UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

July 28, 2025

(Commission File Number: 001-15128)

United Microelectronics Corporation

(Translation of registrant’s name into English)

No. 3 Li-Hsin 2nd Road,

Hsinchu Science Park,

Hsinchu, Taiwan, R.O.C.

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  Form 40-F 

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (1): 

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (7): 

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereto duly authorized.

Date: July 28, 2025

EXHIBIT INDEX

www.umc.com

Exhibit

Exhibit Description

99.1 Announcement on 2025/07/28: Represent major subsidiary United Semiconductor (Xiamen) Co., Ltd. to announce resignation of Director and Vice Chairman

99.2 Announcement on 2025/07/28: Represent major subsidiary United Semiconductor (Xiamen) Co., Ltd. to announce the Board Resolution to Convene a 2025 Extraordinary Shareholders’ Meeting

Exhibit 99.1

Represent major subsidiary United Semiconductor (Xiamen) Co., Ltd. to announce resignation of Director and Vice Chairman

1. Date of the board of directors’ resolution or date of occurrence of the change: 2025/07/28

2. Position (Please enter chairperson or president/general manager): Director and Vice Chairman

3. Name of the previous position holder: HSU, CHIH-CHING

4. Resume of the previous position holder: Director and Vice Chairman

5. Name of the new position holder: Not applicable

6. Resume of the new position holder: Not applicable

7. Circumstances of change (Please enter “resignation”, “dismissal”, “term expired” , “job relocation”, “severance”, “retirement”, “death” or “new appointment”): Resignation

8. Reason for the change: Resignation

9. Effective date of the new appointment: Not applicable

10. Any other matters that need to be specified (the information disclosure also meets the requirements of Article 7, subparagraph 6 of the Securities and Exchange Act Enforcement Rules, which brings forth a significant impact on shareholders rights or the price of the securities on public companies.): None

Exhibit 99.2

Represent major subsidiary United Semiconductor (Xiamen) Co., Ltd. to announce the Board Resolution to Convene a 2025 Extraordinary Shareholders’ Meeting

1. Date of the board of directors’ resolution:2025/07/28

2. Special shareholders meeting date: 2025/08/12

3. Special shareholders meeting location:

No.899 Wan Jia Chun Road, Xiang’an District, Xiamen, Fujian Province, China

4. Cause for convening the meeting (1) Reported matters: None

5. Cause for convening the meeting (2) Acknowledged matters: None

6. Cause for convening the meeting (3) Matters for Discussion:

Release the director from non-competition restrictions

7. Cause for convening the meeting (4) Election matters: Election of one board member

8. Cause for convening the meeting (5) Other Proposals: None

9. Cause for convening the meeting (6) Extemporary Motions: None

10. Book closure starting date: NA

11. Book closure ending date: NA

12. Any other matters that need to be specified: None