Kevin Engel - 31 Dec 2025 Form 4 Insider Report for AMKOR TECHNOLOGY, INC. (AMKR)

Role: Executive Vice President
Signature: /s/ Mark N. Rogers, Attorney-in-Fact for Kevin Engel
Issuer symbol: AMKR
Transactions as of: 31 Dec 2025
Net transactions value: -$147,063
Form type: 4
Filing time: 05 Jan 2026, 16:19:39 UTC
Previous filing: 16 Dec 2025
Next filing: 18 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Engel Kevin	Executive Vice President	2045 EAST INNOVATION CIRCLE, TEMPE	/s/ Mark N. Rogers, Attorney-in-Fact for Kevin Engel	05 Jan 2026	0001965254

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	AMKR	Common Stock	Options Exercise	$0	+8,692	+2491%	$0.000000	9,041	31 Dec 2025	Direct
transaction	AMKR	Common Stock	Tax liability	$147,063	-3,725	-41%	$39.48	5,316	31 Dec 2025	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	AMKR	Restricted Stock Units	Options Exercise	$0	-8,692	-33%	$0.000000	17,384	31 Dec 2025	Common Stock	8,692	$0.000000	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The transaction represents shares withheld by Amkor Technology, Inc. (the "Issuer") in connection with the vesting of certain restricted stock units ("RSUs") granted to the Reporting Person on February 20, 2025 (the "Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan, as amended, and the related award agreement. 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.
F2	On the Grant Date, the Reporting Person was granted 43,459 RSUs which vest in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% will be vested on June 30, 2026.

Content

The transaction represents shares withheld by Amkor Technology, Inc. (the "Issuer") in connection with the vesting of certain restricted stock units ("RSUs") granted to the Reporting Person on February 20, 2025 (the "Grant Date") pursuant to the Issuer's 2021 Equity Incentive Plan, as amended, and the related award agreement. 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.

On the Grant Date, the Reporting Person was granted 43,459 RSUs which vest in five equal quarterly installments on each of June 30, 2025, September 30, 2025, December 31, 2025, March 31, 2026, and June 30, 2026, such that 100% will be vested on June 30, 2026.