AMKR · Amkor Technology, Inc.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

On February 20, 2025, the Reporting Person was granted 43,459 time-vested restricted stock units ("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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

Represents dividend equivalent units ("DEUs") accrued upon the payment of a dividend on June 23, 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.

Represents DEUs accrued upon the payment of a dividend on June 23, 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.

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.