Guillaume Marie Jean Rutten - 20 Feb 2026 Form 4 Insider Report for AMKOR TECHNOLOGY, INC. (AMKR)

Role: Director
Signature: /s/ Mark N. Rogers, Attorney-in-Fact for Guillaume Marie Jean Rutten
Issuer symbol: AMKR
Transactions as of: 20 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 24 Feb 2026, 16:07:34 UTC
Previous filing: 20 Feb 2026
Next filing: 26 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Rutten Guillaume Marie Jean	Director	2045 EAST INNOVATION CIRCLE, TEMPE	/s/ Mark N. Rogers, Attorney-in-Fact for Guillaume Marie Jean Rutten	24 Feb 2026	0001596796

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	AMKR	Common Stock	Options Exercise	$0	+112,941	+30%	$0.000000	493,730	20 Feb 2026	Direct
transaction	AMKR	Common Stock	Options Exercise	$0	+59,388	+12%	$0.000000	553,118	20 Feb 2026	Direct

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	-112,941	-67%	$0.000000	56,470	20 Feb 2026	Common Stock	112,941	$0.000000	Direct	F1
transaction	AMKR	Restricted Stock Units	Options Exercise	$0	-59,388	-33%	$0.000000	118,795	20 Feb 2026	Common Stock	59,388	$0.000000	Direct	F2

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

Explanation of Responses:

Id	Content
F1	Represents shares of Amkor Technology, Inc. (the "Issuer") common stock underlying time-vested restricted stock units ("RSUs") granted on February 20, 2024 (the "2024 Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as a service provider of the Issuer and will vest over three years, with 40% of the RSUs vesting on each of the first anniversary and the second anniversary of the 2024 Grant Date, and 20% vesting on the third anniversary of the 2024 Grant Date, such that 100% will be vested on the third anniversary of the 2024 Grant Date.
F2	Represents shares of the Issuer's common stock underlying time-vested RSUs granted on February 20, 2025 (the "2025 Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as a service provider of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the 2025 Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the 2025 Grant Date.

Content

Represents shares of Amkor Technology, Inc. (the "Issuer") common stock underlying time-vested restricted stock units ("RSUs") granted on February 20, 2024 (the "2024 Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as a service provider of the Issuer and will vest over three years, with 40% of the RSUs vesting on each of the first anniversary and the second anniversary of the 2024 Grant Date, and 20% vesting on the third anniversary of the 2024 Grant Date, such that 100% will be vested on the third anniversary of the 2024 Grant Date.

Represents shares of the Issuer's common stock underlying time-vested RSUs granted on February 20, 2025 (the "2025 Grant Date") pursuant to the Issuer's Equity Incentive Plan. The RSUs were awarded for no consideration other than the Reporting Person's service as a service provider of the Issuer and will vest in three equal annual installments beginning on the first anniversary of the 2025 Grant Date and annually thereafter, such that 100% will be vested on the third anniversary of the 2025 Grant Date.