X0508 4 2025-12-12 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0001405591 Tily Gil C. 2045 EAST INNOVATION CIRCLE TEMPE AZ 85284 1 0 0 0 0 Common Stock 2025-12-12 4 S 0 20000 46.44 D 123806 D The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.91 to $46.83. 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. /s/ Mark N. Rogers, Attorney-in-Fact for Gil C. Tily 2025-12-16