497

PIMCO Active Bond Exchange-Traded Fund

Investment Objective

The Fund seeks current income and long-term capital appreciation, consistent with prudent investment management.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund.You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.55%
Other Expenses (1)	0.01%
Total Annual Fund Operating Expenses	0.56%

“Other Expenses” include interest expense of 0.01%. Interest expense is borne by the Fund separately from the management fees paid to Pacific Investment Management Company LLC (“PIMCO”). Excluding interest expense, Total Annual Fund Operating Expenses are 0.55%.

Example. The Example is intended to help you compare the cost of investing in the Fund with the costs of investing in other exchange-traded funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then hold or sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 Year	3 Years	5 Years	10 Years
$57	$179	$313	$701

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 368 % of the average value of its portfolio.

Principal Investment Strategies

The Fund invests under normal circumstances at least 80% of its assets in a diversified portfolio of Fixed Income Instruments of varying maturities, which may be represented by forwards or derivatives such as options, futures contracts, or swap agreements. “Fixed Income Instruments” include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The Fund will seek to maintain a fairly consistent level of dividend income, subject to market conditions, by investing in a broad

array of fixed income sectors and utilizing income efficient implementation strategies. Long-term capital appreciation sought by the Fund generally arises from decreases in interest rates or improving credit fundamentals for a particular sector or security.

The Fund generally seeks to manage capital gain distributions by, among other things, limiting portfolio turnover and attempting to use losses from sales of securities that have declined in price to offset gains that would otherwise be taxable. However, such strategy may be unsuccessful or only partially successful and the Fund may realize taxable gains. For example, the Fund may realize taxable gains in order to satisfy cash redemption requests or when PIMCO believes the benefits of a transaction resulting in the realization of taxable gains outweigh tax considerations.

In pursuing the Fund’s investment objective, PIMCO may emphasize investment strategies that are more strategic, or long-term in nature, with less emphasis on short-term, tactical trading strategies. In addition, PIMCO will utilize a bottom up approach to seek to identify asset classes and securities that are undervalued, and the Fund’s investment program may involve a longer investment horizon designed to minimize trading volume and distinct investment strategies as compared with other PIMCO-advised funds with names, investment objectives and policies similar to the Fund. As a result, investments made by the Fund and the results achieved by the Fund at any given time are not expected to be the same as or similar to those made by such other PIMCO-advised funds.

The average portfolio duration of this Fund normally varies from two to eight years based on PIMCO’s market forecasts. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates.

The Fund invests primarily in investment grade debt securities, but may invest up to 30% of its total assets in high yield securities (“junk bonds”), as rated by Moody’s Investors Service, Inc. (“Moody’s”), Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), or, if unrated, as determined by PIMCO. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may invest up to 15% of its total assets in securities denominated in foreign currencies, and may invest beyond this limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 15% of its total assets in securities and instruments that are economically tied to emerging market countries. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 10% of its total assets.

The Fund may invest, without limitation, in derivative instruments, such as options, futures contracts or swap agreements, or in mortgage- or asset-backed securities, subject to applicable law and any other restrictions described in the Fund’s prospectus or Statement of Additional Information. The Fund may purchase or sell securities on a

PIMCO ETF Trust | Prospectus 1

PIMCO Active Bond Exchange-Traded Fund

when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund may invest up to 10% of its total assets in preferred securities, convertible securities and other equity related securities.

The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

Market Trading Risk: the risk that an active secondary trading market for Fund shares does not continue once developed, that the Fund may not continue to meet a listing exchange’s trading or listing requirements, or that Fund shares trade at prices other than the Fund’s net asset value, particularly during times of market stress

Interest Rate Risk: the risk that fixed income securities will decline in value because of an increase in interest rates; a fund with a longer average portfolio duration will be more sensitive to changes in interest rates than a fund with a shorter average portfolio duration

Call Risk: the risk that an issuer may exercise its right to redeem a fixed income security earlier than expected (a call). Issuers may call outstanding securities prior to their maturity for a number of reasons ( e.g ., declining interest rates, changes in credit spreads and improvements in the issuer’s credit quality). If an issuer calls a security that the Fund has invested in, the Fund may not recoup the full amount of its initial investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features

Credit Risk: the risk that the Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to a derivative contract, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

High Yield Risk: the risk that high yield securities and unrated securities of similar credit quality (commonly known as “junk bonds”) are subject to greater levels of credit, call and liquidity risks. High yield securities are considered primarily speculative with respect to the issuer’s continuing ability to make principal and interest payments, and may be more volatile than higher-rated securities of similar maturity

Market Risk: the risk that the value of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably, due to factors affecting securities markets generally or particular industries

Issuer Risk: the risk that the value of a security may decline for a reason directly related to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services

Liquidity Risk: the risk that a particular investment may be difficult to purchase or sell and that the Fund may be unable to sell illiquid investments at an advantageous time or price or achieve its desired level of exposure to a certain sector. Liquidity risk may result from the lack of an active market, reduced number and capacity of traditional market participants to make a market in fixed income securities, and may be magnified in a rising interest rate environment or other circumstances where investor redemptions from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity

Derivatives Risk: the risk of investing in derivative instruments (such as forwards, futures, swaps and structured securities) and other similar investments, including leverage, liquidity, interest rate, market, counterparty (including credit), operational, legal and management risks and valuation complexity. Changes in the value of a derivative or other similar investments may not correlate perfectly with, and may be more sensitive to market events than, the underlying asset, rate or index, and the Fund could lose more than the initial amount invested. Changes in the value of a derivative or other similar instrument may also create margin delivery or settlement payment obligations for the Fund. The Fund’s use of derivatives or other similar investments may result in losses to the Fund, a reduction in the Fund’s returns and/or increased volatility. Over-the-counter (“OTC”) derivatives or other similar investments are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivatives or other similar investments. The primary credit risk on derivatives or other similar investments that are exchange-traded or traded through a central clearing counterparty resides with the Fund's clearing broker or the clearinghouse. Changes in regulation relating to a registered fund’s use of derivatives and related instruments could potentially limit or impact the Fund’s ability to invest in derivatives, limit the Fund’s ability to employ certain strategies that use derivatives or other similar investments and/or adversely affect the value of derivatives or other similar investments and the Fund’s performance

Equity Risk: the risk that the value of equity or equity-related securities may decline due to general market conditions which are not specifically related to a particular company or to factors affecting a particular industry or industries. Equity or equity-related securities generally have greater price volatility than fixed income securities

Mortgage-Related and Other Asset-Backed Securities Risk: the risks of investing in mortgage-related and other asset-backed securities, including interest rate risk, extension risk, prepayment risk and credit risk

2 Prospectus | PIMCO ETF Trust

Prospectus

securities, and the risk of unfavorable foreign government actions, including nationalization, expropriation or confiscatory taxation, currency blockage, or political changes, diplomatic developments or the imposition of sanctions and other similar measures. Foreign securities may also be less liquid and more difficult to value than securities of U.S. issuers

Emerging Markets Risk: the risk of investing in emerging market securities, primarily increased foreign (non-U.S.) investment risk

Currency Risk: the risk that foreign (non-U.S.) currencies will change in value relative to the U.S. dollar and affect the Fund’s investments in foreign (non-U.S.) currencies or in securities that trade in, and receive revenues in, or in derivatives that provide exposure to, foreign (non-U.S.) currencies

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions, or derivative instruments, may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

Management Risk: the risk that the investment techniques and risk analyses applied by PIMCO will not produce the desired results and that actual or potential conflicts of interest, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and the individual portfolio manager in connection with managing the Fund and may cause PIMCO to restrict or prohibit participation in certain investments. There is no guarantee that the investment objective of the Fund will be achieved

Short Exposure Risk: the risk of entering into short sales or other short positions, including the potential loss of more money than the actual cost of the investment, and the risk that the third party to the short sale or other short position will not fulfill its contractual obligations, causing a loss to the Fund

Convertible Securities Risk: as convertible securities share both fixed income and equity characteristics, they are subject to risks to which fixed income and equity investments are subject. These risks include equity risk, interest rate risk and credit risk

Tax-Efficient Investing Risk: the risk that investment strategies intended to manage capital gain distributions may not succeed, and that such strategies may reduce investment returns or result in investment losses

Distribution Rate Risk: the risk that the Fund’s distribution rate may change unexpectedly as a result of numerous factors, including changes in realized and projected market returns, fluctuations in market interest rates, Fund performance and other factors

increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty regarding the nature of any replacement rate, and any potential effects of the transition away from LIBOR on the Fund or on certain instruments in which the Fund invests can be difficult to ascertain. The transition process may involve, among other things, increased volatility or illiquidity in markets for instruments that currently rely on LIBOR and may result in a reduction in the value of certain instruments held by the Fund

Please see “Description of Principal Risks” in the Fund's prospectus for a more detailed description of the risks of investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance Information

The performance information shows summary performance information for the Fund in a bar chart and an Average Annual Total Returns table. The information provides some indication of the risks of investing in the Fund by showing changes in its performance from year to year and by showing how the Fund’s average annual returns compare with the returns of a broad-based securities market index. Absent any applicable fee waivers and/or expense limitations, performance would have been lower. The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future.

The Bloomberg U.S. Aggregate Index represents securities that are SEC-registered, taxable, and dollar denominated. The index covers the U.S. investment grade fixed rate bond market, with index components for government and corporate securities, mortgage pass-through securities, and asset-backed securities. These major sectors are subdivided into more specific indexes that are calculated and reported on a regular basis.

Performance for the Fund is updated daily and quarterly and may be obtained as follows: daily and quarterly updates on the net asset value and performance page at https://www.pimco.com/en-us/investments/etf .

Calendar Year Total Returns

Best Quarter	June 30, 2020	4.43%
Worst Quarter	September 30, 2022	-4.61%
Year-to-Date	September 30, 2022	-16.09%

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 3

PIMCO Active Bond Exchange-Traded Fund

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	5 Years	Since Inception	Inception Date
Return Before Taxes	-0.59%	4.06%	4.18%	2/29/2012
Return After Taxes on Distributions (1)	-1.62%	2.78%	2.81%
Return After Taxes on Distributions and Sales of Fund Shares (1)	-0.35%	2.56%	2.62%
Bloomberg U.S. Aggregate Index (reflects no deductions for fees, expenses or taxes)	-1.54%	3.57%	2.86%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. In some cases the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period.

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by David Braun, Jerome Schneider and Daniel Hyman. Messrs. Braun, Schneider and Hyman are Managing Directors of PIMCO, and they have managed the Fund since May 2017.

Other Important Information Regarding Fund Shares

For important information about purchase and sale of Fund shares, tax information, and payments to broker-dealers and other financial intermediaries, please turn to the “Summary of Other Important Information Regarding Fund Shares” section on page 33 of this prospectus.

4 Prospectus | PIMCO ETF Trust

PIMCO Enhanced Low Duration Active Exchange-Traded Fund

Investment Objective

The Fund seeks maximum total return, consistent with preservation of capital and prudent investment management.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.46%
Other Expenses (1)	0.07%
Total Annual Fund Operating Expenses	0.53%

“Other Expenses” include interest expense of 0.07%. Interest expense is borne by the Fund separately from the management fees paid to Pacific Investment Management Company LLC (“PIMCO”). Excluding interest expense, Total Annual Fund Operating Expenses are 0.46%.

1 Year	3 Years	5 Years	10 Years
$54	$170	$296	$665

Portfolio Turnover

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its net assets in a diversified portfolio of Fixed Income Instruments of varying maturities, which may be represented by forwards or derivatives such as options, futures contracts, or swap agreements. “Fixed Income Instruments” include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The average portfolio duration of this Fund normally varies from one to three years based on

PIMCO’s market forecasts. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The Fund will seek to maintain a fairly consistent level of dividend income, subject to market conditions, by investing in a broad array of fixed income sectors and utilizing income efficient implementation strategies.

The Fund invests primarily in investment grade debt securities, but may invest up to 15% of its total assets in high yield securities (“junk bonds”), as rated by Moody’s Investors Service, Inc. (“Moody’s”), Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), or, if unrated, as determined by PIMCO. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may invest, without limitation, in U.S. dollar denominated securities and instruments of foreign issuers. The Fund will normally limit its foreign currency exposure (such as from non-U.S. dollar-denominated currencies) to 5% of its total assets. The Fund may invest up to 10% of its total assets in securities and instruments that are economically tied to emerging market countries.

The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls). The “total return” sought by the Fund

PIMCO ETF Trust | Prospectus 5

PIMCO Enhanced Low Duration Active Exchange-Traded Fund

consists of income earned on the Fund’s investments, plus capital appreciation, if any, which generally arises from decreases in interest rates, foreign currency appreciation, or improving credit fundamentals for a particular sector or security.

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

market participants to make a market in fixed income securities, and may be magnified in a rising interest rate environment or other circumstances where investor redemptions from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity

Foreign (Non-U.S.) Investment Risk: the risk that investing in foreign (non-U.S.) securities may result in the Fund experiencing more rapid and extreme changes in value than a fund that invests exclusively in securities of U.S. companies, due to smaller markets, differing reporting, accounting and auditing standards, increased risk of delayed settlement of portfolio transactions or loss of certificates of portfolio securities, and the risk of unfavorable foreign government actions, including nationalization, expropriation or confiscatory taxation, currency blockage, or political changes, diplomatic developments or the imposition of sanctions and other similar measures. Foreign securities may also be less liquid and more difficult to value than securities of U.S. issuers

Emerging Markets Risk: the risk of investing in emerging market securities, primarily increased foreign (non-U.S.) investment risk

Currency Risk: the risk that foreign (non-U.S.) currencies will change in value relative to the U.S. dollar and affect the Fund’s investments in

6 Prospectus | PIMCO ETF Trust

Prospectus

foreign (non-U.S.) currencies or in securities that trade in, and receive revenues in, or in derivatives that provide exposure to, foreign (non-U.S.) currencies

LIBOR Transition Risk: the risk related to the anticipated discontinuation of the London Interbank Offered Rate (“LIBOR”). Certain instruments held by the Fund rely in some fashion upon LIBOR. Although the transition process away from LIBOR has become increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty regarding the nature of any replacement rate, and any potential effects of the transition away from LIBOR on the Fund or on certain instruments in which the Fund invests can be difficult to ascertain. The transition process may involve, among other things, increased volatility or illiquidity in markets for instruments that currently rely on LIBOR and may result in a reduction in the value of certain instruments held by the Fund

Performance Information

The ICE BofA 1-3 Year U.S. Treasury Index is an unmanaged index comprised of U.S. Treasury securities, other than inflation-protection securities and Separate Trading of Registered Interest and Principal of Securities, with at least $1 billion in outstanding face value and a remaining term to final maturity of at least one year and less than three years.

Calendar Year Total Returns

Best Quarter	June 30, 2020	4.16%
Worst Quarter	March 31, 2020	-1.01%
Year-to-Date	September 30, 2022	-4.87%

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	5 Years	Since Inception	Inception Date
Return Before Taxes	-0.31%	2.38%	2.35%	1/22/2014
Return After Taxes on Distributions (1)	-0.67%	1.43%	1.41%
Return After Taxes on Distributions and Sales of Fund Shares (1)	-0.18%	1.41%	1.38%
ICE BofA 1-3 Year U.S. Treasury Index (reflects no deductions for fees, expenses or taxes)	-0.55%	1.61%	1.27%

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 7

PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund

Investment Objective

The Fund seeks maximum current income, consistent with preservation of capital and daily liquidity, while incorporating PIMCO's ESG investment strategy.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.36%
Other Expenses (1)	0.01%
Total Annual Fund Operating Expenses	0.37%
Fee Waiver and/or Expense Reimbursement (2)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.25%

PIMCO has contractually agreed, through October 31, 2023 , to reduce its management fee by 0.12% of the average daily net assets of the Fund. This waiver will automatically renew for one-year terms unless PIMCO provides written notice to PIMCO ETF Trust at least 30 days prior to the end of the then current term. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived as set forth above (the “Fee Waiver Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any recoupment of organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees pursuant to the Expense Limitation Agreement, exceed 0.0049% (the “Expense Limit”) (calculated as a percentage of average daily net assets) (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Fee Waiver Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

1 Year	3 Years	5 Years	10 Years
$26	$107	$196	$456

Portfolio Turnover

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its net assets in a diversified portfolio of Fixed Income Instruments of varying maturities, which may be represented by forwards. “Fixed Income Instruments” include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The average portfolio duration of this Fund will vary based on PIMCO’s market forecasts and will normally not exceed one year. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The dollar-weighted average portfolio maturity of the Fund is normally not expected to exceed three years.

The Fund may avoid investment in the securities of issuers whose business practices with respect to the environment, social responsibility, and governance (“ESG practices”) are not to PIMCO’s satisfaction. In determining the efficacy of an issuer’s ESG practices, PIMCO will use its own proprietary assessments of material ESG issues and may also reference standards as set forth by recognized global organizations such as entities sponsored by the United Nations. Additionally, PIMCO may engage proactively with issuers to encourage them to improve their ESG practices. PIMCO’s activities in this respect may include, but are not limited to, direct dialogue with company management, such as through in-person meetings, phone calls, electronic communications, and letters. Through these engagement activities, PIMCO seeks to identify opportunities for a company to improve its ESG practices, and will endeavor to work collaboratively with company management to establish concrete objectives and to develop a plan for meeting these objectives. The Fund may invest in securities of issuers whose ESG practices are currently suboptimal, with the expectation that these practices may improve over time either as a result of PIMCO’s engagement efforts or through the company’s own initiatives. It may also exclude those issuers that are not receptive to PIMCO’s engagement efforts, as determined in PIMCO’s sole discretion.

The Fund will not invest in the securities of any non-governmental issuer determined by PIMCO to be engaged principally in the manufacture of alcoholic beverages, tobacco products or military equipment, the operation of gambling casinos, the production or trade of pornographic materials, or in the oil industry, including extraction, production, and refining or the production, distribution of coal and coal fired generation. The Fund can invest in the securities of any issuer determined by PIMCO to be engaged principally in biofuel production, natural gas generation

PIMCO ETF Trust | Prospectus 9

PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund

and sales and trading activities. The Fund may also invest in labeled green, sustainable, social and sustainability-linked bonds from issuers involved in fossil fuel-related sectors. Labeled bonds are those issues with proceeds specifically earmarked to be used for climate, environmental sustainability and/or social projects and, in the case of sustainability-linked bonds, bonds that include sustainability linked covenants, as explained by the issuer through use of a framework and/or legal documentation. Labeled bonds are often verified by a third party, which certifies that the bond will or has been used to fund projects that include eligible benefits or, in the case of a sustainability-linked bond, that the bond includes sustainability-linked covenants. To the extent possible on the basis of information available to PIMCO, an issuer will be deemed to be principally engaged in an activity if it derives more than 10% of its gross revenues from such activities.

In analyzing whether an issuer meets any of the criteria described above, PIMCO may rely upon, among other things, information provided by an independent third party.

The Fund primarily invests in U.S. dollar-denominated investment grade debt securities, rated Baa or higher by Moody’s Investors Service, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), or, if unrated, determined by PIMCO to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may invest, without limitation, in U.S. dollar-denominated securities and instruments of foreign issuers. The Fund may invest up to 10% of its total assets in securities denominated in foreign currencies. The Fund seeks to eliminate foreign (non-U.S.) currency exposure (from non-U.S. dollar-denominated securities or currencies) through hedging techniques, although the Fund may have limited amounts of foreign (non-U.S.) currency exposure due to the difficulty in perfectly hedging such exposures.

The Fund may invest, without limitation, in futures contracts, subject to applicable law and any other restrictions described in the Fund's prospectus or Statement of Additional Information. The Fund may invest in mortgage or asset-backed securities, including to-be-announced transactions. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

evaluate and new funds may not attract sufficient assets to achieve investment and trading efficiencies

Credit Risk: the risk that the Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to a forward commitment transaction, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

10 Prospectus | PIMCO ETF Trust

Prospectus

reporting, accounting and auditing standards, increased risk of delayed settlement of portfolio transactions or loss of certificates of portfolio securities, and the risk of unfavorable foreign government actions, including nationalization, expropriation or confiscatory taxation, currency blockage, or political changes, diplomatic developments or the imposition of sanctions and other similar measures. Foreign securities may also be less liquid and more difficult to value than securities of U.S. issuers

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

Responsible Investing Risk: the risk that, because the Fund’s responsible investment strategy may select or exclude securities of certain issuers for reasons other than performance, the Fund may underperform funds that do not utilize a responsible investment strategy. Responsible investing is qualitative and subjective by nature, and there is no guarantee that the criteria utilized by PIMCO or any judgment exercised by PIMCO will reflect the beliefs or values of any particular investor

the underlying asset may result in an imperfect correlation. Futures contracts may involve risks different from, and possibly greater than, the risks associated with investing directly in the underlying assets. The purchase or sale of a futures contract may result in losses in excess of the amount invested in the futures contract

Performance Information

The FTSE 3-Month Treasury Bill Index is an unmanaged index representing monthly return equivalents of yield averages of the last 3 month Treasury Bill issues.

Calendar Year Total Returns

Best Quarter	June 30, 2020	1.92%
Worst Quarter	March 31, 2020	-0.61%
Year-to-Date	September 30, 2022	-1.31%

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 11

PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	Since Inception	Inception Date
Return Before Taxes	0.20%	1.22%	12/10/2019
Return After Taxes on Distributions (1)	-0.10%	0.76%
Return After Taxes on Distributions and Sales of Fund Shares (1)	0.12%	0.74%
FTSE 3-Month Treasury Bill Index (reflects no deductions for fees, expenses or taxes)	0.05%	0.35%

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by Jerome Schneider, Jelle Brons, CFA, Andrew Wittkop and Nathan Chiaverini. Mr. Schneider is a Managing Director of PIMCO. Messrs. Brons and Wittkop are Executive Vice Presidents of PIMCO. Mr. Chiaverini is a Senior Vice President of PIMCO. Messrs. Schneider, Brons, Wittkop and Chiaverini have managed the Fund since its inception in December 2019.

Other Important Information Regarding Fund Shares

12 Prospectus | PIMCO ETF Trust

PIMCO Enhanced Short Maturity Active Exchange-Traded Fund

Investment Objective

The Fund seeks maximum current income, consistent with preservation of capital and daily liquidity.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.35%
Other Expenses (1)	0.01%
Total Annual Fund Operating Expenses	0.36%

1 Year	3 Years	5 Years	10 Years
$37	$116	$202	$456

Portfolio Turnover

Principal Investment Strategies

the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The dollar-weighted average portfolio maturity of the Fund is normally not expected to exceed three years.

The Fund may invest, without limitation, in futures contracts, subject to applicable law and any other restrictions described in the Fund's prospectus or Statement of Additional Information. The Fund may invest, without limitation, in mortgage or asset-backed securities, including to-be-announced transactions. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

Market Trading Risk: the risk that an active secondary trading market for Fund shares does not continue once developed, that the Fund may not continue to meet a listing exchange’s trading or listing requirements, or that the Fund’s shares trade at prices other than the Fund’s net asset value, particularly during times of market stress

PIMCO ETF Trust | Prospectus 13

PIMCO Enhanced Short Maturity Active Exchange-Traded Fund

by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

Futures Contract Risk: the risk that, while the value of a futures contract tends to correlate with the value of the underlying asset that it represents, differences between the futures market and the market for the underlying asset may result in an imperfect correlation. Futures contracts may involve risks different from, and possibly greater than, the risks associated with investing directly in the underlying assets. The purchase or sale of a futures contract may result in losses in excess of the amount invested in the futures contract

Performance Information

The FTSE 3-Month Treasury Bill Index is an unmanaged index representing monthly return equivalents of yield averages of the last 3 month Treasury Bill issues. The Fund began operations on 11/16/09. Index comparisons began on 11/30/09.

14 Prospectus | PIMCO ETF Trust

Prospectus

Calendar Year Total Returns

Best Quarter	June 30, 2020	2.92%
Worst Quarter	March 31, 2020	-1.98%
Year-to-Date	September 30, 2022	-1.85%

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	5 Years	10 Years
Return Before Taxes	0.00%	1.71%	1.48%
Return After Taxes on Distributions (1)	-0.17%	1.02%	0.93%
Return After Taxes on Distributions and Sales of Fund Shares (1)	0.00%	1.01%	0.89%
FTSE 3-Month Treasury Bill Index (reflects no deductions for fees, expenses or taxes)	0.05%	1.11%	0.60%

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by Jerome Schneider, Andrew Wittkop and Nathan Chiaverini. Mr. Schneider is a Managing Director of PIMCO, and he has managed the Fund since its inception in November 2009. Mr. Wittkop is an Executive Vice President of PIMCO, and he has managed the Fund since July 2021. Mr. Chiaverini is a Senior Vice President of PIMCO, and he has managed the Fund since July 2021.

Other Important Information Regarding Fund Shares

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 15

PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund

Investment Objective

The Fund seeks attractive tax-exempt income, consistent with preservation of capital.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.35%
Total Annual Fund Operating Expenses	0.35%

1 Year	3 Years	5 Years	10 Years
$36	$113	$197	$443

Portfolio Turnover

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its assets in a diversified portfolio of debt securities whose interest is, in the opinion of bond counsel for the issuer at the time of issuance, exempt from federal income tax (“Municipal Bonds”). Municipal Bonds generally are issued by or on behalf of states and local governments and their agencies, authorities and other instrumentalities.

The Fund does not intend to invest in Municipal Bonds whose interest is subject to the federal alternative minimum tax. The Fund may only invest in U.S. dollar-denominated investment grade debt securities, rated Baa or higher by Moody’s Investors Service, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc.

(“Fitch”), or, if unrated, determined by Pacific Investment Management Company LLC (“PIMCO”) to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may invest 25% or more of its total assets in Municipal Bonds that finance similar projects, such as those relating to education, health care, housing, transportation, and utilities, and 25% or more of its total assets in industrial development bonds. The average portfolio duration of this Fund normally varies within (negative) 2 years to positive 4 years of the portfolio duration of the securities comprising the Bloomberg 1-15 Year Municipal Bond Index, as calculated by PIMCO, which, as of September 30, 2022, was 4.87 years. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The portfolio manager focuses on bonds with the potential to offer attractive current income, typically looking for bonds that can provide consistently attractive current yields or that are trading at competitive market prices.

The Fund may invest in derivative instruments, such as options, futures contracts or swap agreements. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

16 PIMCO ETF Trust | Prospectus

Prospectus

participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

Municipal Bond Risk: the risk that by investing in Municipal Bonds the Fund may be affected significantly by the economic, regulatory or political developments affecting the ability of issuers of Municipal Bonds to pay interest or repay principal

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the

use of when-issued, delayed delivery or forward commitment transactions, or derivative instruments, may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

California State-Specific Risk: the risk that by concentrating its investments in California Municipal Bonds, the Fund may be affected significantly by economic, regulatory or political developments affecting the ability of California issuers to pay interest or repay principal

New York State-Specific Risk: the risk that by concentrating its investments in New York Municipal Bonds, the Fund may be affected significantly by economic, regulatory or political developments affecting the ability of New York issuers to pay interest or repay principal

Municipal Project-Specific Risk: the risk that the Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in the bonds of specific projects (such as those relating to education, health care, housing, transportation, and utilities), industrial development bonds, or in bonds from issuers in a single state

Performance Information

The Bloomberg 1-15 Year Municipal Bond Index consists of a broad selection of investment grade general obligation and revenue bonds of maturities ranging from one year to 17 years. It is an unmanaged index representative of the tax exempt bond market.

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 17

PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund

Calendar Year Total Returns

Best Quarter	June 30, 2020	2.97%
Worst Quarter	December 31, 2016	-3.65%
Year-to-Date	September 30, 2022	-9.77%

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	5 Years	10 Years
Return Before Taxes	0.79%	3.66%	2.82%
Return After Taxes on Distributions (1)	0.79%	3.64%	2.72%
Return After Taxes on Distributions and Sales of Fund Shares (1)	1.12%	3.32%	2.59%
Bloomberg 1-15 Year Municipal Bond Index (reflects no deductions for fees, expenses or taxes)	0.86%	3.57%	3.05%

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by David Hammer and Kyle Christine. Mr. Hammer is a Managing Director of PIMCO, and he has managed the Fund since June 2016. Mr. Christine is a Senior Vice President of PIMCO, and he has managed the Fund since April 2023.

Other Important Information Regarding Fund Shares

18 Prospectus | PIMCO ETF Trust

PIMCO Municipal Income Opportunities Active Exchange-Traded Fund

Investment Objective

The Fund seeks current income exempt from federal income tax and long-term capital appreciation.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.49%
Total Annual Fund Operating Expenses	0.49%
Fee Waiver and/or Expense Reimbursement (1) (2)	(0.10%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.39%

Pacific Investment Management Company LLC (“PIMCO”) has contractually agreed, through October 31, 2023 , to waive its management fee, or reimburse the Fund, to the extent that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees’ fees exceed 0.0049% of the Fund’s average net assets (the “Expense Limit”). Under the Expense Limitation Agreement, which renews annually for a full year unless terminated by PIMCO upon at least 30 days’ notice prior to the end of the contract term, PIMCO may recoup these waivers and reimbursements in future periods, not exceeding three years, provided that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees’ fees, plus recoupment, do not exceed the Expense Limit (or the amount of the expense limit in place at the time the amount recouped was originally waived if lower than the Expense Limit).

PIMCO has contractually agreed, through October 31, 2023, to reduce its management fee by 0.10% of the average daily net assets of the Fund. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived as set forth above (the “Fee Waiver Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any recoupment of organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees pursuant to the Expense Limitation Agreement, exceed the Expense Limit (calculated as a percentage of average daily net assets) (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Fee Waiver Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

1 Year	3 Years	5 Years	10 Years
$40	$147	$264	$606

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund’s performance. From September 8, 2021 (commencement of operations) to June 30, 2022, the Fund’s portfolio turnover rate was 238 % of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its assets in debt securities whose interest is, in the opinion of bond counsel for the issuer at the time of issuance, exempt from federal income tax (“Municipal Bonds”). Municipal Bonds generally are issued by or on behalf of states and local governments and their agencies, authorities and other instrumentalities.

The Fund may invest up to 30% of its total assets in high yield securities (those that are rated, at the time of purchase, below investment grade by Moody’s Investors Service, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), or, if unrated, determined by PIMCO to be of comparable quality (commonly known as “junk bonds”)). In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may also invest, without limitation, in higher rated securities. The Fund may invest without limitation in “private activity” bonds whose interest is a tax-preference item for purposes of the federal alternative minimum tax (“AMT”). For shareholders subject to the AMT, distributions derived from “private activity” bonds must be included in their AMT calculations, and as such a portion of the Fund’s distribution may be subject to federal income tax. The average portfolio duration of this Fund normally varies within (negative) 2 years to positive 2 years of the portfolio duration of the securities comprising the Bloomberg Municipal Bond Index, as calculated by PIMCO, which, as of September 30, 2022, was 6.28 years. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. PIMCO’s management of the Fund generally seeks to focus on bonds with the potential to offer attractive current income, typically looking for bonds that can provide consistently attractive current yields or that are trading at competitive market prices.

The Fund may invest significantly in Municipal Bonds of specific projects, including those that finance education, health care, housing, transportation, utilities and other similar projects, and industrial development bonds. The Fund may invest significantly in issuers of particular jurisdictions, such as California and New York.

The Fund may invest in other types of Fixed Income Instruments. “Fixed Income Instruments” include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The Fund may also invest in derivative instruments, such as

PIMCO ETF Trust | Prospectus 19

PIMCO Municipal Income Opportunities Active Exchange-Traded Fund

options, futures contracts or swap agreements. The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

New Fund Risk: the risk that a new fund’s performance may not represent how the fund is expected to or may perform in the long term. In addition, new funds have limited operating histories for investors to evaluate and new funds may not attract sufficient assets to achieve investment and trading efficiencies

Small Fund Risk: the risk that a smaller fund may not achieve investment or trading efficiencies. Additionally, a smaller fund may be more adversely affected by large purchases or redemptions of fund shares

Puerto Rico-Specific Risk: the risk that by investing in Municipal Bonds issued by Puerto Rico or its instrumentalities, the Fund may be

affected by certain developments, such as political, economic, environmental, social, regulatory or debt restructuring developments, that impact the ability or obligation of Puerto Rico municipal issuers to pay interest or repay principal

Credit Risk: the risk that the Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to a derivatives contract, is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

Derivatives Risk: the risk of investing in derivative instruments (such as forwards, futures, swaps and structured securities) and other similar

20 Prospectus | PIMCO ETF Trust

Prospectus

investments, including leverage, liquidity, interest rate, market, counterparty (including credit), operational, legal and management risks and valuation complexity. Changes in the value of a derivative or other similar investment may not correlate perfectly with, and may be more sensitive to market events than, the underlying asset, rate or index, and the Fund could lose more than the initial amount invested. Changes in the value of a derivative or other similar instrument may also create margin delivery or settlement payment obligations for the Fund. The Fund’s use of derivatives or other similar investments may result in losses to the Fund, a reduction in the Fund’s returns and/or increased volatility. Over-the-counter (“OTC”) derivatives or other similar investments are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivatives or other similar investments. The primary credit risk on derivatives or other similar investments that are exchange-traded or traded through a central clearing counterparty resides with the Fund's clearing broker or the clearinghouse. Changes in regulation relating to a registered fund’s use of derivatives and related instruments could potentially limit or impact the Fund’s ability to invest in derivatives, limit the Fund’s ability to employ certain strategies that use derivatives or other similar investments and/or adversely affect the value of derivatives or other similar investments and the Fund’s performance

Performance Information

The Fund does not have a full calendar year of performance. Thus, no bar chart or Average Annual Total Returns table is included for the Fund. Once the Fund commences operations, performance for the Fund will be updated daily and quarterly and may be obtained as follows: daily and quarterly updates on the net asset value and performance page at https://www.pimco.com/en-us/investments/etf .

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by David Hammer and Kyle Christine. Mr. Hammer is a Managing Director of PIMCO, and he has managed the Fund since its inception. Mr. Christine is a Senior Vice President of PIMCO, and he has managed the Fund since its inception.

Other Important Information Regarding Fund Shares

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 21

PIMCO Prime Limited Maturity Active Exchange-Traded Fund

Investment Objective

The Fund seeks maximum current income, consistent with preservation of capital and daily liquidity.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.25%
Other Expenses (1)	0.20%
Total Annual Fund Operating Expenses	0.45%
Fee Waiver and/or Expense Reimbursement (2)	(0.20%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement (3)	0.25%

“Other Expenses” reflect estimated organizational expenses for the Fund’s first fiscal year.

Pacific Investment Management Company LLC (“PIMCO”) has contractually agreed, through October 31, 2023 , to waive a portion of the Fund’s management fees, or reimburse the Fund, to the extent that the Fund’s organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata share of Trustee fees exceed 0.0049% (the “Expense Limit”) (calculated as a percentage of average daily net assets). This Expense Limitation Agreement will automatically renew for one-year terms unless PIMCO provides written notice to PIMCO ETF Trust at least 30 days prior to the end of the then current term. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived or reimbursed as set forth above (the “Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees, exceed, for such month, the Expense Limit (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

To maintain certain net yields for the Fund, PIMCO or its affiliates may temporarily and voluntarily waive, reduce or reimburse all or any portion of the Fund’s fees and expenses. Such waivers, if any, are not reflected in this table. See “Management of the Funds—Temporary Fee Waivers, Reductions and Reimbursements” in the Fund’s prospectus for additional information.

1 Year	3 Years
$26	$124

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund’s performance. The Fund had not yet commenced operations as of the most recent fiscal year end. Thus, no portfolio turnover rate is provided for the Fund.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 65% of its total assets in a diversified portfolio of fixed income securities of varying maturities. The Fund may only invest in U.S. dollar denominated securities that mature within 18 months from the date of purchase or floating rate U.S. government agency securities that mature within two years from the date of purchase. The average portfolio duration of this Fund will vary based on PIMCO’s market forecasts and will normally not exceed 90 days. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates.

The Fund primarily invests in U.S. dollar-denominated investment grade debt securities, rated A or higher by Moody’s Investors Service, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Ratings Services (“S&P”) or Fitch, Inc. (“Fitch”), or, if unrated, determined by PIMCO to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security.

The Fund may purchase and sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

Market Trading Risk: the risk that an active secondary trading market for Fund shares does not continue once developed, that the Fund may

22 PIMCO ETF Trust | Prospectus

Prospectus

not continue to meet a listing exchange’s trading or listing requirements, or that Fund shares trade at prices other than the Fund’s net asset value, particularly during times of market stress

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions may give rise to leverage, magnifying gains and losses and causing the Fund to be more volatile than if it had not been leveraged. This means that leverage entails a heightened risk of loss

prohibit participation in certain investments. There is no guarantee that the investment objective of the Fund will be achieved

Performance Information

Investment Adviser/Portfolio Manager

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is managed by Jerome Schneider. Mr. Schneider is a Managing Director of PIMCO and he will manage the Fund as of its inception.

Other Important Information Regarding Fund Shares

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 23

PIMCO Senior Loan Active Exchange-Traded Fund

Investment Objective

The Fund seeks current income, consistent with prudent investment management.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.70%
Other Expenses (1)	0.02%
Total Annual Fund Operating Expenses	0.72%
Fee Waiver and/or Expense Reimbursement (2) (3)	(0.20%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.52%

“Other Expenses” are estimated for the current fiscal period and include estimated interest expense of 0.02% . Interest expense is borne by the Fund separately from the management fees paid to Pacific Investment Management Company LLC (“PIMCO”). Excluding estimated interest expense, Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement are 0.50%.

PIMCO has contractually agreed, through October 31, 2023 , to waive a portion of the Fund’s management fees, or reimburse the Fund, to the extent that the Fund’s organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata share of Trustee fees exceed 0.0049% (the “Expense Limit”) (calculated as a percentage of average daily net assets). This Expense Limitation Agreement will automatically renew for one-year terms unless PIMCO provides written notice to PIMCO ETF Trust at least 30 days prior to the end of the then current term. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived or reimbursed as set forth above (the “Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees, exceed, for such month, the Expense Limit (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO

PIMCO has contractually agreed, through October 31, 2023, to reduce its management fee by 0.20% of the average daily net assets of the Fund. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by the Fund of any portion of the management fee waived as set forth above (the “Fee Waiver Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any recoupment of organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustee fees pursuant to the Expense Limitation Agreement, exceed the Expense Limit (calculated as a percentage of average daily net assets) (or the amount of the expense limit in place at the time the amount being recouped was originally waived if lower than the Expense Limit); 2) exceed the total Fee Waiver Reimbursement Amount; or 3) include any amounts previously reimbursed to PIMCO.

Example. The Example is intended to help you compare the cost of investing in the Fund with the costs of investing in other exchange-traded funds. The Example assumes that you invest $10,000

in the Fund for the time periods indicated, and then hold or sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 Year	3 Years
$51	$204

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund’s performance. From June 8, 2022 (commencement of operations) to June 30, 2022, the Fund’s portfolio turnover rate was 0.00 % of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its assets in a diversified portfolio of Senior Loans, which may be represented by forwards or derivatives such as options, futures contracts or swap agreements. “Senior Loans” include senior secured floating rate bank loans, also referred to as leveraged loans, bank loans and floating rate loans, that are first or second lien loans. The Fund may also invest in collateralized loan obligations and high-yield corporate debt securities, which may also be represented by forwards or derivatives such as options, futures contracts or swap agreements.

A Senior Loan holds a senior position in the issuer’s capital structure and is typically secured by collateral such that, under normal circumstances, holders (such as the Fund) enjoy a priority claim to some or all of the issuer’s assets in the event of default as compared to other creditors of the issuer. Floating rate bank loans generally pay interest at rates that adjust whenever a specified interest rate changes and/or reset on predetermined dates (such as the last day of a month or calendar quarter).

The Fund may invest, without limitation, in high yield securities (“junk bonds”) rated below investment grade by Moody’s Investors Services, Inc. (“Moody’s”), or equivalently rated by Standard & Poor’s Rating Services (“S&P”) or Fitch, Inc. (“Fitch”), or if, unrated, determined by PIMCO to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may also invest up to 20% of its total assets in securities denominated in foreign currencies. The Fund may invest without limit in U.S. dollar-denominated securities of foreign issuers. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 20% of its total assets.

24 PIMCO ETF Trust | Prospectus

Prospectus

The Fund may invest in derivative instruments, such as credit default swap and total return swap agreements, interest rate swaps, futures and options, subject to applicable law and any other restrictions described in the prospectus or Statement of Additional Information. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis, including currency forwards, and may engage in short sales. The Fund may invest up to 20% of its total assets in preferred stock.

The average portfolio duration of the Fund will normally vary within one year (plus or minus) of the portfolio duration of the securities comprising the Markit iBoxx USD Liquid Leveraged Loan Index, as calculated by PIMCO, which as of September 30, 2022 was 0.11 years. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates.

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

Senior Loan Risk: the risk that investing in senior loans, including bank loans, exposes the Fund to heightened credit risk, call risk, settlement risk and liquidity risk. If an issuer of a senior loan prepays or redeems the loan prior to maturity, the Fund may have to reinvest the proceeds in instruments that pay lower interest rates. To the extent the Fund invests in senior loans that are covenant-lite obligations, the Fund may have fewer rights against a borrower (e.g., covenant-lite obligations may contain fewer maintenance covenants than other obligations, or no maintenance covenants) and may have a greater risk of loss on such investments as compared to investments in traditional loans

Collateralized Loan Obligations Risk: the risk that investing in collateralized loan obligations (“CLOs”) and other similarly structured investments exposes the Fund to heightened credit risk, interest rate risk, liquidity risk, market risk and prepayment and extension risk, as well as the risk of default on the underlying asset. In addition, investments in CLOs carry additional risks including, but not limited to, the risk that: (i) distributions from the collateral may not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) the Fund may invest in tranches of CLOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; and (v) the CLO’s manager may perform poorly

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 25

PIMCO Senior Loan Active Exchange-Traded Fund

Asset-Backed Securities Risk: the risks of investing in asset-backed securities, including interest rate risk, extension risk, prepayment risk and credit risk

Performance Information

26 Prospectus | PIMCO ETF Trust

PIMCO Short Term Municipal Bond Active Exchange-Traded Fund

Investment Objective

The Fund seeks attractive tax-exempt income, consistent with preservation of capital.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.35%
Total Annual Fund Operating Expenses	0.35%

1 Year	3 Years	5 Years	10 Years
$36	$113	$197	$443

Portfolio Turnover

Principal Investment Strategies

(“Fitch”), or, if unrated, determined by Pacific Investment Management Company LLC (“PIMCO”) to be of comparable quality. In the event that ratings services assign different ratings to the same security, PIMCO will use the highest rating as the credit rating for that security. The Fund may invest 25% or more of its total assets in Municipal Bonds that finance similar projects, such as those relating to education, health care, housing, transportation, and utilities, and 25% or more of its total assets in industrial development bonds. The average portfolio duration of this Fund varies based on PIMCO’s market forecasts and under normal market conditions is not expected to exceed three years. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The dollar- weighted average portfolio maturity of the Fund is normally not expected to exceed three years. The portfolio manager focuses on bonds with the potential to offer attractive current income, typically looking for bonds that can provide consistently attractive current yields or that are trading at competitive market prices.

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

28 PIMCO ETF Trust | Prospectus

Prospectus

participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

Leveraging Risk: the risk that certain transactions of the Fund, such as reverse repurchase agreements, loans of portfolio securities, and the

Performance Information

The Bloomberg 1 Year Municipal Bond Index is the 1 Year (1-2) component of the Bloomberg Municipal Bond Index. The Bloomberg Municipal Bond Index is a rules-based, market-value-weighted index engineered for the long term tax-exempt bond market. To be included in the Index, bonds must be rated investment-grade (Baa3/ BBB- or higher) by at least two of the following ratings agencies: Moody’s, S&P and Fitch. If only two of the three agencies rate the security, the lower rating is used to determine index eligibility. If only one of the three agencies rates a security, the rating must be investment-grade. They must have an outstanding par value of at least $7 million and be issued as part of a transaction of at least $75 million. The bonds must be fixed rate, have a dated-date after December 31, 1990, and must be at least one year from their maturity date. Remarketed issues, taxable municipal bonds, bonds with floating rates, and derivatives, are excluded from the benchmark. It is not possible to invest directly in an index.

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 29

PIMCO Short Term Municipal Bond Active Exchange-Traded Fund

Calendar Year Total Returns

Best Quarter	June 30, 2020	1.70%
Worst Quarter	December 31, 2016	-1.22%
Year-to-Date	September 30, 2022	-3.99%

Average Annual Total Returns (for periods ended 12/31/21)

	1 Year	5 Years	10 Years
Return Before Taxes	0.27%	1.97%	1.25%
Return After Taxes on Distributions (1)	0.27%	1.95%	1.21%
Return After Taxes on Distributions and Sales of Fund Shares (1)	0.40%	1.81%	1.17%
Bloomberg 1-Year Municipal Bond Index (reflects no deductions for fees, expenses or taxes)	0.31%	1.44%	1.03%

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is jointly and primarily managed by David Hammer and Kyle Christine. Mr. Hammer is a Managing Director of PIMCO, and he has managed the Fund since August 2015. Mr. Christine is a Senior Vice President of PIMCO, and he has managed the Fund since April 2023.

Other Important Information Regarding Fund Shares

30 Prospectus | PIMCO ETF Trust

PIMCO Ultra Short Government Active Exchange-Traded Fund

Investment Objective

The Fund seeks maximum current income, consistent with preservation of capital and daily liquidity.

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment):

N/A

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Management Fees	0.14%
Other Expenses (1)	0.01%
Total Annual Fund Operating Expenses	0.15%
Fee Waiver and/or Expense Reimbursement (2)	(0.01)%
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	0.14%

“Other Expenses” reflect estimated expenses for the Fund's first fiscal year.

Pacific Investment Management Company LLC (“PIMCO”) has contractually agreed, through October 31, 2023, to waive its management fee, or reimburse the Fund, to the extent that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees’ fees exceed 0.0049% of the Fund’s average net assets (the “Expense Limit”). Under the Expense Limitation Agreement, which renews annually for a full year unless terminated by PIMCO upon at least 30 days’ notice prior to the end of the contract term, PIMCO may recoup these waivers and reimbursements in future periods, not exceeding three years, provided that organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata Trustees’ fees, plus recoupment, do not exceed the Expense Limit (or the amount of the expense limit in place at the time the amount recouped was originally waived if lower than the Expense Limit).

1 Year	3 Years
$14	$47

Portfolio Turnover

The Fund pays transaction costs when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example tables, affect the Fund’s performance. The Fund had not yet commenced operations as of the most recent fiscal year end. Thus, no portfolio turnover rate is provided for the Fund.

Principal Investment Strategies

The Fund invests 100% of its total assets in (i) cash, (ii) U.S. government securities, such as U.S. Treasury bills, notes, and other obligations issued by, or guaranteed as to principal and interest by, the U.S. government (including its agencies and instrumentalities), and (iii) repurchase agreements that are collateralized fully by such U.S. government securities or cash. The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its assets in U.S. government securities.

The dollar-weighted average portfolio maturity of this Fund may not exceed 120 days. The Fund may only invest in securities that mature in 6 months or less. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share.

Principal Risks

It is possible to lose money on an investment in the Fund. The principal risks of investing in the Fund, which could adversely affect its net asset value, yield and total return, are listed below.

PIMCO ETF Trust | Prospectus 31

PIMCO Ultra Short Government Active Exchange-Traded Fund

by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to meet its financial obligations

Performance Information

Investment Adviser/Portfolio Managers

PIMCO serves as the investment adviser for the Fund. The Fund’s portfolio is managed by Jerome Schneider, Andrew Wittkop, William Martinez and Geoffrey Miles. Mr. Schneider is a Managing Director of PIMCO, Mr. Wittkop is an Executive Vice President of PIMCO, Mr. Martinez is a Senior Vice President of PIMCO and Mr. Miles is a Vice President of PIMCO. Messrs. Schneider, Wittkop, Martinez and Miles will manage the Fund as of its inception.

Other Important Information Regarding Fund Shares

32 Prospectus | PIMCO ETF Trust

Summary of Other Important Information Regarding Fund Shares

Purchase and Sale of Fund Shares

Each Fund is an exchange-traded fund (“ETF”). Individual Fund shares may only be purchased and sold on a national securities exchange through a broker-dealer and may not be purchased or redeemed directly with a Fund.

The price of Fund shares is based on market price, and because ETF shares trade at market prices rather than net asset value (“NAV”), shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of a Fund (“bid”) and the lowest price a seller is willing to accept for shares (“ask”) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including information about each Fund’s NAV, market price, premiums and discounts, and bid-ask spreads, is included on the Fund’s website at https://www.pimco.com/en-us/investments/etf.

Tax Information

The Funds' distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account, in which case distributions may be taxable upon withdrawal.

Dividends paid to shareholders of the PIMCO Short Term Municipal Bond Active Exchange-Traded Fund, PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund and PIMCO Municipal Income Opportunities Active Exchange-Traded Fund, derived from interest from debt securities whose interest is, in the opinion of bond counsel for the issuer at the time of issuance, exempt from federal income tax (“Municipal Bonds”) are expected to be designated by the Funds as “exempt-interest dividends” and shareholders may generally exclude such dividends from gross income for federal income tax purposes.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase Fund shares through a broker-dealer or other financial intermediary, PIMCO or other related companies may pay the intermediary for the sale of Fund shares or related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

Summary Information About the Funds

This prospectus describes ten ETFs (each a “Fund,” collectively, the “Funds”) offered by PIMCO ETF Trust (the “Trust”). The Funds provide access to the professional investment advisory services offered by PIMCO. References to “the Fund” or “a Fund” relate to all Funds unless the context requires otherwise.

ETFs are funds that trade like other publicly-traded securities and may be designed to track an index or to be actively managed. Unlike conventional ETFs, the Funds are not index funds. The Funds are actively managed and do not seek to replicate the performance of a specified index. Unlike shares of a mutual fund, which can be bought from and redeemed by the issuing fund by all shareholders at a price based on NAV, shares of a Fund may be directly purchased from and redeemed by the Fund at NAV solely by a member or participant of a clearing agency registered with the Securities and Exchange Commission, which has a written agreement with the Fund’s Distributor that allows such member or participant to place orders for the purchase and redemption of Creation Units (as defined below) (“Authorized Participant“). Also unlike shares of a mutual fund, shares of ETFs are listed on a national securities exchange and trade in the secondary market at market prices that change throughout the day.

Shares of a Fund, except for the PIMCO Active Bond Exchange-Traded Fund, are listed and traded at market prices on NYSE Arca, Inc. (“NYSE Arca”) and other secondary markets, and the shares of the PIMCO Active Bond Exchange-Traded Fund are listed and traded at market prices on New York Stock Exchange (”NYSE“) and other secondary markets. The market price for a Fund’s shares may be different from the Fund’s NAV. The Funds issue and redeem shares at NAV only in aggregations of a specified number of shares (”Creation Units“). Only Authorized Participants may purchase or redeem Creation Units directly with a Fund at NAV. These transactions are in exchange for securities and/or cash. Except when aggregated in Creation Units, shares of a Fund are not redeemable securities. Shareholders who are not Authorized Participants may not purchase or redeem shares directly from a Fund.

If a Fund were to effect redemptions with an Authorized Participant primarily for cash, the Fund may be required to sell portfolio securities in order to obtain the cash needed to distribute redemption proceeds. The sale of portfolio securities could cause a Fund to recognize gains that it might not otherwise have recognized if redemptions were effected in-kind, or to recognize such gain sooner than would otherwise be required. Such gains will generally be distributed to shareholders to avoid taxation at the Fund level and to ensure compliance with other special tax rules that apply to the Funds. Moreover, the sale of portfolio securities will generally subject the Funds to transaction costs, which may be partially or totally offset by the variable transaction fee charged by the Funds to redeeming Authorized Participants.

An investment in a particular Fund alone should not constitute an entire investment program. This prospectus explains what you should know about the Funds before you invest. Please read it carefully. Certain affiliates of the Funds and PIMCO may purchase and resell Fund shares pursuant to this prospectus.

On each business day, before commencement of trading on NYSE Arca or NYSE for the PIMCO Active Bond Exchange-Traded Fund, each Fund will disclose on www.pimcoetfs.com the identities and quantities of the Fund’s portfolio holdings that will form the basis for the Fund’s

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 33

Prospectus

Description of Principal Risks

The value of your investment in a Fund changes with the market price of the Fund’s shares determined in the secondary market. Market price may be determined, in part, by the values of a Fund’s investments. Many factors can affect those values. The factors that are most likely to have a material effect on a particular Fund’s portfolio as a whole are called “principal risks.” The principal risks of each Fund are identified in the Fund Summaries. The principal risks are described in more detail in this section. Each Fund may be subject to additional risks other than those identified and described below because the types of investments made by a Fund can change over time. Securities and investment techniques mentioned in this summary that appear in bold type are described in greater detail under “Characteristics and Risks of Securities and Investment Techniques.” That section and “Investment Objectives and Policies” in the Statement of Additional Information (the “SAI”) also include more information about the Funds, their investments and the related risks. There is no guarantee that a Fund will be able to achieve its investment objective. It is possible to lose money by investing in a Fund.

New Fund Risk

A new fund’s performance may not represent how the fund is expected to or may perform in the long term if and when it becomes larger and has fully implemented its investment strategies. Investment positions may have a disproportionate impact (negative or positive) on performance in new funds. New funds may also require a period of time before they are fully invested in securities that meet their investment objectives and policies and achieve a representative portfolio composition. Fund performance may be lower or higher during this “ramp-up” period, and may also be more volatile, than would be the case after the fund is fully invested. Similarly, a new fund’s investment strategy may require a longer period of time to show returns that are representative of the strategy. New funds have limited performance histories for investors to evaluate and new funds may not attract sufficient assets to achieve investment and trading efficiencies. If a new fund were to fail to successfully implement its investment strategies or achieve its investment objective, performance may be negatively impacted, and any resulting liquidation could create negative transaction costs for the fund and tax consequences for investors.

Small Fund Risk

A smaller fund may not grow to or maintain an economically viable size to achieve investment or trading efficiencies, which may negatively impact performance and/or force the fund to liquidate. Additionally, a smaller fund may be more adversely affected by large purchases or redemptions of fund shares, which can occur at any time and may impact the fund in the same manner as a high volume of purchases or redemptions.

Market Trading Risk

Each Fund is subject to secondary market trading risks. Shares of a Fund are listed for trading on an exchange, however, there can be no guarantee that an active trading market for such shares will develop or continue. Shares of a Fund may be listed or traded on U.S. and foreign (non-U.S.) exchanges other than the Fund’s primary U.S. listing exchange. There can be no guarantee that a Fund’s shares will continue trading on any exchange or in any market or that a Fund’s shares will continue to meet the listing or trading requirements of any exchange or market. A Fund’s shares may experience higher trading volumes on one exchange as compared to another and investors are subject to the execution and settlement risks of the market where their broker directs trades.

Secondary market trading in a Fund’s shares may be halted by an exchange because of market conditions. Pursuant to exchange or market rules, trading in a Fund’s shares on an exchange or in any market may be subject to trading halts caused by extraordinary market volatility. If secondary market trading is halted or an exchange closes earlier than anticipated, you may be unable to purchase or sell Fund shares. There can be no guarantee that a Fund’s exchange listing or ability to trade its shares will continue or remain unchanged. In the event a Fund ceases to be listed on an exchange, the Fund may cease operating as an “exchange-traded” fund and operate as a mutual fund, provided that shareholders are given advance notice.

Buying or selling a Fund’s shares on an exchange may require the payment of brokerage commissions. In addition, an investor who buys or sells may also incur the cost of the spread (the difference between the bid price and the ask price). The commission is frequently a fixed amount and may be a significant cost for investors seeking to buy or sell small amounts of shares. The spread varies over time for shares of a Fund based on their trading volume and market liquidity, and is generally less if the Fund has more trading volume and market liquidity and more if the Fund has less trading volume and market liquidity. Due to the costs inherent in buying or selling a Fund’s shares, frequent trading may detract significantly from investment returns. Investment in a Fund’s shares may not be advisable for investors who expect to engage in frequent trading.

Shares of a Fund may trade on an exchange at prices at, above or below their most recent NAV, which could result in an investor buying shares of the Fund at a higher price than the Fund’s NAV or selling shares of the Fund at a lower price than the Fund’s NAV. The market prices of Fund shares will fluctuate, sometimes rapidly and materially, in response to changes in the Fund’s NAV, the value of Fund holdings and supply and demand for Fund shares. Although the creation/redemption feature of the Funds generally makes it more likely that Fund shares will trade close to NAV, market volatility, lack of an active trading market for Fund shares, disruptions at market participants (such as Authorized Participants or market makers) and any disruptions in the ordinary functioning of the creation/redemption process may result in Fund shares trading significantly above (at a “premium”) or below (at a “discount”) NAV. Additionally, to the extent a Fund holds securities traded in markets that close at a different time from the Fund’s

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 35

PIMCO ETF Trust

listing exchange, liquidity in such securities may be reduced after the applicable closing times, and during the time when the Fund’s listing exchange is open but after the applicable market closing, fixing or settlement times, bid/ask spreads and the resulting premium or discount to the Fund’s shares’ NAV may widen. You may be unable to sell your shares or may incur significant losses if you transact in Fund shares in these and other circumstances. Neither PIMCO nor the Trust can predict whether Fund shares will trade above, below or at NAV. A Fund’s investment results are based on the Fund’s daily NAV. Investors transacting in Fund shares in the secondary market, where market prices may differ from NAV, may experience investment results that differ from results based on the Fund’s daily NAV. There are various methods by which investors can purchase and sell shares and various orders that may be placed. Investors should consult their financial intermediary before purchasing or selling shares of the Funds.

A Fund has a limited number of intermediaries that act as Authorized Participants, and none of these Authorized Participants are or will be obligated to engage in creation or redemption transactions. To the extent that these intermediaries exit the business or are unable to or choose not to proceed with creation and/or redemption orders with respect to a Fund and no other Authorized Participant is able and willing to create or redeem, shares may trade at a discount to NAV and possibly face trading halts and/ or delisting. Additionally, while Fund shares are listed for trading on an exchange, there can be no assurance that active trading markets for Fund shares will be maintained by market makers or Authorized Participants.

Decisions by market makers or Authorized Participants to reduce their role or “step away” from these activities in times of market stress may inhibit the effectiveness of the creation/redemption process in maintaining the relationship between the underlying value of a Fund’s holdings and the Fund’s NAV. Such reduced effectiveness could result in the Fund’s shares trading at a discount to its NAV and also in greater than normal intraday bid/ask spreads for the Fund’s shares.

Senior Loan Risk

To the extent a Fund invests in senior loans, including bank loans, the Fund may be subject to greater levels of credit risk, call risk, settlement risk and liquidity risk than funds that do not invest in such instruments. These instruments are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments and may be more volatile than other types of investments. An economic downturn or individual corporate developments could adversely affect the market for these instruments and reduce a Fund’s ability to sell these instruments at an advantageous time or price. An economic downturn would generally lead to a higher non-payment rate, and a senior loan may lose significant market value before a default occurs. In addition, the senior loans in which a Fund invests may not be listed on any exchange and a secondary market for such loans may be less liquid than markets for other more liquid fixed income securities. Consequently, transactions in senior loans may involve greater costs than transactions in more actively traded instruments. Restrictions on transfers in loan agreements, a lack of publicly-available information, irregular trading activity and wide bid/ask spreads, among other factors, may, in certain circumstances, make senior loans more difficult to value accurately or sell at an advantageous time or price than other types of securities or instruments. These factors may result in a Fund being unable to realize full value for the senior loans and/or may result in a Fund not receiving the proceeds from a sale of a senior loan for an extended period after such sale, each of which could result in losses to a Fund.

Senior loans may have extended trade settlement periods, including settlement periods of greater than 7 days, which may result in sale proceeds not being immediately available to a Fund. If an issuer of a senior loan prepays or redeems the loan prior to maturity, a Fund may have to reinvest the proceeds in instruments that pay lower interest rates. Senior loans in which a Fund invests may be collateralized, although the loans may not be fully collateralized and the collateral may be unavailable or insufficient to meet the obligations of the borrower. A Fund may have limited rights to exercise remedies against such collateral or a borrower, and loan agreements may impose certain procedures that delay receipt of the proceeds of collateral or require the Fund to act collectively with other creditors to exercise its rights with respect to a senior loan. Because of the risks involved in investing in senior loans, an investment in a Fund that invests in such instruments should be considered speculative. Senior loans may not be considered securities under the federal securities laws. In such circumstances, fewer legal protections may be available with respect to the Fund's investment in senior loans. Senior loans that are covenant-lite obligations contain fewer maintenance covenants than other types of loans, or no maintenance covenants, and may not include terms that allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. Covenant-lite obligations may carry more risk than traditional loans as they allow borrowers to engage in activities that would otherwise be difficult or impossible under a covenant-heavy loan agreement. In the event of default, covenant-lite obligations may exhibit diminished recovery values as the lender may not have the opportunity to negotiate with the borrower prior to default. A Fund may have a greater risk of loss on investments in covenant-lite obligations as compared to investments in traditional loans.

Interest Rate Risk

Interest rate risk is the risk that fixed income securities and other instruments in a Fund’s portfolio will fluctuate in value because of a change in interest rates. For example, as nominal interest rates rise, the value of certain fixed income securities held by a Fund is likely to decrease. A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Interest rate changes can be sudden and unpredictable, and a Fund may lose money as a result of movements in interest rates. A Fund may not be able to hedge against changes in interest rates or may choose not to do so for cost or other reasons. In addition, any hedges may not work as intended.

36 Prospectus | PIMCO ETF Trust

Prospectus

Fixed income securities with longer durations tend to be more sensitive to changes in interest rates, usually making them more volatile than securities with shorter durations. The values of equity and other non-fixed income securities may also decline due to fluctuations in interest rates. Inflation-indexed bonds , including Treasury Inflation-Protected Securities (“TIPS”), decline in value when real interest rates rise. In certain interest rate environments, such as when real interest rates are rising faster than nominal interest rates, inflation-indexed bonds may experience greater losses than other fixed income securities with similar durations.

Dividend-paying equity securities , particularly those whose market price is closely related to their yield, may be more sensitive to changes in interest rates. During periods of rising interest rates, the values of such securities may decline and may result in losses to the Fund.

Variable and floating rate securities generally are less sensitive to interest rate changes but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. Inverse floating rate securities may decrease in value if interest rates increase. Inverse floating rate securities may also exhibit greater price volatility than a fixed rate obligation with similar credit quality. When a Fund holds variable or floating rate securities , a decrease (or, in the case of inverse floating rate securities, an increase) in market interest rates will adversely affect the income received from such securities and the NAV of the Fund’s shares.

A wide variety of factors can cause interest rates or yields of U.S. Treasury securities (or yields of other types of bonds) to rise, including but not limited to central bank monetary policies, changing inflation or real growth rates, general economic conditions, increasing bond issuances or reduced market demand for low yielding investments. Risks associated with rising interest rates are heightened under current market conditions given that the U.S. Federal Reserve (the “Federal Reserve”) has begun to raise interest rates from historically low levels and has signaled an intention to continue to do so. Further, in market environments where interest rates are rising, issuers may be less willing or able to make principal and interest payments on fixed-income investments when due.

During periods of very low or negative interest rates, a Fund may be unable to maintain positive returns. Certain European countries have previously experienced negative interest rates on certain fixed income instruments . Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent a Fund is exposed to such interest rates.

Measures such as average duration may not accurately reflect the true interest rate sensitivity of a Fund. This is especially the case if a Fund consists of securities with widely varying durations. Therefore, if a Fund has an average duration that suggests a certain level of interest rate risk, the Fund may in fact be subject to greater interest rate risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivatives in connection with the management of the Fund.

Convexity is an additional measure used to understand a security’s or Fund‘s interest rate sensitivity. Convexity measures the rate of change of duration in response to changes in interest rates. With respect to a security’s price, a larger convexity (positive or negative) may imply more dramatic price changes in response to changing interest rates. Convexity may be positive or negative. Negative convexity implies that interest rate increases result in increased duration , meaning increased sensitivity in prices in response to rising interest rates. Thus, securities with negative convexity, which may include bonds with traditional call features and certain mortgage-backed securities, may experience greater losses in periods of rising interest rates. Accordingly, if a Fund holds such securities, the Fund may be subject to a greater risk of losses in periods of rising interest rates.

Call Risk

Call risk refers to the possibility that an issuer may exercise its right to redeem a fixed income security earlier than expected (a call). Issuers may call outstanding securities prior to their maturity for a number of reasons ( e.g., declining interest rates, changes in credit spreads and improvements in the issuer’s credit quality). If an issuer calls a security in which a Fund has invested, the Fund may not recoup the full amount of its initial investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features.

Credit Risk

A Fund could lose money if the issuer or guarantor of a fixed income security (including a security purchased with securities lending collateral), or the counterparty to a derivatives contract, in the case of each Fund (except the PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund), or a repurchase agreement or a loan of portfolio securities , is unable or unwilling, or is perceived (whether by market participants, rating agencies, pricing services or otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. The risk that such issuer, guarantor or counterparty is less willing or able to do so is heightened in market environments where interest rates are rising. The downgrade of the credit of a security held by a Fund may decrease its value. Securities are subject to varying degrees of credit risk, which are often reflected in credit ratings . Measures such as average credit quality may not accurately reflect the true credit risk of a Fund. This is especially the case if the Fund consists of securities with widely varying credit ratings. Therefore, if a Fund has an average credit rating that suggests a certain credit quality, the Fund may in fact be subject to greater credit risk than the

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 37

PIMCO ETF Trust

average would suggest. This risk is greater to the extent a Fund uses leverage or derivatives in connection with the management of the Fund. Municipal bonds are subject to the risk that litigation, legislation or other political events, local business or economic conditions, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest.

Collateralized Loan Obligations Risk

A Fund may invest in collateralized loan obligation (“CLOs”) and other similarly structured investments. A CLO is a trust typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. A Fund’s investments in CLOs and other similarly structured investments may expose the Fund to heightened credit risk, interest rate risk, liquidity risk, market risk and prepayment and extension risk, as well as the risk of default on the underlying asset. In addition, investments in CLOs carry additional risks including, but not limited to, the risk that: (i) distributions from the collateral may not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) the Funds may invest in tranches of CLOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; and (v) the CLO’s manager may perform poorly CLOs may charge management and other administrative fees, which are in addition to those of the Funds.

The cash flows from a CLO are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the “equity” tranche which bears the bulk of defaults from the bonds or loans in the trust and serves to protect the other, more senior tranches from default in all but the most severe circumstances. Since they are partially protected from defaults, senior tranches from a CLO typically have higher ratings and lower yields than their underlying securities, and can be rated investment grade. Despite the protection from the equity tranche, CLO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as aversion to CLO securities as a class. The risks of an investment in a CLO depend largely on the type of the collateral securities and the class of the instrument in which the Funds invests. Typically, CLOs are privately offered and sold, and thus, are not registered under the securities laws.

High Yield Risk

Funds that invest in high yield securities and unrated securities of similar credit quality (commonly known as “high yield securities” or “junk bonds”) may be subject to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce a Fund’s ability to sell these securities at an advantageous time or price. An economic downturn would generally lead to a higher non-payment rate and, a high yield security may lose significant market value before a default occurs. High yield securities structured as zero-coupon bonds or pay-in-kind securities tend to be especially volatile as they are particularly sensitive to downward pricing pressures from rising interest rates or widening spreads and may require a Fund to make taxable distributions of imputed income without receiving the actual cash currency. Issuers of high yield securities may have the right to “call” or redeem the issue prior to maturity, which may result in a Fund having to reinvest the proceeds in other high yield securities or similar instruments that may pay lower interest rates. A Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities . In addition, the high yield securities in which a Fund invests may not be listed on any exchange and a secondary market for such securities may be comparatively illiquid relative to markets for other more liquid fixed income securities. Consequently, transactions in high yield securities may involve greater costs than transactions in more actively traded securities. A lack of publicly-available information, irregular trading activity and wide bid/ask spreads among other factors, may, in certain circumstances, make high yield debt more difficult to sell at an advantageous time or price than other types of securities or instruments. These factors may result in a Fund being unable to realize full value for these securities and/or may result in a Fund not receiving the proceeds from a sale of a high yield security for an extended period after such sale, each of which could result in losses to a Fund. Because of the risks involved in investing in high yield securities an investment in a Fund that invests in such securities should be considered speculative.

Market Risk

The market price of securities owned by a Fund may go up or down, sometimes rapidly or unpredictably. Securities may decline in value due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of a security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates, adverse changes to credit markets or adverse investor sentiment generally. The value of a security may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Equity securities generally have greater price volatility than fixed income securities . Credit ratings downgrades may also negatively affect securities held by a Fund. Even when markets perform well, there is no assurance that the investments held by a Fund will increase in value along with the broader market.

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In addition, market risk includes the risk that geopolitical and other events will disrupt the economy on a national or global level. For instance, war, terrorism, market manipulation, government defaults, government shutdowns, political changes, diplomatic developments, or the imposition of sanctions and other similar measures, public health emergencies (such as the spread of infectious diseases, pandemics and epidemics) and natural/environmental disasters can all negatively impact the securities markets, which could cause the Funds to lose value. These events could reduce consumer demand or economic output, result in market closures, travel restrictions or quarantines, and significantly adversely impact the economy. The current contentious domestic political environment, as well as political and diplomatic events within the United States and abroad, such as presidential elections in the U.S. or abroad or the U.S. government’s inability at times to agree on a long-term budget and deficit reduction plan, has in the past resulted, and may in the future result, in a government shutdown or otherwise adversely affect the U.S. regulatory landscape, the general market environment and/or investor sentiment, which could have an adverse impact on a Fund’s investments and operations. Additional and/or prolonged U.S. federal government shutdowns may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Governmental and quasi-governmental authorities and regulators throughout the world have previously responded to serious economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or sudden reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect a Fund’s investments. Any market disruptions could also prevent a Fund from executing advantageous investment decisions in a timely manner. Funds that have focused their investments in a region enduring geopolitical market disruption will face higher risks of loss, although the increasing interconnectivity between global economies and financial markets can lead to events or conditions in one country, region or financial market adversely impacting a different country, region or financial market. Thus, investors should closely monitor current market conditions to determine whether a specific Fund meets their individual financial needs and tolerance for risk.

Current market conditions may pose heightened risks with respect to Funds that invest in fixed income securities. As discussed more under “Interest Rate Risk,” the Federal Reserve has begun to raise interest rates from historically low levels and has signaled an intention to continue to do so. Any additional interest rate increases in the future could cause the value of any Fund that invests in fixed income securities to decrease. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk. If rising interest rates cause a Fund to lose enough value, the Fund could also face increased shareholder redemptions, which could force the Fund to liquidate investments at disadvantageous times or prices, therefore adversely affecting the Fund and its shareholders.

Exchanges and securities markets may close early, close late or issue trading halts on specific securities or generally, which may result in, among other things, a Fund being unable to buy or sell certain securities or financial instruments at an advantageous time or accurately price its portfolio investments. In addition, a Fund may rely on various third- party sources to calculate its NAV. As a result, a Fund is subject to certain operational risks associated with reliance on service providers and service providers’ data sources. In particular, errors or systems failures and other technological issues may adversely impact a Fund’s calculations of its NAV, and such NAV calculation issues may result in inaccurately calculated NAVs, delays in NAV calculation and/or the inability to calculate NAVs over extended periods. A Fund may be unable to recover any losses associated with such failures.

Municipal Bond Risk

A Fund that invests in Municipal Bonds may be affected significantly by the economic, regulatory or political developments affecting the ability of issuers of Municipal Bonds to pay interest or repay principal. In addition, the ability of an issuer to make payments or repay interest may be affected by litigation or bankruptcy. In the event of bankruptcy of such an issuer, a Fund investing in the issuer’s securities could experience delays in collecting principal and interest, and the Fund may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in the payment of interest or repayment of principal, or both, a Fund may, in some instances, take possession of, and manage, the assets securing the issuer’s obligations on such securities, which may increase the Fund’s operating expenses. Any income derived from the Fund’s ownership or operation of such assets may not be tax-exempt. Municipal Bonds are subject to interest rate, credit and market risk.

Because many Municipal Bonds are issued to finance similar projects (such as those relating to education, health care, housing, transportation, and utilities), conditions in those sectors may affect the overall municipal securities market. In addition, changes in the financial condition of an individual municipal issuer can affect the overall municipal market. Municipal Bonds backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the discontinuance of the supporting taxation or the inability to collect revenues for the specific project or specific assets. Municipal Bonds are subject to the risk that the Internal Revenue Service (“IRS”) may determine that an issuer has not complied with applicable tax requirements and that interest from the Municipal Bond is taxable, which may result in a significant decline in the value of the security. Municipal Bonds may be less liquid than taxable bonds and there may be less publicly available information on the financial condition of Municipal Bond issuers than for issuers of other securities, and the investment performance of a Fund investing in Municipal Bonds may therefore be more dependent on the analytical abilities of PIMCO than if the Fund held other types of investments such as stocks or taxable bonds. The secondary market for Municipal Bonds also tends to be less well-developed or liquid than many other securities markets, a by-product of lower capital commitments to the asset class by the dealer community, which may adversely affect a Fund’s ability to sell Municipal Bonds it holds at attractive prices or value Municipal Bonds.

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Certain Funds may invest in municipal securities (including taxable municipal securities) issued by Puerto Rico. A Fund's investments in municipal securities issued by Puerto Rico may be particularly affected by political, economic, regulatory or restructuring developments affecting the ability of Puerto Rican municipal issuers to pay interest or repay principal.

Issuer Risk

The value of a security may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services, as well as the historical and prospective earnings of the issuer and the value of its assets. A change in the financial condition of a single issuer may affect securities markets as a whole.

Liquidity Risk

The Securities and Exchange Commission (the “SEC”) defines liquidity risk as the risk that a Fund could not meet requests to redeem shares issued by the Fund without significant dilution of remaining investors’ interests in the Fund. Liquidity risk exists when particular investments are difficult to purchase or sell. Illiquid investments are investments that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Illiquid investments may become harder to value, especially in changing markets. A Fund’s investments in illiquid investments may reduce the returns of the Fund because it may be unable to sell the illiquid investments at an advantageous time or price or possibly require a Fund to dispose of other investments at unfavorable times or prices in order to satisfy its obligations, which could prevent the Fund from taking advantage of other investment opportunities. Additionally, the market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer. Bond markets have consistently grown over the past three decades while the capacity for traditional dealer counterparties to engage in fixed income trading has not kept pace and in some cases has decreased. As a result, dealer inventories of corporate bonds, which provide a core indication of the ability of financial intermediaries to “make markets,” are at or near historic lows in relation to market size. Because market makers seek to provide stability to a market through their intermediary services, the significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty.

In such cases, a Fund, due to regulatory limitations on investments in illiquid investments and the difficulty in purchasing and selling such securities or instruments, may be unable to achieve its desired level of exposure to a certain sector. To the extent that a Fund’s principal investment strategies involve securities of companies with smaller market capitalizations, foreign (non-U.S.) securities , Rule 144A securities, illiquid sectors of fixed income securities , derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk. Further, fixed income securities with longer durations until maturity face heightened levels of liquidity risk as compared to fixed income securities with shorter durations until maturity. Finally, liquidity risk also refers to the risk of unusually high redemption requests, redemption requests by certain large shareholders such as institutional investors or asset allocators, or other unusual market conditions that may make it difficult for a Fund to sell investments within the allowable time period to meet redemptions. Meeting such redemption requests could require a Fund to sell securities at reduced prices or under unfavorable conditions, which would reduce the value of the Fund. It may also be the case that other market participants may be attempting to liquidate fixed income holdings at the same time as a Fund, causing increased supply in the market and contributing to liquidity risk and downward pricing pressure.

Certain accounts or PIMCO affiliates may from time to time own (beneficially or of record) or control a significant percentage of a Fund’s shares. Redemptions by these shareholders of their holdings in a Fund may impact the Fund’s liquidity and NAV. These redemptions may also force a Fund to sell securities, which may negatively impact the Fund’s brokerage costs.

Derivatives Risk

Derivatives and other similar instruments (referred to collectively as “derivatives”) are financial contracts whose value depends on, or is derived from, the value of an underlying asset, reference rate or index. The various derivative instruments that each Fund (except the PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund) may use are referenced under “Characteristics and Risks of Securities and Investment Techniques—Derivatives” in this prospectus and described in more detail under “Investment Objectives and Policies” in the SAI. The Funds typically use derivatives as a substitute for taking a position in the underlying asset, as part of strategies designed to gain exposure to, for example, issuers, portions of the yield curve, indexes, sectors, currencies, and/or geographic regions, and/or to reduce exposure to other risks, such as interest rate, credit or currency risk. The Funds may also use derivatives for leverage, in which case their use would involve leveraging risk, and in some cases, may subject a Fund to the potential for unlimited loss. The use of derivatives may cause the Fund’s investment returns to be impacted by the performance of securities the Fund does not own and result in the Fund’s total investment exposure exceeding the value of its portfolio.

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A Fund’s use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks described elsewhere in this section, such as liquidity risk (which may be heightened for highly-customized derivatives ), interest rate risk, market risk, leverage risk, counterparty (including credit) risk, operational risk, legal risk and management risk, as well as risks arising from changes in applicable requirements. They also involve the risk of improper valuation and the risk that changes in the value of a derivative instrument may not correlate perfectly with the underlying asset, rate or index. By investing in a derivative instrument, the Fund could lose more than the initial amount invested and derivatives may increase the volatility of the Fund, especially in unusual or extreme market conditions. The Fund may be required to hold additional cash or sell other investments in order to obtain cash to close out a position and changes in the value of a derivative may also create margin delivery or settlement payment obligations for the Fund. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that a Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial or that, if used, such strategies will be successful. In addition, a Fund’s use of derivatives may increase or accelerate the amount of taxes payable by shareholders. Over-the-counter (“OTC”) derivatives are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivatives . The primary credit risk on derivatives that are exchange-traded or traded through a central clearing counterparty resides with the Fund’s clearing broker, or the clearinghouse.

Participation in the markets for derivative instruments involves investment risks and transaction costs to which a Fund may not be subject absent the use of these strategies. The skills needed to successfully execute derivative strategies may be different from those needed for other types of transactions. If the Fund incorrectly forecasts the value and/or creditworthiness of securities, currencies, interest rates, counterparties or other economic factors involved in a derivative transaction, the Fund might have been in a better position if the Fund had not entered into such derivative transaction. In evaluating the risks and contractual obligations associated with particular derivative instruments, it is important to consider that certain derivative transactions may be modified or terminated only by mutual consent of a Fund and its counterparty. Therefore, it may not be possible for the Fund to modify, terminate, or offset the Fund’s obligations or the Fund’s exposure to the risks associated with a derivative transaction prior to its scheduled termination or maturity date, which may create a possibility of increased volatility and/or decreased liquidity to the Fund. In such case, the Fund may lose money.

Because the markets for certain derivative instruments (including markets located in foreign countries) are relatively new and still developing, appropriate derivative transactions may not be available in all circumstances for risk management or other purposes. Upon the expiration of a particular contract, a Fund may wish to retain its position in the derivative instrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other suitable counterparty can be found. When such markets are unavailable, a Fund will be subject to increased liquidity and investment risk.

When a derivative is used as a hedge against a position that a Fund holds, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. Although hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying instrument, and there can be no assurance that a Fund’s hedging transactions will be effective.

The regulation of the derivatives markets has increased over the past several years, and additional future regulation of the derivatives markets may make derivatives more costly, may limit the availability or reduce the liquidity of derivatives , or may otherwise adversely affect the value or performance of derivatives . Any such adverse future developments could impair the effectiveness or raise the costs of a Fund’s derivative transactions, impede the employment of the Fund’s derivatives strategies, or adversely affect the Fund’s performance.

Equity Risk

Equity securities represent an ownership interest, or the right to acquire an ownership interest, in an issuer. Equity securities also include, among other things, preferred securities, convertible stocks and warrants. The values of equity securities, such as common stocks and preferred securities, may decline due to general market conditions which are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. Equity securities generally have greater price volatility than fixed income securities. These risks are generally magnified in the case of equity investments in distressed companies.

Mortgage-Related and Other Asset-Backed Securities Risk

Mortgage-related and other asset-backed securities represent interests in “pools” of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Generally, rising interest rates tend to extend the duration of fixed rate mortgage-related securities , making them more sensitive to changes in interest rates. As a result, in a period of rising interest rates, if a Fund holds mortgage-related securities , it may exhibit additional volatility since individual mortgage holders are less likely to exercise prepayment options, thereby putting additional downward pressure on the value

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of these securities and potentially causing the Fund to lose money. This is known as extension risk. Mortgage-backed securities can be highly sensitive to rising interest rates, such that even small movements can cause an investing Fund to lose value. Mortgage-backed securities , and in particular those not backed by a government guarantee, are subject to credit risk. In addition, adjustable and fixed rate mortgage-related securities are subject to prepayment risk. When interest rates decline, borrowers may pay off their mortgages sooner than expected. This can reduce the returns of a Fund because the Fund may have to reinvest that money at the lower prevailing interest rates. A Fund’s investments in other asset-backed securities are subject to risks similar to those associated with mortgage-related securities , as well as additional risks associated with the nature of the assets and the servicing of those assets. Payment of principal and interest on asset-backed securities may be largely dependent upon the cash flows generated by the assets backing the securities, and asset-backed securities may not have the benefit of any security interest in the related assets.

Foreign (Non-U.S.) Investment Risk

Certain Funds may invest in foreign (non-U.S.) securities and may experience more rapid and extreme changes in value than a fund that invests exclusively in securities of U.S. issuers or securities that trade exclusively in U.S. markets. The securities markets of many foreign (non-U.S.) countries are relatively small, with a limited number of companies representing a small number of industries. Additionally, issuers of foreign (non-U.S.) securities are usually not subject to the same degree of regulation as U.S. issuers. Reporting, accounting and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. Also, nationalization, expropriation or confiscatory taxation, currency blockage, market disruptions, political changes, security suspensions, diplomatic developments or the imposition of sanctions or other similar measures could adversely affect a Fund’s investments in a foreign country. In the event of nationalization, expropriation or other confiscation, a Fund could lose its entire investment in foreign (non-U.S.) securities . The type and severity of sanctions and other similar measures, including counter sanctions and other retaliatory actions, that may be imposed could vary broadly in scope, and their impact is difficult to ascertain. These types of measures may include, but are not limited to, banning a sanctioned country or certain persons or entities associated with such country from global payment systems that facilitate cross-border payments, restricting the settlement of securities transactions by certain investors, and freezing the assets of particular countries, entities or persons. The imposition of sanctions and other similar measures could, among other things, result in a decline in the value and/or liquidity of securities issued by the sanctioned country or companies located in or economically tied to the sanctioned country, downgrades in the credit ratings of the sanctioned country's securities or those of companies located in or economically tied to the sanctioned country, currency devaluation or volatility, and increased market volatility and disruption in the sanctioned country and throughout the world. Sanctions and other similar measures could directly or indirectly limit or prevent a Fund from buying and selling securities (in the sanctioned country and other markets), significantly delay or prevent the settlement of securities transactions and adversely impact a Fund's liquidity and performance. Adverse conditions in a certain region can adversely affect securities of other countries whose economies appear to be unrelated. To the extent that a Fund invests a significant portion of its assets in a specific geographic region or in securities denominated in a particular foreign (non-U.S.) currency , the Fund will generally have more exposure to regional economic risks, including weather emergencies and natural disasters, associated with foreign (non-U.S.) investments. Foreign (non-U.S.) securities may also be less liquid and more difficult to value than securities of U.S. issuers.

Emerging Markets Risk

Foreign (non-U.S.) investment risk may be particularly high to the extent a Fund invests in emerging market securities . Emerging market securities may present market, credit, currency, liquidity, legal, political, technical and other risks different from, and potentially greater than, the risks of investing in securities and instruments economically tied to developed foreign countries. To the extent a Fund invests in emerging market securities that are economically tied to a particular region, country or group of countries, the Fund may be more sensitive to adverse political or social events affecting that region, country or group of countries. Economic, business, political, or social instability may affect emerging market securities differently, and often more severely, than developed market securities. A Fund that focuses its investments in multiple asset classes of emerging market securities may have a limited ability to mitigate losses in an environment that is adverse to emerging market securities in general. Emerging market securities may also be more volatile, less liquid (particularly during market closures due to local holidays or other reasons) and more difficult to value than securities economically tied to developed foreign countries. The systems and procedures for trading and settlement of securities in emerging markets are less developed and less transparent and transactions may take longer to settle. Emerging market countries typically have less established legal, accounting and financial reporting systems than those in more developed markets, which may reduce the scope or quality of financial information available to investors. Governments in emerging market countries are often less stable and more likely to take extra-legal action with respect to companies, industries, assets, or foreign ownership than those in more developed markets. Moreover, it can be more difficult for investors to bring litigation or enforce judgments against issuers in emerging markets or for U.S. regulators to bring enforcement actions against such issuers. A Fund may also be subject to Emerging Markets Risk if they invest in derivatives or other securities or instruments whose value or return are related to the value or returns of emerging markets securities. Rising interest rates, combined with widening credit spreads, could negatively impact the value of emerging market debt and increase funding costs for foreign issuers. In such a scenario, foreign issuers might not

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be able to service their debt obligations, the market for emerging market debt could suffer from reduced liquidity, and any investing Funds could lose money. The economy of some emerging markets may be particularly exposed to or affected by a certain industry or sector, and therefore issuers and/or securities of such emerging markets may be more affected by the performance of such industries or sectors.

Currency Risk

If a Fund invests directly in foreign (non-U.S.) currencies or in securities that trade in, and receive revenues in, foreign (non-U.S.) currencies , or, in the case of each Fund (except the PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund), in derivatives or other instruments that provide exposure to foreign (non-U.S.) currencies , it will be subject to the risk that those currencies will decline in value relative to the U.S. dollar, or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency being hedged.

Currency rates in foreign (non-U.S.) countries may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates, rates of inflation, balance of payments and governmental surpluses or deficits, intervention (or the failure to intervene) by U.S. or foreign (non-U.S.) governments, central banks or supranational entities such as the International Monetary Fund, or by the imposition of currency controls or other political developments in the United States or abroad. As a result, a Fund’s investments in foreign (non-U.S.) currencies and/or foreign currency-denominated securities may reduce the returns of the Fund.

Currency risk may be particularly high to the extent that a Fund invests in foreign (non-U.S.) currencies or engages in foreign currency transactions that are economically tied to emerging market countries. These currency transactions may present market, credit, currency, liquidity, legal, political and other risks different from, or greater than, the risks of investing in developed foreign (non-U.S.) currencies or engaging in foreign currency transactions that are economically tied to developed foreign countries.

Leveraging Risk

Certain transactions may give rise to a form of leverage. Such transactions may include, among others, reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions . Each Fund's (except the PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund) use of derivatives may also create leveraging risk. The Funds also may be exposed to leveraging risk by borrowing money for investment purposes. Leverage may cause a Fund to liquidate portfolio positions to satisfy its obligations when it may not be advantageous to do so. Leverage, including borrowing, may cause a Fund to be more volatile than if the Fund had not been leveraged. This is because leverage tends to exaggerate the effect of any increase or decrease in the value of a Fund's portfolio securities. Certain types of leveraging transactions, such as short sales that are not “against the box,” (i.e., short sales where the Fund does not hold the security or have the right to acquire it without payment of further consideration), could theoretically be subject to unlimited losses in cases where a Fund, for any reason, is unable to close out the transaction. In addition, to the extent a Fund borrows money, interest costs on such borrowings may not be recovered by any appreciation of the securities purchased with the borrowed amounts and could exceed the Fund’s investment returns, resulting in greater losses. Moreover, to make payments of interest and other loan costs, a Fund may be forced to sell portfolio securities when it is not otherwise advantageous to do so.

Management Risk

Each Fund is subject to management risk because it is an actively managed investment portfolio. PIMCO and each individual portfolio manager will apply investment techniques and risk analysis in making investment decisions for the Funds, but there can be no guarantee that these decisions will produce the desired results. Certain securities or other instruments in which a Fund seeks to invest may not be available in the quantities desired, including in circumstances where other funds for which PIMCO acts as investment adviser, including funds with names, investment objectives and policies, and/or portfolio management teams, similar to the Fund, are seeking to invest in the same or similar securities or instruments. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments. In such circumstances, PIMCO or the individual portfolio managers may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund. Each Fund is also subject to the risk that deficiencies in the internal systems or controls of PIMCO or another service provider will cause losses for the Fund or hinder Fund operations. For example, trading delays or errors (both human and systemic) could prevent a Fund from purchasing a security expected to appreciate in value. To the extent a Fund employs strategies targeting perceived pricing inefficiencies, arbitrage strategies or similar strategies, it is subject to the risk that the pricing or valuation of the securities and instruments involved in such strategies may change unexpectedly, which may result in reduced returns or losses to the Fund. Additionally, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and each individual portfolio manager in connection with managing the Funds and may also adversely affect the ability of the Funds to achieve their investment objectives. There also can be no assurance that all of the personnel of PIMCO will continue to be associated with PIMCO for any length of time. The loss of services of one or more key employees of PIMCO could have an adverse impact on the Fund’s ability to realize its investment objective.

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California State-Specific Risk

A Fund that concentrates its investments in California Municipal Bonds may be affected significantly by economic, regulatory or political developments affecting the ability of California issuers to pay interest or repay principal. Certain issuers of California Municipal Bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain California issuers to pay principal or interest on their obligations. Provisions of the California Constitution and State statutes that limit the taxing and spending authority of California governmental entities may impair the ability of California issuers to pay principal and/or interest on their obligations. While California’s economy is broad, it does have major concentrations in advanced technology, aerospace and defense-related manufacturing, trade, entertainment, real estate and financial services, and may be sensitive to economic problems affecting those industries. Future California political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation and voter initiatives could have an adverse effect on the debt obligations of California issuers.

New York State-Specific Risk

A Fund that concentrates its investments in New York Municipal Bonds may be affected significantly by economic, regulatory or political developments affecting the ability of New York issuers to pay interest or repay principal. While New York’s economy is broad, it does have concentrations in the financial services industry, and may be sensitive to economic problems affecting that industry. Certain issuers of New York Municipal Bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain New York issuers to pay principal or interest on their obligations. The financial health of New York City affects that of the State, and when New York City experiences financial difficulty it may have an adverse affect on New York Municipal Bonds held by such Fund. The growth rate of New York has at times been somewhat slower than the nation overall. The economic and financial condition of New York also may be affected by various financial, social, economic and political factors.

Puerto Rico-Specific Risk

A Fund that invests in Municipal Bonds issued by Puerto Rico or its instrumentalities may be affected by certain developments, such as political, economic, environmental, social, regulatory or debt restructuring developments, that impact the ability or obligation of Puerto Rico municipal issuers to pay interest or repay principal. Certain issuers of Puerto Rico Municipal Bonds have experienced significant financial difficulties and the continuation or reoccurrence of these difficulties may impair their ability to pay principal or interest on their obligations. Provisions of the Puerto Rico Constitution and Commonwealth laws, including a federally-appointed oversight board to oversee the Commonwealth’s financial operations, which limit the taxing and spending authority of Puerto Rico governmental entities, may impair the ability of Puerto Rico issuers to pay principal and/or interest on their obligations. Puerto Rico’s economy has sizable concentrations in certain industries, such as the manufacturing and service industries, and may be sensitive to economic problems affecting those industries. Future Puerto Rico-related developments, such as political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation, debt restructuring, and voter initiatives as well as environmental events, natural disasters, pandemics, epidemics or social unrest could have an adverse effect on the debt obligations of Puerto Rico issuers.

Municipal Project-Specific Risk

A Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in the bonds of specific projects (such as those relating to education, health care, housing, transportation, and utilities), industrial development bonds, or in general obligation bonds, particularly if there is a large concentration from issuers in a single state. This is because the value of municipal securities can be significantly affected by the political, economic, legal, and legislative realities of the particular issuer’s locality or municipal sector events. In addition, a significant restructuring of federal income tax rates or even serious discussion on the topic in Congress could cause municipal bond prices to fall. The demand for municipal securities is strongly influenced by the value of tax-exempt income to investors. Lower income tax rates could reduce the advantage of owning municipal securities. Similarly, changes to state or federal regulation tied to a specific sector, such as the hospital sector, could have an impact on the revenue stream for a given subset of the market.

Municipal securities are also subject to interest rate, credit, and liquidity risk.

Interest Rate Risk . The value of municipal securities, similar to other fixed income securities, will likely drop as interest rates rise in the general market. Conversely, when rates decline, bond prices generally rise.

Credit Risk . The risk that a borrower may be unable to make interest or principal payments when they are due. Funds that invest in municipal securities rely on the ability of the issuer to service its debt. This subjects a Fund to credit risk in that the municipal issuer may be fiscally unstable or exposed to large liabilities that could impair its ability to honor its obligations. Municipal issuers with significant debt service requirements, in the near-to mid-term; unrated issuers and those with less capital and liquidity to absorb additional expenses may be most at risk. A Fund that invests in lower quality or high yield municipal securities may be more sensitive to the adverse credit events in the municipal market. The treatment of municipalities in bankruptcy is more uncertain, and potentially more adverse to debt holders, than for corporate issues.

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Liquidity Risk . The risk that investors may have difficulty finding a buyer when they seek to sell, and therefore, may be forced to sell at a discount to the market value. Liquidity may sometimes be impaired in the municipal market and Funds that primarily invest in municipal securities may find it difficult to purchase or sell such securities at opportune times. Liquidity can be impaired due to interest rate concerns, credit events, or general supply and demand imbalances. These adverse developments sometimes cause a Fund to endure higher redemption rates. Depending on the particular issuer and current economic conditions, municipal securities could be deemed more volatile investments.

In addition to general municipal market risks, different municipal sectors may face different risks. For instance, general obligation bonds are secured by the full faith, credit, and taxing power of the municipality issuing the obligation. As such, timely payment depends on the municipality’s ability to raise tax revenue and maintain a fiscally sound budget. The timely payments may also be influenced by any unfunded pension liabilities or other post- employee benefit plan (“OPEB”) liabilities.

Revenue bonds are secured by special tax revenues or other revenue sources. If the specified revenues do not materialize, then the bonds may not be repaid.

Private activity bonds are yet another type of municipal security. Municipalities use private activity bonds to finance the development of industrial facilities for use by private enterprise. Principal and interest payments are to be made by the private enterprise benefitting from the development, which means that the holder of the bond is exposed to the risk that the private issuer may default on the bond.

Moral obligation bonds are usually issued by special purpose public entities. If the public entity defaults, repayment becomes a “moral obligation” instead of a legal one. The lack of a legally enforceable right to payment in the event of default poses a special risk for a holder of the bond because it has little or no ability to seek recourse in the event of default.

Municipal notes are similar to general municipal debt obligations, but they generally possess shorter terms. Municipal notes can be used to provide interim financing and may not be repaid if anticipated revenues are not realized.

Short Exposure Risk

A Fund’s short sales and short positions, if any, are subject to special risks. A short sale involves the sale by the Fund of a security that it does not own with the hope of purchasing the same security at a later date at a lower price. A Fund may also enter into a short position through a forward commitment or, in the case of each Fund (except PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund), a short derivative position through a futures contract or, except the PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund and PIMCO Enhanced Short Maturity Active Exchange-Traded Fund, swap agreement. If the price of the security or derivative has increased during this time, then the Fund will incur a loss equal to the increase in price from the time that the short sale was entered into plus any transaction costs ( i.e. , premiums and interest) paid to the broker-dealer to borrow securities. Therefore, short sales involve the risk that losses may be exaggerated, potentially losing more money than the actual cost of the investment. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security’s value cannot decrease below zero.

By investing the proceeds received from selling securities short, a Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase a Fund’s exposure to long security positions and make any change in the Fund’s NAV greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that any leveraging strategy a Fund employs will be successful during any period in which it is employed.

In times of unusual or adverse market, economic, regulatory or political conditions, a Fund may not be able, fully or partially, to implement its short selling strategy. Periods of unusual or adverse market, economic, regulatory or political conditions generally may exist for as long as six months and, in some cases, much longer. Also, there is the risk that the third party to the short sale or short position will not fulfill its contractual obligations, causing a loss to the Fund.

Convertible Securities Risk

Convertible securities are fixed income securities , preferred securities or other securities that are convertible into or exercisable for common stock of the issuer (or cash or securities of equivalent value) at either a stated price or a stated rate. The market values of convertible securities may decline as interest rates increase and, conversely, may increase as interest rates decline. A convertible security’s market value, however, tends to reflect the market price of the common stock of the issuing company when that stock price approaches or is greater than the convertible security’s “conversion price.” The conversion price is defined as the predetermined price at which the convertible security could be exchanged for the associated stock. As the market price of the underlying common stock declines, the price of the convertible security tends to be influenced more by the yield of the convertible security . Thus, it may not decline in price to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities may be paid before the company’s common stockholders but after holders of any senior debt obligations of the company. Consequently, the issuer’s convertible securities generally entail less risk than its common stock but more risk than its debt obligations.

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 45

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Synthetic convertible securities involve the combination of separate securities that possess the two principal characteristics of a traditional convertible security ( i.e. , an income-producing component and a right to acquire an equity security ). Synthetic convertible securities are often achieved, in part, through investments in warrants or options to buy common stock (or options on a stock index), and therefore are subject to the risks associated with derivatives . The value of a synthetic convertible security will respond differently to market fluctuations than a traditional convertible security because a synthetic convertible is composed of two or more separate securities or instruments, each with its own market value. Because the convertible component is typically achieved by investing in warrants or options to buy common stock at a certain exercise price, or options on a stock index, synthetic convertible securities are subject to the risks associated with derivatives . In addition, if the value of the underlying common stock or the level of the index involved in the convertible component falls below the exercise price of the warrant or option, the warrant or option may lose all value.

Tax-Efficient Investing Risk

A Fund may engage in investment strategies intended to manage capital gain distributions. For example, a Fund may attempt to use losses from sales of securities that have declined to offset future gains that would otherwise be taxable. Any such strategy may be unsuccessful or only partially successful, and investors may experience adverse tax effects, including, but not limited to potentially greater tax liability than other PIMCO-advised funds. Additionally, such strategies may reduce investment returns or result in investment losses, which could cause the Fund and investors to lose money. Further, a Fund’s focus on income generation may result in a higher overall tax liability as income may be taxed at a higher rate than capital gains.

Distribution Rate Risk

Although a Fund may seek to maintain a level distribution rate, the Fund’s distribution rate may be affected by numerous factors, including but not limited to changes in realized and projected market returns, fluctuations in market interest rates, Fund performance, and other factors. For instance, during periods of low or declining interest rates, the Fund’s distributable income and dividend levels may decline for many reasons. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund’s distribution rate or that the rate will be sustainable in the future.

Responsible Investing Risk

A Fund’s responsible investment strategy, which may select or exclude securities of certain issuers for reasons other than performance, carries the risk that a Fund may underperform funds that do not utilize a responsible investment strategy. The application of this strategy may affect a Fund’s exposure to certain sectors or types of investments, which could negatively impact a Fund’s performance. Responsible investing is qualitative and subjective by nature, and there is no guarantee that the criteria utilized by PIMCO or any judgment exercised by PIMCO will reflect the beliefs or values of any particular investor. In evaluating a company, PIMCO is dependent upon information and data obtained through voluntary or third-party reporting that may be incomplete, inaccurate or unavailable, which could cause PIMCO to incorrectly assess a company’s business practices with respect to the environment, social responsibility and corporate governance (“ESG practices”). Socially responsible norms differ by region, and a company’s ESG practices or PIMCO’s assessment of a company’s ESG practices may change over time. In addition, as a result of PIMCO’s engagement activities, a Fund may purchase securities that do not currently engage in ESG practices to PIMCO’s satisfaction, in an effort to improve an issuer’s ESG practices. Successful application of a Fund’s responsible investment strategy and PIMCO’s engagement efforts will depend on PIMCO’s skill in properly identifying and analyzing material ESG issues, and there can be no assurance that the strategy or techniques employed will be successful. Past performance is not a guarantee or reliable indicator of future results.

LIBOR Transition Risk

Certain instruments in which a Fund may invest rely in some fashion upon the London Interbank Offered Rate (“LIBOR”). LIBOR is an average interest rate, determined by the ICE Benchmark Administration, that banks charge one another for the use of short-term money. On July 27, 2017, the Chief Executive of the Financial Conduct Authority (“FCA”), the United Kingdom’s financial regulatory body and regulator of LIBOR, announced that after 2021 it would cease its active encouragement of banks to provide the quotations needed to sustain LIBOR due to the absence of an active market for interbank unsecured lending and other reasons. On March 5, 2021, the FCA announced that all U.S. Dollar LIBOR settings will either cease to be provided by any administrator or will no longer be representative (i) immediately after December 31, 2021 for one-week and two-month U.S. Dollar LIBOR settings and (ii) immediately after June 30, 2023 for the remaining U.S. Dollar LIBOR settings. As of January 1, 2022, as a result of supervisory guidance from U.S. regulators, some U.S. regulated entities have ceased entering into new LIBOR contracts with limited exceptions. While publication of the one-, three- and six- month Sterling and Japanese yen LIBOR settings will continue at least through calendar year 2022 on the basis of a changed methodology (known as “synthetic LIBOR”), these rates have been designated by the FCA as unrepresentative of the underlying market they seek to measure and are solely available for use in legacy transactions. Certain bank-sponsored committees in other jurisdictions, including Europe, the United Kingdom, Japan and Switzerland, have selected alternative reference rates denominated in other currencies. Although the transition process away from LIBOR has become increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty

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regarding the future utilization of LIBOR and the nature of any replacement rate. Any potential effects of the transition away from LIBOR on a Fund or on certain instruments in which a Fund invests can be difficult to ascertain, and they may vary depending on factors that include, but are not limited to: (i) existing fallback or termination provisions in individual contracts and (ii) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new products and instruments. For example, certain of a Fund's investments may involve individual contracts that have (i) no existing fallback provision or language that contemplates the discontinuation of LIBOR or (ii) inadequate fallback provisions or language that does not contemplate a permanent discontinuation of LIBOR, and those investments could experience increased volatility or reduced liquidity as a result of the transition process. In addition, interest rate provisions included in such contracts may need to be renegotiated in contemplation of the transition away from LIBOR. On March 15, 2022, the Adjustable Interest Rate (LIBOR) Act was signed into law. This law provides a statutory fallback mechanism on a nationwide basis to replace LIBOR with a benchmark rate that is selected by the Board of Governors of the Federal Reserve System and based on the Secured Overnight Financing Rate (“SOFR”) for certain contracts that reference LIBOR and contain no, or insufficient, fallback provisions. The Federal Reserve proposed implementing regulations for the law on July 28, 2022, and it is expected that final regulations will follow. The transition of investments from LIBOR to a replacement rate as a result of amendment, application of existing fallbacks, statutory requirements or otherwise may also result in a reduction in the value of certain instruments held by a Fund or a reduction in the effectiveness of related Fund transactions such as hedges. In addition, an instrument's transition to a replacement rate could result in variations in the reported yields of a Fund that holds such instrument. Any such effects of the transition away from LIBOR, as well as other unforeseen effects, could result in losses to a Fund.

Disclosure of Portfolio Holdings

Please see “Disclosure of Portfolio Holdings” in the SAI for information about the availability of the complete schedule of each Fund’s holdings.

November 1, 2022 (as supplemented June 21, 2023) | Prospectus 47

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Management of the Funds

Investment Manager

PIMCO serves as the investment manager for the Funds. Subject to the supervision of the Board of Trustees, PIMCO is responsible for managing the investment activities of the Funds and the Funds’ business affairs and other administrative matters.

PIMCO is located at 650 Newport Center Drive, Newport Beach, CA 92660. Organized in 1971, PIMCO provides investment management and advisory services to private accounts of institutional and individual clients and to mutual funds. As of September 30, 2022, PIMCO had approximately $1.70 trillion in assets under management.

Management Fees

Each Fund pays for the advisory and supervisory and administrative services it requires under what is essentially an all-in fee structure. For the fiscal year ended June 30, 2022, the Funds paid monthly Management Fees to PIMCO at the following annual rates (stated as a percentage of the average daily net assets of the Fund taken separately):

Fund Name	Management Fees (1)
PIMCO Active Bond Exchange-Traded Fund	0.55%
PIMCO Enhanced Low Duration Active Exchange-Traded Fund	0.46%
PIMCO Enhanced Short Maturity Active ESG Echange-Traded Fund	0.36%
PIMCO Enhanced Short Maturity Active Exchange-Traded Fund	0.35%
PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund	0.35%
PIMCO Municipal Income Opportunities Active Exchange-Traded Fund	0.49%
PIMCO Senior Loan Active Exchange-Traded Fund	0.70%
PIMCO Short Term Municipal Bond Active Exchange-Traded Fund	0.35%

For details regarding changes to this rate within the last 5 years, please see the footnote disclosures for the Funds in the Financial Highlights section beginning on page 76 .

The PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund were not operational during the fiscal year ended June 30, 2022. The management fees for each of the PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund are at the annual rate (stated as a percentage of the average daily net assets of each Fund taken separately) of 0.25% and 0.14%, respectively.

In addition to providing investment advisory services, PIMCO provides or procures supervisory and administrative services for shareholders and also bears the costs of various third-party services required by the Funds, including audit, custodial, portfolio accounting, legal, transfer agency and printing costs. The Funds bear other expenses which are not covered under the management fee which may vary and affect the total level of expenses paid by shareholders, such as taxes and governmental fees, brokerage fees, commissions and other transaction expenses, costs of borrowing money, including interest expenses, securities lending expenses, extraordinary expenses (such as litigation and indemnification expenses) and fees and expenses of the Trust’s Independent Trustees and their counsel. PIMCO generally earns a profit on the management fee paid by the Funds. Also, under the terms of the investment management agreement, PIMCO, and not Fund shareholders, would benefit from any price decreases in third-party services, including decreases resulting from an increase in net assets.

A discussion of the basis for the Board of Trustees’ approval of the Funds’ (other than the PIMCO Senior Loan Active Exchange-Traded Fund, PIMCO Prime Limited Maturity Active Exchange-Traded Fund and PIMCO Ultra Short Government Active Exchange-Traded Fund) investment management agreement is available in the Funds’ semi-annual report to shareholders for the fiscal half-year ended December 31, 2021. A discussion of the basis for the Board of Trustees’ approval of the PIMCO Senior Loan Active Exchange-Traded Fund’s investment management agreement is available in the Fund’s annual report to shareholders for the fiscal year ended June 30, 2022. A discussion of the basis for the Board of Trustees’ approval of the PIMCO Prime Limited Maturity Active Exchange-Traded and PIMCO Ultra Short Government Active Exchange-Traded Fund's investment management agreement will be available in the Fund’s first annual or semi-annual report to shareholders.

Expense Limitation Agreement

PIMCO has contractually agreed, through October 31, 2023, to waive a portion of each Fund’s Management Fee, or reimburse the Fund, to the extent that the Fund’s organizational expenses, pro rata share of expenses related to obtaining or maintaining a Legal Entity Identifier and pro rata share of Trustee fees exceed 0.0049% (the “ Expense Limit”) (calculated as a percentage of the Fund’s average daily net assets). The Expense Limitation Agreement will automatically renew for one-year terms unless PIMCO provides written notice to the Trust at least 30 days prior to the end of the then current term. In any month in which the investment management agreement is in effect, PIMCO is entitled to reimbursement by each Fund of any portion of the Management Fee waived or reimbursed as set forth above (the “Reimbursement Amount”) within thirty-six months of the time of the waiver, provided that such amount paid to PIMCO will not: 1) together with any organizational expenses, pro rata share of expenses related to

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	TICKER	EXCHANGE
SHORT DURATION
PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund	EMNT	NYSE Arca
PIMCO Enhanced Short Maturity Active Exchange-Traded Fund	MINT	NYSE Arca
PIMCO Prime Limited Maturity Active Exchange-Traded Fund	PPRM
PIMCO Ultra Short Government Active Exchange-Traded Fund	BILZ	NYSE Arca
CORE
PIMCO Active Bond Exchange-Traded Fund	BOND	NYSE
PIMCO Enhanced Low Duration Active Exchange-Traded Fund	LDUR	NYSE Arca
TAX-EXEMPT MUNICIPAL
PIMCO Short Term Municipal Bond Active Exchange-Traded Fund	SMMU	NYSE Arca
PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund	MUNI	NYSE Arca
PIMCO Municipal Income Opportunities Active Exchange-Traded Fund	MINO	NYSE Arca
SENIOR LOANS
PIMCO Senior Loan Active Exchange-Traded Fund	LONZ	NYSE Arca

	Page
Fund Summaries	1
PIMCO Active Bond Exchange-Traded Fund	1
PIMCO Enhanced Low Duration Active Exchange-Traded Fund	5
PIMCO Enhanced Short Maturity Active ESG Exchange-Traded Fund	9
PIMCO Enhanced Short Maturity Active Exchange-Traded Fund	13
PIMCO Intermediate Municipal Bond Active Exchange-Traded Fund	16
PIMCO Municipal Income Opportunities Active Exchange-Traded Fund	19
PIMCO Prime Limited Maturity Active Exchange-Traded Fund	22
PIMCO Senior Loan Active Exchange-Traded Fund	24
PIMCO Short Term Municipal Bond Active Exchange-Traded Fund	28
PIMCO Ultra Short Government Active Exchange-Traded Fund	31
Summary of Other Important Information Regarding Fund Shares	33
Summary Information About the Funds	33
Description of Principal Risks	35
Disclosure of Portfolio Holdings	47
Management of the Funds	48
Buying and Selling Shares	53
How Net Asset Value Is Determined	55
Fund Distributions	56
Tax Consequences	56
Characteristics and Risks of Securities and Investment Techniques	57
Financial Highlights	76
Appendix A - Description of Securities Ratings	A - 1