Koppers Holdings Inc. 10-Q

ITEM 5. OTHER INFORMATION During the three months ended June 30, 2025 , none of our directors or executive officers adopted , modified or terminated any Rule 10b5-1 trading arrangement or any non-Rule 10b5-1 trading arrangement (as such terms are defined in Item 408 of Regulation S-K). ITEM 6. EXHIBITS 10.1 Amendment No. 6, dated as of June 17, 2025, to the Credit Agreement, dated as of June 17, 2022, by and among Koppers Inc., as Borrower, Koppers Holdings Inc., as Holdings, the Lenders and L/C issuers party thereto, PNC Bank, National Association, as Revolving Administrative Agent, Collateral Agent and Swingline Loan Lender, and Wells Fargo Bank, National Association, as Term Administrative Agent (incorporated by reference to Exhibit 10.1 to the Company's Current Report on Form 8-K filed on June 18, 2025). 31.1* Certification of Chief Executive Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. 31.2* Certification of Chief Financial Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. 32.1* Certification of Chief Executive Officer and Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. 101.INS* Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because its XBRL tags are embedded with the Inline XBRL document. 101.SCH* Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Documents 104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) * Filed herewith. 29 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. K OPPERS H OLDINGS I NC . (R EGISTRANT ) Date: August 8, 2025 By: /s/ J immi S ue S mith Jimmi Sue Smith Chief Financial Officer (Principal Financial Officer and Duly Authorized Officer) 30