This fund aims to replicate the overall performance, encompassing both price appreciation and interest income, of the debt securities included in the Bloomberg U.S. Aggregate Bond Index. Typically, at least 80% of the fund's total assets are dedicated to these specific debt instruments. To achieve efficient index mirroring with a more concentrated portfolio of holdings, the advisor employs statistical sampling. This analytical approach evaluates factors such as bond duration, maturity, interest rate sensitivity, security structure, and credit quality. Furthermore, the fund allocates a portion of its investments to Fidelity's proprietary central funds.