Director Winston J. Churchill Receives Dividend Equivalent Units from Amkor Technology RSUs

This Form 4 filing reports that Winston J. Churchill, 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 with respect to time-vested RSUs granted to Churchill on May 13, 2026. The DEUs are subject to the same provisions as the original RSUs and have no exercise price. Following this transaction, Churchill's total holdings in Amkor Technology common stock (through RSUs) increased to 2,615.5166 shares. The filing represents a routine dividend reinvestment in director compensation rather than a market transaction.