AMKR

SEC source: 0001628280-26-010234 · wk-form4_1771622508.xml · nonDerivative · entry 4

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 107,224

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010234 · wk-form4_1771622508.xml · nonDerivative · entry 3

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 111,220

F3 · kind: The transaction represents the vesting on February 18, 2026 of 9,325 shares of common stock of the Issuer's underlying PSUs granted to the Reporting Person on February 20, 2025 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010234 · wk-form4_1771622508.xml · nonDerivative · entry 2

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 101,895

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010234 · wk-form4_1771622508.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 103,840

F1 · kind: This Form 4 reports the vesting on February 18, 2026 of 4,538 shares of common stock of Amkor Technology, Inc. (the "Issuer") underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 20, 2024 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010230 · wk-form4_1771622431.xml · derivative · entry 5

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,185

Underlying: Common Stock · 18,185 shares

Expires not disclosed

F4 · derivative.exercise_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

F4 · derivative.expiration_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

SEC source: 0001628280-26-010230 · wk-form4_1771622431.xml · nonDerivative · entry 4

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,265

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010230 · wk-form4_1771622431.xml · nonDerivative · entry 3

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,886

F3 · kind: The transaction represents the vesting on February 18, 2026 of 5,594 shares of common stock of the Issuer's underlying PSUs granted to the Reporting Person on February 20, 2025 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010230 · wk-form4_1771622431.xml · nonDerivative · entry 2

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,292

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010230 · wk-form4_1771622431.xml · nonDerivative · entry 1

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,330

F1 · kind: This Form 4 reports the vesting on February 18, 2026 of 2,003 shares of common stock of Amkor Technology, Inc. (the "Issuer") underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 20, 2024 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010222 · wk-form4_1771622350.xml · nonDerivative · entry 2

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 380,789

F2 · kind: This Form 4 reports the vesting on February 18, 2026 of 30,587 shares of common stock of the Issuer's underlying PSUs granted to the Reporting Person on February 20, 2025 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010222 · wk-form4_1771622350.xml · nonDerivative · entry 1

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 350,202

F1 · kind: This Form 4 reports the vesting on February 18, 2026 of 10,891 shares of common stock of Amkor Technology, Inc. (the "Issuer") underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 20, 2024 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · derivative · entry 6

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,394

Underlying: Common Stock · 21,394 shares

Expires not disclosed

F5 · derivative.exercise_date: Represents shares of the Issuer's common stock underlying time-vested RSUs granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in two equal annual installments beginning on December 31, 2026 such that 100% will be vested on December 31, 2027.

F5 · derivative.expiration_date: Represents shares of the Issuer's common stock underlying time-vested RSUs granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in two equal annual installments beginning on December 31, 2026 such that 100% will be vested on December 31, 2027.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · derivative · entry 5

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 53,487

Underlying: Common Stock · 53,487 shares

Expires not disclosed

F4 · derivative.exercise_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

F4 · derivative.expiration_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · nonDerivative · entry 4

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,945

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · nonDerivative · entry 3

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 7,343

F3 · kind: The transaction represents the vesting on February 18, 2026 of 5,594 shares of common stock of the Issuer's underlying PSUs granted to the Reporting Person on February 20, 2025 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · nonDerivative · entry 2

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,749

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010213 · wk-form4_1771622186.xml · nonDerivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,563

F1 · kind: This Form 4 reports the vesting on February 18, 2026 of 1,777 shares of common stock of Amkor Technology, Inc. (the "Issuer") underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 20, 2024 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010206 · wk-form4_1771622134.xml · derivative · entry 5

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,976

Underlying: Common Stock · 14,976 shares

Expires not disclosed

F4 · derivative.exercise_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

F4 · derivative.expiration_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 18, 2026 (the "Grant Date") pursuant to the Issuer's Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the Grant Date.

SEC source: 0001628280-26-010206 · wk-form4_1771622134.xml · nonDerivative · entry 4

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,623

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010206 · wk-form4_1771622134.xml · nonDerivative · entry 3

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,541

F3 · kind: The transaction represents the vesting on February 18, 2026 of 4,475 shares of common stock of the Issuer's underlying PSUs granted to the Reporting Person on February 20, 2025 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-010206 · wk-form4_1771622134.xml · nonDerivative · entry 2

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,066

F2 · kind: The transaction represents shares of the Issuer's common stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person.

SEC source: 0001628280-26-010206 · wk-form4_1771622134.xml · nonDerivative · entry 1

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,925

F1 · kind: This Form 4 reports the vesting on February 18, 2026 of 2,003 shares of common stock of Amkor Technology, Inc. (the "Issuer") underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 20, 2024 pursuant to the Issuer's Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic earnings per share performance goal over a one-year performance period beginning January 1, 2025 and ending on December 31, 2025.

SEC source: 0001628280-26-009053 · wk-form4_1771449298.xml · nonDerivative · entry 2

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 339,311

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 June 06, 2025.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $44.33 to $46.92. 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 (2) to this Form 4.

SEC source: 0001628280-26-009045 · wk-form4_1771449187.xml · nonDerivative · entry 3

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 786

SEC source: 0001628280-26-009033 · wk-form4_1771448939.xml · derivative · entry 6

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 100,000

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.

F4 · derivative.exercise_date: This stock option (the "Option") to acquire 200,000 shares of the Issuer's 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: 0001628280-26-009033 · wk-form4_1771448939.xml · nonDerivative · entry 4

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 24,922

F2 · 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: 0001628280-26-009033 · wk-form4_1771448939.xml · nonDerivative · entry 3

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 29,922

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: 0001628280-26-009053 · wk-form4_1771449298.xml · derivative · entry 3

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 13,919

Underlying: Common Stock · 13,920 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.

F3 · derivative.exercise_price: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 16, 2023 (the "RSU Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in four equal annual installments beginning on the first anniversary of the RSU Grant Date.

F3 · derivative.exercise_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 16, 2023 (the "RSU Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in four equal annual installments beginning on the first anniversary of the RSU Grant Date.

F3 · derivative.expiration_date: Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 16, 2023 (the "RSU Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan (the "RSUs"). The RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in four equal annual installments beginning on the first anniversary of the RSU Grant Date.

SEC source: 0001628280-26-009053 · wk-form4_1771449298.xml · nonDerivative · entry 1

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 349,311

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: 0001628280-26-009045 · wk-form4_1771449187.xml · derivative · entry 4

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,391

Underlying: Common Stock · 1,345 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: On the Grant Date, the Reporting Person was granted 5,567 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.exercise_date: On the Grant Date, the Reporting Person was granted 5,567 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 5,567 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

SEC source: 0001628280-26-009045 · wk-form4_1771449187.xml · nonDerivative · entry 2

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,102

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 16, 2023 (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: 0001628280-26-009045 · wk-form4_1771449187.xml · nonDerivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,661

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: 0001628280-26-009033 · wk-form4_1771448939.xml · derivative · entry 5

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 1,855

Underlying: Common Stock · 1,856 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.

F3 · derivative.exercise_price: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F3 · derivative.exercise_date: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F3 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

SEC source: 0001628280-26-009033 · wk-form4_1771448939.xml · nonDerivative · entry 2

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 24,922

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 16, 2023 (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: 0001628280-26-009033 · wk-form4_1771448939.xml · nonDerivative · entry 1

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 25,718

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: 0001628280-26-009037 · wk-form4_1771449088.xml · derivative · entry 3

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,175

Underlying: Common Stock · 4,176 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: On the Grant Date, the Reporting Person was granted 16,703 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.exercise_date: On the Grant Date, the Reporting Person was granted 16,703 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 16,703 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

SEC source: 0001628280-26-009037 · wk-form4_1771449088.xml · nonDerivative · entry 2

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 99,302

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 16, 2023 (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: 0001628280-26-009037 · wk-form4_1771449088.xml · nonDerivative · entry 1

Faust Megan · CIK 0001684564 · CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 101,214

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: 0001628280-26-009026 · wk-form4_1771448815.xml · derivative · entry 3

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,855

Underlying: Common Stock · 1,789 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: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.exercise_date: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 7,423 RSUs which vest in four equal annual installments beginning on the first anniversary of the Grant Date.

SEC source: 0001628280-26-009026 · wk-form4_1771448815.xml · nonDerivative · entry 2

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,327

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 16, 2023 (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: 0001628280-26-009026 · wk-form4_1771448815.xml · nonDerivative · entry 1

Haghighi Farshad · CIK 0001887579 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,143

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: 0001158926-26-000003 · wk-form4_1771363260.xml · nonDerivative · entry 1

KIM JOHN T · CIK 0001158926 · 10% owner · Member of 10% owner group (6)

10b5-1 filing: No plan indicated

Ownership: Indirect · By 915 Investments, LP

Disclosed balance after: 29,594,980

F1 · kind: On February 12, 2026, 915 Investments, LP sold 10,000,000 shares of Common Stock of Amkor Technology, Inc. (the "Issuer") pursuant to an underwritten secondary offering. The Reporting Person is the general partner of 915 Investments, LP.

F2 · balance_after: The Reporting Person is (i) a trustee of family trusts for the benefit of his immediate family members (other than Grantor Retained Annuity Trusts ("GRATS") which own 9,846,944 shares of the Issuer's Common Stock, (ii) a trustee of GRATs of which the Reporting Person was the settlor and is the sole annuitant which own 1,253,250 shares of the Issuer's Common Stock, (iii) a general partner of a limited partnership (Sujochil, LP) which owns 19,484,809 shares of the Issuer's Common Stock (iv) a manager of a limited liability company being treated as a corporation for purposes of Section 16 which owns 16,710,668 shares of the Issuer's Common Stock

F3 · balance_after: (continued from Footnote 2) (v) a general partner of a limited partnership which owns 29,594,980 shares of the Issuer's Common Stock and (vi) as referenced in Footnote 4, a member of Sujoda Management, LLC, which indirectly owns 3,789,479 shares of the Issuer's Common Stock. Pursuant to the Form 4 instructions, the Reporting Person is being treated as having a pecuniary interest in all of such shares.

F4 · 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: 0001460579-26-000002 · wk-form4_1771363148.xml · nonDerivative · entry 1

915 Investments, LP · CIK 0001460579 · Member of 10% owner group (2)

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 29,594,980

F1 · kind: On February 12, 2026, the Reporting Person sold 10,000,000 shares of Common Stock of Amkor Technology, Inc. pursuant to an underwritten secondary offering. John T. Kim is the general partner of the Reporting Person.

SEC source: 0001628280-26-002637 · wk-form4_1768944616.xml · derivative · entry 3

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 105,000

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.

F2 · derivative.expiration_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: 0001628280-26-002637 · wk-form4_1768944616.xml · nonDerivative · entry 2

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 23,862

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: 0001628280-26-002637 · wk-form4_1768944616.xml · nonDerivative · entry 1

ROGERS MARK N · CIK 0001201997 · EVP & General Counsel

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 28,862

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: 0001628280-26-002639 · wk-form4_1768944674.xml · nonDerivative · entry 1

Rutten Guillaume Marie Jean · CIK 0001596796 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 335,391

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 June 06, 2025.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $52.25 to $54.00. 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 (2) to this Form 4.

SEC source: 0001628280-26-000450 · wk-form4_1767647970.xml · derivative · entry 3

Engel Kevin · CIK 0001965254 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,384

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 vest 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% will be vested on June 30, 2026.

F2 · derivative.expiration_date: On the Grant Date, the Reporting Person was granted 43,459 RSUs which vest 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% will be vested on June 30, 2026.

SEC source: 0001628280-26-000450 · wk-form4_1767647970.xml · nonDerivative · entry 2

Engel Kevin · CIK 0001965254 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,316

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: 0001628280-26-000450 · wk-form4_1767647970.xml · nonDerivative · entry 1

Engel Kevin · CIK 0001965254 · Executive Vice President

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,041

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.