Amkor EVP Engel exercises RSUs, shares withheld for taxes

Amkor Technology Executive Vice President Kevin Engel reported the vesting and exercise of 8,692 Restricted Stock Units into common stock on September 30, 2025, together with a tax-withholding disposition of 3,725 shares at $28.40 per share.

Rhea-AI Filing Summary

Amkor Technology Executive Vice President Kevin Engel reported the vesting and exercise of 8,692 Restricted Stock Units into common stock on September 30, 2025, together with a tax-withholding disposition of 3,725 shares at $28.40 per share. After these events he directly holds 11,321 shares of common stock. The RSUs stem from a 43,459-unit grant awarded on February 20, 2025 that vests in five equal quarterly installments through June 30, 2026.

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.

Insider Trade Summary

8,692 shares exercised/converted

Exercise 3 txns

Insider Engel Kevin

Role Executive Vice President

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	8,692	$0.00	$0.00
Exercise	Common Stock	8,692	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	3,725	$28.40	$106K

Holdings After Transaction: Restricted Stock Units — 26,076 contracts (Direct); Common Stock — 11,321 shares (Direct)

Footnotes (2)

1. 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.
2. 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.

Key Figures

RSUs exercised: 8,692 shares Shares withheld for taxes: 3,725 shares Tax withholding price: $28.40 per share +3 more

6 metrics

RSUs exercised 8,692 shares Restricted Stock Units converted to common stock on September 30, 2025

Shares withheld for taxes 3,725 shares Common shares withheld to satisfy tax obligations at vesting

Tax withholding price $28.40 per share Price used for tax-withholding share disposition

Post-transaction holdings 11,321 shares Direct common stock held after reported transactions

RSU grant size 43,459 RSUs Restricted Stock Units granted on February 20, 2025

RSU vesting completion date June 30, 2026 Date on which 100% of the RSU grant will be vested

Key Terms

Restricted Stock Units, 2021 Equity Incentive Plan, tax withholding obligations, Grant Date, +1 more

5 terms

Restricted Stock Units financial

"The transaction represents shares withheld in connection with the vesting of certain restricted stock units ("RSUs")"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

2021 Equity Incentive Plan financial

"granted to the Reporting Person pursuant to the Issuer's 2021 Equity Incentive Plan, as amended"

tax withholding obligations financial

"These shares were withheld to satisfy the Reporting Person's tax withholding obligations."

Grant Date financial

"On the Grant Date, the Reporting Person was granted 43,459 RSUs"

The grant date is the day a company formally gives an employee or contractor the right to receive stock-based compensation, such as stock options or restricted shares. It matters to investors because it fixes key terms—like the price, the start of the ownership clock, and when the award will affect the company’s financial statements and share count—so it can influence dilution, reported expenses, and potential future selling pressure.

quarterly installments financial

"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"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did Kevin Engel report for AMKR on this Form 4?

Kevin Engel reported 8,692 RSUs vesting and converting into Amkor common stock on September 30, 2025, plus a tax-withholding disposition of 3,725 shares at $28.40 per share related to that vesting.

How many AMKR shares does Kevin Engel hold after the reported transactions?

Following the September 30, 2025 transactions, Kevin Engel directly holds 11,321 shares of Amkor common stock, as reported in the holdings summary attached to this Form 4 filing.

What was the size of Kevin Engel’s RSU grant referenced in the AMKR Form 4?

On the February 20, 2025 Grant Date, Kevin Engel received 43,459 Restricted Stock Units, which vest in five equal quarterly installments from June 30, 2025 through June 30, 2026 under Amkor’s 2021 Equity Incentive Plan.

How many AMKR shares were withheld for taxes in Kevin Engel’s Form 4?

Amkor withheld 3,725 shares of common stock at $28.40 per share to satisfy Kevin Engel’s tax withholding obligations arising from RSU vesting; the issuer will pay these taxes on his behalf.

Under what plan were Kevin Engel’s AMKR RSUs granted and vested?

The RSUs were granted to Kevin Engel under Amkor’s 2021 Equity Incentive Plan, as amended, and vest quarterly on specific dates from June 30, 2025 to June 30, 2026 pursuant to the related award agreement.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 10/02/2025 - 04:38 PM Learn about SEC filing dates

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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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