Item 1.01 Entry into a Material Definitive Agreement.

On December 12, 2025, Diameter Credit Company Holdings LLC ("DCC Holdings"), a wholly owned subsidiary of Diameter Credit Company, a Delaware statutory trust (the "Company"), entered into Amendment No. 4 ("Amendment No. 4") to its Credit and Security Agreement (as amended, restated or otherwise modified from time to time, including pursuant to the Amendment No. 1 to Credit and Security Agreement, dated as of May 22, 2024, the Amendment No. 2 to Credit and Security Agreement, dated as of January 14, 2025, the Amendment No. 3 to Credit and Security Agreement, dated as of August 1, 2025 and as further amended by Amendment No. 4, the "Secured Credit Facility"), dated as of January 10, 2024, by and among DCC Holdings, as borrower, the Company, in its capacity as collateral manager and in its capacity as equity holder, the lenders from time to time parties thereto, Citibank, N.A., as administrative agent, Citibank, N.A. (acting through its Agency and Trust division), as collateral agent and custodian, and Siepe, LLC, as collateral administrator.

Amendment No. 4 amends the Secured Credit Facility to, among other things, (i) reduce the interest rate charged under the Secured Credit Facility to the applicable reference rate plus a spread of 2.00%, (ii) increase the maximum commitment to $650,000,000 and (iii) amend the accordion provision to permit increases to the maximum commitment up to an aggregate amount of $800,000,000.

The foregoing description of Amendment No. 4 to the Secured Credit Facility does not purport to be complete and is qualified in its entirety by reference to the full text of Amendment No. 4 to the Secured Credit Facility, filed as Exhibit 10.1 hereto and incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.