Cash Reserve [Member] Investment Strategy - CASH RESERVE - BLACKROCK SELECT TREASURY BASED LIQUIDITY FUND

Oct. 31, 2025

Prospectus [Line Items]

Strategy [Heading]

Principal Investment Strategies of the Fund

Strategy Narrative [Text Block]

BlackRock Select Treasury Based Liquidity Fund invests 100% of its total assets in cash, U.S. Treasury bills, notes and other obligations issued or guaranteed as to principal and interest by the U.S. Treasury (collectively, “Treasury Instruments”), with a maturity of 93 days or less, and overnight repurchase agreements that purchase Treasury Instruments. The Fund’s portfolio will have a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less. The Fund may transact in securities on a when-issued, delayed delivery or forward commitment basis.

The Fund will invest, under normal circumstances, at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in U.S. Treasury bills, notes and other obligations of the U.S. Treasury, and repurchase agreements secured by such obligations. This policy is a non-fundamental policy of the Fund and the Fund will not change the policy without providing shareholders with at least 60 days’ prior notice of any change in the policy.

The securities purchased by the Fund are subject to the quality, diversification, and other requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”), and other rules of the Securities and Exchange Commission.