Sec Form 4 Filing - KIM JAMES J @ AMKOR TECHNOLOGY, INC. - 2023-02-22

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 KIM JAMES J 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 X __ 10% Owner _____ Officer (give title below) X __ Other (specify below) Member of 10% owner group (12) (Last) (First) (Middle) C/O SIANA CARR O'CONNOR & LYNAM, 1500 EAST LANCASTER AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 02/22/2023 (Street) PAOLI, PA19301-9713 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 02/22/2023 J V 384,000 A $ 25.28 3,584,499 ( 1 ) D Common Stock 02/22/2023 J V 384,000 A $ 25.28 3,968,499 ( 2 ) D Common Stock 02/22/2023 J V 384,000 A $ 25.28 4,352,499 ( 3 ) D Common Stock 02/22/2023 J V 384,000 A $ 25.28 4,736,499 ( 4 ) D Common Stock 02/22/2023 J V 384,000 A $ 25.28 5,120,499 ( 5 ) D Common Stock 02/22/2023 A( 6 ) 59,477 A $ 0 5,179,976 D Common Stock 02/22/2023 F( 7 ) 25,267 D $ 25.28 5,154,709 D Common Stock 02/24/2023 M 2,599 A $ 0 ( 8 ) 5,157,308 D Common Stock 02/24/2023 F( 9 ) 1,053 D $ 25.27 5,156,255 D Common Stock 3,278,001 ( 10 ) I By spouse Common Stock 49,594,980 ( 10 ) ( 11 ) I By 915 Investments, LP Common Stock 1,957,350 ( 10 ) ( 11 ) I By John T. Kim G-S Trust dtd. 12/11/12 Common Stock 7,828,682 ( 10 ) ( 11 ) I By John T. Kim Family Trust U/A dtd. 12/11/12 Common Stock 1,379,943 ( 10 ) ( 11 ) I By Susan Y. Kim 2018-1 GRAT dtd. 8/29/18 Common Stock 2,298,355 ( 10 ) ( 11 ) I By Susan Y. Kim 2020-1 GRAT dtd. 4/1/20 Common Stock 164,678 ( 10 ) ( 11 ) I By self as Trustee of Trust U/A dtd. 12/11/12 Common Stock 2,985,370 ( 10 ) ( 11 ) I By self as Trustee of own GRATs

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 $ 0 ( 8 ) 02/24/2023 M 2,599 ( 8 ) ( 8 ) Common Stock 2,599 $ 0 8,149 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other KIM JAMES J C/O SIANA CARR O'CONNOR & LYNAM 1500 EAST LANCASTER AVENUE PAOLI, PA19301-9713 X X Member of 10% owner group (12) Signatures Mark N. Rogers, Attorney-in-Fact for James J. Kim 02/24/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On February 22, 2023, the Irrevocable Deed of Trust of James J. Kim for Alexandra Kim Panichello dated 12/24/92 sold 384,000 shares of Common Stock of Amkor Technology, Inc. (the "Issuer") to the Reporting Person in full payment of the principal and accrued interest of a note payable to the Reporting Person by such trust. This transaction is exempt pursuant to Section 16 of the Securities Exchange Act of 1934, as amended ("Section 16"), and is voluntarily reported. ( 2 )On February 22, 2023, the Irrevocable Deed of Trust of James J. Kim for Allyson Lee Kim dated 10/15/01 sold 384,000 shares of the Issuer's Common Stock to the Reporting Person in full payment of the principal and accrued interest of a note payable to the Reporting Person by such trust. This transaction is exempt pursuant to Section 16 and is voluntarily reported. ( 3 )On February 22, 2023, the Irrevocable Deed of Trust of James J. Kim for Dylan James Panichello dated 10/15/01 sold 384,000 shares of the Issuer's Common Stock to the Reporting Person in full payment of the principal and accrued interest of a note payable to the Reporting Person by such trust. This transaction is exempt pursuant to Section 16 and is voluntarily reported. ( 4 )On February 22, 2023, the Irrevocable Deed of Trust of James J. Kim for Jacqueline Mary Panichello dated 10/3/94 sold 384,000 shares of the Issuer's Common Stock to the Reporting Person in full payment of the principal and accrued interest of a note payable to the Reporting Person by such trust. This transaction is exempt pursuant to Section 16 and is voluntarily reported. ( 5 )On February 22, 2023, the Irrevocable Deed of Trust of James J. Kim, Settlor, FBO Jason Lee Kim dated 11/17/03 sold 384,000 shares of the Issuer's Common Stock to the Reporting Person in full payment of the principal and accrued interest of a note payable to the Reporting Person by such trust. This transaction is exempt pursuant to Section 16 and is voluntarily reported. ( 6 )This Form 4 reports the vesting on February 22, 2023, of 59,477 shares of the Issuer's Common Stock underlying performance-vested restricted stock units ("PSUs") granted to the Reporting Person on February 11, 2021 pursuant to the Issuer's Second Amended and Restated 2007 Equity Incentive Plan, as amended, and the related award agreement. The PSUs vested based on the attainment of a basic cumulative earnings per share performance goal over a two-year performance period beginning January 1, 2021 and ending on December 31, 2022. ( 7 )The transaction represents shares of the Issuer's Common Stock withheld by the Issuer in connection with the vesting of PSUs to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person. ( 8 )On February 24, 2022 (the "RSU Grant Date"), the Reporting Person was granted 10,748 time-vested restricted stock units ("RSUs") pursuant to the Issuer's 2021 Equity Incentive Plan, as amended, and the applicable award agreement. The RSUs convert into shares of the Issuer's Common Stock on a one-to-one basis and vest in four equal annual installments beginning on the first anniversary of the RSU Grant Date. ( 9 )The transaction represents shares withheld by the Issuer in connection with the vesting of certain RSUs granted to the Reporting Person on the RSU Grant Date. These shares were withheld to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person. ( 10 )The Reporting Person disclaims beneficial ownership of these securities, except to the extent of the Reporting Person's pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such securities, except to the extent of the Reporting Person's pecuniary interest therein, for purposes of Section 16, or for any other purpose. ( 11 )The Reporting Person is (i) a trustee of trusts for the benefit of his immediate family members which own 13,464,330 shares of the Issuer's Common Stock, (ii) a trustee of a trust which is a controlling member of a limited liability company being treated as a corporation for purposes of Section 16, which limited liability company holds 164,678 shares of the Issuer's Common stock, (iii) a trustee of grantor retained annuity trusts of which he was the settlor and is the sole annuitant which own 2,985,370 shares of the Issuer's Common Stock and (iv) a general partner of a limited partnership which owns 49,594,980 shares of the Issuer's Common Stock. Pursuant to the Form 4 instructions, the Reporting Person is being treated as having a pecuniary interest in all of such shares.

Remarks: (12) The Reporting Person states that the filing of this Form 4 shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities owned by the other members of the group, for the purpose of Section 16, or for any other purpose.

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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