Koppers Holdings Inc

On December 20, 2023, Leslie S. Hyde, Senior Vice President and Chief Sustainability Officer (an officer of the Company as defined in Rule 16a-1(f) of the Securities and Exchange Act of 1934), adopted a trading plan (the Plan) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Securities Exchange Act of 1934. The Plan provides for the exercise of 7,962 options (granted on March 6, 2019 and set to expire on March 5, 2029) and 14,441 options (granted on March 3, 2020 and set to expire on March 2, 2030) to purchase shares of the Company's stock and the subsequent sale of the shares received from the exercise of such options. The Plan will commence on March 21, 2024, and terminate on the earlier of (i)November 29, 2024, (ii) the execution of all trades contemplated by the Plan, or (iii) the valid exercise of termination rights under the Plan by either Leslie S. Hyde or the broker of the Plan.

During the three months ended December 31, 2023, none of our other directors or executive officers adopted orterminated 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-X).