X0609 4 2026-09-22 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0001158922 KIM SUSAN Y false C/O SIANA CARR O'CONNOR & LYNAM 1500 EAST LANCASTER AVENUE PAOLI PA 19301-9713 1 0 1 1 Member of 10% owner group (5) 0 Common Stock 6120387 D Common Stock 3244594 I 2025 Grantor Retained Annuity Trust No. 1 of James J. Kim Common Stock 2538000 I 2025 Grantor Retained Annuity Trust No. 1 of Agnes C. Kim Common Stock 1235000 I By James J. Kim 2024 GRAT dtd. 8/5/24 Common Stock 895000 I By Agnes C. Kim 2024 GRAT dtd. 8/5/24 Common Stock 1124000 I By own GRATs Common Stock 3713610 I By trusts (excl. GRATs) Common Stock 3789479 I By Sujoda Investments, LP Common Stock 19484809 I By Sujochil, LP Restricted Stock Units 0 2026-09-22 4 A 0 3.9978 0 A Common Stock 3.9978 2619.5144 D The Reporting Person is (i) a trustee of trusts for the benefit of her immediate family members (other than grantor retained annuity trusts ("GRATs")) which own 3,713,610 shares of the Common Stock of Amkor Technology, Inc. (the "Issuer"), (ii) a trustee of GRATs for the benefit of members of her immediate family which own 7,912,594 shares of the Issuer's Common Stock, (iii) a trustee of GRATs of which the Reporting Person was the settlor and is the sole annuitant which own 1,124,000 shares of the Issuer's Common Stock, (iv) a general partner of a limited partnership (Sujochil, LP) which owns 19,484,809 shares of the Issuer's Common Stock, and (v) 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. 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. The sole general partner of Sujoda Investments, LP is Sujoda Management, LLC. The Reporting Person is one of three members of Sujoda Management, LLC. Sujoda Management, LLC is being treated as a limited partnership for purposes of Section 16, and pursuant to the Form 4 instructions, the Reporting Person has elected to treat all of the shares of the Issuer's Common Stock owned by Sujoda Investments, LP as beneficially owned by the Reporting Person. 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. 5. The Reporting Person states that the filing of this Form 4 shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities owned by the other members of the group, for the purpose. /s/ Mark N. Rogers, Attorney-in-Fact for Susan Y. Kim 2026-09-24