X0206 3 2021-09-20 0 0001047127 AMKOR TECHNOLOGY, INC. AMKR 0001881170 Jacqueline Investments, LLC C/O SIANA CARR O'CONNOR & LYNAM, 1500 EAST LANCASTER AVENUE PAOLI PA 19301-9713 0 0 0 1 Exhibit 99.1 Common Stock 2733333 D On September 20, 2021, the Susan Y. Kim Irrevocable Trust Dated 4/16/98 fbo Jacqueline Mary Panichello transferred 2,733,333 shares of the Issuer's Common Stock to Jacqueline Investments, LLC in exchange for 100% of the latter's Units. Susan Y. Kim and John T. Kim are the co-trustees of the trust. Susan Y. Kim and Liam E. Blaney are the managers of the limited liability company. Richard D. Rosen, as Attorney-in-Fact 2021-09-21