6-K

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

May 11, 2026

(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: May 11, 2026

EXHIBIT INDEX

EX-99

www.umc.com

Exhibit

Exhibit Description

99.1 Announcement on 2026/05/11: To announce accumulative shares repurchased exceeding NTD$300 million in value

99.2 Announcement on 2026/05/10: the trading and pledge of UMC common shares by directors, executive officers and 10% shareholders of UMC

Exhibit 99.1

To announce accumulative shares repurchased exceeding NTD$300 million in value

1. Date the cumulative no. of shares currently repurchased accounted for 2 percent or more of the shares issued by the company, or amounted to NT$300 million or more: 2026/05/11

2. No. of shares currently repurchased (shares): 4,166,000 shares

3. Type of shares currently repurchased: Common share

4. Total monetary amount of shares currently repurchased (NTD): NTD$391,855,237

5. Current average repurchase price per share (NTD): NTD$94.06

6. Cumulative no. of the company's own shares held during the repurchase period (shares): 8,332,000 shares

7. Cumulative no. of the company's own shares held during the repurchase period as a percentage of the total no. of the company’s issued shares: 0.07%

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

Exhibit 99.2

United Microelectronics Corporation

For the month of April, 2026

This is to report 1) the trading of directors, executive officers and 10% shareholders of United Microelectronics Corporation (“UMC”) (NYSE: UMC); 2) the pledge and clear of pledge of UMC common shares by directors, executive officers and 10% shareholders of UMC;

• The trading of directors, executive officers and 10% shareholders

• The pledge and clear of pledge of UMC common shares by directors, executive officers and 10% shareholders: