AMKR

SEC source: 0001628280-26-065246 · wk-form4_1791318954.xml · derivative · entry 3

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 9,657

Underlying: Common Stock · 5,000 shares

Expires 2028-05-01

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_date: This stock option to acquire 20,000 shares of the Issuer's Common Stock was granted on May 1, 2018, vested in full on May 1, 2019.

SEC source: 0001628280-26-065246 · wk-form4_1791318954.xml · nonDerivative · entry 2

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 29,109

F1 · kind: The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 8, 2026.

SEC source: 0001628280-26-065246 · wk-form4_1791318954.xml · nonDerivative · entry 1

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 34,109

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.

SEC source: 0001628280-26-063436 · wk-form4_1790282705.xml · derivative · entry 10

KIM SUSAN Y · CIK 0001158922 · Director · 10% owner · Member of 10% owner group (5)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F4 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F4 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F4 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063433 · wk-form4_1790282634.xml · derivative · entry 1

WATSON DAVID N · CIK 0001276908 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063431 · wk-form4_1790282577.xml · derivative · entry 1

Tily Gil C. · CIK 0001405591 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063429 · wk-form4_1790282534.xml · derivative · entry 1

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063425 · wk-form4_1790282476.xml · derivative · entry 3

Morse Robert Randolph · CIK 0001569086 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F3 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063425 · wk-form4_1790282476.xml · derivative · entry 2

Morse Robert Randolph · CIK 0001569086 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,917.4618

Underlying: Common Stock · 14.9767 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063425 · wk-form4_1790282476.xml · derivative · entry 1

Morse Robert Randolph · CIK 0001569086 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,916.9241

Underlying: Common Stock · 12.9709 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063422 · wk-form4_1790282412.xml · derivative · entry 2

McCourt MaryFrances · CIK 0001730724 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063422 · wk-form4_1790282412.xml · derivative · entry 1

McCourt MaryFrances · CIK 0001730724 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,916.9241

Underlying: Common Stock · 12.9709 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063420 · wk-form4_1790282368.xml · derivative · entry 2

Liao Daniel JL · CIK 0001775769 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063420 · wk-form4_1790282368.xml · derivative · entry 1

Liao Daniel JL · CIK 0001775769 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,917.4618

Underlying: Common Stock · 14.9767 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063417 · wk-form4_1790282318.xml · derivative · entry 1

CHURCHILL WINSTON J · CIK 0000923792 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063414 · wk-form4_1790282274.xml · derivative · entry 3

Carolin Roger Anthony · CIK 0001351909 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F3 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063414 · wk-form4_1790282274.xml · derivative · entry 2

Carolin Roger Anthony · CIK 0001351909 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,917.4618

Underlying: Common Stock · 14.9767 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063414 · wk-form4_1790282274.xml · derivative · entry 1

Carolin Roger Anthony · CIK 0001351909 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,916.9241

Underlying: Common Stock · 12.9709 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063410 · wk-form4_1790282217.xml · derivative · entry 4

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,619.5144

Underlying: Common Stock · 3.9978 shares

Expires not disclosed

F4 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F4 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F4 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 13, 2026. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063410 · wk-form4_1790282217.xml · derivative · entry 3

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,917.4618

Underlying: Common Stock · 14.9767 shares

Expires not disclosed

F3 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F3 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 15, 2025. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063410 · wk-form4_1790282217.xml · derivative · entry 2

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,916.9241

Underlying: Common Stock · 12.9709 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.exercise_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F2 · derivative.expiration_date: Represents DEUs accrued upon the payment of a dividend on September 22, 2026 with respect to RSUs of the Issuer granted to the Reporting Person on May 16, 2023. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-063410 · wk-form4_1790282217.xml · derivative · entry 1

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,260.1362

Underlying: Common Stock · 13.3198 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 17, 2022. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.exercise_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 17, 2022. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

F1 · derivative.expiration_date: Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on September 22, 2026 with respect to time-vested restricted stock units ("RSUs") of Amkor Technology, Inc. (the "Issuer") granted to the Reporting Person on May 17, 2022. Each DEU represents an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued.

SEC source: 0001628280-26-061378 · wk-form4_1789072623.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 134,105

F1 · kind: The sale reported in the Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 17, 2026.

SEC source: 0001628280-26-057994 · wk-form4_1787171860.xml · derivative · entry 3

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 70,000

Underlying: Common Stock · 5,000 shares

Expires 2029-06-10

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_date: This stock option (the "Option") to acquire 200,000 shares of Amkor Technology, Inc. common stock (the "Option Shares") was granted on June 10, 2019 (the "Option Grant Date") and vested over four years as follows: (i) with respect to 25% of the Option Shares, on the first anniversary of the Option Grant Date; and (ii) with respect to the remainder of the Option Shares, in equal quarterly installments thereafter, such that 100% of the Option vested on the fourth anniversary of the Option Grant Date.

SEC source: 0001628280-26-057994 · wk-form4_1787171860.xml · nonDerivative · entry 2

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 38,904

F1 · kind: The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 1, 2025.

SEC source: 0001628280-26-057994 · wk-form4_1787171860.xml · nonDerivative · entry 1

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 43,904

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.

SEC source: 0001628280-26-056790 · wk-form4_1786653433.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 135,105

F1 · kind: The sale reported in the Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 17, 2026.

SEC source: 0001628280-26-055750 · wk-form4_1786480565.xml · derivative · entry 3

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 14,657

Underlying: Common Stock · 5,000 shares

Expires 2028-05-01

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_date: This stock option to acquire 20,000 shares of the Issuer's Common Stock was granted on May 1, 2018, vested in full on May 1, 2019.

SEC source: 0001628280-26-055750 · wk-form4_1786480565.xml · nonDerivative · entry 2

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 29,109

F1 · kind: The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 8, 2026.

SEC source: 0001628280-26-055750 · wk-form4_1786480565.xml · nonDerivative · entry 1

ALEXANDER DOUGLAS A · CIK 0001195858 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 34,109

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.

SEC source: 0001628280-26-054882 · wk-form4_1786134969.xml · nonDerivative · entry 2

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 461,732

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $54.48 to $54.62. The Reporting Person hereby undertakes to provide, upon request, to the staff of the Securities and Exchange Commission, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001628280-26-054882 · wk-form4_1786134969.xml · nonDerivative · entry 1

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 486,732

F1 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $55.31 to $55.43. The Reporting Person hereby undertakes to provide, upon request, to the staff of the Securities and Exchange Commission, Amkor Technology, Inc. (the "Issuer"), or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (1) to this Form 4.

SEC source: 0001628280-26-051439 · wk-form4_1785530280.xml · nonDerivative · entry 1

CHURCHILL WINSTON J · CIK 0000923792 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,681

SEC source: 0001628280-26-051435 · wk-form4_1785530197.xml · nonDerivative · entry 1

Engel Kevin K. · CIK 0001965254 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,666

SEC source: 0001158840-26-000001 · wk-form4_1784752398.xml · nonDerivative · entry 2

KIM AGNES C · CIK 0001158840 · Member of 10% owner group (4)

10b5-1 filing: No plan indicated

Ownership: Indirect · By Spouse

Disclosed balance after: 11,187,355

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.

F3 · shares: On July 20, 2026, the Reporting Person's spouse exercised a stock option to acquire 250,000 shares of the Issuer's Common Stock that was granted to the Reporting Person's spouse on February 15, 2019.

F2 · balance_after: The Reporting Person disclaims beneficial ownership of these securities, except to the extent of the Reporting Person's pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities, except to the extent of the Reporting Person's pecuniary interest therein, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended ("Section 16"), or for any other purpose.

SEC source: 0001158840-26-000001 · wk-form4_1784752398.xml · nonDerivative · entry 1

KIM AGNES C · CIK 0001158840 · Member of 10% owner group (4)

10b5-1 filing: No plan indicated

Ownership: Indirect · By Spouse

Disclosed balance after: 10,937,355

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: On July 20, 2026, the Reporting Person's spouse exercised a stock option to acquire 200,000 shares of the Common Stock of Amkor Technology, Inc. (the "Issuer") that was granted to the Reporting Person's spouse on February 27, 2017.

F2 · balance_after: The Reporting Person disclaims beneficial ownership of these securities, except to the extent of the Reporting Person's pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities, except to the extent of the Reporting Person's pecuniary interest therein, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended ("Section 16"), or for any other purpose.

SEC source: 0001158839-26-000001 · wk-form4_1784752346.xml · derivative · entry 8

KIM JAMES J · CIK 0001158839 · 10% owner · Member of 10% owner group (5)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 250,000 shares

Expires 2026-10-31

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.

F4 · derivative.exercise_date: This stock option (the "2019 Option") to acquire 250,000 shares of the Issuer's Common Stock (the "2019 Option Shares") was granted on February 15, 2019 (the "2019 Option Grant Date") and vested over four years as follows: (i) with respect to 25% of the 2019 Option Shares, on the first anniversary of the 2019 Option Grant Date; and (ii) with respect to the remainder of the 2019 Option Shares, in equal quarterly installments thereafter, such that 100% of the 2019 Option vested on the fourth anniversary of the 2019 Option Grant Date.

SEC source: 0001158839-26-000001 · wk-form4_1784752346.xml · derivative · entry 7

KIM JAMES J · CIK 0001158839 · 10% owner · Member of 10% owner group (5)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 200,000 shares

Expires 2026-10-31

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.

F3 · derivative.exercise_date: This stock option (the "2017 Option") to acquire 200,000 shares of the Issuer's Common Stock (the "2017 Option Shares") was granted on February 27, 2017 (the "2017 Option Grant Date") and vested over four years as follows: (i) with respect to 25% of the 2017 Option Shares, on the first anniversary of the 2017 Option Grant Date; and (ii) with respect to the remainder of the 2017 Option Shares, in equal quarterly installments thereafter, such that 100% of the 2017 Option vested on the fourth anniversary of the 2017 Option Grant Date.

SEC source: 0001158839-26-000001 · wk-form4_1784752346.xml · nonDerivative · entry 2

KIM JAMES J · CIK 0001158839 · 10% owner · Member of 10% owner group (5)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 511,645

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.

SEC source: 0001158839-26-000001 · wk-form4_1784752346.xml · nonDerivative · entry 1

KIM JAMES J · CIK 0001158839 · 10% owner · Member of 10% owner group (5)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 261,645

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.

SEC source: 0001628280-26-048825 · wk-form4_1784579878.xml · derivative · entry 3

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 75,000

Underlying: Common Stock · 5,000 shares

Expires 2029-06-10

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_date: This stock option (the "Option") to acquire 200,000 shares of Amkor Technology, Inc. common stock (the "Option Shares") was granted on June 10, 2019 (the "Option Grant Date") and vested over four years as follows: (i) with respect to 25% of the Option Shares, on the first anniversary of the Option Grant Date; and (ii) with respect to the remainder of the Option Shares, in equal quarterly installments thereafter, such that 100% of the Option vested on the fourth anniversary of the Option Grant Date.

SEC source: 0001628280-26-048825 · wk-form4_1784579878.xml · nonDerivative · entry 2

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 38,904

F1 · kind: The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 1, 2025.

SEC source: 0001628280-26-048825 · wk-form4_1784579878.xml · nonDerivative · entry 1

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 43,904

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.

SEC source: 0001628280-26-048476 · wk-form4_1784234202.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 136,105

F1 · kind: The sale reported in the Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 17, 2026.

SEC source: 0001628280-26-046962 · wk-form4_1783024659.xml · derivative · entry 3

Engel Kevin K. · CIK 0001965254 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 8,692 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_date: On the Grant Date, the Reporting Person was granted 43,459 RSUs, which vested in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% was vested on June 30, 2026.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 43,459 RSUs, which vested in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% was vested on June 30, 2026.

SEC source: 0001628280-26-046962 · wk-form4_1783024659.xml · nonDerivative · entry 2

Engel Kevin K. · CIK 0001965254 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 12,887

F1 · kind: The transaction represents shares withheld by Amkor Technology, Inc. (the "Issuer") in connection with the vesting of certain restricted stock units ("RSUs") granted to the Reporting Person on February 20, 2025 (the "Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan, as amended, and the related award agreement. These shares were withheld to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-046962 · wk-form4_1783024659.xml · nonDerivative · entry 1

Engel Kevin K. · CIK 0001965254 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 16,612

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.

SEC source: 0001628280-26-046958 · wk-form4_1783024596.xml · derivative · entry 3

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 8,692 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_date: On the Grant Date, the Reporting Person was granted 43,459 RSUs, which vested in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% was vested on June 30, 2026.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 43,459 RSUs, which vested in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% was vested on June 30, 2026.

SEC source: 0001628280-26-046958 · wk-form4_1783024596.xml · nonDerivative · entry 2

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 137,105

F1 · kind: The transaction represents shares withheld by Amkor Technology, Inc. (the "Issuer") in connection with the vesting of certain restricted stock units ("RSUs") granted to the Reporting Person on February 20, 2025 (the "Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan, as amended, and the related award agreement. These shares were withheld to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-046958 · wk-form4_1783024596.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 140,830

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.