Material Agreement, Financial Obligation (Form 8-K)

Item 1.01 - Entry into a Material Definitive Agreement.

On October 28, 2025, Phillip Street Middle Market Lending Investments LLC ("SPV"), an indirectly wholly owned subsidiary of Phillip Street Middle Market Lending Fund LLC (the "Company") entered into a fourth amendment (the "Amendment") to its secured credit facility, dated as of February 10, 2023 (as amended, supplemented or otherwise modified and in effect from time to time, including by the Amendment, the "Ally Credit Facility") by and among the Company, as collateral manager and transferor, Phillip Street Middle Market Lending Investment Holdings LLC, as equityholder, the SPV, as borrower, each of the lenders from time to time party thereto (the "Lenders"), Ally Bank, as administrative agent, arranger and swingline lender, and State Street Bank and Trust Company, as collateral custodian. The Amendment, among other things, decreases the Facility Amount to $480,000,000, decreases the Applicable Spread to 1.85%, amends certain components of the Borrowing Base, resulting in an increase to the Borrowing Base and adds the ability to borrow under a swingline subfacility that is available on a same day basis. Capitalized terms used but not otherwise defined herein have the meanings ascribed thereto in the Amendment.

The foregoing description is only a summary of the material provisions of the Amendment and is qualified in its entirety by reference to a copy of the Amendment, which is filed as Exhibit 10.1 to this Current Report on Form 8-Kand incorporated by reference herein.

Item 2.03 - Creation of a Direct Financial Obligation or an Obligation under an Off-BalanceSheet Arrangement of a Registrant.

The information set forth under Item 1.01 above is incorporated by reference into this Item 2.03.