Sec Form 4 Filing - Shin Sung @ AMKOR TECHNOLOGY, INC. - 2023-02-16

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Shin Sung 2. Issuer Name and Ticker or Trading Symbol AMKOR TECHNOLOGY, INC. [ AMKR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Executive Vice President (Last) (First) (Middle) 2045 EAST INNOVATION CIRCLE 3. Date of Earliest Transaction (MM/DD/YY) 02/16/2023 (Street) TEMPE, AZ85284 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 1,634 ( 1 ) ( 2 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Restricted Stock Units ( 1 ) ( 1 ) ( 1 ) Common Stock ( 1 ) 1,634 ( 1 ) D Restricted Stock Units ( 2 ) ( 2 ) ( 2 ) Common Stock ( 2 ) 3,761 ( 2 ) D Restricted Stock Units ( 3 ) 02/16/2023 A 3,247 ( 3 ) ( 3 ) Common Stock 3,247 $ 0 3,247 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Shin Sung 2045 EAST INNOVATION CIRCLE TEMPE, AZ85284 Executive Vice President Signatures Mark N. Rogers, Attorney-in-Fact for Sung Shin 02/21/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )As previously reported in a Form 3 filed by the Reporting Person on March 17, 2021 (the "Form 3"), on February 11, 2021 (the "2021 Grant Date"), 3,268 shares of Amkor Technology, Inc. (the "Issuer") common stock underlying time-vested restricted stock units (the "2021 RSUs") were granted to the Reporting Person. The 2021 RSUs vest in four equal annual installments beginning on the first anniversary of the 2021 Grant Date. In the Form 3 and in subsequent Forms 4 filed by the Reporting Person, the 2021 RSUs were incorrectly reported in Table I. On February 10, 2023, 817 of the 2021 RSUs vested, and such vested RSUs are properly reported in Table I of this Form 4. Table I, Column 5 and Table II, Column 9 of this Form 4 have been adjusted to include the remaining vested and unvested 2021 RSUs, respectively, and reflect the proper number of 2021 RSUs beneficially owned by the Reporting Person as of the filing of this Form 4. ( 2 )As previously reported in a Form 4 filed by the Reporting Person on February 25, 2022 (the "Original Form 4"), on February 24, 2022 (the "2022 Grant Date"), 3,761 shares of the Issuer's common stock underlying time-vested restricted stock units (the "2022 RSUs") were granted to the Reporting Person. The 2022 RSUs vest in four equal annual installments beginning on the first anniversary of the 2022 Grant Date. In the Original Form 4, the 2022 RSUs were incorrectly reported in Table I. Table II, Column 9 of this Form 4 has been adjusted to include the 2022 RSUs and reflects the proper number of 2022 RSUs beneficially owned by the Reporting Person as of the filing of this Form 4. ( 3 )Represents shares of the Issuer's common stock underlying time-vested restricted stock units granted on February 16, 2023 (the "2023 Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan (the "2023 RSUs"). The 2023 RSUs were awarded for no consideration other than the Reporting Person's service as an officer of the Issuer and will vest in four equal annual installments beginning on the first anniversary of the 2023 Grant Date.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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