iShares^®

iShares, Inc.

iShares Trust

iShares U.S. ETF Trust

Supplement dated May 3, 2021 (the “Supplement”)

to the Prospectus (the “Prospectus”)

and Statement of Additional Information (“SAI”)

for each of the Funds listed below (each, a “Fund”)

The information in this Supplement updates information in, and should be read in conjunction with, each Fund’s Prospectus and SAI.

Change in each Fund’s “Shareholder Information”

The paragraphs entitled “Determination of Net Asset Value” of the section of the Prospectus entitled “Shareholder Information” for each of the Funds in Appendix A shall be deleted in its entirety and replaced with the following:

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 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 are determined pursuant to valuation policies and procedures approved by the Board.

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 BlackRock 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 business on 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 BlackRock to be unreliable, the Fund’s investments are valued at fair value. Fair value determinations are made by BlackRock in accordance with policies and procedures approved by the Board. BlackRock 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 BlackRock 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 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.

The paragraphs entitled “Determination of Net Asset Value” of the section of the Prospectus entitled “Shareholder Information” for each of the Funds in Appendix B shall be deleted in its entirety and replaced with the following:

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

Generally, trading in non-U.S. securities and money market instruments is substantially completed each day at various times prior to the close of business on 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 BlackRock to be unreliable, the Fund’s investments are valued at fair value. Fair value determinations are made by BlackRock in accordance with policies and procedures approved by the Board. BlackRock 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 BlackRock 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 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.

Change in each Fund’s “Determination of Net Asset Value”

The section entitled “Determination of Net Asset Value” of the SAI for each of the Funds shall be deleted in its entirety and replaced with the following:

Determination of Net Asset Value

Valuation of Shares. The NAV for each Fund is generally calculated as of the close of regular trading hours on the New York Stock Exchange (“NYSE”) NYSE (currently 4:00 p.m. Eastern Time) on each business day the NYSE is open. Valuation of assets held by a Fund is as follows:

Equity Investments. Equity securities traded on a recognized securities exchange (e.g., NYSE), on separate trading boards of a securities exchange or through a market system that provides contemporaneous transaction pricing information (each an “Exchange”) are valued using information obtained via independent pricing services, generally at the closing price or if an Exchange closing price is not available, the last traded price on that Exchange prior to the time as of which the assets or liabilities are valued. However, under certain circumstances, other means of determining current market value may be used. If an equity security is traded on more than one Exchange, the current market value

of the security where it is primarily traded generally will be used. In the event that there are no sales involving an equity security held by a Fund on a day on which a Fund values such security, the prior day’s price will be used, unless BlackRock determines that such prior day’s price no longer reflects the fair value of the security, in which case such asset would be treated as a Fair Valued Asset (as defined below).

Fixed-Income Investments. Fixed-income securities for which market quotations are readily available are generally valued using such securities’ current market value. A Fund values fixed-income portfolio securities using the 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 the policies and procedures approved by the Funds’ Board (the “Valuation Procedures”). The pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values, including transaction data (e.g., recent representative bids and offers), credit quality information, perceived market movements, news, and other relevant information and by other methods, which may include consideration of: yields or prices of securities of comparable quality, coupon, maturity and type; indications as to values from dealers; general market conditions; and/or other factors and assumptions. 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 may trade at lower prices than institutional round lots. The amortized cost method of valuation may be used with respect to debt obligations with 60 days or less remaining to maturity unless such method does not represent fair value. Certain fixed-income investments, including asset-backed and mortgage related securities, may be valued based on valuation models that consider the estimated cash flows of each tranche of the issuer, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche.

Options, Futures, Swaps and Other Derivatives. Exchange-traded equity options for which market quotations are readily available are valued at the mean of the last bid and ask prices as quoted on the Exchange or the board of trade on which such options are traded. In the event that there is no mean price available for an exchange traded equity option held by a Fund on a day on which the Fund values such option, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such option. If no bid or ask price

is available on a day on which a Fund values such option, the prior day’s price will be used, unless BlackRock determines that such prior day’s price no longer reflects the fair value of the option, in which case such option will be treated as a fair value asset. OTC derivatives may be valued using a mathematical model which may incorporate a number of market data factors. Financial futures contracts and options thereon, which are traded on exchanges, are valued at their last sale price or settle price as of the close of such exchanges. Swap agreements and other derivatives are generally valued daily based upon quotations from market makers or by a pricing service in accordance with the Valuation Procedures.

Underlying Funds. Shares of underlying open-end funds (including money market funds) are valued at NAV. Shares of underlying exchange-traded closed-end funds or other ETFs will be valued at their most recent closing price.

General Valuation Information

Prices obtained from independent third-party pricing services, broker-dealers or market makers to value each Fund’s securities and other assets and liabilities are based on information available at the time the Fund values its assets and liabilities. In the event that a pricing service quotation is revised or updated subsequent to the day on which the Fund valued such security, the revised pricing service quotation generally will be applied prospectively. Such determination will be made considering pertinent facts and circumstances surrounding the revision.

The price the Fund could receive upon the sale of any particular portfolio investment may differ from the Fund’s valuation of the investment, particularly for assets that trade in thin or volatile markets or that are valued using a fair valuation methodology or a price provided by an independent pricing service. As a result, the price received upon the sale of an investment may be less than the value ascribed by the Fund, and the Fund could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. The Fund’s ability to value its investment may also be impacted by technological issues and/or errors by pricing services or other third-party service providers.

All cash, receivables and current payables are carried on a Fund’s books at their fair value.

In the event that application of the methods of valuation discussed above result in a price for a security which is deemed not to be representative of the fair market value of such security, the security will

be valued by, under the direction of or in accordance with a method approved by the Fund’s Board as reflecting fair value. All other assets and liabilities (including securities for which market quotations are not readily available) held by a Fund (including restricted securities) are valued at fair value as determined in good faith by the Board or BlackRock’s Valuation Committee (the “Valuation Committee”) (its delegate) pursuant to the Valuation Procedures. Any assets and liabilities which are denominated in a foreign currency are translated into U.S. dollars at the prevailing market rates.

Use of fair value prices and certain current market valuations could result in a difference between the prices used to calculate a Fund’s NAV and the prices used in its Underlying Index, which, in turn, could result in a difference between a Fund’s performance and the performance of its Underlying Index.

Fair Value. When market quotations are not readily available or are believed by BlackRock to be unreliable, a Fund’s investments are valued at fair value (“Fair Value Assets”). Fair Value Assets are valued by BlackRock in accordance with the Valuation Procedures. BlackRock may reasonably conclude that a market quotation is not readily available or is unreliable if, among other things, a security or other asset or liability does not have a price source due to its complete lack of trading, if BlackRock believes a market quotation from a broker-dealer or other source is unreliable (e.g., where it varies significantly from a recent trade, or no longer reflects the fair value of the security or other asset or liability subsequent to the most recent market quotation), or where the security or other asset or liability is only thinly traded or due to the occurrence of a significant event subsequent to the most recent market quotation. For this purpose, a “significant event” is deemed to occur if BlackRock determines, in its reasonable business judgment, that an event has occurred after the close of trading for an asset or liability but prior to or at the time of pricing a Fund’s assets or liabilities, is likely to cause a material change to the last exchange closing price or closing market price of one or more assets or liabilities held by the Fund. On any day the NYSE is open and a foreign market or the primary exchange on which a foreign asset or liability is traded is closed, such asset or liability will be valued using the prior day’s price, provided that BlackRock is not aware of any significant event or other information that would cause such price to no longer reflect the fair value of the asset or liability, in which case such asset or liability would be treated as a Fair Value Asset.

BlackRock, with input from portfolio management, will submit its recommendations regarding the valuation and/or valuation

methodologies for Fair Value Assets to the Valuation Committee. The Valuation Committee may accept, modify or reject any recommendations. In addition, the Funds’ accounting agent periodically endeavors to confirm the prices it receives from all third-party pricing services, index providers and broker-dealers, and, with the assistance of BlackRock, to regularly evaluate the values assigned to the securities and other assets and liabilities of the Funds. The pricing of all Fair Value Assets is subsequently reported to the Board or a committee thereof.

When determining the price for a Fair Value Asset, the Valuation Committee will seek to determine the price that a Fund might reasonably expect to receive from the current sale of that asset or liability in an arm’s-length transaction on the date on which the asset or liability is being valued, and does not seek to determine the price a Fund might reasonably expect to receive for selling an asset or liability at a later time or if it holds the asset or liability to maturity. Fair value determinations will be based upon all available factors that the Valuation Committee deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third-party valuation models.

Fair value represents a good faith approximation of the value of an asset or liability. When determining the fair value of an investment, one or more fair value methodologies may be used (depending on certain factors, including the asset type). For example, the investment may be initially priced based on the original cost of the investment or, alternatively, using proprietary or third-party models that may rely upon one or more unobservable inputs. Prices of actual, executed or historical transactions in the relevant investment (or comparable instruments) or, where appropriate, an appraisal by a third-party experienced in the valuation of similar instruments, may also be used as a basis for establishing the fair value of an investment.

The fair value of one or more assets or liabilities may not, in retrospect, be the price at which those assets or liabilities could have been sold during the period in which the particular fair values were used in determining a Fund’s NAV. As a result, a Fund’s sale or redemption of its shares at NAV, at a time when a holding or holdings are valued at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

Each Fund’s annual audited financial statements, which are prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”), follow the requirements for valuation set forth in Financial Accounting Standards Board Accounting

Standards Codification Topic 820, “Fair Value Measurements and Disclosures” (“ASC 820”), which defines and establishes a framework for measuring fair value under US GAAP and expands financial statement disclosure requirements relating to fair value measurements.

Generally, ASC 820 and other accounting rules applicable to funds and various assets in which they invest are evolving. Such changes may adversely affect a Fund. For example, the evolution of rules governing the determination of the fair market value of assets or liabilities, to the extent such rules become more stringent, would tend to increase the cost and/or reduce the availability of third-party determinations of fair market value. This may in turn increase the costs associated with selling assets or affect their liquidity due to a Fund’s inability to obtain a third-party determination of fair market value. The SEC recently adopted new Rule 2a-5 under the 1940 Act, which will establish an updated regulatory framework for registered investment company valuation practices and may impact the Fund’s valuation policies. The Fund will not be required to comply with the new rule until September 8, 2022.

iShares Funds

Appendix A

Supplement to the Prospectus dated as of June 29, 2020 (as revised August 17, 2020) and to the Statement of Additional Information dated as of June 29, 2020 (as revised April 1, 2021):

iShares ESG Aware 1-5 Year USD Corporate Bond ETF

iShares ESG Aware USD Corporate Bond ETF

Supplement to the Prospectus and the Statement of Additional Information both dated as of March 1, 2021:

iShares Bloomberg Roll Select Commodity Strategy ETF

iShares Commodity Curve Carry Strategy ETF

iShares GSCI Commodity Dynamic Roll Strategy ETF

iShares Gold Strategy ETF

iShares International High Yield Bond ETF

iShares J.P. Morgan EM Corporate Bond ETF

iShares J.P. Morgan EM Local Currency Bond ETF

iShares US & Intl High Yield Corp Bond ETF

iShares Yield Optimized Bond ETF

Supplement to the Prospectus dated as of March 1, 2021 and to the Statement of Additional Information dated as of March 1, 2021 (as revised April 1, 2021):

iShares 0-5 Year Investment Grade Corporate Bond ETF

iShares 1-3 Year International Treasury Bond ETF

iShares Aaa-A Rated Corporate Bond ETF

iShares Core International Aggregate Bond ETF

iShares Fallen Angels USD Bond ETF

iShares Global Green Bond ETF

iShares International Treasury Bond ETF

iShares J.P. Morgan USD Emerging Markets Bond ETF

Supplement to the Prospectus and the Statement of Additional Information both dated as of March 1, 2021 (as revised April 1, 2021):

iShares Floating Rate Bond ETF

Supplement to the Prospectus dated as of March 1, 2021 and to the Statement of Additional Information dated as of March 1, 2021 (as revised April 27, 2021):

BlackRock Short Maturity Bond ETF

Supplement to the Prospectus and the Statement of Additional Information both dated as of March 1, 2021 (as revised April 27, 2021):

BlackRock Ultra Short-Term Bond ETF

Appendix B

Supplement to the Prospectus and the Statement of Additional Information both dated as of December 1, 2020:

iShares Core Aggressive Allocation ETF

iShares Core Conservative Allocation ETF

iShares Core Growth Allocation ETF

iShares Core Moderate Allocation ETF

iShares ESG Aware Aggressive Allocation ETF

iShares ESG Aware Conservative Allocation ETF

iShares ESG Aware Growth Allocation ETF

iShares ESG Aware Moderate Allocation ETF

iShares Morningstar Multi-Asset Income ETF

If you have any questions, please call 1-800-iShares (1-800-474-2737)

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