X0508 4 2026-01-02 0 0001315257 Koppers Holdings Inc. KOP 0001776180 Pearce Bradley A 436 SEVENTH AVENUE PITTSBURGH PA 15219 0 1 0 0 Chief Accounting Officer 0 Common Stock 2026-01-05 4 A 0 7128 0 A 38312 D Common Stock 2026-01-05 4 M 0 104 0 A 38416 D Common Stock 2026-01-05 4 F 0 2470 26.93 D 35946 D Restricted Stock Units 2026-01-02 4 A 0 357 0 A Common Stock 357 357 D Dividend Equivalent Rights 2026-01-02 4 A 0 3 0 A Common Stock 3 171 D Dividend Equivalent Rights 2026-01-05 4 M 0 104 0 D Common Stock 104 67 D The reporting person was awarded time-based restricted stock units ("RSUs") on January 5, 2026, which will vest in annual installments of 25 percent over four years. Represents shares acquired upon release of dividend equivalent rights ("DERs"), as reported in Table II, on a one-for-one basis. Shares surrendered to the issuer by the reporting person as payment for the tax withholding related to the vesting of RSUs. Restricted stock units convert into common stock on a one-for-one basis. On January 3, 2025, the reporting person was granted performance share units ("PSUs") for which the performance criteria for the one-year performance period from January 1, 2025 through December 31, 2025 have been satisfied. All of the restricted stock units reported here are subject to vesting based on the continued service of the reporting person through January 5, 2028. If the Company's total shareholder return over the three-year period of January 1, 2025 through December 31, 2027 is negative, then the cumulative number of units that may vest for such three-year period will be capped at 150% of the target number. The DERs accrued with respect to additional PSUs credited to the reporting person with respect to PSUs granted on January 3, 2025. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock. These DERs were released in connection with the vesting of RSUs granted on January 4, 2022, January 4, 2023, January 4, 2024, and January 3, 2025. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock. /s/ Stephanie L. Apostolou, Attorney in Fact 2026-01-06