X0306 4 2021-11-29 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0000923792 CHURCHILL WINSTON J 500 SE MIZNER BLVD. APT 305A BOCA RATON FL 33432-6083 1 0 0 0 Common Stock 2021-11-29 4 M 0 20000 7.31 A 34394 D Common Stock 2021-11-29 4 S 0 20000 22.42 D 14394 D Director Stock Option (Right-to-Buy) 7.31 2021-11-29 4 M 0 20000 0.00 D 2020-05-15 2029-05-15 Common Stock 20000 0 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.40 to $22.47. The Reporting Person hereby undertakes to provide, upon request, to the staff of the Securities and Exchange Commission, Amkor Technology, Inc. (the "Issuer"), or any security holder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (1) to this Form 4. This stock option (the "Option") to acquire 20,000 shares of the Issuer's common stock (the "Option Shares") was granted on May 15, 2019 (the "Grant Date") and vested with respect to 100% of the Option Shares on the earlier of the the first anniversary of the Grant Date or the date of the first annual meeting of the Company immediately following the Grant Date. Mark N. Rogers, Attorney-in-Fact for Winston J. Churchill 2021-12-01