The investment seeks to provide investment returns that correspond, before fees and expenses, generally to the performance of the Fidelity Low Duration Investment Grade Factor Index¿. The fund normally invests at least 80% of assets in securities included in the index. The index is designed to optimize the balance of interest rate risk and credit risk such that both returns and risk measures may be improved relative to traditional U.S. investment grade floating rate note indices. The index is comprised solely of U.S. investment grade floating rate notes and U.S. Treasury notes.