www.umc.com

Exhibit

Exhibit Description

99.1 Announcement on 2026/07/14: UMC will convene Q2 2026 Investor Conference

99.2 Announcement on 2026/07/10: the trading and pledge of UMC common shares by directors, executive officers and 10% shareholders of UMC

Exhibit 99.1

UMC will convene Q2 2026 Investor Conference

1. Date of institutional investor conference: 2026/07/29

2. Time of institutional investor conference: 17:00

3. Location of institutional investor conference: Online teleconference

4. Outline of institutional investor conference: UMC Q2 2026 Financial and Operating Results

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

Exhibit 99.2

United Microelectronics Corporation

For the month of June, 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;