Strategy. The Fund seeks to track the investment results of the S&P 100 (the Underlying Index ), which measures the performance of the large-capitalization sector of the U.S. equity market. It is a subset of the S&P 500 (the Parent Index ) and consists of blue chip stocks from a diverse range of industries in the Parent Index with exchange listed options. As of March 31, 2025, the Underlying Index represented approximately 50.14% of the market capitalization of U.S. equities. As of March 31, 2025, stocks must have a market capitalization of at least $20.5 billion for initial inclusion in the Parent Index; this threshold and constituents' market capitalization may fluctuate depending on the overall level of the equity markets. As … Show more… The Fund seeks to track the investment results of the S&P 100 (the Underlying Index ), which measures the performance of the large-capitalization sector of the U.S. equity market. It is a subset of the S&P 500 (the Parent Index ) and consists of blue chip stocks from a diverse range of industries in the Parent Index with exchange listed options. As of March 31, 2025, the Underlying Index represented approximately 50.14% of the market capitalization of U.S. equities. As of March 31, 2025, stocks must have a market capitalization of at least $20.5 billion for initial inclusion in the Parent Index; this threshold and constituents' market capitalization may fluctuate depending on the overall level of the equity markets. As of March 31, 2025, a significant portion of the Underlying Index is represented by securities of companies in the technology industry or sector. The components of the Underlying Index are likely to change over time. BFA uses an indexing approach to try to achieve the Funds investment objective. 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 capitalization and industry weightings), fundamental characteristics (such as return variability 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 80% of its assets in the component securities of its 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 money market funds advised by BFA or its affiliates, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. Cash and cash equivalent investments associated with a derivative position will be treated as part of that position for the purposes of calculating the percentage of investments included in 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 a product of S&P Dow Jones Indices LLC (the Index Provider or SPDJI ), 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) and repurchase agreements collateralized by U.S. government securities are not considered to be issued by members of any industry. Diversification Policy. The Fund intends to be diversified in approximately the same proportion as the Underlying Index is diversified. The Fund may become non-diversified, as defined in the Investment Company Act of 1940 (the 1940 Act ), solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the Underlying Index. Shareholder approval will not be sought if the Fund becomes non-diversified due solely to a change in the relative market capitalization or index weighting of one or more constituents of the Underlying Index. The Fund discloses its portfolio holdings and weightings at www.iShares.com. Show less