Fund Description: Fidelity Low Duration Bond Factor ETF is an exchange-traded index fund or Index ETF which is a separate investment portfolio of the Fidelity Merrimack Street Trust, an open-end investment management company. INVESTMENT OBJECTIVE: The Fidelity Low Duration Bond Factor ETF seeks to provide investment returns that correspond, before fees and expenses, generally to the performance of the Fidelity Low Duration Investment Grade Factor Index. INDEX DESCRIPTION: The Fidelity Low Duration Investment Grade Factor 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. Normally maintaining a duration of 1 year or less. FUND STRATEGY: The Fund normally invests at least 80% of assets in securities included in the Index. The Fund uses statistical sampling techniques based on duration, maturity, interest rate sensitivity, security structure, and credit quality to attempt to replicate the returns of the Index using a smaller number of securities. The Fund lends securities to earn income for the fund. FUND MANAGEMENT: Fidelity Investments Money Management, Inc. (FIMM) (the Adviser), an affiliate of Fidelity Management & Research Company (FMR), is the fund's manager. Other investment advisers serve as sub-advisers for the fund.