The Fund is a money market fund whose investment objective is to seek a high level of current income consistent with preserving principal and liquidity and maintaining a stable $1.00 per share net asset value. It invests primarily in short-term U.S. Treasury obligations and repurchase agreements collateralized by such obligations, generally investing through a master-feeder structure in the State Street Treasury Money Market Portfolio. TRIXX is the fund's Premier Class of shares; the same fund also offers Institutional, Administration, Investment, Investor, and Opportunity share classes, each with different fee structures and minimum investment requirements, all representing interests in the same underlying portfolio.