WILKERSON SONJA MICHELLE

SEC source: 0001245155-26-000006 · wk-form4_1789503624.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 385.202

Underlying: Common Stock · 29.352 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001245155-26-000004 · wk-form4_1781726864.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 355.85

Underlying: Common Stock · 30.347 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001245155-26-000002 · wk-form4_1778530632.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,976

Underlying: Common Stock · 3,280 shares

Expires not disclosed

F1 · derivative.exercise_price: Restricted Stock Units ("RSUs") represent the right to receive shares of common stock on a one-for-one basis.

F2 · derivative.exercise_date: The RSUs 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.

F2 · derivative.expiration_date: The RSUs 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.

SEC source: 0001315257-26-000024 · wk-form4_1774470018.xml · derivative · entry 2

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 325.503

Underlying: Common Stock · 25.35 shares

Expires not disclosed

F3 · derivative.exercise_price: 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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001315257-26-000024 · wk-form4_1774470018.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 300.153

Underlying: Common Stock · 50 shares

Expires not disclosed

F1 · derivative.exercise_price: 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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001315257-25-000015 · wk-form4_1766009124.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 250.153

Underlying: Common Stock · 28.344 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001315257-25-000003 · wk-form4_1758140121.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 221.809

Underlying: Common Stock · 28.255 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional restricted stock unites ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

F3 · balance_after: Includes 25.518 DERs that inadvertently were not previously reported.

SEC source: 0000950170-25-068027 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,696

Underlying: Common Stock · 4,778 shares

Expires not disclosed

F1 · derivative.exercise_price: Restricted Stock Units ("RSUs") represent the right to receive shares of common stock on a one-for-one basis.

F2 · derivative.exercise_date: The RSUs 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.

F2 · derivative.expiration_date: The RSUs 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.

SEC source: 0000950170-25-045258 · ownership.xml · derivative · entry 2

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 168.036

Underlying: Common Stock · 22.202 shares

Expires not disclosed

F4 · derivative.exercise_price: 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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0000950170-25-045258 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 145.834

Underlying: Common Stock · 17 shares

Expires not disclosed

F1 · derivative.exercise_price: 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 2, 2024. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

F3 · balance_after: Includes 0.80 DERs that inadvertently were not previously reported.

SEC source: 0000950170-25-037432 · ownership.xml · derivative · entry 4

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 128.34

Underlying: Common Stock · 20.219 shares

Expires not disclosed

F7 · derivative.exercise_price: The DERs accrued with respect to additional time-based 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.

F4 · derivative.exercise_date: Once released, the RSUs corresponding to these dividend equivalent rights ("DERs") will become payable according to the election of payment designation that was filed by the reporting person subject to 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.

F4 · derivative.expiration_date: Once released, the RSUs corresponding to these dividend equivalent rights ("DERs") will become payable according to the election of payment designation that was filed by the reporting person subject to 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.

SEC source: 0000950170-25-037432 · ownership.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,216

F1 · kind: As disclosed in this Form 4 amendment, the reporting person inadvertently reported 3,513 RSUs and 20 DERs in Table I in the reporting person's previously-filed Forms 4. In fact, as reported in this amendment, the reporting person directly owns 17,216 shares of common stock.

F1 · shares: As disclosed in this Form 4 amendment, the reporting person inadvertently reported 3,513 RSUs and 20 DERs in Table I in the reporting person's previously-filed Forms 4. In fact, as reported in this amendment, the reporting person directly owns 17,216 shares of common stock.

F1 · price: As disclosed in this Form 4 amendment, the reporting person inadvertently reported 3,513 RSUs and 20 DERs in Table I in the reporting person's previously-filed Forms 4. In fact, as reported in this amendment, the reporting person directly owns 17,216 shares of common stock.

F1 · balance_after: As disclosed in this Form 4 amendment, the reporting person inadvertently reported 3,513 RSUs and 20 DERs in Table I in the reporting person's previously-filed Forms 4. In fact, as reported in this amendment, the reporting person directly owns 17,216 shares of common stock.

SEC source: 0000950170-24-137392 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 88.615

Underlying: Common Stock · 9.399 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0000950170-24-107877 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 79.216

Underlying: Common Stock · 8.345 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0000950170-24-072464 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 70.871

Underlying: Common Stock · 7.377 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0000950170-24-053683 · ownership.xml · derivative · entry 3

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,405

Underlying: Common Stock · 2,079 shares

Expires not disclosed

F3 · derivative.exercise_price: Restricted Stock Units ("RSUs") represent the right to receive shares of common stock on a one-for-one basis.

F4 · derivative.exercise_date: The RSUs 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.

F4 · derivative.expiration_date: The RSUs 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.

SEC source: 0000950170-24-053683 · ownership.xml · derivative · entry 2

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 63.494

Underlying: Common Stock · 20 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: These DERs were released in connection with the vesting of time-based restricted stock units granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F2 · shares: These DERs were released in connection with the vesting of time-based restricted stock units granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F2 · derivative.exercise_date: These DERs were released in connection with the vesting of time-based restricted stock units granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F2 · derivative.expiration_date: These DERs were released in connection with the vesting of time-based restricted stock units granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

SEC source: 0000950170-24-053683 · ownership.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 20,749

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · shares: Represents shares acquired upon release of dividend equivalent rights ("DERs"), as reported in Table II, on a one-for-one basis.

F1 · price: Represents shares acquired upon release of dividend equivalent rights ("DERs"), as reported in Table II, on a one-for-one basis.

SEC source: 0000950170-24-037229 · ownership.xml · derivative · entry 2

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 83.494

Underlying: Common Stock · 20 shares

Expires not disclosed

F4 · derivative.exercise_price: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F4 · derivative.exercise_date: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F4 · derivative.expiration_date: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

SEC source: 0000950170-24-037229 · ownership.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 63.494

Underlying: Common Stock · 5.652 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

F3 · balance_after: Includes 5.934 DERs that inadvertently were not previously reported.

SEC source: 0000950170-25-037432 · ownership.xml · derivative · entry 3

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 108.615

Underlying: Common Stock · 20 shares

Expires not disclosed

F5 · derivative.exercise_price: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F6 · shares: This Form 4 amendment is being filed to correctly report in Table II the accrual of 20 DERs to the reporting person with respect to RSUs granted to the reporting person on May 4, 2023. These DERs were inadvertently reported in Table I as the conversion of a derivative security on the reporting person's Form 4 filed May 6, 2024.

F5 · derivative.exercise_date: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F5 · derivative.expiration_date: The DERs accrued with respect to additional RSUs credited to the reporting person with respect to RSUs granted on May 4, 2023. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

SEC source: 0001209191-23-049288 · doc4.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51.908

Underlying: Common Stock · 6.971 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001209191-23-037063 · doc4.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 44.937

Underlying: Common Stock · 7.937 shares

Expires not disclosed

F1 · derivative.exercise_price: The dividend equivalent rights ("DERs") accrued with respect to additional time-based restricted stock units ("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.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001209191-23-027996 · doc4.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 20,729

F1 · security: The reporting person was awarded time-based restricted stock units.

SEC source: 0000950170-25-037432 · ownership.xml · derivative · entry 2

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,918

Underlying: Common Stock · 3,513 shares

Expires not disclosed

F2 · derivative.exercise_price: Restricted Stock Units ("RSUs") represent the right to receive shares of common stock on a one-for-one basis.

F3 · shares: This Form 4 amendment is being filed to correctly report in Table II the award of 3,513 RSUs to the reporting person that are subject to the Koppers Holdings Inc. Director Deferred Compensation Plan (the "Plan"). These RSUs were inadvertently reported in Table I on the reporting person's Form 4 filed May 8, 2023.

F4 · derivative.exercise_date: Once released, the RSUs corresponding to these dividend equivalent rights ("DERs") will become payable according to the election of payment designation that was filed by the reporting person subject to 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.

F4 · derivative.expiration_date: Once released, the RSUs corresponding to these dividend equivalent rights ("DERs") will become payable according to the election of payment designation that was filed by the reporting person subject to 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.

SEC source: 0001209191-23-026286 · doc4.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 37

Underlying: Common Stock · 37 shares

Expires not disclosed

F1 · derivative.exercise_price: 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 5, 2022. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.

SEC source: 0001127602-22-013585 · form4.xml · derivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 4,326

Underlying: Common Stock · 4,326 shares

Expires not disclosed

F1 · derivative.exercise_price: Restricted Stock Units represent the right to receive shares of common stock on a one-for-one basis.

F2 · derivative.exercise_date: The Restricted Stock Units 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.

F2 · derivative.expiration_date: The Restricted Stock Units 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.

SEC source: 0001209191-21-030857 · doc4.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,216

F1 · security: The reporting person was awarded time-based restricted stock units.

SEC source: 0001209191-20-027626 · doc4.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 14,138

F1 · security: The reporting person was awarded time-based restricted stock units.

SEC source: 0001209191-19-027623 · doc4.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 5,704

F1 · security: The reporting person was awarded time-based restricted stock units.

SEC source: 0001209191-18-050708 · doc4.xml · nonDerivative · entry 1

WILKERSON SONJA MICHELLE · CIK 0001245155 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,768

F1 · security: The reporting person was awarded time-based restricted stock units.