Sec Form 4 Filing - Tily Gil C. @ AMKOR TECHNOLOGY, INC. - 2023-05-16

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 Tily Gil C. 2. Issuer Name and Ticker or Trading Symbol AMKOR TECHNOLOGY, INC. [ AMKR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 2045 EAST INNOVATION CIRCLE 3. Date of Earliest Transaction (MM/DD/YY) 05/16/2023 (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 05/16/2023 M 8,809 ( 1 ) A $ 0 ( 1 ) 138,027 ( 1 ) 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 ) 05/16/2023 M 8,809.4075 ( 1 ) ( 1 ) ( 1 ) Common Stock 8,809.4075 ( 1 ) $ 0 0 D Restricted Stock Units ( 2 ) 05/16/2023 A 8,478 ( 2 ) ( 2 ) Common Stock 8,478 $ 0 8,478 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Tily Gil C. 2045 EAST INNOVATION CIRCLE TEMPE, AZ85284 X Signatures Mark N. Rogers, Attorney-in-Fact for Gil C. Tily 05/18/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On May 17, 2022, the Reporting Person was granted 8,706 time-vested restricted stock units ("RSUs") pursuant to the Amkor Technology, Inc. (the "Issuer") 2021 Equity Incentive Plan, as amended (the "Plan"), and the applicable award agreement (the "2022 RSUs"). In connection with the vesting of the 2022 RSUs on May 16, 2023: (i) 0.4075 of the 2022 RSUs, which had accrued as dividend equivalent units ("DEUs") with each DEU representing an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued, were settled in cash; and (ii) the remainder of the 2022 RSUs, including 103 DEUs, converted into common stock of the Issuer on a one-for-one basis. ( 2 )Represents shares of common stock underlying RSUs granted on May 16, 2023 (the "Grant Date") pursuant to the Plan (the "2023 RSUs"). Subject to the terms and conditions of the applicable award agreement, the 2023 RSUs may be converted into common stock of the Issuer on a one-for-one basis and will vest in full on the earlier of the first anniversary of the Grant Date or the date of the Issuers first annual meeting of stockholders immediately following the Grant Date. The 2023 RSUs were awarded for no consideration other than the Reporting Person's service as a director of the Issuer.

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