Susan Y. Kim Form 4 Filing - RSU Vesting and Indirect Ownership Disclosure

This Form 4 filing reports that Susan Y. Kim, a director and 10% owner of Amkor Technology, Inc., received 9,893 shares of common stock on June 12, 2026, through the vesting of 9,789 restricted stock units (RSUs) plus 104 dividend equivalent units (DEUs) granted under the company's 2021 Equity Incentive Plan. The RSUs were originally granted on May 15, 2025, and vested on May 13, 2026, before converting to common stock. The filing also discloses Kim's extensive indirect ownership through various trusts and investment vehicles, including GRATs (Grantor Retained Annuity Trusts) and limited partnerships, totaling over 35 million shares. Kim disclaims beneficial ownership of securities held by other members of the 10% owner group and notes that the filing should not be construed as an admission of beneficial ownership for Section 16 purposes.