		1,022.90	0.38			1.94
Hypothetical 5% Annual Return		1,000		1,023.29	0.38			1.94

Principal Value ETF
Actual Fund Return		1,000		1,074.10	0.15			0.78
Hypothetical 5% Annual Return		1,000		1,024.45	0.15			0.77

^(a)	Expenses are equal to a Fund’s annualized expense ratio multiplied by the average account value over the period, multiplied by 184/365.

161

PRINCIPAL EXCHANGE-TRADED FUNDS
(unaudited)

Notification of Source of Distributions
Pursuant to Rule 19a-1 of the Investment Company Act of 1940

As noted in the table provided below, certain of the Principal Exchange-Traded Funds made distributions for the month of December 2021 for which a portion is estimated to be in excess of the Fund’s current and accumulated net income. As of December 2021, the estimated sources of these distributions were as follows:


	December 2021
Fund	Net Income		Realized Gain		Capital Sources
Principal Healthcare Innovators ETF	0.00	%	100.00	%	0.00	%
Principal International Adaptive Multi-Factor ETF	85.24		0.00		14.76
Principal Millennials ETF	98.02		1.98		0.00
Principal U.S. Mega-Cap ETF	94.15		5.85		0.00
Principal U.S. Small-Cap Adaptive Multi-Factor ETF	99.21		0.00		0.79
Principal Value ETF	97.49		2.51		0.00

The ultimate composition of these distributions may vary from the estimates provided above due to a variety of factors including future income and expenses, and realized gains and losses from the purchase and sale of securities.

Please note that this information is being provided to satisfy certain notice requirements under the Investment Company Act of 1940. Tax reporting information for shareholders of the Funds will not be available until the end of the Funds’ fiscal year.

As a result, shareholders should not use the information provided in this notice for tax reporting purposes.

162

FUND BOARD OF TRUSTEES AND OFFICERS

The Board of Trustees (the “Board”) has overall responsibility for overseeing the Fund’s operations in accordance with the Investment Act of 1940, as amended (the “1940 Act”), other applicable laws, and the Fund’s charter. Each member of the Board (“Board Member”) serves on the Board of the following investment companies sponsored by Principal Life Insurance Company: Principal Funds, Inc., Principal Variable Contracts Funds, Inc., Principal Exchange-Traded Funds, and Principal Diversified Select Real Asset Fund which are collectively referred to as the “Fund Complex”. Board Members that are affiliated persons of any investment advisor, the principal distributor, or the principal underwriter of the Fund Complex are considered “interested persons” of the Fund (as defined in the 1940 Act) and are shown below as “Interested Board Members”. Board Members who are not Interested Board Members are shown below as “Independent Board Members”.

Each Board Member generally serves until the next annual meeting of stockholders or until such Board Member’s earlier death, resignation, or removal. Independent Board Members have a 72-year age limit and, for Independent Board Members elected on or after September 14, 2021, a 72-year age limit or a 15-year term limit, whichever occurs first. The Board may waive the age or term limits in the Board’s discretion. Officers serve at the pleasure of the Board, and each officer has the same position with each investment company in the Fund Complex.


INDEPENDENT BOARD MEMBERS
			Other
Name,	Principal	Number of Portfolios	Directorships
Position Held with the Fund Complex,	Occupation(s)	in Fund Complex	Held by Board Member
Year of Birth	During past 5 years	Overseen by Board Member	During Past 5 Years


Leroy T. Barnes, Jr.	Retired	125	McClatchy Newspapers, Inc.;
Board Member since 2014			Frontier Communications,
Member, Audit Committee			Inc.; formerly, Herbalife Ltd.
1951

Craig Damos	President, C.P. Damos	125	None
Lead Independent Board Member since 2020	Consulting LLC
Board Member since 2014
Member, Nominating and Governance
Committee
Member, Executive Committee
1954

Fritz S. Hirsch	Interim CEO, MAM	125	MAM USA
Board Member since 2014	USA: February 2020 to
Member, Nominating and Governance	October
Committee	2020
Chair, 15(c) Committee
1951

Victor Hymes	Founder and Managing	125	Formerly, Montgomery Street
Board Member since 2020	Member of Legato		Income Securities Inc.
Chair, Audit Committee	Capital Management,
Member, Nominating and Governance	LLC
Committee
1957

163


			Other
Name,	Principal	Number of Portfolios	Directorships
Position Held with the Fund Complex,	Occupation(s)	in Fund Complex	Held by Board Member
Year of Birth	During past 5 years	Overseen by Board Member	During Past 5 Years

Padelford (“Padel”) L. Lattimer	TBA Management	125	None
Board Member since 2020	Consulting LLC
Member, Operations Committee
Member, 15(c) Committee
1961

Karen (“Karrie”) McMillan	Founder/Owner, Tyche	125	None
Board Member since 2014	Consulting LLC
Chair, Operations Committee	Formerly, Managing
1961	Director, Patomak
	Global Partners, LLC.

Elizabeth A. Nickels	Retired	125
Board Member since 2015			SpartanNash; formerly:
Member, Audit Committee			Charlotte Russe; Follet
Chair, Nominating and Governance			Corporation; PetSmart;
Committee			Spectrum Health Systems
1962

Mary M. (“Meg”) VanDeWeghe	CEO and President,	125	Helmerich & Payne;
Board Member since 2018	Forte Consulting, Inc.		Formerly: B/E Aerospace;
Member, Audit Committee			Brown Advisory; Denbury
Member, 15(c) Committee			Resources Inc.; Nalco (and its
1959			successor Ecolab); and WP
			Carey

164


INTERESTED BOARD MEMBERS

			Number of	Other
Name,			Portfolios in	Directorships
Position Held with the Fund			Fund Complex	Held by Board
Complex,	Principal Occupation(s)		Overseen	Member
Year of Birth	During past 5 years		by Trustee	During Past 5 Years
Timothy M. Dunbar	President-Principal Global Asset Management		125	None
Chair and Trustee since 2019	(“PGAM”), Principal Global Investors, LLC
Chair, Executive Committee	(“PGI”) (2018-2021)
1957	Director, PGI (2018-2020)
	Division President, Principal Financial Services,
	Inc. (“PFSI) and Principal Life Insurance
	Company (“PLIC”) (2020–2021)
	Executive Vice President and Chief Investment
	Officer, PFSI and PLIC (2014-2018)
	President-PGAM, PFSI and PLIC (2018-2020)
	Director, Post Advisory Group, LLC (“Post”)
	(2018-2020)
	Chair and Executive Vice President,
	RobustWealth, Inc. (2018-2020)

Patrick G. Halter	Chair, PGI (since 2018)		125	None
Trustee since 2017	Chief Executive Officer and President, PGI and
Member, Executive Committee	Principal Real Estate Investors, LLC (“Principal-
1959	REI”) (since 2018)
	Chief Operating Officer, PGI (2017-2018)
	Director, PGI (2003-2018)
	Director, Origin Asset Management LLP (2018-
	2019	)
	President, PGAM, PFSI, and PLIC (since 2020)
	Chief Executive Officer and President, PLIC
	(2018-2020)
	Chair, Post (2017-2020)
	Director, Post (since 2017)
	Chair, Principal-REI (since 2004)
	Chief Executive Officer, Principal-REI (2005-
	2018	)
	Chair, Spectrum Asset Management, Inc.
	(“Spectrum”) (since 2017)

Correspondence intended for each Board Member who is other than an Interested Board Member may be sent to 655 9^thStreet, Des
Moines, IA 50392.

165


FUND COMPLEX OFFICERS

Name, Position Held with the Fund Complex,	Principal Occupation(s)
Address, and Year of Birth	During past 5 years

Kamal Bhatia	Director, PGI (since 2019)
President and Chief Executive Officer	President-Principal Funds, PGI (since 2019)
Des Moines, IA 50392	Principal Executive Officer, OPC Private Capital (2017-2019)
1972	Senior Vice President, OppenheimerFunds (2011-2019)
	Director, Principal Funds Distributor, Inc. (“PFD”) (since 2019)
	Senior Executive Director and Chief Operating Officer, PFSI and PLIC (since 2020)
	President, Principal Funds, PFSI and PLIC (2019-2020)
	Director, Post (since 2020)
	Director, Principal-REI (since 2020)
	Chair and Executive Vice President, (Principal Shareholder Services, Inc. (“PSS’)
	(since 2019)

Randy D. Bolin	Vice President/Associate General Counsel, PGI (since 2016)
Assistant Tax Counsel	Vice President/Associate General Counsel, PFSI (since 2013)
Des Moines, IA 50392	Vice President/Associate General Counsel, PLIC (since 2013)
1961

Beth Graff	Director – Fund Accounting, PLIC (since 2016)
Vice President and Assistant Controller
Des Moines, IA 50392
1968

Gina L. Graham	Vice President and Treasurer, PGI (since 2016)
Treasurer	Vice President and Treasurer, PFD (since 2016)
Des Moines, IA 50392	Vice President and Treasurer, PFSI (since 2016)
1965	Vice President and Treasurer, PLIC (since 2016)
	Vice President and Treasurer, Principal-REI (since 2017)
	Vice President and Treasurer, Principal Securities, Inc. (“PSI”) (since 2016)
	Vice President and Treasurer, PSS (since 2016)
	Vice President and Treasurer, RobustWealth, Inc. (since 2018)

Megan Hoffmann	Director – Accounting, PLIC (since 2020)
Vice President and Controller	Assistant Director – Accounting, PLIC (2017-2020)
Des Moines, IA 50392	Prior thereto, Senior Accounting Analyst, PLIC
1979

Laura B. Latham	Counsel, PGI (since 2018)
Assistant Counsel and Assistant Secretary	Counsel, PLIC (since 2018)
Des Moines, IA 50392	Prior thereto, Attorney in Private Practice
1986


Diane K. Nelson	Chief Compliance Officer/AML Officer, PSS (since 2015)
AML Officer
Des Moines, IA 50392
1965


Tara Parks	Director - Accounting, PLIC (since 2019)
Vice President and Assistant Controller	Tax Manager – ALPS Fund Services (2011-2019)
Des Moines, IA 50392
1983

166


Name, Position Held with the Fund Complex,	Principal Occupation(s)
Address, and Year of Birth	During past 5 years

Sara L. Reece	Vice President and Controller (2016-2021)
Vice President and Chief Operating Officer	Managing Director – Global Funds Ops, PLIC (since 2021)
Des Moines, IA 50392	Managing Director – Financial Analysis/Planning, PLIC (2021)
1975	Director - Accounting, PLIC (2015-2021)


Teri R. Root	Chief Compliance Officer – Funds, PGI (since 2018)
Chief Compliance Officer	Interim Chief Compliance Officer (2018)
Des Moines, IA 50392	Deputy Chief Compliance Officer, PGI (2017-2018)
1979	Deputy Chief Compliance Officer (2015-2018)
	Vice President and Chief Compliance Officer, Principal Management
	Corporation (“PMC”) (2015–2017)
	Vice President, PSS (since 2015)

Britney L. Schnathorst	Counsel, PGI (since 2018)
Assistant Counsel and Assistant	Counsel, PLIC (since 2013)
Secretary
Des Moines, IA 50392
1981

Michael Scholten	Chief Financial Officer, PFD (since 2016)
Chief Financial Officer	Assistant Vice President and Actuary, PLIC (since 2021)
Des Moines, IA 50392	Chief Financial Officer – Funds/Platforms, PLIC (since 2015)
1979	Chief Financial Officer, PSS (since 2015)


Adam U. Shaikh	Assistant General Counsel, PGI (since 2018)
Assistant Counsel	Counsel, PGI (2017-2018)
Des Moines, IA 50392	Counsel, PLIC (since 2006)
1972	Counsel, PMC (2007-2017)

John L. Sullivan	Counsel, PGI (since 2020)
Assistant Counsel and Assistant Secretary	Counsel, PLIC (since 2019)
Des Moines, IA 50392	Prior thereto, Attorney in Private Practice
1970

Dan L. Westholm	Assistant Vice President-Treasury, PGI (since 2013)
Assistant Treasurer	Assistant Vice President-Treasury, PFD (since 2013)
Des Moines, IA 50392	Assistant Vice President-Treasury, PLIC (since 2014)
1966	Assistant Vice President-Treasury, PSI (since 2013)
	Assistant Vice President-Treasury, PSS (since 2013)

Beth C. Wilson	Director and Secretary – Funds, PLIC (since 2007)
Vice President and Secretary
Des Moines, IA 50392
1956

167


Name, Position Held with the Fund Complex,	Principal Occupation(s)
Address, and Year of Birth	During past 5 years


Clint L. Woods	Of Counsel (2017-2018)
Counsel, Vice President and Assistant Secretary	Vice President (2016-2017)
Des Moines, IA 50392	Counsel (2015-2017)
1961	Vice President, Associate General Counsel and Assistant Secretary,
PGI (since 2021)
	Vice President, Associate General Counsel and Secretary,
PGI (2020-2021)
	Principal-REI (since 2020)
	PSI (since 2021)
PSS (since 2021)
	Vice President, Associate General Counsel, Governance Officer, and Assistant
	Corporate Secretary,
PGI (2018-2020)
PFSI (since 2015)
PLIC (since 2015)
Principal-REI (2020)
	Vice President, Associate General Counsel and Assistant Corporate Secretary,
PFD (since 2019)
	PSI (2019-2021)
PSS (2019-2021)
	RobustWealth, Inc. (since 2019)
	Secretary,
Post (2020-2021)
	Spectrum (2020-2021)
	Assistant Secretary,
Post (since 2021)
	Spectrum (since 2021)

Jared A.Yepsen	Counsel, PGI (2017-2019)
Assistant Tax Counsel	Counsel, PLIC (since 2015)
Des Moines, IA 50392
1981

168

The 15(c) Committee’s primary purpose is to assist the Board in performing the annual review of the Fund’s advisory and sub-advisory agreements pursuant to Section 15(c) of the 1940 Act. The Committee responsibilities include requesting and reviewing related materials.

The Audit Committee’s primary purpose is to assist the Board by serving as an independent and objective party to monitor the Fund Complex’s accounting policies, financial reporting and internal control system, as well as the work of the independent registered public accountants. The Audit Committee assists Board oversight of 1) the integrity of the Fund Complex’s financial statements; 2) the Fund Complex’s compliance with certain legal and regulatory requirements; 3) the independent registered public accountants’ qualifications and independence; and 4) the performance of the Fund Complex’s independent registered public accountants. The Audit Committee also provides an open avenue of communication among the independent registered public accountants, the Manager’s internal auditors, Fund Complex management, and the Board.

The Executive Committee’s primary purpose is to exercise certain powers of the Board when the Board is not in session. When the Board is not in session, the Committee may exercise all powers of the Board in the management of the Fund Complex's business except the power to 1) issue stock, except as permitted by law; 2) recommend to the stockholders any action which requires stockholder approval; 3) amend the bylaws; or 4) approve any merger or share exchange which does not require stockholder approval.

The Nominating and Governance Committee’s primary purpose is to oversee the structure and efficiency of the Board and the committees. The Committee is responsible for evaluating Board membership and functions, committee membership and functions, insurance coverage, and legal matters. The Committee's nominating functions include selecting and nominating Independent Board Member candidates for election to the Board. Generally, the Committee requests nominee suggestions from Board Members and management. In addition, the Committee considers candidates recommended by shareholders of the Fund Complex. Recommendations should be submitted in writing to the Principal Funds Complex Secretary, in care of the Principal Funds Complex, 711 High Street, Des Moines, IA 50392. Such recommendations must include all information specified in the Committee’s charter and must conform with the procedures set forth in Appendix A thereto, which can be found at https://www.principalglobal.com/documentdownload/160950. Examples of such information include the nominee’s biographical information; relevant educational and professional background of the nominee; the number of shares of each Fund owned of record and beneficially by the nominee and by the recommending shareholder; any other information regarding the nominee that would be required to be disclosed in a proxy statement or other filing required to be made in connection with the solicitation of proxies for the election of board members; whether the nominee is an “interested person” of the Fund as defined in the 1940 Act; and the written consent of the nominee to be named as a nominee and serve as a board member if elected.

When evaluating a potential nominee for Independent Board Member, the Committee may consider, among other factors: educational background; relevant business and industry experience; whether the person is an "interested person" of the Fund as defined in the 1940 Act; and whether the person is willing to serve, and willing and able to commit the time necessary to attend meetings and perform the duties of an Independent Board Member. In addition, the Committee may consider whether a candidate’s background, experience, skills and views would complement the background, experience, skills and views of other Board Members and would contribute to the diversity of the Board. The Committee meets with nominees and conducts a reference check. The final decision is based on a combination of factors, including the strengths and the experience an individual may bring to the Board. The Board does not regularly use the services of professional search firms to identify or evaluate potential candidates or nominees.

The Operations Committee’s primary purpose is to oversee the provision of administrative and distribution services to the Fund Complex, communications with the Fund Complex’s shareholders, and review and oversight of the Fund Complex’s operations.

Additional information about the Trust is available in the Prospectuses and the Statement of Additional Information dated November 1, 2021 and as supplemented. These documents may be obtained free of charge by writing Principal Exchange-Traded Funds, c/o ALPS Distributors, Inc., 1290 Broadway, Suite 1100, Denver, CO 80203 or telephoning 1-800-787-1621. The prospectuses may be viewed at www.PrincipalETFs.com.

PROXY VOTING POLICIES

A description of the policies and procedures the Trust uses to determine how to vote proxies relating to portfolio securities and the results of the proxy votes for the most recent twelve months ended June 30 may be obtained free of charge by telephoning 1-800-787-1621, or on the SEC website at www.sec.gov.

SCHEDULES OF INVESTMENTS

The Trust files complete schedules of investments with the Securities and Exchange Commission for the first and third quarters of each year as a part of Form N-PORT. The Trust’s Form N-PORT reports are available on the Commission’s website at www.sec.gov.

169

BOARD CONSIDERATION OF INVESTMENT ADVISORY CONTRACTS

During the period covered by this report, the Board of Trustees of Principal Exchange-Traded Funds (“PETF”) approved the annual review and renewal of the Management Agreements for all Funds and the annual renew and review of the Subadvisory Agreements for the Principal Spectrum Preferred Securities Active ETF and the Principal Spectrum Tax-Advantaged Dividend Active ETF.

Annual Review and Renewal of Management Agreement and Subadvisory Agreements

At its September 14, 2021 meeting, the Board performed its annual review and renewal process relating to the Management Agreement and the Subadvisory Agreement for all Funds.

Section 15(c) of the Investment Company Act of 1940 (the “1940 Act”) requires the Board, including a majority of the Directors who have no direct or indirect interest in the investment advisory agreements and who are not “interested persons” of PETF, as defined in the 1940 Act (the “Independent Directors”), annually to review and to consider the continuation of: (1) the Management Agreement between the Principal Global Investors, LLC (the “Manager”) and PETF, on behalf of each of the thirteen (13) series of PETF (each series is referred to as a “Fund”); and (2) the Subadvisory Agreement between the Manager and Spectrum Asset Management Inc. (“Spectrum”) (the “Subadvisor”). The Management Agreement and the Subadvisory Agreement are collectively referred to as the “Advisory Agreements.”

The Board considered the factors and reached the conclusions described below relating to the continuation of the Advisory Agreements. In evaluating the Advisory Agreements, the Board reviewed a broad range of information requested for this purpose, including, among other information, information regarding performance, investment advisory fees, total expenses, profitability from the Advisory Agreements to the Manager and information about economies of scale and fall out benefits. The Board reviewed the materials provided and concluded that it was provided all information reasonably necessary to evaluate the Advisory Agreements. For the Principal International Adaptive Multi-Factor ETF, Principal U.S. Large-Cap Adaptive Multi-Factor ETF and Principal U.S. Small-Cap Adaptive Multi-Factor ETF, each of which began operations after the previous annual evaluation of the Advisory Agreements in September 2020, the Board considered that the Fund had less than a full year of operations and reviewed the information that they had considered in connection with the initial approval of the Advisory Agreements for the Fund, as updated, along with such additional information as the Board requested. The Board reviewed the materials provided and, with the assistance of independent legal counsel, concluded that they were provided information reasonably necessary to evaluate the Advisory Agreements.

170

Management Agreement

With respect to the Management Agreement for each Fund, the Board considered, among other factors, that the Manager and its affiliates have demonstrated a long-term commitment to support the Funds. In addition, the Board considered the following factors, and made certain findings and conclusions with respect thereto, for each of the Funds. The Board concluded that a relationship with a capable and conscientious adviser is in the best interests of each Fund.

Nature, Extent and Quality of Services

The Board considered the nature, quality and extent of the services provided under the Management Agreement, including accounting and administrative services, as applicable. The Board considered the experience and skills of senior management leading Fund operations, the experience and skills of the personnel performing the functions under the Management Agreement and the resources made available to such personnel, the ability of the Manager to attract and retain high-quality personnel and the organizational depth and stability of the Manager. The Board concluded that appropriate resources were provided under the Management Agreement. The Board also considered that, during the periods reviewed, the Manager had delegated day-to-day portfolio management responsibility for the Principal Spectrum Preferred Securities Active ETF and the Principal Spectrum Tax-Advantaged Dividend Active ETF to Spectrum. The Board noted that the Manager’s process for the selection of subadvisors emphasizes the selection of Principal-affiliated subadvisors that are determined to be qualified under the Manager’s due diligence process, but that the Manager will select an unaffiliated subadvisor to manage all or a portion of a Fund’s investment portfolio when deemed necessary or appropriate based upon a consideration of the Fund’s investment mandate and available expertise and resources within the Principal organization. Based upon all relevant factors, the Board concluded that the nature, quality and extent of the services provided by the Manager to the Funds under the Management Agreement was satisfactory.

Investment Performance

The Board reviewed each Fund’s investment performance over longer-term periods, reviewing both the investment return during the three-year period ended March 31, 2021 and the blended investment return (50%/50%) of the three- and five-year periods ended March 31, 2021, and compared those returns to various agreed-upon performance measures, including peer-group data based upon a broad-based, industry category determined by Morningstar.

For Funds that did not have a three-year or five-year performance history, the Board reviewed performance for a one-year or three-year period ended March 31, 2021, respectively, if available. The Board also compared each Fund’s investment performance over the one-, three- and five-year periods ended March 31, 2021, as available, to one or more relevant benchmark indices. The Board noted that certain Funds had commenced operations recently and, accordingly, no or limited performance information was considered. The Board also considered whether investment results were consistent with a Fund’s investment objective(s) and policies. For most Funds, the Board concluded that the Fund’s investment returns met acceptable levels of investment performance. There were certain Funds that had not attained during the relevant period(s) a level of investment performance considered satisfactory by the Board. For such Funds, the Board also considered other

171

factors, such as the longer-term performance of each such Fund, remedial efforts being taken to improve performance and/or the Manager’s explanation for the performance of such Fund. The Board considered the Manager’s due diligence process for evaluating the performance of all Funds for which they received regular reporting and concluded that the Manager has in place an effective due diligence process to monitor investment performance, and to encourage remedial action if necessary.

Investment Management Fees

The Board considered each Fund’s effective unitary management fee rate. For each Fund, the Board received certain information from Broadridge including comparing unitary management fee rate and total expense ratio for the Fund’s commons shares to investment advisory fee rates and expense ratios of funds in an appropriate Expense Group and Expense Universe provided by Broadridge.

In evaluating the effective management fee rates, the Board considered a variety of factors, including the effective fee rates, comparison to fee rates of peer group funds and other funds and non-fund accounts managed by the Manager, subadvisory fee rates paid, services provided, investment performance, total net expense ratios, profitability, the existence and sharing of economies of scale, fall-out benefits and expense caps and fee waivers.

Considering all factors they deemed relevant, the Board concluded that the management fee payable by each Fund was reasonable in light of the nature, quality and extent of the services provided by the Manager and other relevant factors.

Profitability

The Board reviewed detailed information regarding revenues the Manager, received under the Management Agreement and the estimated direct and indirect costs incurred in providing to each Fund the services described in the Management Agreement for the year ended December 31, 2020. The Board also considered the returns on revenue generated in connection with the payment of subadvisory fees to Spectrum and the aggregated return on revenue to the Manager and its affiliates for the year ended December 31, 2020. The Board concluded that the management fee for each Fund was reasonable, taking into account the profitability information presented by the Manager.

Economies of Scale

The Board noted that the Funds pay a unitary fee and determined that no breakpoints are necessary at this time, due, among other factors, to their current asset levels and taking into account levels of profitability to the Manager.

Subadvisory Agreement

Nature, Quality and Extent of Services

The Board consideredthe nature, quality and extent of the services provided under the Subadvisory Agreement with Spectrum with respect to the Principal Spectrum Preferred Securities Active ETF and the Principal Spectrum Tax-Advantaged Dividend Active ETF. The Board considered the reputation, qualifications and background of Spectrum, the investment approach of Spectrum, the

172

experience and skills of investment personnel responsible for the day-to-day management of the Principal Spectrum Preferred Securities Active ETF and the Principal Spectrum Tax-Advantaged Dividend Active ETF and the resources made available to such personnel. The Board also considered Spectrum’s compliance with investment policies and general legal compliance. Based upon all relevant factors, the Board concluded that the nature, quality and extent of the services provided by Spectrum to the Principal Spectrum Preferred Securities Active ETF and the Principal Spectrum Tax-Advantaged Dividend Active ETF Funds under the Subadvisory Agreement is satisfactory.

Investment Performance

The Manager had advised the Board that the investment services delivered by Spectrum was reasonable. Based upon all relevant factors, the Board concluded that Spectrum is qualified and that the investment performance of the Subadvisor met acceptable levels of investment performance

Subadvisory Fees, Economies of Scale and Profitability

The Board considered the subadvisory fee rates, noting that the Manager compensates Spectrum from its own management fee, so that shareholders pay only the management fee.

Other Benefits to the Manager and Subadvisor

The Board also considered the character and amount of other incidental benefits received by the Manager and its affiliates from their relationships with the Funds. The Board concluded that the management and subadvisory fees were reasonable in light of these fall-out benefits.

The Board also considered the character and amount of other incidental benefits received by Spectrum when evaluating the subadvisory fee. The Board concluded that taking into account these fall-out benefits, the subadvisory fee was reasonable.

Overall Conclusions

Based upon all of the information considered and the conclusions reached, the Board determined that the terms of each Advisory Agreement, including the fee rate payable thereunder, continue to be fair and reasonable and that the continuation of each Advisory Agreement, with the actions proposed by the Manager, is in the best interests of each Fund.

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Financial Statements	1
Notes to Financial Statements	25
Schedules of Investments	41
Financial Highlights (Includes performance information)	146
Shareholder Expense Example	160
Supplemental Information	162


INVESTMENT COMPANIES — 0.28%	Shares Held		Value
Money Market Fund — 0.28%
State Street Institutional U.S. Government Money Market Fund — Institutional
Class 0.03% ^(b)	270,326	$	270,326
TOTAL INVESTMENT COMPANIES		$	270,326
Total Investments		$	96,797,640
Other Assets and Liabilities — (0.07)%			(68,771	)
Total Net Assets — 100.00%		$	96,728,869