X0508 4 2025-11-21 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0001158839 KIM JAMES J C/O SIANA CARR O'CONNOR & LYNAM 1500 EAST LANCASTER AVENUE PAOLI PA 19301-9713 0 0 1 1 Member of 10% owner group (4) 0 Common Stock 2025-11-21 4 G 0 965000 0 A 965000 I By trusts (excluding GRATs) Common Stock 2341239 D Common Stock 1833000 I By Spouse Common Stock 1957350 I By John T. Kim G-S Trust dtd. 12/11/12 Common Stock 164678 I By self as Trustee of Trust U/A dtd. 12/11/12 Common Stock 7828682 I By John T. Kim Family Trust U/A dtd. 12/11/12 On November 20, 2025, the 2024 Grantor Retained Annuity Trust of James J. Kim 8/5/2024 distributed 965,000 shares of the Common Stock of Amkor Technology, Inc. (the "Issuer") to the James J. Kim 2018-1 Qualified Annuity Trust U/A dated 8/30/18. The Reporting Person and Susan Y. Kim are co-trustees of the trust. 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 Reporting Person is (i) a trustee of trusts for the benefit of his immediate family members which own 9,786,032 shares of the Issuer's Common Stock (ii) a trustee of a trust which is a controlling member of a limited liability company being treated as a corporation for purposes of Section 16, which limited liability company holds 164,678 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. 2. 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. /s/ Brian D. Short, Attorney-in-Fact for James J. Kim 2025-11-24