Item 1.01 Entry into a Material Definitive Agreement. On October 27, 2025, New Mountain Finance Corporation (the “ Company”) entered into the Third Amended and Restated Uncommitted Revolving Loan Agreement (the “ Amendment”), which amended and restated that certain Uncommitted Revolving Loan Agreement (the “ Loan Agreement”) by and between NMF Investments III, L. L. C., an affiliate of the Company’s investment adviser, New Mountain Finance Advisers, L. L. C, as the lender (the “ Lender”), and the Company, as borrower. Under the Loan Agreement, the Lender previously established a discretionary unsecured revolving credit facility for the Company (the “ Facility”), pursuant to which the Lender agrees to consider advancing, from time to time during the facility period, revolving loans to the Company. The Amendment among other things extends the maturity date of the Facility from December 2027 to December 2030. The description above is qualified in its entirety by reference to the copy of the Amendment, which will be filed as an exhibit to the Company’s Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2025.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure set forth above under Item 1.01 is incorporated by reference herein.

Item 8.01 Other Events. In connection with the termination of the Company’s existing stock repurchase program (the “ Prior Repurchase Program”), on October 23, 2025, the Company’s board of directors authorized and established a new stock repurchase program (the “Repurchase Program”). The Prior Repurchase Program terminated on October 8, 2025 upon the repurchase of $50 million of the Company’s common stock. Pursuant to the Repurchase Program, the Company is authorized to repurchase up to $100 million worth of its common stock at the discretion of the Company’s management. The Repurchase Program will expire upon the earlier of December 31, 2026 or the Company repurchasing $100 million worth of its common stock. Under the Repurchase Program, the Company may, but is not obligated to, repurchase its outstanding common stock in the open market from time to time provided that the Company complies with the prohibitions under its Code of Ethics and the guidelines specified in Rule 10b-18 of the Securities Exchange Act of 1934, as amended, including certain price, market volume and timing constraints.

Item 9.01 Financial Statements and Exhibits (d) Exhibits. Exhibit No.