The Vanguard Short-Term Treasury Index Fund Admiral Shares (VSBSX) is a mutual fund that invests in a diverse portfolio of short-term US Treasury securities. This fund aims to provide investors with a low-risk investment option that offers stability and potential for modest returns. As an "Admiral Shares" fund, it is designed for larger investors and offers lower expense ratios compared to other share classes. With a focus on short-term Treasury securities, this fund may be suitable for investors seeking a conservative investment strategy or looking to diversify their portfolio.