Fidelity U.S. Bond Index Fund (FXNAX)

Fidelity U.S. Bond Index Fund is an open-end mutual fund designed to track the performance of the Bloomberg U.S. Aggregate Bond Index. Its primary purpose is to mirror the aggregate price and yield performance of U.S.-dollar-denominated investment-grade fixed-rate debt securities. The fund invests at least 80% of its assets in bonds from its benchmark, using statistical sampling to closely replicate index characteristics across duration, maturity, interest rate sensitivity, and credit quality. Its holdings are broadly diversified among U.S. government, corporate, mortgage-backed, and asset-backed securities, giving investors exposure to the core of the U.S. bond market. As an intermediate core bond fund, it provides moderate interest rate sensitivity and high overall credit quality, with AAA-rated bonds comprising a large share of assets. Known for its low expense ratio and cost efficiency, the fund plays a key role for investors seeking broad, low-cost exposure to the U.S. fixed income market—supporting strategies in portfolio diversification, income generation, and risk management for both individual and institutional participants.