March 1, 2022

    

2022 Prospectus

•	iShares Yield Optimized Bond ETF | BYLD |  NYSE ARCA

  

The Securities and Exchange Commission (“SEC”) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Fund Overview	S-1
More Information About the Fund	1
A Further Discussion of Principal Risks	2
A Further Discussion of Other Risks	17
Portfolio Holdings Information	27
A Further Discussion of Principal Investment Strategies	27
Management	31
Shareholder Information	34
Distribution	43
Financial Highlights	44
Index Provider	45
Disclaimer	45

“Morningstar^®” and “Morningstar^® U.S. Bond Market Yield-Optimized Index^SM” are trademarks or servicemarks of Morningstar, Inc. and have been licensed for use for certain purposes by BlackRock Fund Advisors or its affiliates. iShares^® and BlackRock^® are registered trademarks of BlackRock Fund Advisors and its affiliates. The Fund is not sponsored, endorsed, sold or promoted by Morningstar, Inc., and Morningstar, Inc. makes no representation regarding the advisability of investing in the Fund.

i

[THIS PAGE INTENTIONALLY LEFT BLANK]

iSHARES^® YIELD OPTIMIZED BOND ETF

Investment Objective

The iShares Yield Optimized Bond ETF (the “Fund”) seeks to track the investment results of an index composed of underlying fixed income funds that collectively seek to deliver current income.

Fees and Expenses

The following table describes the fees and expenses that you will incur if you buy, hold and sell shares of the Fund. The investment advisory agreement between iShares Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except: (i) the management fees, (ii) interest expenses, (iii) taxes, (iv) expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, (v) distribution fees or expenses, and (vi) litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive its management fees through February 28, 2026. The contractual waiver may be terminated prior to February 28, 2026 only upon written agreement of the Trust and BFA.

You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

---

 

Performance Information

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide some indication of the risks of investing in the Fund by showing how the Fund’s average annual returns for 1 and 5 years and since inception compare with those of a broad measure of market performance. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

Year by Year Returns (Years Ended December 31)

The best calendar quarter return during the periods shown above was 5.24% in the 1st quarter of 2019; the worst was -3.69% in the 1st quarter of 2020. 

Updated performance information, including the Fund’s current NAV, may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free). 

Average Annual Total Returns

(for the periods ended December 31, 2021)

---

[THIS PAGE INTENTIONALLY LEFT BLANK]

More Information About the Fund

This Prospectus contains important information about investing in the Fund. Please read this Prospectus carefully before you make any investment decisions. Additional information regarding the Fund is available at www.iShares.com.

BFA is the investment adviser to the Fund. Shares of the Fund are listed for trading on NYSE Arca, Inc. (“NYSE Arca”). The market price for a share of the Fund may be different from the Fund’s most recent NAV.

ETFs are funds that trade like other publicly-traded securities. The Fund is designed to track an index. Similar to shares of an index mutual fund, each share of the Fund represents an ownership interest in an underlying portfolio of securities and other instruments intended to track a market index. Unlike shares of a mutual fund, which can be bought and redeemed from the issuing fund by all shareholders at a price based on NAV, shares of the Fund may be purchased or redeemed directly from the Fund at NAV solely by Authorized Participants and only in aggregations of a specified number of shares (“Creation Units”). Also unlike shares of a mutual fund, shares of the Fund are listed on a national securities exchange and trade in the secondary market at market prices that change throughout the day.

An index is a financial calculation, based on a grouping of financial instruments, and is not an investment product, while the Fund is an actual investment portfolio. The performance of the Fund and the Underlying Index may vary for a number of reasons, including transaction costs, non-U.S. currency valuations, asset valuations, corporate actions (such as mergers and spin-offs), timing variances and differences between the Fund’s portfolio and the Underlying Index resulting from the Fund's or Underlying Fund's use of representative sampling or from legal restrictions (such as diversification requirements) that apply to the Fund but not to the Underlying Index. From time to time, the Index Provider may make changes to the methodology or other adjustments to the Underlying Index. Unless otherwise determined by BFA, any such change or adjustment will be reflected in the calculation of the Underlying Index performance on a going-forward basis after the effective date of such change or adjustment. Therefore, the Underlying Index performance shown for periods prior to the effective date of any such change or adjustment will generally not be recalculated or restated to reflect such change or adjustment.

“Tracking error” is the divergence of the Fund's performance from that of the Underlying Index. To the extent that the Fund uses a representative sampling indexing strategy, it can be expected to have a larger tracking error than if it used a replication indexing strategy. “Replication” is an indexing strategy in which a fund invests in substantially all of the securities in its underlying index in approximately the same proportions as in the underlying index.

An investment in the Fund is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, BFA or any of its affiliates.

1

The Fund's investment objective and the Underlying Index may be changed without shareholder approval.

A Further Discussion of Principal Risks

The Fund is subject to various risks, including the principal risks noted below, any of which may adversely affect the Fund’s NAV, trading price, yield, total return and ability to meet its investment objective. The Fund may be exposed to these risks directly or indirectly through the Fund's investments in the Underlying Funds. You could lose all or part of your investment in the Fund, and the Fund could underperform other investments. The order of the below risk factors does not indicate the significance of any particular risk factor.

Affiliated Fund Risk. In managing the Fund, BFA has the ability to select Underlying Funds and substitute other ETFs consistent with the sector allocations of the Underlying Index which it believes will achieve the Fund’s objective. BFA may be subject to potential conflicts of interest in selecting Underlying Funds and substituting other ETFs because the fees paid to BFA by some Underlying Funds and other ETFs managed by BFA may be higher than the fees paid by other Underlying Funds. This risk may be reduced to the extent BFA has agreed to waive Acquired Fund Fees and Expenses with respect to an Underlying Fund. If an Underlying Fund or other ETF holds interests in an affiliated fund, the Fund may be prohibited from purchasing shares of that Underlying Fund or other ETF.

Allocation Risk. The Fund’s ability to achieve its investment objective depends upon the Index Provider’s ability to develop a model that accurately assesses the Fund’s asset class allocation and selects the best mix of Underlying Funds and other ETFs. There is a risk that the Index Provider’s evaluations and assumptions regarding asset classes or Underlying Funds, which are utilized as inputs in the model, may be incorrect in view of actual market conditions. The Fund’s Underlying Index may overweight certain asset classes relative to market capitalization-weighted benchmarks. The Fund will underperform such benchmarks when asset classes that are overweighted in the Fund’s Underlying Index underperform other asset classes.

Asset Class Risk. The securities and other assets in the Underlying Index or in the Fund’s or an Underlying Fund's portfolio may underperform in comparison to other securities or indexes that track other countries, groups of countries, regions, industries, groups of industries, markets, market segments, asset classes or sectors. Various types of securities, currencies and indexes may experience cycles of outperformance and underperformance in comparison to the general financial markets depending upon a number of factors including, among other things, inflation, interest rates, productivity, global demand for local products or resources, and regulation and governmental controls. This may cause the Fund to underperform other investment vehicles that invest in different asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the

2

extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund and an Underlying Fund may “call” or repay the security before its stated maturity, and the Fund and an Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund’s income, or in securities with greater risks or with other less favorable features.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or an Underlying Fund's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class. The Fund may be more adversely affected by the underperformance of those securities and/or other assets, may experience increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting those securities and/or other assets than a fund that does not concentrate its investments.

Credit Risk. Credit risk is the risk that the issuer or guarantor of a debt instrument or the counterparty to a derivatives contract, repurchase agreement or loan of portfolio securities will be unable or unwilling to make its timely interest and/or principal payments when due or otherwise honor its obligations. There are varying degrees of credit risk, depending on an issuer’s or counterparty’s financial condition and on the terms of an obligation, which may be reflected in the issuer’s or counterparty’s credit rating. There is the chance that the Fund’s or an Underlying Fund's portfolio holdings will have their credit ratings downgraded or will default (i.e., fail to make scheduled interest or principal payments), or that the market’s perception of an issuer’s creditworthiness may worsen, potentially reducing the Fund’s or an Underlying Fund's income level or share price, which may adversely affect the value of the Fund.

Cybersecurity Risk. With the increased use of technologies such as the internet to conduct business, the Fund, the Underlying Funds, Authorized Participants, service providers and the relevant listing exchange are susceptible to operational, information security and related “cyber” risks both directly and through their service providers. Similar types of cybersecurity risks are also present for issuers of securities in which the Fund or the Underlying Funds invest, which could result in material adverse consequences for such issuers and may cause the Fund’s or the Underlying Funds' investment in such issuers to lose value. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber incidents include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyberattacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites (i.e., efforts to make network services unavailable

3

to intended users). Recently, geopolitical tensions may have increased the scale and sophistication of deliberate attacks, particularly those from nation-states or from entities with nation-state backing.

Cybersecurity failures by, or breaches of, the systems of the Fund's or the Underlying Funds' adviser, distributor and other service providers (including, but not limited to, index and benchmark providers, fund accountants, custodians, transfer agents and administrators), market makers, Authorized Participants or the issuers of securities in which the Fund or the Underlying Funds invest have the ability to cause disruptions and impact business operations, potentially resulting in: financial losses, interference with the Fund’s or an Underlying Fund's ability to calculate its NAV, disclosure of confidential trading information, impediments to trading, submission of erroneous trades or erroneous creation or redemption orders, the inability of the Fund, the Underlying Funds or their service providers to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. In addition, cyberattacks may render records of Fund assets and transactions, shareholder ownership of Fund shares, and other data integral to the functioning of the Fund or an Underlying Fund inaccessible, inaccurate or incomplete. Substantial costs may be incurred by the Fund or an Underlying Fund in order to resolve or prevent cyber incidents in the future. While the Fund and the Underlying Funds have established business continuity plans in the event of, and risk management systems to prevent, such cyber incidents, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified, that prevention and remediation efforts will not be successful or that cyberattacks will go undetected. Furthermore, the Fund cannot control the cybersecurity plans and systems put in place by service providers to the Fund, issuers in which the Fund invests, the Index Provider, market makers or Authorized Participants. The Fund and its shareholders could be negatively impacted as a result.

Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or an Underlying Fund's income and potentially in the value of the Fund’s or an Underlying Fund's investments.

Geographic Risk. Some of the companies in which the Fund or Underlying Funds invest are located in parts of the world that have historically been prone to natural disasters such as earthquakes, volcanic eruptions, droughts, floods, hurricanes or tsunamis and are economically sensitive to environmental events. Any such event may adversely impact the economies of these geographic areas or business operations of companies in these geographic areas, causing an adverse impact on the value of the Fund.

High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch, or below “Baa3” by Moody’s), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default.

The major risks of high yield securities investments include:

4

■	High yield securities may be issued by less creditworthy issuers. Issuers of high yield securities may have a larger amount of outstanding debt relative to their assets than issuers of investment-grade bonds. In the event of an issuer’s bankruptcy, claims of other creditors may have priority over the claims of high yield securities holders, leaving few or no assets available to repay high yield securities holders.
■	Prices of high yield securities are subject to extreme price fluctuations. Adverse changes in an issuer’s industry and general economic conditions may have a greater impact on the prices of high yield securities than on other higher rated fixed-income securities. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.
■	Issuers of high yield securities may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.
■	High yield securities frequently have redemption features that permit an issuer to repurchase the security from the Fund or an Underlying Fund before it matures. If the issuer redeems high yield securities held by the Fund or an Underlying Fund, the Fund or an Underlying Fund may have to invest the proceeds in bonds with lower yields and may lose income.
■	High yield securities may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the high yield securities market, and there may be significant differences in the prices quoted for high yield securities by the dealers. Because high yield securities may be less liquid than higher rated fixed-income securities, judgment may play a greater role in valuing certain of the Fund's  securities than is the case with securities trading in a more liquid market.
■	The Fund or an Underlying Fund may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. An investment may be illiquid due to, among other things, the reduced number and capacity of traditional market participants to make a market in securities or instruments or the lack of an active market for such securities or instruments. To the extent that the Fund invests in securities or instruments with substantial market and/or credit risk, the Fund will tend to have increased exposure to the risks associated with illiquid investments. Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an illiquid investment pursuant to the Fund’s liquidity risk management program. Illiquid investments may be harder to value,

5

especially in changing markets. Although the Fund primarily seeks to redeem shares of the Fund on an in-kind basis, if the Fund is forced to sell underlying investments at reduced prices or under unfavorable conditions to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be magnified in a rising interest rate environment or other circumstances where redemptions from the Fund may be greater than normal. Other market participants may be attempting to liquidate holdings at the same time as the Fund, causing increased supply of the Fund’s underlying investments in the market and contributing to illiquid investments risk and downward pricing pressure. During periods of market volatility, liquidity in the market for the Fund’s shares may be impacted by the liquidity in the market for the underlying securities or instruments held by the Fund, which could lead to the Fund’s shares trading at a premium or discount to the Fund's NAV.

Income Risk. The Fund’s income may decline if interest rates fall. This decline in income can occur because an Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, or an Underlying Fund otherwise needs to purchase additional bonds.

Index-Related Risk. The Fund seeks to achieve a return that corresponds generally to the price and yield performance, before fees and expenses, of the Underlying Index as published by the Index Provider. There is no assurance that the Index Provider or any agents that may act on its behalf will compile the Underlying Index accurately, or that the Underlying Index will be determined, composed or calculated accurately. While the Index Provider provides descriptions of what the Underlying Index is designed to achieve, neither the Index Provider nor its agents provide any warranty or accept any liability in relation to the quality, accuracy or completeness of the Underlying Index or its related data, and they do not guarantee that the Underlying Index will be in line with the Index Provider’s methodology. BFA’s mandate as described in this Prospectus is to manage the Fund consistently with the Underlying Index provided by the Index Provider to BFA. BFA does not provide any warranty or guarantee against the Index Provider’s or any agent’s errors. Errors in respect of the quality, accuracy and completeness of the data used to compile the Underlying Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the indices are less commonly used as benchmarks by funds or managers. In addition, there may be heightened risks associated with the adequacy and reliability of the information the Index Provider uses given the Fund's exposure to emerging markets, as certain emerging markets may have less information available or less regulatory oversight. Such errors may negatively or positively impact the Fund and its shareholders. For example, during a period where the Underlying Index contains incorrect constituents, the Fund would have market exposure to such constituents and would be underexposed to the Underlying Index’s other constituents. Shareholders should understand that any gains from Index Provider errors will be kept by the Fund and its shareholders and any losses or costs resulting from Index Provider errors will be borne by the Fund and its shareholders.

Unusual market conditions may cause the Index Provider to postpone a scheduled rebalance to the Underlying Index, which could cause the Underlying Index to vary from its normal or expected composition. The postponement of a scheduled rebalance

6

in a time of market volatility could mean that constituents of the Underlying Index that would otherwise be removed at rebalance due to changes in market value, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Underlying Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Underlying Index due to reaching certain weighting constraints, unusual market conditions or corporate events or, for example, to correct an error in the selection of index constituents. When the Underlying Index is rebalanced and the Fund in turn rebalances its portfolio to attempt to increase the correlation between the Fund’s portfolio and the Underlying Index, any transaction costs and market exposure arising from such portfolio rebalancing will be borne directly by the Fund and its shareholders. Therefore, errors and additional ad hoc rebalances carried out by the Index Provider or its agents to the Underlying Index may increase the costs to and the tracking error risk of the Fund.

Similar risks exist for the Underlying Funds in tracking their benchmarks, which may result in the Fund's performance deviating from the return of the Underlying Index.

Infectious Illness Risk. An outbreak of an infectious respiratory illness, COVID-19, caused by a novel coronavirus that was first detected in December 2019 has spread globally. The impact of this outbreak has adversely affected the economies of many nations and the global economy, and may impact individual issuers and capital markets in ways that cannot be foreseen. Although vaccines have been developed and approved for use by various governments, the duration of the outbreak and its effects cannot be predicted with certainty. Any market or economic disruption can be expected to result in elevated tracking error and increased premiums or discounts to the Fund's NAV.

■	General Impact. This outbreak has resulted in travel restrictions, closed international borders, enhanced health screenings at ports of entry and elsewhere, disruption of, and delays in, healthcare service preparation and delivery, prolonged quarantines, cancellations, supply chain disruptions, lower consumer demand, temporary and permanent closures of stores, restaurants and other commercial establishments, layoffs, defaults and other significant economic impacts, as well as general concern and uncertainty.
■	Market Volatility. The outbreak has also resulted in extreme volatility, severe losses, and disruptions in markets which can adversely impact the Fund and its investments, including impairing hedging activity to the extent the Fund engages in such activity, as expected correlations between related markets or instruments may no longer apply. In addition, to the extent the Fund invests in short-term instruments that have negative yields, the Fund’s value may be impaired as a result. Certain issuers of equity securities have cancelled or announced the suspension of dividends. The outbreak has, and may continue to, negatively affect the credit ratings of some fixed-income securities and their issuers.
■	Market Closures. Certain local markets have been or may be subject to closures, and there can be no assurance that trading will continue in any local markets in which the Fund or an Underlying Fund may invest, when any resumption of trading will occur or, once such markets resume trading, whether they will face further

7

	closures. Any suspension of trading in markets in which the Fund or an Underlying Fund invests will have an impact on the Fund and its investments and will impact the Fund’s or an Underlying Fund's ability to purchase or sell securities in such markets.
■	Operational Risk. The outbreak could also impair the information technology and other operational systems upon which the Fund’s service providers, including BFA, rely, and could otherwise disrupt the ability of employees of the Fund's service providers to perform critical tasks relating to the Fund, for example, due to the service providers’ employees performing tasks in alternate locations than under normal operating conditions or the illness of certain employees of the Fund's service providers.
■	Governmental Interventions. Governmental and quasi-governmental authorities and regulators throughout the world have responded to the outbreak and the resulting economic disruptions with a variety of fiscal and monetary policy changes, including direct capital infusions into companies and other issuers, new monetary policy tools, and lower interest rates. An unexpected or sudden reversal of these policies, or the ineffectiveness of such policies, is likely to increase market volatility, which could adversely affect the Fund’s investments.
■	Pre-Existing Conditions. Public health crises caused by the outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally, which could adversely affect the Fund and its investments and could result in increased premiums or discounts to the Fund's NAV.

Other infectious illness outbreaks that may arise in the future could have similar or other unforeseen effects.

Interest Rate Risk. If interest rates rise, the value of fixed-income securities or other instruments held by the Fund or an Underlying Fund would likely decrease. A measure investors commonly use to determine this price sensitivity is called duration. Fixed-income securities with longer durations tend to be more sensitive to interest rate changes, usually making their prices more volatile than those of securities with shorter durations. To the extent the Fund or an Underlying Fund invests a substantial portion of its assets in fixed-income securities with longer duration, rising interest rates may cause the value of the Fund's or an Underlying Fund's investments to decline significantly, which would adversely affect the value of the Fund. An increase in interest rates may lead to heightened volatility in the fixed-income markets and adversely affect certain fixed-income investments, including those held by the Fund or an Underlying Fund. Because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. In addition, decreases in fixed income dealer market-making capacity may lead to lower trading volume, heightened volatility, wider bid-ask spreads and less transparent pricing in certain fixed-income markets.

The historically low interest rate environment was created in part by the world’s major central banks keeping their overnight policy interest rates at, near or below zero percent and implementing monetary policy facilities, such as asset purchase programs, to anchor longer-term interest rates below historical levels. During periods of very low

8

or negative interest rates, the Fund may be unable to maintain positive returns or pay dividends to Fund shareholders. Certain countries have recently 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, result in heightened market volatility and detract from the Fund’s performance to the extent the Fund is exposed to such interest rates. Additionally, under certain market conditions in which interest rates are set at low levels and the market prices of portfolio securities have increased, the Fund or an Underlying Fund may have a very low or even negative yield. A low or negative yield would cause the Fund or an Underlying Fund to lose money in certain conditions and over certain time periods. Central banks may increase their short-term policy rates or begin phasing out, or “tapering,” accommodative monetary policy facilities in the future. The timing, coordination, magnitude and effect of such policy changes on various markets are uncertain, and such changes in monetary policy may adversely affect the value of the Fund’s investments.

Investment in Underlying Funds Risk. The Fund expects to invest substantially all of its assets in the Underlying Funds, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Funds. The Fund may also invest in other funds, including money market funds. The Fund’s NAV will change with changes in the value of the Underlying Funds and other securities in which the Fund invests based on their market valuations. An investment in the Fund will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds. For example, in addition to the expenses of the Fund, the Fund indirectly pays a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds, although some of such fees will be offset by the fee waiver by BFA.

One Underlying Fund may buy the same securities that another Underlying Fund sells. Also, an investor in the Fund may receive taxable gains from portfolio transactions by the Underlying Funds, as well as taxable gains from transactions in shares of the Underlying Funds by the Fund.

As the Underlying Funds, or the Fund's allocations among the Underlying Funds, change from time to time, or to the extent that the total annual fund operating expenses of the Underlying Funds change, the weighted average operating expenses borne by the Fund may increase or decrease.

Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund or the Underlying Funds have exposure. The Fund may be adversely affected if an issuer of underlying securities held by the Fund or an Underlying Fund is unable or unwilling to repay principal or interest when due. Any issuer of these securities may perform poorly, causing the value of its securities to decline. Poor performance may be caused by poor management decisions, competitive pressures, changes in technology, expiration of patent protection, disruptions in supply, labor problems or shortages, corporate restructurings, fraudulent disclosures, credit deterioration of the issuer or other factors. Changes to the financial condition or credit rating of an issuer of those securities may cause the value of the securities to

9

decline. An issuer may also be subject to risks associated with the countries, states and regions in which the issuer resides, invests, sells products, or otherwise conducts operations.

Management Risk. Because BFA uses a representative sampling indexing strategy, the Fund will not fully replicate the Underlying Index and may hold securities not included in the Underlying Index. As a result, the Fund is subject to the risk that BFA’s investment strategy, the implementation of which is subject to a number of constraints, may not produce the intended results. The Fund is also subject to the risk that the investment strategy of an Underlying Fund may not produce the intended results.

Market Risk. The Fund and the Underlying Funds could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market risk arises mainly from uncertainty about future values of financial instruments and may be influenced by price, currency and interest rate movements. It represents the potential loss the Fund or an Underlying Fund may suffer through holding financial instruments in the face of market movements or uncertainty. The value of a security or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, recessions, or other events could have a significant impact on the Fund, the Underlying Funds and their investments and could result in increased premiums or discounts to the Fund’s or Underlying Fund's NAV. During a general market downturn, multiple asset classes may be negatively affected. Fixed-income securities with short-term maturities are generally less sensitive to such changes than are fixed-income securities with longer-term maturities. Changes in market conditions and interest rates generally do not have the same impact on all types of securities and instruments.

Market Trading Risk.

Absence of Active Market. Although shares of the Fund and the Underlying Funds are listed for trading on one or more stock exchanges, there can be no assurance that an active trading market for such shares will develop or be maintained by market makers or Authorized Participants.

Risk of Secondary Listings. The Fund's and each Underlying Fund's shares may be listed or traded on U.S. and non-U.S. stock exchanges other than the U.S. stock exchange where the Fund's or Underlying Fund's primary listing is maintained, and may otherwise be made available to non-U.S. investors through funds or structured investment vehicles similar to depositary receipts. There can be no assurance that the Fund’s or each Underlying Fund's shares will continue to trade on any such stock exchange or in any market or that the Fund’s or each Underlying Fund's shares will continue to meet the requirements for listing or trading on any exchange or in any market. The Fund's or Underlying Fund's shares may be less actively traded in certain markets than in others, and investors are subject to the execution and settlement risks and market standards of the market where they or their broker direct their trades for

10

execution. Certain information available to investors who trade Fund or Underlying Fund shares on a U.S. stock exchange during regular U.S. market hours may not be available to investors who trade in other markets, which may result in secondary market prices in such markets being less efficient.

Secondary Market Trading Risk. Shares of the Fund or the Underlying Funds may trade in the secondary market at times when the Fund or the Underlying Funds do not accept orders to purchase or redeem shares. At such times, shares may trade in the secondary market with more significant premiums or discounts than might be experienced at times when the Fund or the Underlying Funds accept purchase and redemption orders. If the Fund purchases shares of an Underlying Fund at a time when the market price of Underlying Fund shares is at a premium to their NAV or sells Underlying Fund shares when their market price is at a discount to their NAV, the Fund may incur losses.

Secondary market trading in Fund or Underlying Fund shares may be halted by a stock exchange because of market conditions or for other reasons. In addition, trading in Fund or Underlying Fund shares on a stock exchange or in any market may be subject to trading halts caused by extraordinary market volatility pursuant to “circuit breaker” rules on the stock exchange or market.

Shares of the Fund and the Underlying Funds, similar to shares of other issuers listed on a stock exchange, may be sold short and are therefore subject to the risk of increased volatility and price decreases associated with being sold short. In addition, trading activity in derivative products based on the Fund or an Underlying Fund may lead to increased trading volume and volatility in the secondary market for the shares of the Fund.

Shares of the Fund and the Underlying Funds May Trade at Prices Other Than NAV. Shares of the Fund and the Underlying Funds each trade on stock exchanges at prices at, above or below the Fund’s and the Underlying Fund's most recent respective NAV. The NAV of the Fund and each Underlying Fund is calculated at the end of each business day and fluctuates with changes in the market value of the Fund’s or an Underlying Fund's holdings. The trading price of each of the Fund's and Underlying Funds' shares fluctuates continuously throughout trading hours based on both market supply of and demand for their shares and the underlying value of their portfolio holdings or NAV. As a result, the trading prices of the Fund’s and each Underlying Fund's shares may deviate significantly from NAV during periods of market volatility, including during periods of significant redemption requests or other unusual market conditions. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S OR THE UNDERLYING FUNDS' SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. However, because shares can be created and redeemed in Creation Units at NAV, BFA believes that large discounts or premiums to the NAV of the Fund or the Underlying Funds, as applicable, are not likely to be sustained over the long term (unlike shares of many closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their NAVs). While the creation/redemption feature is designed to make it more likely that the Fund’s or an Underlying Fund's shares normally will trade on stock exchanges at prices close to the Fund’s or an Underlying Fund's next calculated NAV, exchange prices are not expected

11

to correlate exactly with the NAV due to timing reasons, supply and demand imbalances and other factors. In addition, disruptions to creations and redemptions, including disruptions at market makers, Authorized Participants, or other market participants, and during periods of significant market volatility, may result in trading prices for shares of the Fund or an Underlying Fund that differ significantly from their respective NAV. Authorized Participants may be less willing to create or redeem Fund or Underlying Fund shares if there is a lack of an active market for such shares or its underlying investments, which may contribute to the Fund’s or Underlying Fund's shares trading at a premium or discount to NAV.

Costs of Buying or Selling Fund Shares. Buying or selling Fund shares on an exchange involves two types of costs that apply to all securities transactions. When buying or selling shares of the Fund through a broker, you will likely incur a brokerage commission and other charges. In addition, you may incur the cost of the “spread”; that is, the difference between what investors are willing to pay for Fund shares (the “bid” price) and the price at which they are willing to sell Fund shares (the “ask” price). The spread, which varies over time for shares of the Fund based on trading volume and market liquidity, is generally narrower if the Fund has more trading volume and market liquidity and wider if the Fund has less trading volume and market liquidity. In addition, increased market volatility may cause wider spreads. There may also be regulatory and other charges that are incurred as a result of trading activity. Because of the costs inherent in buying or selling Fund shares, frequent trading may detract significantly from investment results and an investment in Fund shares may not be advisable for investors who anticipate regularly making small investments through a brokerage account.

Model Risk. Neither the Fund nor BFA can offer any assurance that the allocation model used to calculate the Underlying Index will achieve its intended results or maximize returns or minimize risks, nor can the Fund or BFA offer assurance that a particular allocation will be the appropriate allocation in all circumstances for every investor seeking a particular risk profile or time horizon.

Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers have different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, uncertainties of transnational litigation, and potential restrictions on the flow of international capital, including the possible seizure or nationalization of the securities issued by non-U.S. issuers held by the Fund or an Underlying Fund. Non-U.S. issuers may be subject to less governmental regulation than U.S. issuers. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions. Unfavorable political, economic or governmental developments in non-U.S. countries could affect the payment of a security’s principal and interest. Securities issued by non-U.S. issuers may also be less liquid than, and more difficult to value than, securities of U.S. issuers.

12

In addition, the value of these securities may fluctuate due to changes in the exchange rate of the issuer’s local currency against the U.S. dollar.

Operational Risk. The Fund and the Underlying Funds are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's or each Underlying Fund's service providers, counterparties or other third parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Funds and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Passive Investment Risk. The Fund and the Underlying Funds are not actively managed and may be affected by a general decline in market segments related to their underlying indexes. The Fund and Underlying Funds invest in securities included in, or representative of, the applicable underlying index, regardless of their investment merits. BFA generally does not attempt to invest the Fund's assets in defensive positions under any market conditions, including declining markets. The Fund may also be exposed to passive investment risk through its investment in the Underlying Funds.

Privately Issued Securities Risk. The Fund or Underlying Funds may invest in privately issued securities, including those that are normally purchased pursuant to Rule 144A or Regulation S under the 1933 Act. Privately issued securities typically may be resold only to qualified institutional buyers, or in a privately negotiated transaction, or to a limited number of purchasers, or in limited quantities after they have been held for a specified period of time and other conditions are met for an exemption from registration. Because there may be relatively few potential purchasers for such securities, especially under adverse market or economic conditions or in the event of adverse changes in the financial condition of the issuer, the Fund or an Underlying Fund may find it more difficult to sell such securities when it may be advisable to do so or it may be able to sell such securities only at prices lower than if such securities were more widely held and traded. At times, it also may be more difficult to determine the fair value of such securities for purposes of computing the Fund’s NAV due to the absence of an active trading market. There can be no assurance that a privately issued security that is deemed to be liquid when purchased will continue to be liquid for as long as it is held by the Fund or an Underlying Fund, and its value may decline as a result.

Reinvestment Risk. The Fund or an Underlying Fund may invest a portion of its assets in short-term fixed-income instruments and as a result, may be adversely affected when interest rates fall because they may have to invest in lower yielding bonds as bonds in the Underlying Index are substituted. This may cause the Fund's or an Underlying Fund's income to decline, which may adversely affect the value of the Fund. This risk is typically greater with respect to short-term bond funds and lower for long-term bond funds.

Risk of Investing in Saudi Arabia. The ability of foreign investors (such as the Fund and Underlying Fund) to invest in the securities of Saudi Arabian issuers is relatively new. Such ability could be restricted by the Saudi Arabian government at any time, and unforeseen risks could materialize with respect to foreign ownership in such

13

securities. In addition, the Saudi Arabian government places investment limitations on the ownership of Saudi Arabian issuers by foreign investors, including a limitation on the Fund’s and Underlying Fund's ownership of any single issuer listed on the Saudi Arabian Stock Exchange, which may prevent the Fund and Underlying Fund from investing in accordance with its strategy and contribute to tracking error against the Underlying Index. Saudi Arabia is highly reliant on income from the sale of petroleum and trade with other countries involved in the sale of petroleum, and its economy is therefore vulnerable to changes in foreign currency values and the market for petroleum. As global demand for petroleum fluctuates, Saudi Arabia may be significantly impacted. Like most Middle Eastern governments, the government of Saudi Arabia exercises substantial influence over many aspects of the private sector. Although liberalization in the wider economy is underway, in many areas it has lagged significantly: restrictions on foreign ownership persist, and the government has an ownership stake in many key industries. The situation is exacerbated by the fact that Saudi Arabia is governed by an absolute monarchy. Saudi Arabia has historically experienced strained relations with economic partners worldwide, including other countries in the Middle East due to geopolitical events. Governmental actions in the future could have a significant effect on economic conditions in Saudi Arabia, which could affect private sector companies and the Fund and Underlying Fund, as well as the value of securities in the Fund’s or Underlying Fund's portfolio. Any economic sanctions on Saudi Arabian individuals or Saudi Arabian corporate entities, or even the threat of sanctions, may result in the decline of the value and liquidity of Saudi Arabian securities, a weakening of the Saudi riyal or other adverse consequences to the Saudi Arabian economy. In addition, Saudi Arabia’s economy relies heavily on cheap, foreign labor, and changes in the availability of this labor supply could have an adverse effect on the economy.

Investments in the securities of Saudi Arabian issuers involve risks not typically associated with investments in securities of issuers in more developed countries that may negatively affect the value of the Fund’s or Underlying Fund's investments. Such heightened risks may include, among others, expropriation and/or nationalization of assets, restrictions on and government intervention in international trade, confiscatory taxation, political instability, including authoritarian and/or military involvement in governmental decision making, armed conflict, crime and instability as a result of religious, ethnic and/or socioeconomic unrest. Although the political situation in Saudi Arabia is largely stable, Saudi Arabia has historically experienced political instability, and there remains the possibility that instability in the larger Middle East region could adversely impact the economy of Saudi Arabia. Political instability in the larger Middle East region has caused significant disruptions to many industries. Continued political and social unrest in these areas may negatively affect the value of securities in the Fund’s or Underlying Fund's portfolio.

Risk of Investing in the U.S. A decrease in imports or exports, changes in trade regulations and/or an economic recession in the U.S. may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the U.S. are changing many aspects of financial, commercial, public health, environmental, and other regulation and may have a significant effect on U.S. markets generally, as well as on the value of certain

14

securities. Governmental agencies project that the U.S. will continue to maintain elevated public debt levels for the foreseeable future. Although elevated debt levels do not necessarily indicate or cause economic problems, elevated public debt service costs may constrain future economic growth.

The U.S. has developed increasingly strained relations with a number of foreign countries. If relations with certain countries deteriorate, it could adversely affect U.S. issuers as well as non-U.S. issuers that rely on the U.S. for trade. The U.S. has also experienced increased internal unrest and discord, as well as significant challenges in managing and containing the outbreak of COVID-19. If these trends were to continue, it may have an adverse impact on the U.S. economy and the issuers in which the Fund or an Underlying Fund invests.

Securities Lending Risk. The Fund and the Underlying Funds may engage in securities lending. Securities lending involves the risk that the Fund or an Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or an Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or an Underlying Fund. BlackRock Institutional Trust Company, N.A. (“BTC”), the Fund's securities lending agent, will take into account the tax impact to shareholders of substitute payments for dividends when managing the Fund's securities lending program.

Tracking Error Risk. The Fund may be subject to “tracking error,” which is the divergence of the Fund’s or an Underlying Fund's performance from that of the applicable underlying index. Tracking error may occur because of differences between the securities and other instruments held in the Fund’s or an Underlying Fund's portfolio and those included in the applicable underlying index, pricing differences (including, as applicable, differences between a security’s price at the local market close and the Fund's or an Underlying Fund's valuation of a security at the time of calculation of the Fund's or Underlying Fund's NAV, respectively), transaction costs incurred by the Fund, the Fund’s  or an Underlying Fund's holding of uninvested cash, differences in timing of the accrual of or the valuation of dividends or interest, the requirements to maintain pass-through tax treatment, portfolio transactions carried out to minimize the distribution of capital gains to shareholders, acceptance of custom baskets, changes to the applicable underlying index or the costs to the Fund or an Underlying Fund of complying with various new or existing regulatory requirements, among other reasons. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the Fund or an Underlying Fund incurs fees and expenses, while the applicable underlying index does not.

U.S. Agency Mortgage-Backed Securities Risk. Certain Underlying Funds invest in securities backed by pools of mortgages issued or guaranteed by the U.S. government or one of its agencies or sponsored entities, including Fannie Mae, Ginnie Mae or Freddie Mac. While securities guaranteed by Ginnie Mae are backed by the full faith and credit of the U.S. government, securities issued by Fannie Mae and Freddie Mac are not backed by the full faith and credit of the U.S. government, and there can be no

15

assurance that the U.S. government would provide financial support to its agencies or sponsored entities where it is not obligated to do so. Bonds or debentures that do not carry the backing of the full faith and credit of the U.S. government are subject to more credit risk than securities that are supported by the full faith and credit of the U.S. government. To the extent that the U.S. government has provided support to a U.S. agency or sponsored entity in the past, there can be no assurance that the U.S. government will provide support in the future if it is not obligated to do so. If a U.S. government agency or sponsored entity that is the issuer of securities in which an Underlying Fund invests is unable to meet its obligations or ceases to exist and no plan is made for repayment of securities, the performance of an Underlying Fund will be adversely affected.

MBS represent interests in “pools” of mortgages and, due to the nature of these loans they represent, are subject to prepayment and extension risk. Prepayment risk is the risk that, during periods of falling interest rates, an issuer of mortgages and other fixed-income securities may be able to repay principal prior to the security’s maturity. This may cause an Underlying Fund to have to reinvest in securities with a lower yield or higher risk of default, resulting in a decline in an Underlying Fund's income or return potential.

MBS are also subject to extension risk, which is the risk that when interest rates rise, certain MBS will be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in income and potentially in the value of the investment.

Because of prepayment and extension risks, MBS react differently to changes in interest rates than other bonds. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain MBS. These securities are also subject to the risk of default on the underlying mortgage loans, particularly during periods of economic downturn.

Certain Underlying Funds seek to obtain exposure to the fixed-rate portion of U.S. agency mortgage pass-through securities primarily through TBA securities, or TBA transactions. TBAs refer to a commonly used mechanism for the forward settlement of U.S. agency MBS, and not to a separate type of MBS. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible losses because of adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction.

The Fund intends to invest cash pending settlement of TBA transactions in money market instruments, repurchase agreements, or other high quality, liquid short-term instruments, including money market funds advised by BFA. The Fund will pay its pro rata share of fees and expenses of any money market fund that it may invest in, in addition to the Fund’s own fees and expenses.

U.S. Treasury Obligations Risk. U.S. Treasury obligations may differ from other securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's or an Underlying Fund's U.S. Treasury obligations to decline. On August 5, 2011, S&P Global Ratings

16

downgraded U.S. Treasury securities from AAA rating to AA+ rating. A further downgrade of the ratings of U.S. government debt obligations, which are often used as a benchmark for other borrowing arrangements, could result in higher interest rates for individual and corporate borrowers, cause disruptions in the international bond markets and have a substantial negative effect on the U.S. economy. A downgrade of U.S. Treasury securities from another ratings agency or a further downgrade below AA+ rating by S&P Global Ratings may cause the value of the Fund’s or an Underlying Fund's U.S. Treasury obligations to decline.

Valuation Risk. The price the Fund or an Underlying Fund could receive upon the sale of a security or other asset may differ from the Fund's or an Underlying Fund's valuation of the security or other asset and from the value used by the Underlying Index, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. Because non-U.S. exchanges may be open on days when the Fund or an Underlying Fund does not price its shares, the value of the securities or other assets in the Fund or an Underlying Fund's portfolio may change on days or during time periods when the Fund will not be able to purchase or sell the Fund or an Underlying Fund’s shares. In addition, for purposes of calculating the Fund's NAV, the value of assets denominated in non-U.S. currencies is translated into U.S. dollars at the prevailing market rates. This translation may result in a difference between the prices used to calculate the Fund's NAV and the prices used by the Underlying Index, which, in turn, could result in a difference between the Fund's performance and the performance of the Underlying Index. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

A Further Discussion of Other Risks

The Fund may also be subject to certain other risks associated with its investments and investment strategies. The order of the below risk factors does not indicate the significance of any particular risk factor.

Asian Economic Risk. Many Asian economies have experienced rapid growth and industrialization in recent years, but there is no assurance that this growth rate will be maintained. Other Asian economies, however, have experienced high inflation, high unemployment, currency devaluations and restrictions, and over-extension of credit. Geopolitical hostility, political instability, and economic or environmental events in any one Asian country may have a significant economic effect on the entire Asian region, as well as on major trading partners outside Asia. Any adverse event in the Asian markets may have a significant adverse effect on some or all of the economies of the countries in which the Fund or an Underlying Fund invests. In particular, China is a key trading partner of many Asian countries and any changes in trading relationships between China and other Asian countries may affect the region as a whole. Many Asian countries are subject to political risk, including political instability, corruption and

17

regional conflict with neighboring countries. North Korea and South Korea each have substantial military capabilities, and historical tensions between the two countries present the risk of war. Escalated tensions involving the two countries and any outbreak of hostilities between the two countries, or even the threat of an outbreak of hostilities, could have a severe adverse effect on the entire Asian region. Certain Asian countries have developed increasingly strained relationships with the U.S. or with China, and if these relations were to worsen, they could adversely affect Asian issuers that rely on the U.S. or China for trade. In addition, many Asian countries are subject to social and labor risks associated with demands for improved political, economic and social conditions. These risks, among others, may adversely affect the value of the Fund's or an Underlying Fund's investments.

Central and South American Economic Risk. Certain Central and South American countries have experienced high interest rates, economic volatility, high levels of inflation, currency devaluations, government defaults and high unemployment rates. Additionally, commodities such as oil and gas, minerals and metals represent a significant percentage of the region’s exports, and the economies of countries in the region are particularly sensitive to fluctuations in commodity prices as a result. The impact of any of the foregoing events in one country could have a significant effect on the entire region.

Close-Out Risk for Qualified Financial Contracts. Regulations adopted by global prudential regulators require counterparties that are part of U.S. or foreign global systemically important banking organizations to include contractual restrictions on close-out and cross-default in agreements relating to qualified financial contracts. Qualified financial contracts include agreements relating to swaps, currency forwards and other derivatives as well as repurchase agreements and securities lending agreements. The restrictions prevent the Fund from closing out a qualified financial contract during a specified time period if the counterparty is subject to resolution proceedings and also prohibit the Fund from exercising default rights due to a receivership or similar proceeding of an affiliate of the counterparty. These requirements may increase credit risk and other risks to the Fund.

Consumer Services Industry Risk. The success of firms in the consumer services industry and certain retailers (including food and beverage, general retailers, media, and travel and leisure companies) is tied closely to the performance of the domestic and international economies, interest rates, exchange rates and consumer confidence. The consumer services industry depends heavily on disposable household income and consumer spending. Companies in the consumer services industry may be subject to severe competition, which may also have an adverse impact on their profitability. Companies in the consumer services industry are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action. Changes in consumer demographics and preferences in the countries in which the issuers of securities held by the Fund or an Underlying Fund are located and in the countries to which they export their products may affect the success of consumer products.

Custody Risk. An Underlying Fund may be exposed to custody risk. Custody risk refers to the risks inherent in the process of clearing and settling trades, as well as the

18

holding of securities by local banks, agents and depositories. Low trading volumes and volatile prices in less developed markets may make trades harder to complete and settle, and governments or trade groups may compel local agents to hold securities in designated depositories that may not be subject to independent evaluation. Local agents are held only to the standards of care of their local markets. In general, the less developed a country’s securities markets are, the higher the degree of custody risk.

Energy Sector Risk. The success of companies in the energy sector may be cyclical and highly dependent on energy prices. The market value of securities issued by companies in the energy sector may decline for the following reasons, among others: changes in the levels and volatility of global energy prices, energy supply and demand, and capital expenditures on exploration and production of energy sources; exchange rates, interest rates, economic conditions, and tax treatment; and energy conservation efforts, increased competition and technological advances. Companies in this sector may be subject to substantial government regulation and contractual fixed pricing, which may increase the cost of doing business and limit the earnings of these companies. A significant portion of the revenues of these companies may depend on a relatively small number of customers, including governmental entities and utilities. As a result, governmental budget constraints may have a material adverse effect on the stock prices of companies in this sector. Energy companies may also operate in, or engage in transactions involving, countries with less developed regulatory regimes or a history of expropriation, nationalization or other adverse policies. Energy companies also face a significant risk of liability from accidents resulting in injury or loss of life or property, pollution or other environmental problems, equipment malfunctions or mishandling of materials and a risk of loss from terrorism, cyber incident, political strife or natural disasters. Any such event could have serious consequences for the general population of the affected area and could have an adverse impact on the Fund’s or an Underlying Fund's portfolio and the performance of the Fund. Energy companies can be significantly affected by the supply of, and demand for, specific products (e.g., oil and natural gas) and services, exploration and production spending, government subsidization, world events and general economic conditions. In the context of the COVID-19 outbreak and disputes among oil-producing countries regarding potential limits on the production of crude oil, the energy sector has recently experienced increased volatility. In particular, significant market volatility in the crude oil markets as well as the oil futures markets resulted in the market price of the front month WTI crude oil futures contracts falling below zero for a period of time. Energy companies may have relatively high levels of debt and may be more likely than other companies to restructure their businesses if there are downturns in energy markets or in the global economy.

European Economic Risk. The Economic and Monetary Union (the “eurozone”) of the European Union (the “EU”) requires compliance by member states that are members of the eurozone with restrictions on inflation rates, deficits, interest rates and debt levels, as well as fiscal and monetary controls, each of which may significantly affect every country in Europe, including those countries that are not members of the eurozone. Additionally, European countries outside of the eurozone may present economic risks that are independent of the indirect effects that eurozone policies have on them. In particular, the United Kingdom's (the “U.K.”) economy may be affected by global

19

economic, industrial and financial shifts. Changes in imports or exports, changes in governmental or EU regulations on trade, changes in the exchange rate of the euro (the common currency of eurozone countries), the default or threat of default by an EU member state on its sovereign debt and/or an economic recession in an EU member state may have a significant adverse effect on the economies of other EU member states and their trading partners. The European financial markets have historically experienced volatility and adverse trends due to concerns about economic downturns or rising government debt levels in several European countries, including, but not limited to, Austria, Belgium, Cyprus, France, Greece, Ireland, Italy, Portugal, Spain and Ukraine. These events have adversely affected the exchange rate of the euro and may continue to significantly affect European countries.

Responses to financial problems by European governments, central banks and others, including austerity measures and reforms, may not produce the desired results, may result in social unrest, may limit future growth and economic recovery or may have other unintended consequences. Further defaults or restructurings by governments and other entities of their debt could have additional adverse effects on economies, financial markets and asset valuations around the world. In addition, one or more countries may abandon the euro and/or withdraw from the EU. The U.K. left the EU (“Brexit”) on January 31, 2020. The U.K. and EU have reached an agreement on the terms of their future trading relationship effective January 1, 2021, which principally relates to the trading of goods rather than services, including financial services. Further discussions are to be held between the U.K. and the EU in relation to matters not covered by the trade agreement, such as financial services. The Fund and the Underlying Funds face risks associated with the potential uncertainty and consequences that may follow Brexit, including with respect to volatility in exchange rates and interest rates. Brexit could adversely affect European or worldwide political, regulatory, economic or market conditions and could contribute to instability in global political institutions, regulatory agencies and financial markets. Brexit has also led to legal uncertainty and could lead to politically divergent national laws and regulations as a new relationship between the U.K. and EU is defined and the U.K. determines which EU laws to replace or replicate. Any of these effects of Brexit could adversely affect any of the companies to which the Fund has exposure and any other assets in which the Fund or an Underlying Fund invests. The political, economic and legal consequences of Brexit are not yet fully known. In the short term, financial markets may experience heightened volatility, particularly those in the U.K. and Europe, but possibly worldwide. The U.K. and Europe may be less stable than they have been in recent years, and investments in the U.K. and the EU may be difficult to value or subject to greater or more frequent volatility. In the longer term, there is likely to be a period of significant political, regulatory and commercial uncertainty as the U.K. continues to negotiate the terms of its future trading relationships.

Secessionist movements, such as the Catalan movement in Spain and the independence movement in Scotland, as well as governmental or other responses to such movements, may also create instability and uncertainty in the region. In addition, the national politics of countries in the EU have been unpredictable and subject to influence by disruptive political groups and ideologies. The governments of EU countries may be subject to change and such countries may experience social and

20

political unrest. Unanticipated or sudden political or social developments may result in sudden and significant investment losses. The occurrence of terrorist incidents throughout Europe could also impact financial markets. The impact of these events is not clear but could be significant and far-reaching and could adversely affect the value and liquidity of the Fund's or an Underlying Fund's investments.

Financials Sector Risk. Companies in the financials sector of an economy are subject to extensive governmental regulation and intervention, which may adversely affect the scope of their activities, the prices they can charge, the amount of capital they must maintain and, potentially, their size. The extent to which the Fund or an Underlying Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. Governmental regulation may change frequently and may have significant adverse consequences for companies in the financials sector, including effects not intended by such regulation. Recently enacted legislation in the U.S. has relaxed capital requirements and other regulatory burdens on certain U.S. banks. While the effect of the legislation may benefit certain companies in the financials sector, increased risk taking by affected banks may also result in greater overall risk in the U.S. and global financials sector. The impact of changes in capital requirements, or recent or future regulation in various countries, on any individual financial company or on the financials sector as a whole cannot be predicted.

Certain risks may impact the value of investments in the financials sector more severely than those of investments outside this sector, including the risks associated with companies that operate with substantial financial leverage. Companies in the financials sector are exposed directly to the credit risk of their borrowers and counterparties, who may be leveraged to an unknown degree, including through swaps and other derivatives products. Financial services companies may have significant exposure to the same borrowers and counterparties, with the result that a borrower’s or counterparty’s inability to meet its obligations to one company may affect other companies with exposure to the same borrower or counterparty. This interconnectedness of risk may result in significant negative impacts to companies with direct exposure to the defaulting counterparty as well as adverse cascading effects in the markets and the financials sector generally. Companies in the financials sector may also be adversely affected by increases in interest rates and loan losses, decreases in the availability of money or asset valuations, credit rating downgrades and adverse conditions in other related markets. Insurance companies, in particular, may be subject to severe price competition and/or rate regulation, which may have an adverse impact on their profitability. The financials sector is particularly sensitive to fluctuations in interest rates. The financials sector is also a target for cyberattacks, and may experience technology malfunctions and disruptions. In recent years, cyberattacks and technology malfunctions and failures have become increasingly frequent in this sector and have reportedly caused losses to companies in this sector, which may negatively impact the Fund.

Healthcare Sector Risk. The profitability of companies in the healthcare sector may be adversely affected by the following factors, among others: extensive government regulations, restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure, an increased emphasis on outpatient services, changes in the demand for medical products and services, a

21

limited number of products, industry innovation, changes in technologies and other market developments. A number of issuers in the healthcare sector have recently merged or otherwise experienced consolidation. The effects of this trend toward consolidation are unknown and may be far-reaching. Many healthcare companies are heavily dependent on patent protection. The expiration of a company’s patents may adversely affect that company’s profitability. Many healthcare companies are subject to extensive litigation based on product liability and similar claims. Healthcare companies are subject to competitive forces that may make it difficult to raise prices and, in fact, may result in price discounting. Many new products in the healthcare sector may be subject to regulatory approvals. The process of obtaining such approvals may be long and costly, and such efforts ultimately may be unsuccessful. Companies in the healthcare sector may be thinly capitalized and may be susceptible to product obsolescence. In addition, a number of legislative proposals concerning healthcare have been considered by the U.S. Congress in recent years. It is unclear what proposals will ultimately be enacted, if any, and what effect they may have on companies in the healthcare sector.

Middle Eastern Economic Risk. Many Middle Eastern countries have little or no democratic tradition, and the political and legal systems in such countries may adversely impact the companies in which the Fund or Underlying Fund invests and, as a result, the value of the Fund or Underlying Fund. Middle Eastern governments have exercised and continue to exercise substantial influence over many aspects of the private sector. Many economies in the Middle East are highly reliant on income from the sale of oil and natural gas or trade with countries involved in the sale of oil and natural gas, and their economies are therefore vulnerable to changes in the market for oil and natural gas and foreign currency values. As global demand for oil and natural gas fluctuates, many Middle Eastern economies may be significantly impacted. A sustained decrease in commodity prices could have a significant negative impact on all aspects of the economy in the region. Middle Eastern economies may be subject to acts of terrorism, political strife, religious, ethnic or socioeconomic unrest and sudden outbreaks of hostilities with neighboring countries.

Certain Middle Eastern countries have strained relations with other Middle Eastern countries due to territorial disputes, historical animosities, international alliances, religious tensions or defense concerns, which may adversely affect the economies of these countries. Certain Middle Eastern countries experience significant unemployment, as well as widespread underemployment.

Many Middle Eastern countries periodically have experienced political, economic and social unrest as protestors have called for widespread reform. Some of these protests have resulted in a governmental regime change, internal conflict or civil war. If further regime changes were to occur, internal conflict were to intensify, or a civil war were to continue in any of these countries, such instability could adversely affect the economies of Middle Eastern countries in which the Fund or Underlying Fund invests and could decrease the value of the Fund’s or Underlying Fund's investments.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market

22

instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the FDIC or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

Non-U.S. Agency Debt Risk. The Fund and certain Underlying Funds may invest in uncollateralized bonds issued by agencies, subdivisions or instrumentalities of foreign governments. Bonds issued by these foreign government agencies, subdivisions or instrumentalities are generally backed only by the creditworthiness and reputation of the entities issuing the bonds and may not be backed by the full faith and credit of the foreign government. Moreover, a foreign government that explicitly provides its full faith and credit to a particular entity may be, due to changed circumstances, unable or unwilling to actually provide that support. If a non-U.S. agency is unable to meet its obligations, the performance of the Fund or Underlying Fund will be adversely impacted. A non-U.S. agency’s operations and financial condition are influenced by the foreign government’s economic and other policies. Changes to the financial condition or credit rating of a foreign government may cause the value of debt issued by that particular foreign government’s agencies, subdivisions or instrumentalities to decline. During periods of economic uncertainty, the trading of non-U.S. agency bonds may be less liquid while market prices may be more volatile than prices of U.S. agency bonds. Additional risks associated with non-U.S. agency investing include differences in accounting, auditing and financial reporting standards, adverse changes in investment or exchange control regulations, political instability, which could affect U.S. investments in foreign countries, and potential restrictions of the flow of international capital.

Privatization Risk. Some countries in which the Fund or an Underlying Fund invests have privatized, or have begun the process of privatizing, certain entities and industries. Newly privatized companies may face strong competition from government-sponsored competitors that have not been privatized. In some instances, investors in newly privatized entities have suffered losses due to the inability of the newly privatized entities to adjust quickly to a competitive environment or changing regulatory and legal standards or, in some cases, due to re-nationalization of such privatized entities. There is no assurance that similar losses will not recur.

Reliance on Trading Partners Risk. The economies of many countries in which certain of the Underlying Funds invest are highly dependent on trade with certain key trading partners. Reduction in spending on products and services by these key trading partners, institution of tariffs or other trade barriers or a slowdown in the economies of key trading partners may adversely affect the performance of any company in which such Underlying Funds invest and may have a material adverse effect on the Underlying Funds' performance.

Risk of Investing in Developed Countries. Investment in developed country issuers may subject the Fund or an Underlying Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries generally tend to rely on services sectors (e.g., the financial services sector) as the primary means of economic growth. A prolonged slowdown in one or more services

23

sectors is likely to have a negative impact on economies of certain developed countries, although economies of individual developed countries can be impacted by slowdowns in other sectors. In the past, certain developed countries have been targets of terrorism, and some geographic areas in which the Fund or an Underlying Fund invests have experienced strained international relations due to territorial disputes, historical animosities, defense concerns and other security concerns. These situations may cause uncertainty in the financial markets in these countries or geographic areas and may adversely affect the performance of the issuers to which the Fund or an Underlying Fund has exposure. Heavy regulation of certain markets, including labor and product markets, may have an adverse effect on certain issuers. Such regulations may negatively affect economic growth or cause prolonged periods of recession. Many developed countries are heavily indebted and face rising healthcare and retirement expenses. In addition, price fluctuations of certain commodities and regulations impacting the import of commodities may negatively affect developed country economies.

Risk of Investing in Emerging Markets. Investments in emerging market issuers are subject to a greater risk of loss than investments in issuers located or operating in more developed markets. This is due to, among other things, the potential for greater market volatility, lower trading volume, higher levels of inflation, political and economic instability, greater risk of a market shutdown and more governmental limitations on foreign investments in emerging market countries than are typically found in more developed markets. Companies in many emerging markets are not subject to the same degree of regulatory requirements, accounting standards or auditor oversight as companies in more developed countries, and as a result, information about the securities in which the Fund or an Underlying Fund invests may be less reliable or complete. Moreover, emerging markets often have less reliable securities valuations and greater risks associated with custody of securities than developed markets. There may be significant obstacles to obtaining information necessary for investigations into or litigation against companies and shareholders may have limited legal remedies. The Fund and the Underlying Funds are not actively managed and do not select investments based on investor protection considerations.

In addition, emerging markets often have greater risk of capital controls through such measures as taxes or interest rate control than developed markets. Certain emerging market countries may also lack the infrastructure necessary to attract large amounts of foreign trade and investment. Local securities markets in emerging market countries may trade a small number of securities and may be unable to respond effectively to changes in trading volume, potentially making prompt liquidation of holdings difficult or impossible at times. Settlement procedures in emerging market countries are frequently less developed and reliable than those in the U.S. (and other developed countries). In addition, significant delays may occur in certain markets in registering the transfer of securities. Settlement or registration problems may make it more difficult for the Fund or an Underlying Fund to value its portfolio securities and could cause the Fund or an Underlying Fund to miss attractive investment opportunities.

Investing in emerging market countries involves a higher risk of loss due to expropriation, nationalization, confiscation of assets and property or the imposition of

24

restrictions on foreign investments and on repatriation of capital invested in certain emerging market countries.

Sovereign and Quasi-Sovereign Obligations Risk. An investment in sovereign or quasi-sovereign debt obligations involves special risks not present in corporate debt obligations. Sovereign debt includes securities issued by or guaranteed by a foreign sovereign government, and quasi-sovereign debt includes securities issued by or guaranteed by an entity affiliated with or backed by a sovereign government. The issuer of the sovereign debt that controls the repayment of the debt may be unable or unwilling to repay principal or interest when due, and the Fund or Underlying Funds may have limited recourse in the event of a default. Similar to other issuers, changes to the financial condition or credit rating of a government may cause the value of a sovereign debt obligation, including U.S. Treasury obligations, to decline. During periods of economic uncertainty, the market prices of sovereign debt may be more volatile than prices of U.S. debt obligations and may affect the Fund's or Underlying Fund's NAV. Quasi-sovereign debt obligations are typically less liquid and less standardized than sovereign debt obligations. In the past, certain emerging market countries have encountered difficulties in servicing their debt obligations, withheld payments of principal and interest and declared moratoria on the payment of principal and interest on their sovereign debts. Several countries in which the Fund or an Underlying Fund invests have defaulted on their sovereign debt obligations in the past or encountered downgrades of their sovereign debt obligations, and those countries (or other countries) may default or risk further downgrades in the future.

Structural Risk. Certain political, economic, legal and currency risks could contribute to a high degree of price volatility in the equity markets of some of the countries in which the Fund or an Underlying Fund may invest and could adversely affect investments in the Fund or an Underlying Fund.

Political and Social Risk. Disparities of wealth, the pace and success of democratization and ethnic, religious and racial disaffection, among other factors, may exacerbate social unrest, violence and labor unrest in some of the countries in which the Fund or an Underlying Fund may invest. Unanticipated or sudden political or social developments may result in sudden and significant investment losses.

Economic Risk. Some countries in which the Fund or an Underlying Fund may invest may experience economic instability, including instability resulting from substantial rates of inflation or significant devaluations of their currency, or economic recessions, which would have a negative effect on the economies and securities markets of their economies. Some of these countries may also impose restrictions on the exchange or export of currency or adverse currency exchange rates and may be characterized by a lack of available currency hedging instruments.

Expropriation Risk. Investments in certain countries in which the Fund or an Underlying Fund may invest may be subject to loss due to expropriation or nationalization of assets and property or the imposition of restrictions on foreign investments and repatriation of capital.

Large Government Debt Risk. Chronic structural public sector deficits in some countries in which the Fund or an Underlying Fund may invest may adversely impact securities held by the Fund or an Underlying Fund.

25

Threshold/Underinvestment Risk. If certain aggregate and/or fund-level ownership thresholds are reached through transactions undertaken by BFA, its affiliates or the Fund, or as a result of third-party transactions or actions by an issuer or regulator, the ability of BFA and its affiliates on behalf of clients (including the Fund) to purchase or dispose of investments, or exercise rights or undertake business transactions, may be restricted by regulation or otherwise impaired. The capacity of the Fund to make investments in certain securities may be affected by the relevant threshold limits, and such limitations may have adverse effects on the liquidity and performance of the Fund’s portfolio holdings compared to the performance of the Underlying Index. This may increase the risk of the Fund being underinvested to the Underlying Index and increase the risk of tracking error.

For example, in certain circumstances where the Fund invests in securities issued by companies that operate in certain regulated industries or in certain emerging or international markets, is subject to corporate or regulatory ownership restrictions, or invests in certain futures or other derivative transactions, there may be limits on the aggregate and/or fund-level amount invested or voted by BFA and its affiliates for their proprietary accounts and for client accounts (including the Fund) that may not be exceeded without the grant of a license or other regulatory or corporate consent or, if exceeded, may cause BFA and its affiliates, the Fund or other client accounts to suffer disadvantages or business restrictions.

Utilities Sector Risk. Companies in the utilities sector may be adversely affected by changes in exchange rates, domestic and international competition, and governmental limitations on rates charged to consumers. The value of regulated utility debt securities (and, to a lesser extent, equity securities) tends to have an inverse relationship to the movement of interest rates. Deregulation may subject utility companies to greater competition and may adversely affect their profitability. As deregulation allows utility companies to diversify outside of their original geographic regions and their traditional lines of business, utility companies may engage in riskier ventures. In addition, deregulation may eliminate restrictions on the profits of certain utility companies, but may also subject these companies to greater risk of loss. Companies in the utilities industry may have difficulty obtaining an adequate return on invested capital, raising capital, or financing large construction projects during periods of inflation or unsettled capital markets; face restrictions on operations and increased cost and delays attributable to environmental considerations and regulation; find that existing plants, equipment or products have been rendered obsolete by technological innovations; or be subject to increased costs because of the scarcity of certain fuels or the effects of man-made or natural disasters. Existing and future regulations or legislation may make it difficult for utility companies to operate profitably. Government regulators monitor and control utility revenues and costs, and therefore may limit utility profits. There is no assurance that regulatory authorities will grant rate increases in the future or that such increases will be adequate to permit the payment of coupon payments on bonds issued by such company. Energy conservation and changes in climate policy may also have a significant adverse impact on the revenues and expenses of utility companies.

26

Portfolio Holdings Information

A description of the Trust's policies and procedures with respect to the disclosure of the Fund’s portfolio securities is available in the Fund's Statement of Additional Information (“SAI”). The Fund discloses its portfolio holdings daily at www.iShares.com. Fund fact sheets provide information regarding the Fund's top holdings and may be requested by calling 1-800-iShares (1-800-474-2737).

A Further Discussion of Principal Investment Strategies

Overview

The Fund allocates and reallocates its assets among the Underlying Funds consistent with the allocation and reallocation of securities in the Underlying Index as determined by Morningstar. In addition to investing in the Underlying Funds, the Fund may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and may invest the collateral in certain short-term instruments, either directly or through one or more money market funds, as described in greater detail in the Fund's SAI.

Certain Underlying Funds may invest in non-U.S. securities, emerging markets securities and debt instruments, which are subject to additional risks, as described in this Prospectus and in the Fund's SAI. The investment model for the Underlying Index is intended to represent a fixed income allocation strategy designed to deliver high current income.

The Underlying Funds

The Fund seeks to track the investment results of an index composed of underlying fixed-income funds that collectively seek to deliver high current income. Each Underlying Fund generally holds assets that form a subset of the securities composing the Underlying Index. The Fund's allocation of assets to the Underlying Funds will generally closely reflect the allocation weights represented in the Underlying Index.

The following table lists the Fund's investments and asset allocation in each Underlying Fund as of October 31, 2021. BFA allocates the Fund’s assets among the Underlying Funds in accordance with the Fund’s investment objective and policies. Any remaining assets are allocated to the BlackRock Cash Funds. BFA is not required to invest the Fund’s assets in all of the Underlying Funds or in any particular percentage in any given Underlying Fund.

Underlying Fund Allocation Weights
(as of October 31, 2021)

Underlying Funds
iShares 1-5 Year Investment Grade Corporate Bond ETF	8.67%
iShares 7-10 Year Treasury Bond ETF	29.73%
iShares 10+ Year Investment Grade Corporate Bond ETF	1.36%
iShares iBoxx $ High Yield Corporate Bond ETF	20.09%

27

Underlying Funds
iShares J.P. Morgan USD Emerging Markets Bond ETF	9.89%
iShares MBS ETF	30.22%

	Note: The allocation percentages may not add up to, or may appear to exceed, 100% due to rounding.
	Bloomberg® is a trademark of Bloomberg Finance L.P. and its affiliates (collectively “Bloomberg”). The “Bloomberg U.S. MBS Index” is a trademark of Bloomberg and its licensors and has been licensed for use for certain purposes by BFA or its affiliates.
	ICE®,“ICE BofA 1-5 Year US Corporate Index,” “ICE U.S. Treasury 7-10 Year Bond Index,” and “ICE BofA 10+ Year US Corporate Index” are trademarks of ICE Data Indices, LLC or its affiliates (“IDI”) and have been licensed for use for certain purposes by BFA or its affiliates. BofA® is a registered trademark of Bank of America Corporation licensed by Bank of America Corporation and its affiliates (“BofA”), and may not be used without BofA’s prior written approval.
	“J.P. Morgan” and “J.P. Morgan EMBI® Global Core Index” are trademarks of JPMorgan Chase & Co. and have been licensed for use for certain purposes by BFA or its affiliates.
	Markit® and iBoxx® are registered trademarks of Markit Group Limited and Markit Indices Limited, respectively, and have been licensed for use for certain purposes by BFA or its affiliates.

In managing certain of the Underlying Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that collectively have an investment profile similar to a specified benchmark index. Securities selected for the Underlying Funds are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability and yield) and liquidity measures similar to those of the applicable underlying index. The Underlying Funds may or may not hold all of the securities that are included in their respective underlying indexes and may hold certain securities that are not included in their respective underlying indexes. Additional information regarding the Underlying Funds and their principal investment strategies is provided below.

The iShares 1-5 Year Investment Grade Corporate Bond ETF seeks to track the investment results of the ICE BofA 1-5 Year US Corporate Index, which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated and publicly issued in the U.S. domestic market, have a remaining maturity of greater than or equal to one year and less than five years and have $250 million or more of outstanding face value. As of February 28, 2021, there were 3,196 issues in the ICE BofA 1-5 Year US Corporate Index. As of February 28, 2021, a significant portion of the ICE BofA 1-5 Year US Corporate Index is represented by securities of companies in the financials industry or sector. The components of the ICE BofA 1-5 Year US Corporate Index are likely to change over time.

IDI deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or

28

Standard & Poor's^® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the ICE BofA 1-5 Year US Corporate Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the ICE BofA 1-5 Year US Corporate Index are equity-linked securities, securities in legal default, hybrid securitized corporate bonds, Eurodollar bonds (U.S. dollar-denominated securities not issued in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The ICE BofA 1-5 Year US Corporate Index is market capitalization-weighted, and the securities in the ICE BofA 1-5 Year US Corporate Index are updated on the last calendar day of each month. Under normal circumstances, the iShares 1-5 Year Investment Grade Corporate Bond ETF will seek to maintain a weighted average maturity that is less than or equal to three years. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the iShares 1-5 Year Investment Grade Corporate Bond ETF’s portfolio.

The iShares 7-10 Year Treasury Bond ETF seeks to track the investment results of the ICE^® U.S. Treasury 7-10 Year Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System. As of February 28, 2021, there were 18 issues in the ICE U.S. Treasury 7-10 Year Bond Index.

The securities in the ICE U.S. Treasury 7-10 Year Bond Index must be fixed-rate and denominated in U.S. dollars. Excluded from the ICE U.S. Treasury 7-10 Year Bond Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee and zero-coupon issues that have been stripped from coupon-paying bonds. The ICE U.S. Treasury 7-10 Year Bond Index is market value-weighted, and the securities in the ICE U.S. Treasury 7-10 Year Bond Index are updated on the last business day of each month.

The iShares 10+ Year Investment Grade Corporate Bond ETF seeks to track the investment results of the ICE^® BofA^® 10+ Year US Corporate Index, which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated and publicly issued in the U.S. domestic market, have a remaining maturity of greater than or equal to ten years and have $250 million or more of outstanding face value. As of February 28, 2021, there were 3,105 issues in the ICE BofA 10+ Year US Corporate Index. As of February 28, 2021, a significant portion of the ICE BofA 10+ Year US Corporate Index is represented by securities of companies in the energy, healthcare and utilities industries or sectors. The components of the ICE BofA 10+ Year US Corporate Index are likely to change over time.

IDI deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or Standard & Poor's^® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the ICE BofA 10+ Year US Corporate Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the ICE BofA 10+ Year US Corporate Index are equity-linked securities, securities in legal default, hybrid securitized corporates, Eurodollar bonds (U.S. dollar-denominated securities not issued

29

in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The ICE BofA 10+ Year US Corporate Index is market capitalization-weighted, and the securities in the ICE BofA 10+ Year US Corporate Index are updated on the last calendar day of each month. Under normal circumstances, the iShares 10+ Year Investment Grade Corporate Bond ETF will seek to maintain a weighted average maturity that is greater than ten years. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the iShares 10+ Year Investment Grade Corporate Bond ETF's portfolio.

The iShares iBoxx $ High Yield Corporate Bond ETF seeks to track the investment results of the Markit iBoxx^® USD Liquid High Yield Index, which is a rules-based index consisting of U.S. dollar-denominated, high yield (as determined by Markit Indices Limited) corporate bonds for sale in the U.S. The Markit iBoxx^® USD Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated, liquid high yield corporate bond market. The Markit iBoxx^® USD Liquid High Yield Index is a modified market value-weighted index with a cap on each issuer of 3%. There is no limit to the number of issues in the Markit iBoxx^® USD Liquid High Yield Index. As of February 28, 2021, the Markit iBoxx^® USD Liquid High Yield Index included approximately 1,219 constituents. As of February 28, 2021, a significant portion of the Markit iBoxx^® USD Liquid High Yield Index is represented by securities of companies in the consumer services industry or sector. The components of the Markit iBoxx^® USD Liquid High Yield Index are likely to change over time.

Bonds in the Markit iBoxx^® USD Liquid High Yield Index are selected from the universe of eligible bonds in the Markit iBoxx USD Corporate Bond Index using defined rules. As of the date of the iShares iBoxx $ High Yield Corporate Bond ETF’s Prospectus, the bonds eligible for inclusion in the Markit iBoxx^® USD Liquid High Yield Index include U.S. dollar-denominated high yield corporate bonds that: (i) are issued by companies domiciled in countries classified as developed markets by Markit; (ii) have an average rating of sub-investment grade (ratings from Fitch, Moody's or S&P Global Ratings are considered; if more than one agency provides a rating, the average rating is attached to the bond); (iii) are from issuers with at least $1 billion outstanding face value; (iv) have at least $400 million of outstanding face value; (v) have an original maturity date of less than 15 years; (vi) have at least one year to maturity; and (vii) have at least one year and 6 months to maturity for new index insertions.

The iShares J.P. Morgan USD Emerging Markets Bond ETF seeks to track the investment results of the J.P. Morgan EMBI^® Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark that tracks the total return of actively traded external debt instruments in emerging market countries. The methodology is designed to distribute the weight of each country within the J.P. Morgan EMBI^® Global Core Index by limiting the weights of countries with higher debt outstanding and reallocating this excess to countries with lower debt outstanding.

The J.P. Morgan EMBI^® Global Core Index was composed of 58 countries as of October 31, 2021. As of October 31, 2021, the J.P. Morgan EMBI^® Global Core Index’s five highest-weighted countries were Indonesia, Mexico, Qatar, Saudi Arabia and the United Arab Emirates.

30

The J.P. Morgan EMBI^® Global Core Index may change its composition and weighting monthly upon rebalancing. The J.P. Morgan EMBI^® Global Core Index includes both fixed-rate and floating-rate instruments issued by sovereign and quasi-sovereign entities from index-eligible countries. Quasi-sovereign entities are defined as entities that are 100% guaranteed or 100% owned by the national government and reside in the index-eligible country. Only instruments which meet the following criteria are considered for inclusion in the J.P. Morgan EMBI^® Global Core Index: (i) are denominated in U.S. dollars, (ii) have a current face amount outstanding of $1 billion or more, (iii) have at least 2.5 years until maturity to be eligible for inclusion and, at each subsequent rebalance, have at least one year until maturity to remain in the index, (iv) are able to settle internationally through Euroclear or another institution domiciled outside the issuing country and (v) have bid and offer prices that are available on a daily and timely basis sourced from a third party valuation vendor. As of October 31, 2021, the J.P. Morgan EMBI^® Global Core Index consisted of both investment-grade and non-investment-grade bonds (commonly referred to as “junk bonds”), each as defined by JPMorgan Chase & Co. Convertible bonds are not eligible for inclusion in the J.P. Morgan EMBI^® Global Core Index. The J.P. Morgan EMBI^® Global Core Index is market value-weighted and is rebalanced monthly on the last business day of the month.

The iShares MBS ETF seeks to track the investment results of the Bloomberg U.S. MBS Index, which measures the performance of investment-grade (as determined by Bloomberg Index Services Limited) MBS issued or guaranteed by U.S. government agencies or sponsored entities. The Bloomberg U.S. MBS Index includes fixed-rate MBS issued by Ginnie Mae, Fannie Mae and Freddie Mac that have 30-, 20-, or 15-year maturities. All securities in the Bloomberg U.S. MBS Index must have a remaining weighted average maturity of at least one year, must be denominated in U.S. dollars and must be non-convertible. The Bloomberg U.S. MBS Index is market capitalization-weighted, and its securities are updated on the last business day of each month.

As of February 28, 2021, approximately 100% of the bonds represented in the Bloomberg U.S. MBS Index were U.S. agency MBS. Most transactions in MBS occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (TBA transactions). The iShares MBS ETF may enter into such contracts for fixed-rate pass-through securities on a regular basis. The iShares MBS ETF, pending settlement of such contracts, will invest its assets in liquid, short-term instruments, including shares of money market funds advised by BFA or its affiliates. The iShares MBS ETF will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to the iShares MBS ETF's own fees and expenses. The iShares MBS ETF may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery.

Management

Investment Adviser. As investment adviser, BFA has overall responsibility for the general management and administration of the Fund. BFA provides an investment program for the Fund and manages the investment of the Fund’s assets. In managing the Fund, BFA may draw upon the research and expertise of its asset management

31

affiliates with respect to certain portfolio securities. In seeking to achieve the Fund's investment objective, BFA uses teams of portfolio managers, investment strategists and other investment specialists. This team approach brings together many disciplines and leverages BFA’s extensive resources.

Pursuant to the Investment Advisory Agreement between BFA and the Trust (entered into on behalf of the Fund), BFA is responsible for substantially all expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, and litigation expenses and any extraordinary expenses (as determined by a majority of the Trustees who are not “interested persons” of the Trust).

For its investment advisory services to the Fund, BFA is paid a management fee from the Fund based on a percentage of the Fund's average daily net assets, at the annual rate of 0.28%. BFA has contractually agreed to waive its management fees through February 28, 2026. The contractual waiver may be terminated prior to February 28, 2026 only upon written agreement of the Trust and BFA. In addition, BFA may from time to time voluntarily waive and/or reimburse fees or expenses in order to limit total annual fund operating expenses (excluding Acquired Fund Fees and Expenses, if any). Any such voluntary waiver or reimbursement may be eliminated by BFA at any time.

BFA is located at 400 Howard Street, San Francisco, CA 94105. It is an indirect wholly-owned subsidiary of BlackRock, Inc. (“BlackRock”). As of December 31, 2021, BFA and its affiliates provided investment advisory services for assets in excess of $10.01 trillion. BFA and its affiliates trade and invest for their own accounts in the actual securities and types of securities in which the Fund may also invest, which may affect the price of such securities.

A discussion regarding the basis for the approval by the Trust's Board of Trustees (the “Board”) of the Investment Advisory Agreement with BFA is available in the Fund's Annual Report for the period ended October 31.

Portfolio Managers. James Mauro and Karen Uyehara are primarily responsible for the day-to-day management of the Fund. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of his portfolio management team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy and overseeing members of his portfolio management team that have more limited responsibilities.

James Mauro has been employed by BFA or its affiliates as a portfolio manager since 2011. Prior to that, Mr. Mauro was a Vice President at State Street Global Advisors. Mr. Mauro has been a Portfolio Manager of the Fund since 2014.

Karen Uyehara has been employed by BFA or its affiliates as a senior portfolio manager since 2010. Prior to that, Ms. Uyehara was a portfolio manager at Western Asset Management Company (WAMCO). Ms. Uyehara has been a Portfolio Manager of the Fund since 2021.

32

The Fund's SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers and the Portfolio Managers' ownership (if any) of shares in the Fund.

Administrator, Custodian and Transfer Agent. State Street Bank and Trust Company (“State Street”) is the administrator, custodian and transfer agent for the Fund. JPMorgan Chase Bank, N.A. serves as custodian for the Fund in connection with certain securities lending activities.

Conflicts of Interest. The investment activities of BFA and its affiliates (including BlackRock and its subsidiaries (collectively, the “Affiliates”)), and their respective directors, officers or employees, in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BFA and its Affiliates provide investment management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Fund. BFA and its Affiliates are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. BFA or one or more Affiliates act, or may act, as an investor, research provider, investment manager, commodity pool operator, commodity trading advisor, financier, underwriter, adviser, trader, lender, index provider, agent and/or principal, and have other direct and indirect interests in securities, currencies, commodities, derivatives and other instruments in which the Fund may directly or indirectly invest. The Fund may invest in securities of, or engage in other transactions with, companies with which an Affiliate has significant debt or equity investments or other interests. The Fund may also invest in issuances (such as structured notes) by entities for which an Affiliate provides and is compensated for cash management services relating to the proceeds from the sale of such issuances. The Fund also may invest in securities of, or engage in other transactions with, companies for which an Affiliate provides or may in the future provide research coverage. An Affiliate may have business relationships with, and purchase or distribute or sell services or products from or to, distributors, consultants or others who recommend the Fund or who engage in transactions with or for the Fund, and may receive compensation for such services. BFA or one or more Affiliates may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Fund and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. This may include transactions in securities issued by other open-end and closed-end investment companies (which may include investment companies that are affiliated with the Fund and BFA, to the extent permitted under the Investment Company Act of 1940, as amended (the “1940 Act”)). The trading activities of BFA and these Affiliates are carried out without reference to positions held directly or indirectly by the Fund and may result in BFA or an Affiliate having positions in certain securities that are senior or junior to, or have interests different from or adverse to, the securities that are owned by the Fund.

Neither BlackRock nor any Affiliate is under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, an Affiliate may compete with

33

the Fund for appropriate investment opportunities. The results of the Fund's investment activities, therefore, may differ from those of an Affiliate and of other accounts managed by BlackRock or an Affiliate, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Fund may, from time to time, enter into transactions in which BFA or an Affiliate or its or their directors, officers, employees or clients have an adverse interest. Furthermore, transactions undertaken by clients advised or managed by BFA or its Affiliates may adversely impact the Fund. Transactions by one or more clients or by BFA or its Affiliates or their directors, officers or employees may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Fund.

The Fund's activities may be limited because of regulatory restrictions applicable to BFA or one or more Affiliates and/or their internal policies designed to comply with such restrictions.

Under a securities lending program approved by the Board, the Fund has retained BTC, an Affiliate of BFA, to serve as the securities lending agent for the Fund to the extent that the Fund participates in the securities lending program. For these services, the securities lending agent will receive a fee from the Fund, including a fee based on the returns earned on the Fund’s investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Fund may lend its portfolio securities under the securities lending program.

It is also possible that, from time to time, BlackRock and/or its advisory clients (including other funds and separately managed accounts) may, subject to compliance with applicable law, purchase and hold shares of the Fund. The price, availability, liquidity, and (in some cases) expense ratio of the Fund may be impacted by purchases and sales of the Fund by BlackRock and/or its advisory clients.

The activities of BFA and its Affiliates and their respective directors, officers or employees may give rise to other conflicts of interest that could disadvantage the Fund and its shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest. See the SAI for further information.

Shareholder Information

Additional shareholder information, including how to buy and sell shares of the Fund, is available free of charge by calling toll-free: 1-800-iShares (1-800-474-2737) or visiting our website at www.iShares.com.

Buying and Selling Shares. Shares of the Fund may be acquired or redeemed directly from the Fund only in Creation Units or multiples thereof, as discussed in the Creations and Redemptions section of this Prospectus. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. Once created, shares of the Fund generally trade in the secondary market in amounts less than a Creation Unit.

34

Shares of the Fund are listed on a national securities exchange for trading during the trading day. Shares can be bought and sold throughout the trading day like shares of other publicly-traded companies. The Trust does not impose any minimum investment for shares of the Fund purchased on an exchange or otherwise in the secondary market. The Fund's shares trade under the ticker symbol “BYLD.”

Buying or selling Fund shares on an exchange or other secondary market involves two types of costs that may apply to all securities transactions. When buying or selling shares of the Fund through a broker, you may incur a brokerage commission and other charges. The commission is frequently a fixed amount and may be a significant proportional cost for investors seeking to buy or sell small amounts of shares. In addition, you may incur the cost of the “spread,” that is, any difference between the bid price and the ask price. The spread varies over time for shares of the Fund based on the Fund’s trading volume and market liquidity, and is generally lower if the Fund has high trading volume and market liquidity, and higher if the Fund has little trading volume and market liquidity (which is often the case for funds that are newly launched or small in size). The Fund's spread may also be impacted by the liquidity or illiquidity of the underlying securities held by the Fund, particularly for newly launched or smaller funds or in instances of significant volatility of the underlying securities.

The Board has adopted a policy of not monitoring for frequent purchases and redemptions of Fund shares (“frequent trading”) that appear to attempt to take advantage of a potential arbitrage opportunity presented by a lag between a change in the value of the Fund’s portfolio securities after the close of the primary markets for the Fund’s portfolio securities and the reflection of that change in the Fund’s NAV (“market timing”), because the Fund sells and redeems its shares directly through transactions that are in-kind and/or for cash, subject to the conditions described below under Creations and Redemptions. The Board has not adopted a policy of monitoring for other frequent trading activity because shares of the Fund are listed for trading on a national securities exchange.

The national securities exchange on which the Fund's shares are listed is open for trading Monday through Friday and is closed on weekends and the following holidays (or the days on which they are observed): New Year’s Day, Martin Luther King, Jr. Day, Presidents’ Day, Good Friday, Memorial Day, Juneteenth, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Fund’s primary listing exchange is NYSE Arca.

Section 12(d)(1) of the 1940 Act generally restricts investments by investment companies, including foreign and unregistered investment companies, in the securities of other investment companies. For example, a registered investment company (the “Acquired Fund”), such as the Fund, may not knowingly sell or otherwise dispose of any security issued by the Acquired Fund to any investment company (the “Acquiring Fund”) or any company or companies controlled by the Acquiring Fund if, immediately after such sale or disposition: (i) more than 3% of the total outstanding voting stock of the Acquired Fund is owned by the Acquiring Fund and any company or companies controlled by the Acquiring Fund or (ii) more than 10% of the total outstanding voting stock of the Acquired Fund is owned by the Acquiring Fund and other investment companies and companies controlled by them. Although SEC rules may permit

35

registered investment companies and unit investment trusts (“Investing Funds”) that enter into an investment agreement with the Trust to invest in iShares funds beyond the limits set forth in Section 12(d)(1) of the 1940 Act subject to certain terms and conditions, the Fund does not permit such investments. Accordingly, Investing Funds must adhere to the limits set forth in Section 12(d)(1) of the 1940 Act when investing in the Fund. In addition, foreign investment companies are permitted to invest in the Fund only up to the limits set forth in Section 12(d)(1), subject to any applicable SEC no-action relief.

Book Entry. Shares of the Fund are held in book-entry form, which means that no stock certificates are issued. The Depository Trust Company (“DTC”) or its nominee is the record owner of, and holds legal title to, all outstanding shares of the Fund.

Investors owning shares of the Fund are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for shares of the Fund. DTC participants include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of shares, you are not entitled to receive physical delivery of stock certificates or to have shares registered in your name, and you are not considered a registered owner of shares. Therefore, to exercise any right as an owner of shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other securities that you hold in book-entry or “street name” form.

Share Prices. The trading prices of the Fund’s shares in the secondary market generally differ from the Fund’s daily NAV and are affected by market forces such as the supply of and demand for ETF shares and underlying securities held by the Fund, economic conditions and other factors.

Determination of Net Asset Value. The NAV of the Fund normally is determined once daily Monday through Friday, generally as of the close of regular trading hours of the New York Stock Exchange (“NYSE”) (normally 4:00 p.m., Eastern time) on each day that the NYSE is open for trading, based on prices at the time of closing, provided that any Fund assets or liabilities denominated in currencies other than the U.S. dollar are translated into U.S. dollars at the prevailing market rates on the date of valuation as quoted by one or more data service providers. The NAV of the Fund is calculated by dividing the value of the net assets of the Fund (i.e., the value of its total assets, which includes the values of the Underlying Fund shares in which the Fund invests, less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

The value of the securities and other assets and liabilities held by the Fund is determined pursuant to valuation policies and procedures approved by the Board.

Equity securities and other equity instruments for which market quotations are readily available are valued at market value, which is generally determined using the last reported official closing price or, if a reported closing price is not available, the last traded price on the exchange or market on which the security or instrument is primarily traded at the time of valuation. Shares of underlying open-end funds (including money market funds) are valued at net asset value. Shares of underlying

36

exchange-traded closed-end funds or other ETFs are valued at their most recent closing price.

The Fund values fixed-income portfolio securities using last available bid prices or current market quotations provided by dealers or prices (including evaluated prices) supplied by the Fund's approved independent third-party pricing services, each in accordance with valuation policies and procedures approved by the Board. Pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values. Pricing services generally value fixed-income securities assuming orderly transactions of an institutional round lot size, but the Fund may hold or transact in such securities in smaller odd lot sizes. Odd lots often trade at lower prices than institutional round lots. An amortized cost method of valuation may be used with respect to debt obligations with sixty days or less remaining to maturity unless BFA determines in good faith that such method does not represent fair value.

Generally, trading in non-U.S. securities and money market instruments is substantially completed each day at various times prior to the close of regular trading hours of the NYSE. The values of such securities used in computing the NAV of the Fund are determined as of such times.

When market quotations are not readily available or are believed by BFA to be unreliable, the Fund’s investments are valued at fair value. Fair value determinations are made by BFA in accordance with policies and procedures approved by the Board. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of trading or other reasons, if a market quotation differs significantly from recent price quotations or otherwise no longer appears to reflect fair value, where the security or other asset or liability is thinly traded, when there is a significant event subsequent to the most recent market quotation, or if the trading market on which a security is listed is suspended or closed and no appropriate alternative trading market is available. A “significant event” is deemed to occur if BFA determines, in its reasonable business judgment prior to or at the time of pricing the Fund’s assets or liabilities, that the event is likely to cause a material change to the last exchange closing price or closing market price of one or more assets held by, or liabilities of, the Fund.

Fair value represents a good faith approximation of the value of an asset or liability. The fair value of an asset or liability held by the Fund is the amount the Fund might reasonably expect to receive from the current sale of that asset or the cost to extinguish that liability in an arm’s-length transaction. Valuing the Fund’s investments using fair value pricing will result in prices that may differ from current market valuations and that may not be the prices at which those investments could have been sold during the period in which the particular fair values were used. Use of fair value prices and certain current market valuations could result in a difference between the prices used to calculate the Fund’s NAV and the prices used by the Underlying Index, which, in turn, could result in a difference between the Fund’s performance and the performance of the Underlying Index.

37

Dividends and Distributions

General Policies. Dividends from net investment income, if any, generally are declared and paid at least once a year by the Fund. The Fund generally distributes its net capital gains, if any, to shareholders annually. Distributions of net realized securities gains, if any, generally are declared and paid once a year, but the Trust may make distributions on a more frequent basis for the Fund. The Trust reserves the right to declare special distributions if, in its reasonable discretion, such action is necessary or advisable to preserve its status as a regulated investment company or to avoid imposition of income or excise taxes on undistributed income or realized gains.

Dividends and other distributions on shares of the Fund are distributed on a pro rata basis to beneficial owners of such shares. Dividend payments are made through DTC participants and indirect participants to beneficial owners then of record with proceeds received from the Fund.

Dividend Reinvestment Service. No dividend reinvestment service is provided by the Trust. Broker-dealers may make available the DTC book-entry Dividend Reinvestment Service for use by beneficial owners of the Fund for reinvestment of their dividend distributions. Beneficial owners should contact their broker to determine the availability and costs of the service and the details of participation therein. Brokers may require beneficial owners to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and realized gains will be automatically reinvested in additional whole shares of the Fund purchased in the secondary market.

Taxes. As with any investment, you should consider how your investment in shares of the Fund will be taxed. The tax information in this Prospectus is provided as general information, based on current law. You should consult your own tax professional about the tax consequences of an investment in shares of the Fund.

Unless your investment in Fund shares is made through a tax-exempt entity or tax-deferred retirement account, such as an IRA, you need to be aware of the possible tax consequences when the Fund makes distributions or you sell Fund shares.

Taxes on Distributions. Distributions from the Fund’s net investment income, including distributions of income from securities lending and distributions out of the Fund’s net short-term capital gains, if any, are taxable to you as ordinary income. Distributions by the Fund of net long-term capital gains, if any, in excess of net short-term capital losses (capital gain dividends) are taxable to you as long-term capital gains, regardless of how long you have held the Fund’s shares. Long-term capital gains and qualified dividend income are generally eligible for taxation at a maximum rate of 15% or 20% for non-corporate shareholders, depending on whether their income exceeds certain threshold amounts. In addition, a 3.8% U.S. federal Medicare contribution tax is imposed on “net investment income,” including, but not limited to, interest, dividends, and net gain, of U.S. individuals with income exceeding $200,000 (or $250,000 if married and filing jointly) and of estates and trusts.

You may lose the ability to use foreign tax credits passed through by the Fund if your Fund shares are loaned out pursuant to a securities lending agreement.

38

In general, your distributions are subject to U.S. federal income tax for the year when they are paid. Certain distributions paid in January, however, may be treated as paid on December 31 of the prior year.

Because the Fund invests in Underlying Funds, the Fund’s realized losses on sales of shares of an Underlying Fund may be indefinitely or permanently deferred as “wash sales.” Distributions of short-term capital gains by an Underlying Fund will be recognized as ordinary income by the Fund and would not be offset by the Fund’s capital loss carryforwards, if any. Capital loss carryforwards of an Underlying Fund, if any, would not offset net capital gains of the Fund.

If the Fund’s distributions exceed current and accumulated earnings and profits, all or a portion of the distributions made in the taxable year may be recharacterized as a return of capital to shareholders. Distributions in excess of the Fund’s minimum distribution requirements, but not in excess of the Fund’s earnings and profits, will be taxable to shareholders and will not constitute nontaxable returns of capital. A return of capital distribution generally will not be taxable but will reduce the shareholder’s cost basis and result in a higher capital gain or lower capital loss when those shares on which the distribution was received are sold. Once a shareholder's cost basis is reduced to zero, further distributions will be treated as capital gain, if the shareholder holds shares of the Fund as capital assets.

Dividends, interest and capital gains earned by an Underlying Fund with respect to securities issued by non-U.S. issuers may give rise to withholding and other taxes imposed by non-U.S. countries. Tax conventions between certain countries and the U.S. may reduce or eliminate such taxes. If more than 50% of the total assets of an Underlying Fund at the close of a year consists of non-U.S. stocks or securities (generally, for this purpose, depositary receipts, no matter where traded, of non-U.S. companies are treated as “non-U.S.”) (and 50% of the total assets of the Fund at the close of the year consists of securities issued by non-U.S. issuers, or, at the close of each quarter, shares of an Underlying Fund), the Fund may “pass through” to you certain non-U.S. income taxes (including withholding taxes) paid by the Fund or an Underlying Fund. This means that you would be considered to have received as an additional dividend your share of such non-U.S. taxes, but you may be entitled to either a corresponding tax deduction in calculating your taxable income, or, subject to certain limitations, a credit in calculating your U.S. federal income tax.

For purposes of foreign tax credits for U.S. shareholders of the Fund, foreign capital gains taxes may not produce associated foreign source income, limiting the availability of such credits for U.S. persons.

If you are neither a resident nor a citizen of the U.S. or if you are a non-U.S. entity (other than a pass-through entity to the extent owned by U.S. persons), the Fund’s ordinary income dividends (which include distributions of net short-term capital gains) will generally be subject to a 30% U.S. withholding tax, unless a lower treaty rate applies, provided that withholding tax will generally not apply to any gain or income realized by a non-U.S. shareholder in respect of any distributions of long-term capital gains or upon the sale or other disposition of shares of the Fund.

39

Separately, a 30% withholding tax is currently imposed on U.S.-source dividends, interest and other income items paid to (i) foreign financial institutions, including non-U.S. investment funds, unless they agree to collect and disclose to the U.S. Internal Revenue Service (“IRS”) information regarding their direct and indirect U.S. account holders and (ii) certain other foreign entities, unless they certify certain information regarding their direct and indirect U.S. owners. To avoid withholding, foreign financial institutions will need to (i) enter into agreements with the IRS that state that they will provide the IRS information, including the names, addresses and taxpayer identification numbers of direct and indirect U.S. account holders, comply with due diligence procedures with respect to the identification of U.S. accounts, report to the IRS certain information with respect to U.S. accounts maintained, agree to withhold tax on certain payments made to non-compliant foreign financial institutions or to account holders who fail to provide the required information, and determine certain other information concerning their account holders, or (ii) in the event that an applicable intergovernmental agreement and implementing legislation are adopted, provide local revenue authorities with similar account holder information. Other foreign entities will need to provide the name, address, and taxpayer identification number of each substantial U.S. owner or certifications of no substantial U.S. ownership unless certain exceptions apply.

As the Fund invests in only a limited number of positions, the Fund may be required to defer for tax purposes significant amounts of realized losses on the sale of shares in Underlying Funds indefinitely.

If you are a resident or a citizen of the U.S., by law, backup withholding at a 24% rate will apply to your distributions and proceeds if you have not provided a taxpayer identification number or social security number and made other required certifications.

Taxes When Shares Are Sold. Currently, any capital gain or loss realized upon a sale of Fund shares is generally treated as a long-term gain or loss if the shares have been held for more than one year. Any capital gain or loss realized upon a sale of Fund shares held for one year or less is generally treated as short-term gain or loss, except that any capital loss on the sale of shares held for six months or less is treated as long-term capital loss to the extent that capital gain dividends were paid with respect to such shares. Any such capital gains, including from sales of Fund shares or from capital gain dividends, are included in “net investment income” for purposes of the 3.8% U.S. federal Medicare contribution tax mentioned above.

The foregoing discussion summarizes some of the consequences under current U.S. federal tax law of an investment in the Fund. It is not a substitute for personal tax advice. You may also be subject to state and local taxation on Fund distributions and sales of shares. Consult your personal tax advisor about the potential tax consequences of an investment in shares of the Fund under all applicable tax laws.

Creations and Redemptions. Prior to trading in the secondary market, shares of the Fund are “created” at NAV by market makers, large investors and institutions only in block-size Creation Units or multiples thereof. Each “creator” or authorized participant (an “Authorized Participant”) has entered into an agreement with the Fund's distributor, BlackRock Investments, LLC (the “Distributor”), an affiliate of BFA. An Authorized Participant is a member or participant of a clearing agency registered with the SEC,

40

which has a written agreement with the Fund or one of its service providers that allows such member or participant to place orders for the purchase and redemption of Creation Units.

A creation transaction, which is subject to acceptance by the Distributor and the Fund, generally takes place when an Authorized Participant deposits into the Fund a designated portfolio of securities, assets or other positions (a “creation basket”), and an amount of cash (including any cash representing the value of substituted securities, assets or other positions), if any, which together approximate the holdings of the Fund in exchange for a specified number of Creation Units. Similarly, shares can be redeemed only in Creation Units, generally for a designated portfolio of securities, assets or other positions (a “redemption basket”) held by the Fund and an amount of cash (including any portion of such securities for which cash may be substituted). The Fund may, in certain circumstances, offer Creation Units partially or solely for cash. Except when aggregated in Creation Units, shares are not redeemable by the Fund. Creation and redemption baskets may differ and the Fund will accept “custom baskets.” More information regarding custom baskets is contained in the Fund's SAI.

The prices at which creations and redemptions occur are based on the next calculation of NAV after a creation or redemption order is received in an acceptable form under the authorized participant agreement.

Only an Authorized Participant may create or redeem Creation Units with the Fund. Authorized Participants may create or redeem Creation Units for their own accounts or for customers, including, without limitation, affiliates of the Fund.

In the event of a system failure or other interruption, including disruptions at market makers or Authorized Participants, orders to purchase or redeem Creation Units either may not be executed according to the Fund's instructions or may not be executed at all, or the Fund may not be able to place or change orders.

To the extent the Fund engages in in-kind transactions, the Fund intends to comply with the U.S. federal securities laws in accepting securities for deposit and satisfying redemptions with redemption securities by, among other means, assuring that any securities accepted for deposit and any securities used to satisfy redemption requests will be sold in transactions that would be exempt from registration under the 1933 Act. Further, an Authorized Participant that is not a “qualified institutional buyer,” as such term is defined in Rule 144A under the 1933 Act, will not be able to receive restricted securities eligible for resale under Rule 144A.

Creations and redemptions must be made through a firm that is either a member of the Continuous Net Settlement System of the National Securities Clearing Corporation or a DTC participant that has executed an agreement with the Distributor with respect to creations and redemptions of Creation Unit aggregations. Information about the procedures regarding creation and redemption of Creation Units (including the cut-off times for receipt of creation and redemption orders) is included in the Fund's SAI.

Because new shares may be created and issued on an ongoing basis, at any point during the life of the Fund a “distribution,” as such term is used in the 1933 Act, may be occurring. Broker-dealers and other persons are cautioned that some activities on their part may, depending on the circumstances, result in their being deemed

41

participants in a distribution in a manner that could render them statutory underwriters subject to the prospectus delivery and liability provisions of the 1933 Act. Any determination of whether one is an underwriter must take into account all the relevant facts and circumstances of each particular case.

Broker-dealers should also note that dealers who are not “underwriters” but are participating in a distribution (as contrasted to ordinary secondary transactions), and thus dealing with shares that are part of an “unsold allotment” within the meaning of Section 4(a)(3)(C) of the 1933 Act, would be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the 1933 Act. For delivery of prospectuses to exchange members, the prospectus delivery mechanism of Rule 153 under the 1933 Act is available only with respect to transactions on a national securities exchange.

Householding. Householding is an option available to certain Fund investors. Householding is a method of delivery, based on the preference of the individual investor, in which a single copy of certain shareholder documents can be delivered to investors who share the same address, even if their accounts are registered under different names. Please contact your broker-dealer if you are interested in enrolling in householding and receiving a single copy of prospectuses and other shareholder documents, or if you are currently enrolled in householding and wish to change your householding status.

42

Distribution

The Distributor or its agent distributes Creation Units for the Fund on an agency basis. The Distributor does not maintain a secondary market in shares of the Fund. The Distributor has no role in determining the policies of the Fund or the securities that are purchased or sold by the Fund. The Distributor’s principal address is 1 University Square Drive, Princeton, NJ 08540.

BFA or its affiliates make payments to broker-dealers, registered investment advisers, banks or other intermediaries (together, “intermediaries”) related to marketing activities and presentations, educational training programs, conferences, the development of technology platforms and reporting systems, data provision services, or their making shares of the Fund and certain other iShares funds available to their customers generally and in certain investment programs. Such payments, which may be significant to the intermediary, are not made by the Fund. Rather, such payments are made by BFA or its affiliates from their own resources, which come directly or indirectly in part from fees paid by the iShares funds complex. Payments of this type are sometimes referred to as revenue-sharing payments. A financial intermediary may make decisions about which investment options it recommends or makes available, or the level of services provided, to its customers based on the payments or other financial incentives it is eligible to receive. Therefore, such payments or other financial incentives offered or made to an intermediary create conflicts of interest between the intermediary and its customers and may cause the intermediary to recommend the Fund or other iShares funds over another investment. More information regarding these payments is contained in the Fund's and each Underlying Fund's SAI. Please contact your salesperson or other investment professional for more information regarding any such payments his or her firm may receive from BFA or its affiliates.

43

Financial Highlights

The financial highlights table is intended to help investors understand the Fund’s financial performance for the past five years. Certain information reflects financial results for a single share of the Fund. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the Fund, assuming reinvestment of all dividends and distributions. This information has been audited by PricewaterhouseCoopers LLP, whose report is included, along with the Fund's financial statements, in the Fund's Annual Report (available upon request).

Financial Highlights (For a share outstanding throughout each period)

	iShares Yield Optimized Bond ETF
	Year Ended 10/31/21		Year Ended 10/31/20		Year Ended 10/31/19		Year Ended 10/31/18		Year Ended 10/31/17
Net asset value, beginning of year	$25.63		$25.60		$23.77		$25.08		$25.05
Net investment income(a)	0.63		0.80		0.92		0.91		0.82
Net realized and unrealized gain (loss)(b)	(0.51)		0.04		1.94		(1.33)		0.04
Net increase (decrease) from investment operations	0.12		0.84		2.86		(0.42)		0.86
Distributions(c)
From net investment income	(0.65)		(0.81)		(1.03)		(0.89)		(0.83)
From net realized gain	(0.07)		—		—		—		—
Total distributions	(0.72)		(0.81)		(1.03)		(0.89)		(0.83)
Net asset value, end of year	$25.03		$25.63		$25.60		$23.77		$25.08
Total Return(d)
Based on net asset value	0.47%		3.33%		12.31%		(1.70)%		3.53%
Ratios to Average Net Assets
Total expenses(e)	0.28%		0.28%		0.28%		0.28%		0.28%
Total expenses after fees waived(e)	0.00%(f)		0.00%(f)		0.00%		0.00%(f)		0.00%(f)
Net investment income	2.49%		3.12%		3.69%		3.75%		3.30%
Supplemental Data
Net assets, end of year (000)	$148,924		$190,935		$147,173		$34,462		$27,593
Portfolio turnover rate(g)(h)	57%		118%		58%		48%		27%
(a) Based on average shares outstanding.
(b) The amounts reported for a share outstanding may not accord with the change in aggregate gains and losses in securities for the fiscal period due to the timing of capital share transactions in relation to the fluctuating market values of the Fund’s underlying securities.
(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.
(d) Where applicable, assumes the reinvestment of distributions.
(e) The Fund indirectly bears its proportionate share of fees and expenses incurred by the underlying funds in which the Fund is invested (“acquired fund fees and expenses”). This ratio does not include these acquired fund fees and expenses.
(f) Rounds to less than 0.01%.
(g) Portfolio turnover rate excludes in-kind transactions.
(h) Portfolio turnover rate excludes the portfolio activity of the underlying funds in which the Fund is invested. See each underlying fund's financial highlights for its respective portfolio turnover rates.

44

Index Provider

Morningstar is a leading provider of independent investment research in North America, Europe, Australia, and Asia. Morningstar offers an extensive line of products and services for individual investors, financial advisors, asset managers, retirement plan providers and sponsors, and institutional investors in the debt and private capital markets. Morningstar provides data and research insights on a wide range of investment offerings, including managed investment products, publicly listed companies, private capital markets, debt securities, and real-time global market data. Morningstar also offers investment management services through its investment advisory subsidiaries, with approximately $260 billion in assets under advisement and management as of September 30, 2021. Morningstar has operations in 29 countries. Morningstar is not affiliated with the Trust, BFA, State Street, or the Distributor.

BFA or its affiliates have entered into a license agreement with the Index Provider to use the Underlying Index. BFA or its affiliates sublicense rights in the Underlying Index to the Trust at no charge.

Disclaimer

“Bloomberg^®” and the Bloomberg U.S. MBS Index are service marks of Bloomberg Finance L.P. and its affiliates, including Bloomberg Index Services Limited (“BISL”), the administrator of the index (collectively, “Bloomberg”), and have been licensed for use for certain purposes by BFA.

The iShares MBS ETF is not sponsored, endorsed, sold or promoted by Bloomberg. Bloomberg does not make any representation or warranty, express or implied, to the owners of or counterparties to the iShares MBS ETF or any member of the public regarding the advisability of investing in securities generally or in the iShares MBS ETF particularly. The only relationship of Bloomberg to BFA is the licensing of certain trademarks, trade names and service marks and of the underlying index, which is determined, composed and calculated by BISL without regard to BFA or the iShares MBS ETF. Bloomberg has no obligation to take the needs of BFA or the owners of the iShares MBS ETF into consideration in determining, composing or calculating the underlying index. Bloomberg is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MBS ETF to be issued. Bloomberg shall not have any obligation or liability, including, without limitation, to the iShares MBS ETF’s customers, in connection with the administration, marketing or trading of the iShares MBS ETF.

BLOOMBERG DOES NOT GUARANTEE THE ACCURACY AND/OR THE COMPLETENESS OF THE UNDERLYING INDEX OR ANY DATA RELATED THERETO AND SHALL HAVE NO LIABILITY FOR ANY ERRORS, OMISSIONS OR INTERRUPTIONS THEREIN. BLOOMBERG DOES NOT MAKE ANY WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY BFA, OWNERS OF THE ISHARES MBS ETF OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE UNDERLYING INDEX OR ANY DATA RELATED THERETO. BLOOMBERG DOES NOT MAKE ANY EXPRESS OR IMPLIED WARRANTIES AND EXPRESSLY

45

DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE WITH RESPECT TO THE UNDERLYING INDEX OR ANY DATA RELATED THERETO. WITHOUT LIMITING ANY OF THE FOREGOING, TO THE MAXIMUM EXTENT ALLOWED BY LAW, BLOOMBERG, ITS LICENSORS, AND ITS AND THEIR RESPECTIVE EMPLOYEES, CONTRACTORS, AGENTS, SUPPLIERS, AND VENDORS SHALL HAVE NO LIABILITY OR RESPONSIBILITY WHATSOEVER FOR ANY INJURY OR DAMAGES—WHETHER DIRECT, INDIRECT, CONSEQUENTIAL, INCIDENTAL, PUNITIVE OR OTHERWISE—ARISING IN CONNECTION WITH THE ISHARES MBS ETF OR UNDERLYING INDEX OR ANY DATA OR VALUES RELATING THERETO—WHETHER ARISING FROM THEIR NEGLIGENCE OR OTHERWISE, EVEN IF NOTIFIED OF THE POSSIBILITY THEREOF.

Source ICE Data Indices, LLC is used with permission. ICE^® is a trademark of IDI or its affiliates and has been licensed, along with the ICE BofA 1-5 Year US Corporate Index, the ICE BofA 10+ Year US Corporate Index and the ICE U.S. Treasury 7-10 Year Bond Index for use by BFA in connection with the the iShares 1-5 Year Investment Grade Corporate Bond ETF, the iShares 10+ Year Investment Grade Corporate Bond ETD and the iShares 7-10 Year Treasury Bond ETF (the “iShares IDI Underlying Funds”). Neither BlackRock, Inc., the Trust nor the iShares IDI Underlying Funds, as applicable, is sponsored, endorsed, sold or promoted by IDI, its affiliates or its third party suppliers (“IDI and its Suppliers”). IDI and its Suppliers make no representations or warranties regarding the advisability of investing in securities generally, in the iShares IDI Underlying Funds particularly, the Trust or the ability of the applicable underlying index to track general market performance. IDI’s only relationship to BlackRock is the licensing of certain trademarks and trade names and the applicable underlying index or components thereof. The applicable underlying index is determined, composed and calculated by IDI without regard to BlackRock or the iShares IDI Underlying Funds or their holders. IDI has no obligation to take the needs of BlackRock or the holders of the iShares IDI Underlying Funds into consideration in determining, composing or calculating the applicable underlying index. IDI is not responsible for and has not participated in the determination of the timing of, prices of, or quantities of the iShares IDI Underlying Funds to be issued or in the determination or calculation of the equation by which the iShares IDI Underlying Funds are to be priced, sold, purchased, or redeemed. Except for certain custom index calculation services, all information provided by IDI is general in nature and not tailored to the needs of BlackRock or any other person, entity or group of persons. IDI has no obligation or liability in connection with the administration, marketing, or trading of the iShares IDI Underlying Funds. IDI is not an investment advisor. Inclusion of a security within an index is not a recommendation by IDI to buy, sell, or hold such security, nor is it considered to be investment advice.

IDI AND ITS SUPPLIERS DISCLAIM ANY AND ALL WARRANTIES AND REPRESENTATIONS, EXPRESS AND/OR IMPLIED, INCLUDING ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR

46

PURPOSE OR USE, INCLUDING THE APPLICABLE UNDERLYING INDEX, INDEX DATA AND ANY INFORMATION INCLUDED IN, RELATED TO, OR DERIVED THEREFROM (“INDEX DATA”). IDI AND ITS SUPPLIERS SHALL NOT BE SUBJECT TO ANY DAMAGES OR LIABILITY WITH RESPECT TO THE ADEQUACY, ACCURACY, TIMELINESS OR COMPLETENESS OF THE APPLICABLE UNDERLYING INDEX AND THE INDEX DATA, WHICH ARE PROVIDED ON AN “AS IS” BASIS AND YOUR USE IS AT YOUR OWN RISK.

The iShares iBoxx $ High Yield Corporate Bond ETF is not sponsored, endorsed, sold or promoted by Markit. Markit makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond ETF or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond ETF in particular, or the ability of the underlying index to track general market performance. Markit's only relationship to the Trust and BFA or its affiliates is the licensing of certain trademarks and trade names of Markit and of the underlying index which is determined, composed and calculated by Markit without regard to the Trust, BFA or its affiliates or the iShares iBoxx $ High Yield Corporate Bond ETF. Markit has no obligation to take the needs of BFA or its affiliates or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond ETF into consideration in determining, composing or calculating the underlying index. Markit is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond ETF, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond ETF are to be converted into cash. Markit has no obligation or liability in connection with the administration, marketing or trading of shares of the iShares iBoxx $ High Yield Corporate Bond ETF. Markit does not guarantee the accuracy or the completeness of the underlying index or any data included therein and Markit shall have no liability for any errors, omissions, or interruptions therein.

Markit makes no warranty, express or implied, as to results to be obtained by BFA or its affiliates, owners of shares of the iShares iBoxx $ High Yield Corporate Bond ETF or any other person or entity from the use of the underlying index or any data included therein. Markit makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the underlying index or any data included therein. Without limiting any of the foregoing, in no event shall Markit have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the underlying index or any data included therein, even if notified of the possibility of such damages.

The iShares J.P. Morgan USD Emerging Markets Bond ETF is not sponsored, endorsed, sold or promoted by J.P. Morgan. J.P. Morgan makes no representation or warranty, express or implied, to the owners of shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF or any member of the

47

public regarding the advisability of investing in securities generally or in the iShares J.P. Morgan USD Emerging Markets Bond ETF in particular, or the ability of the underlying index to track general market performance. J.P. Morgan's only relationship to the Trust and BFA or its affiliates is the licensing of certain trademarks and trade names of J.P. Morgan and of the underlying index which is determined, composed and calculated by J.P. Morgan without regard to the Trust, BFA or its affiliates or the iShares J.P. Morgan USD Emerging Markets Bond ETF. J.P. Morgan has no obligation to take the needs of BFA or its affiliates or the owners of shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF into consideration in determining, composing or calculating the underlying index. J.P. Morgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF are to be converted into cash. J.P. Morgan has no obligation or liability in connection with the administration, marketing or trading of shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF. J.P. Morgan does not guarantee the accuracy or the completeness of the underlying index or any data included therein and J.P. Morgan shall have no liability for any errors, omissions or interruptions therein.

J.P. Morgan makes no warranty, express or implied, as to results to be obtained by BFA or its affiliates, owners of shares of the iShares J.P. Morgan USD Emerging Markets Bond ETF or any other person or entity from the use of the underlying index or any data included therein. J.P. Morgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the underlying index or any data included therein. Without limiting any of the foregoing, in no event shall J.P. Morgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the underlying index or any data included therein, even if notified of the possibility of such damages.

The Fund is not sponsored, endorsed, sold or promoted by Morningstar. Morningstar makes no representation or warranty, express or implied, to the owners of shares of the Fund or any member of the public regarding the advisability of investing in securities generally or in the Fund in particular, or the ability of the Underlying Index to track general market performance. Morningstar’s only relationship to the Trust and BFA or its affiliates is the licensing of certain trademarks and trade names of Morningstar and of the Underlying Index which is determined, composed and calculated by Morningstar without regard to the Trust, BFA or its affiliates or the Fund. Morningstar has no obligation to take the needs of BFA or its affiliates or the owners of shares of the Fund into consideration in determining, composing or calculating the Underlying Index. Morningstar is not responsible for and has not participated in the determination of the prices and amount of shares of the Fund, or the timing of the issuance or sale of such shares or in the

48

determination or calculation of the equation by which shares of the Fund are to be converted into cash. Morningstar has no obligation or liability in connection with the administration, marketing or trading of shares of the Fund. Morningstar does not guarantee the accuracy or the completeness of the Underlying Index or any data included therein and Morningstar shall have no liability for any errors, omissions or interruptions therein.Morningstar makes no warranty, express or implied, as to results to be obtained by BFA or its affiliates, owners of shares of the Fund or any other person or entity from the use of the Underlying Index or any data included therein. Morningstar makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Index or any data included therein. Without limiting any of the foregoing, in no event shall Morningstar have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Index or any data included therein, even if notified of the possibility of such damages.

Shares of the Fund are not sponsored, endorsed or promoted by NYSE Arca. NYSE Arca makes no representation or warranty, express or implied, to the owners of shares of the Fund or any member of the public regarding the ability of the Fund to track the total return performance of the Underlying Index or the ability of the Underlying Index to track market performance. NYSE Arca is not responsible for, nor has it participated in, the determination of the compilation or the calculation of the Underlying Index, nor in the determination of the timing of, prices of, or quantities of shares of the Fund to be issued, nor in the determination or calculation of the equation by which the shares are redeemable. NYSE Arca has no obligation or liability to owners of the shares of the Fund in connection with the administration, marketing or trading of shares of the Fund.

NYSE Arca does not guarantee the accuracy and/or the completeness of the Underlying Index or any data included therein. NYSE Arca makes no warranty, express or implied, as to results to be obtained by the Trust on behalf of the Fund as licensee, licensee’s customers and counterparties, owners of shares of the Fund, or any other person or entity from the use of the Underlying Index or any data included therein in connection with the rights licensed as described herein or for any other use.

NYSE Arca makes no express or implied warranties and hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the Underlying Index or any data included therein. Without limiting any of the foregoing, in no event shall NYSE Arca have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The past performance of the Underlying Index is not a guide to future performance. BFA and its affiliates do not guarantee the accuracy or the completeness of the Underlying Index or any data included therein and BFA and its affiliates shall have no liability for any errors, omissions or

49

interruptions therein. BFA and its affiliates make no warranty, express or implied, to the owners of shares of the Fund or to any other person or entity, as to results to be obtained by the Fund from the use of the Underlying Index or any data included therein. Without limiting any of the foregoing, in no event shall BFA or its affiliates have any liability for any special, punitive, direct, indirect, consequential or any other damages (including lost profits), even if notified of the possibility of such damages.

50

     

[THIS PAGE INTENTIONALLY LEFT BLANK]

[THIS PAGE INTENTIONALLY LEFT BLANK]

Want to know more?

iShares.com     |    1-800-474-2737

Information on the Fund’s net asset value, market price, premiums and discounts, and bid-ask spreads can be found at www.iShares.com. Copies of the Prospectus, SAI and recent shareholder reports can be found on our website at www.iShares.com. For more information about the Fund, you may request a copy of the SAI. The SAI provides detailed information about the Fund and is incorporated by reference into this Prospectus. This means that the SAI, for legal purposes, is a part of this Prospectus.

Additional information about the Fund's investments is available in the Fund's Annual and Semi-Annual Reports to shareholders. In the Fund's Annual Report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund's performance during the last fiscal year.

If you have any questions about the Trust or shares of the Fund or you wish to obtain the SAI, Semi-Annual or Annual Report free of charge, please:

Call:	1-800-iShares or 1-800-474-2737 (toll free) Monday through Friday, 8:30 a.m. to 6:30 p.m. (Eastern time)
Email:	[email protected]
Write:	c/o BlackRock Investments, LLC 1 University Square Drive, Princeton, NJ 08540

Reports and other information about the Fund are available on the EDGAR database on the SEC's website at www.sec.gov, and copies of this information may be obtained, after paying a duplicating fee, by electronic request at the following e-mail address: [email protected].

No person is authorized to give any information or to make any representations about the Fund and its shares not contained in this Prospectus and you should not rely on any other information. Read and keep this Prospectus for future reference.

©2022 BlackRock, Inc. All rights reserved. iSHARES^® and BLACKROCK^® are registered trademarks of BFA and its affiliates. All other marks are the property of their respective owners.

Investment Company Act File No.: 811-09729

IS-P-BYLD-0322