X0306 4 2021-12-21 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0001581432 Stone John Charles 2045 EAST INNOVATION CIRCLE TEMPE AZ 85284 0 1 0 0 Executive Vice President Common Stock 2021-12-21 4 F 0 59 22.60 D 31493 D Common Stock 2000 I Held in Trust The reporting transaction involved the withholding of 59 shares of stock issuable upon the early vesting of an equal number of restricted stock units to pay taxes associated with the reporting person becoming retirement eligible. The total reported in Column 5 includes 6,477 previously reported restricted stock units. Mark N. Rogers, Attorney-in-Fact for John Stone 2021-12-23