X0508 4 2023-09-14 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 1 0 1 1 Member of 10% owner group (4) 0 Common Stock 2023-09-14 4 G 0 1958355 0.00 D 0 I By Susan Y. Kim 2020-1 GRAT dtd. 4/1/20 Common Stock 2023-09-14 4 G 0 1958355 0.00 A 1958355 I By Susan Y. Kim Family Trust U/A dtd. 4/1/20 Common Stock 269252 D Common Stock 1957350 I By John T. Kim G-S Trust dtd. 12/11/12 Common Stock 7828682 I By John T. Kim Family Trust U/A dtd. 12/11/12 Common Stock 1379943 I By Susan Y. Kim 2018-1 GRAT dtd. 8/29/18 Common Stock 1867747 I By self as Trustee of own GRATs Common Stock 164678 I By self as Trustee of Trust U/A dtd. 12/11/12 Common Stock 39594980 I By 915 Investments, LP On September 14, 2023, the Qualified Annuity Trust under the Susan Y. Kim 2020-1 Irrevocable Trust Agreement dated 4/1/20 (the "SYK 2020 GRAT") distributed 1,958,355 shares of the Common Stock of Amkor Technology, Inc. (the "Issuer") to the Family Trust under the Susan Y. Kim 2020-1 Irrevocable Trust Agreement dated 4/1/20 (the "SYK 2020 Family Trust"). The Reporting Person and Susan Y. Kim are co-trustees of the SYK 2020 GRAT and SYK 2020 Family 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 grantor retained annuity trusts of which he was the settlor and is the sole annuitant which own 1,867,747 shares of the Issuer's Common Stock, (ii) a trustee of trusts for the benefit of his immediate family members which own 13,124,330 shares of the Issuer's Common Stock, (iii) 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, and (iv) a general partner of a limited partnership which owns 39,594,980 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. (4) 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 of Section 16, or for any other purpose. /s/ Brian D. Short, Attorney-in-Fact for James J. Kim 2023-09-18