Director Gil C. Tily Receives Dividend Equivalent Units from Amkor Technology RSUs

This Form 4 filing reports that Gil C. Tily, a director of Amkor Technology, Inc., received 2.5166 dividend equivalent units (DEUs) on June 23, 2026. These DEUs represent additional restricted stock units that accrued upon the payment of a dividend on time-vested RSUs previously granted to Tily on May 13, 2026. The DEUs are subject to the same provisions as the original RSUs. Following this transaction, Tily's total holdings in Amkor Technology common stock equivalents increased to 2,615.5166 shares. The filing was signed by Mark N. Rogers as attorney-in-fact for Gil C. Tily on June 25, 2026. This transaction represents a routine dividend reinvestment feature of the company's equity compensation program for directors.