The iShares Total U.S. Stock Market Index Fund - Institutional (BITSX) is a mutual fund that aims to provide investors with broad exposure to the entire U.S. stock market. This fund is designed for institutional investors, such as large corporations or pension funds, and seeks to track the performance of the total U.S. stock market by investing in a diverse range of stocks across all sectors and market capitalizations. With a low expense ratio and a focus on long-term growth, BITSX offers a convenient and cost-effective way for institutional investors to gain exposure to the U.S. stock market.