AMKR Form 4: Engel Vesting 8,692 RSUs, 3,725 Shares Disposed at $28.40

Rhea-AI Filing Summary

Kevin Engel, Executive Vice President and director at Amkor Technology, Inc. (AMKR), reported transactions tied to the vesting of restricted stock units. On 09/30/2025 a grant-related event recorded 8,692 RSUs vested and withheld to satisfy tax obligations, and 3,725 shares were disposed at a price of $28.40 each. After these transactions the filing shows beneficial ownership related totals of 26,076 shares of common stock (derivative-related) and direct holdings reported as 15,046 and 11,321 on separate lines in Table I.

The filing explains the RSUs were originally granted on 02/20/2025 for 43,459 RSUs vesting in five equal quarterly installments through 06/30/2026, and that withheld shares were used to satisfy tax withholding with the Issuer paying the taxes on behalf of the reporting person.

Positive

• 8,692 RSUs vested on 09/30/2025, reflecting progress toward the 43,459 RSU grant
• Issuer will pay taxes on behalf of the reporting person for the withheld shares, per the filing

Negative

• 3,725 shares were disposed at $28.40, reducing the reporting person’s direct share count
• Direct beneficial ownership lines show decreased holdings after withholding/disposition events

Insights

Corporate Governance Analyst

Routine equity compensation vesting recorded; shares withheld for taxes.

The filing documents the vesting of 8,692 RSUs on 09/30/2025 from a 02/20/2025 grant of 43,459 RSUs that vest in five quarterly installments through 06/30/2026. The company withheld 3,725 shares at a price of $28.40 to satisfy tax withholding, with the Issuer paying the associated taxes on behalf of the reporting person.

This is a standard compensation-related Form 4 disclosure showing a change in share counts but not indicating a voluntary open-market sale for other purposes.

Executive Compensation Specialist

Grant schedule and withholding details clarify insider economics.

The RSU grant of 43,459 shares vests in five equal quarters; the 8,692 vested portion on 09/30/2025 increases derivative-linked ownership to 26,076 shares (per Table II). The withholding of 3,725 shares at $28.40 reduced the reported direct share count on the same date.

Because the Issuer pays the taxes on the reporting person’s behalf, the transaction reflects common payroll tax withholding mechanics tied to equity awards.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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

1. Name and Address of Reporting Person^*

Engel Kevin

(Last) (First) (Middle)

2045 EAST INNOVATION CIRCLE

(Street)

TEMPE AZ 85284

(City) (State) (Zip)

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

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	09/30/2025		M		8,692	A	$0	15,046	D
Common Stock	09/30/2025		F(1)		3,725	D	$28.4	11,321	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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	09/30/2025		M			8,692	(2)	(2)	Common Stock	8,692	$0	26,076	D

Explanation of Responses:

1. 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.

2. 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.

Remarks:

	/s/ Mark N. Rogers, Attorney-in-Fact for Kevin Engel	10/02/2025
	** Signature of Reporting Person	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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What did Kevin Engel file on Form 4 for AMKR?

The filing reports vesting of 8,692 RSUs on 09/30/2025, withholding/disposition of 3,725 shares at $28.40, and resulting beneficial ownership figures.

How many RSUs were originally granted to Kevin Engel?

The filing states a grant of 43,459 RSUs awarded on 02/20/2025 that vest in five equal quarterly installments.

Why were shares withheld in the transaction?

The filing explains the shares were withheld to satisfy the reporting person's tax withholding obligations and the Issuer will pay those taxes on the reporting person's behalf.

What are the post-transaction beneficial ownership totals reported?

Table II reports 26,076 common shares equivalent from RSUs; Table I shows direct holdings of 15,046 and 11,321 on separate lines following the transactions.

On what schedule do the RSUs fully vest?

The RSUs vest in five equal quarterly installments on 06/30/2025, 09/30/2025, 12/31/2025, 03/31/2026, and 06/30/2026, reaching 100% vesting on 06/30/2026.