Transaction Details

Footnotes

The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("RSUs") credited to the reporting person with respect to RSUs granted on May 8, 2025. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock. | The DERs accrued with respect to additional RSUs credited to the reporting person with respect to deferred compensation. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock. | Once released, the RSUs corresponding to these DERs will become payable according to the election of payment designation that was filed by the reporting person subject to the Koppers Holdings Inc. Director Deferred Compensation Plan (the "Plan"). Such payment will be either lump sum or in annual installments commencing on the May 31st next following the reporting person's separation from service (as defined under the Plan) or, if later, and elected by the reporting person at the time he/she first elects to defer any payment under the Plan, May 31st of the year specified by the reporting person.