Fidelity Treasury Only Money Market Fund (FDLXX), managed by Fidelity Investments, operates as a money market mutual fund that seeks as high a level of current income as is consistent with the security of principal and liquidity. The fund normally invests at least 99.5% of its total assets in cash, U.S. Treasury securities, and repurchase agreements collateralized by such securities; at least 80% of assets are allocated to U.S. Treasury securities whose interest is exempt from state and local income taxes; and it maintains compliance with industry-standard regulatory requirements for money market funds regarding quality, maturity, liquidity, and diversification. Assets under management stand at approximately $14.7 billion, with a gross expense ratio of 0.42%, a 7-day yield around 3.89%, and a stable net asset value (NAV) of $1.00.
Established in 1988 and headquartered in Boston, Massachusetts as part of Fidelity Hereford Street Trust, the fund serves institutional and retail investors seeking low-risk, liquid cash management solutions within the taxable money market category.
In September 2025, Fidelity Investments launched a tokenized version of its Treasury money market fund on the Ethereum blockchain, introducing Fidelity Digital Interest Tokens (FDIT) backed by U.S. Treasury bills as part of the firm's expansion into blockchain-based assets amid the growing $7.5 billion tokenized U.S. Treasuries market.