iShares iBoxx USD High Yield Corporate Bond ETF (HYG) Exchange: NYSE ARCA

The Fund seeks to track the investment results of the Markit iBoxx® USD Liquid High Yield Index (the “Underlying Index”), which is a rules-based index consisting of U.S. dollar-denominated, high yield (as determined by Markit Indices Limited (the “Index Provider” or “Markit”)) corporate bonds for sale in the U.S. The Underlying Index is designed to provide a broad representation of the U.S. dollar-denominated liquid high yield corporate bond market. The Underlying 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 Underlying Index. As of February 29, 2020, the Underlying Index included approximately 994 constituents. As of February 29, 2020, a significant portion of the Underlying Index is represented by securities of companies in the consumer services industry or sector. The components of the Underlying Index are likely to change over time.Bonds in the Underlying 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 this prospectus (the “Prospectus”), the bonds eligible for inclusion in the Underlying 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 Ratings, Inc. (“Fitch”), Moody's Investors Service, Inc. (“Moody's”) or Standard & Poor's® Global Ratings, a subsidiary of S&P Global (“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.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 security selection. 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 that collectively has an investment profile similar to that of an applicable underlying index. The securities 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 in the Underlying Index.The Fund generally will invest at least 90% of its assets in the component securities of the Underlying Index and may invest up to 10% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates (“BlackRock Cash Funds”), as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. From time to time when conditions warrant, however, the Fund may invest at least 80% of its assets in the component securities of the Underlying Index and may invest up to 20% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of BlackRock Cash Funds, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund.The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of any collateral received).The Underlying Index is sponsored by Markit, 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.Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.