# EDGAR Filing Document

**Accession Number:** 0001047127
**File Stem:** 0001628280-26-035656
**Filing Date:** 2026-5
**Character Count:** 7267
**Document Hash:** 641ffb456e7199b47d555a036631d284
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-035656.hdr.sgml**: 20260515

**ACCESSION NUMBER**: 0001628280-26-035656

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260513

**FILED AS OF DATE**: 20260515

**DATE AS OF CHANGE**: 20260515

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Tily Gil C.
- **CENTRAL INDEX KEY:** 0001405591

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-29472
- **FILM NUMBER:** 26988803

**MAIL ADDRESS:**
- **STREET 1:** 1900 S. PRICE ROAD
- **CITY:** CHANDLER
- **STATE:** AZ
- **ZIP:** 85248

**FORMER NAME:**
- **FORMER CONFORMED NAME:** Tily Gil Coleman
- **DATE OF NAME CHANGE:** 20070703
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** AMKOR TECHNOLOGY, INC.
- **CENTRAL INDEX KEY:** 0001047127
- **STANDARD INDUSTRIAL CLASSIFICATION:** SEMICONDUCTORS & RELATED DEVICES [3674]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 231722724
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 2045 EAST INNOVATION CIRCLE
- **CITY:** TEMPE
- **STATE:** AZ
- **ZIP:** 85284
- **BUSINESS PHONE:** 480-821-5000

**MAIL ADDRESS:**
- **STREET 1:** 2045 EAST INNOVATION CIRCLE
- **CITY:** TEMPE
- **STATE:** AZ
- **ZIP:** 85284

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AMKOR TECHNOLOGY INC
- **DATE OF NAME CHANGE:** 19971001

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Tily Gil C.<br><sub>(Last) (First) (Middle)</sub><br>2045 EAST INNOVATION CIRCLE<br><sub>(Street)</sub><br>TEMPE, AZ 85284<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-05-13 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>AMKOR TECHNOLOGY, INC. [ AMKR ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-05-13 |  | M |  | 9893<sup>(1)</sup> | A | 0<sup>(1)</sup> | 118699<sup>(1)</sup> | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Units | <sup>(1)</sup> | 2026-05-13 |  | M |  |  | 9893.0573 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 9893.0573 | $0 | 0 | D |  |
| Restricted Stock Units | <sup>(2)</sup> | 2026-05-13 |  | A |  | 2613 |  | <sup>(2)</sup> | <sup>(2)</sup> | Common Stock | 2613 | $0 | 2613 | D |  |

---

### Footnotes:

(1) On May 15, 2025, the Reporting Person was granted 9,789 time-vested restricted stock units ("RSUs") pursuant to the Amkor Technology, Inc. (the "Issuer") 2021 Equity Incentive Plan, as amended (the "Plan"), and theapplicable award agreement (the "2025 RSUs"). In connection with the vesting of the 2025 RSUs on May 13, 2026: (i) 0.0573 of the 2025 RSUs, which had accrued as dividend equivalent units ("DEUs") with each DEUrepresenting an additional RSU subject to the same provisions as the RSU with respect to which the DEU was accrued, were settled in cash; and (ii) the remainder of the 2025 RSUs, including 104 DEUs, converted intocommon stock of the Issuer on a one-for-one basis.

(2) Represents shares of common stock underlying RSUs granted on May 13, 2026 (the "Grant Date") pursuant to the Plan (the "2026 RSUs"). Subject to the terms and conditions of the applicable award agreement, the 2026
RSUs may be converted into common stock of the Issuer on a one-for-one basis and will vest in full on the earlier of the first anniversary of the Grant Date or the date of the Issuer's first annual meeting of stockholdersimmediately following the Grant Date. The 2026 RSUs were awarded for no consideration other than the Reporting Person's service as a director of the Issuer.

**Signature:** /s/ Mark N. Rogers, Attorney-in-Fact for Gil C. Tily  
**Date:** 2026-05-15

### Remarks:

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.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**