IMPORTANT NOTICE REGARDING CHANGE IN INVESTMENT POLICY

iShares^®

iShares U.S. ETF Trust

Supplement dated December 22, 2020 (the “Supplement”)

to the Summary Prospectus dated September 2, 2020, Prospectus dated August 24, 2020, and the Statement of Additional Information (the “SAI”) dated August 24, 2020 for the iShares Commodity Curve Carry Strategy ETF (CCRV) (the “Fund”)

The information in this Supplement updates information in, and should be read in conjunction with, the Summary Prospectus, Prospectus, and the SAI for the Fund.

The following changes will take effect for the Fund on or around March 1, 2021:

Current Investment Objective	New Investment Objective
The iShares Commodity Curve Carry Strategy ETF seeks to provide exposure to a select group of commodities that exhibit higher roll yields, on a total return basis, than a broad group of commodities.	The iShares Commodity Curve Carry Strategy ETF seeks to track the investment results of an index composed of commodities with the top ten highest ranking roll yields, on a total return basis, selected from a broad commodity universe.

In connection with this change, all references in the Summary Prospectus, Prospectus, and SAI to the “Reference Benchmark” or “benchmark” are replaced with “Underlying Index”.

Changes in the Fund’s “Principal Investment Strategies”

The first three paragraphs of the section of the Summary Prospectus and Prospectus entitled “Principal Investment Strategies” shall be deleted in their entirety and replaced with the following:

The Fund seeks to track the investment results of the ICE BofA Commodity Enhanced Carry Total Return Index (the “Underlying Index”), which measures the performance of the 10 futures contracts having the highest degree of backwardation or lowest degree of contango (as explained below) among a universe of 18 futures contracts on physical agricultural, energy, precious metals, and

industrial metals commodities listed on U.S. and non-U.S. futures exchanges futures contracts, as determined by ICE Data Indices, LLC or its affiliates (collectively “Index Provider” or “IDI”). The Underlying Index is rebalanced on a monthly basis. The Fund seeks to achieve its investment objective primarily by investing in total return swaps that provide exposure to commodity futures contracts referenced in the Underlying Index.

The Fund, through its Subsidiary (as defined below) will invest in financial instruments that provide exposure to commodities, and not in the physical commodities themselves. Although the Fund reserves the right to invest in a broad range of financial instruments, the Fund expects to obtain a substantial amount of its exposure to the investment results of the Underlying Index by entering into total return swaps that provide returns similar to the commodity futures contracts referenced in the Underlying Index.

After the fifth paragraph of the section of the Summary Prospectus and Prospectus entitled “Principal Investment Strategies,” the following paragraphs are added:

BFA uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued.

Indexing may eliminate the chance that the Fund will substantially outperform the Underlying Index but also may reduce some of the risks of active management, such as poor selection of securities and/or other instruments. Indexing seeks to achieve lower costs and better after-tax performance by aiming to keep portfolio turnover low in comparison to actively managed investment companies.

BFA uses a representative sampling indexing strategy to manage the Fund. “Representative sampling” is an indexing strategy that involves investing in a representative sample of securities and/or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The securities and/or other instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration, maturity, credit ratings and yield) and liquidity measures similar to those of an applicable underlying index. The Fund may or may not hold all of the securities and/or other instruments in the Underlying Index.

The seventh paragraph of the section of the Summary Prospectus and Prospectus entitled “Principal Investment Strategies” shall be deleted in its entirety.

After the last paragraph of the section of the Summary Prospectus and Prospectus entitled “Principal Investment Strategies,” the following paragraph is added:

The Underlying Index is sponsored by IDI, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of the Underlying Index.

Changes in the “Summary of Principal Risks”

The first paragraph of the section of the Summary Prospectus and Prospectus entitled “Summary of Principal Risks” is deleted in its entirety and replaced with the following:

As with any investment, you could lose all or part of your investment in the Fund, and the Fund’s performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund’s net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. The order of the below risk factors does not indicate the significance of any particular risk factor.

The section of the Summary Prospectus and Prospectus entitled “Management Risk” is deleted in its entirety and replaced with the following:

Management Risk. As the Fund may not fully replicate the Underlying Index, it is subject to the risk that BFA’s investment strategy may not produce the intended results.

The section of the Summary Prospectus and Prospectus entitled “Summary of Principal Risks” is updated to add the following:

Index-Related Risk. There is no guarantee that the Fund’s investment results will have a high degree of correlation to those of the Underlying Index or that the Fund will achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the Fund’s ability to adjust its exposure to the required levels in order to track the Underlying Index. Errors in index data, index computations or the construction of the Underlying Index in accordance with its

methodology 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, which may have an adverse impact on the Fund and its shareholders. Unusual market conditions may cause the Index Provider to postpone a scheduled rebalance, which could cause the Underlying Index to vary from its normal or expected composition.

Passive Investment Risk. The Fund is not actively managed, and BFA generally does not attempt to take defensive positions under any market conditions, including declining markets.

Tracking Error Risk. The Fund may be subject to tracking error, which is the divergence of the Fund’s performance from that of the Underlying Index. Tracking error may occur because of differences between the securities and other instruments held in the Fund’s portfolio and those included in the Underlying Index, pricing differences (including, as applicable, differences between a security’s price at the local market close and the Fund’s valuation of a security at the time of calculation of the Fund’s NAV), transaction costs incurred by the Fund, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of distributions, 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 (as applicable), changes to the Underlying Index or the costs to the Fund of complying with various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the Fund incurs fees and expenses, while the Underlying Index does not. INDEX EXCHANGE TRADED FUNDS (“ETFs”) THAT TRACK INDICES WITH SIGNIFICANT WEIGHT IN FUTURES CONTRACTS MAY EXPERIENCE HIGHER TRACKING ERROR THAN OTHER INDEX ETFs THAT DO NOT TRACK SUCH INDICES.

Changes in “More Information About the Fund”

The second paragraph of the section of the Prospectus entitled “More Information About the Fund” is deleted in its entirety and replaced with the following:

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.

The fourth paragraph of the section of the Prospectus entitled “More Information About the Fund” is deleted in its entirety.

The sub-sections “Additional Information on Principal Investment Strategies” and “Investment Process” of the section of the Prospectus entitled “More Information About the Fund” are deleted in their entirety and replaced with the following:

The Fund invests in a particular segment of the financial markets and seeks to track the performance of an index that is not representative of the market as a whole. The Fund is designed to be used as part of broader asset allocation strategies. Accordingly, an investment in the Fund should not constitute a complete investment program.

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 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. Because 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.

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

Changes in “A Further Discussion of Principal Risks”

The section of the Prospectus entitled “Management Risk” is deleted in its entirety and replaced with the following:

Management Risk. Because BFA uses a representative sampling indexing strategy, the Fund may 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 section of the Prospectus entitled “A Further Discussion of Principal Risks” is updated to add the following:

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. 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, which could cause the Underlying Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, 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 in order, 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.

Passive Investment Risk. The Fund is not actively managed and may be affected by a general decline in market segments related to the Underlying Index. The Fund invests in securities included in, or representative of, the 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.

Tracking Error Risk. The Fund may be subject to tracking error, which is the divergence of the Fund’s performance from that of the Underlying Index. Tracking error may occur because of differences between the securities and other instruments held in the Fund’s portfolio and those included in the Underlying Index, pricing differences (including, as applicable, differences between a security’s price at the local market close and the Fund’s valuation of a security at the time of calculation of the Fund’s NAV), transaction costs incurred by the Fund, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of distributions, 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 Underlying Index or the costs to the Fund of complying with various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or

other unusual market conditions. Tracking error also may result because the Fund incurs fees and expenses, while the Underlying Index does not. INDEX ETFs THAT TRACK INDICES WITH SIGNIFICANT WEIGHT IN FUTURES CONTRACTS MAY EXPERIENCE HIGHER TRACKING ERROR THAN OTHER INDEX ETFs THAT DO NOT TRACK SUCH INDICES.

Change in “General Description of the Trust and the Fund”

The second paragraph of the section of the SAI entitled “General Description of the Trust and the Fund” shall be deleted in its entirety and replaced by the following:

The Fund is managed by BlackRock Fund Advisors (“BFA”), an indirect wholly-owned subsidiary of BlackRock, Inc., and generally seeks to track the investment results of the specific benchmark index identified in the Fund’s Prospectus (the “Underlying Index”).

Changes in “Investment Strategies and Risks”

The first paragraph of the section of the SAI entitled “Investment Strategies and Risks” shall be deleted in its entirety and replaced by the following:

The Fund seeks to achieve its investment objective primarily by investing in total return swaps that provide exposure to commodities futures contracts referenced by the Underlying Index. The Fund operates as an index fund and is not actively managed. Adverse performance of an instrument in the Fund’s portfolio will ordinarily not result in the elimination of the instrument from the Fund’s portfolio.

The Fund engages in representative sampling, which is investing in a sample of securities and/or other instruments selected by BFA to have a collective investment profile similar to that of the Fund’s Underlying Index. Securities and/or other instruments selected have aggregate investment characteristics (based on market capitalization value and industry weightings), fundamental characteristics (such as yield, credit rating, maturity and duration) and liquidity measures similar to those of the Fund’s Underlying Index. A fund that uses representative sampling generally does not hold all of the securities and/or other instruments that are in its underlying index.

The seventh paragraph of the section of the SAI entitled “Investment Strategies and Risks” shall be deleted in its entirety.

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

iShares^® is a registered trademark of BlackRock Fund Advisors and its affiliates.

IS-A-CCRV-1220

PLEASE RETAIN THIS SUPPLEMENT

FOR FUTURE REFERENCE