1229 United Microelectronics Corporation - MiTAC Digital Technology Announces Board Resolution on Dividend Distribution

Announcement Date: June 26, 115 (2026) Statement Date: June 25, 115 (2026) Statement Time: 17:33:50 Company Code: 1229 Company Name: United Microelectronics Corporation Subject: Announcement by significant subsidiary MiTAC Digital Technology Co., Ltd. regarding board resolution on dividend distribution Dividend reference date Applicable Clause: Clause 14 Event Date: June 25, 115 (2026)

Details: 1. Date of board resolution, shareholders' meeting, or company decision: June 25, 115 (2026) 2. Type of ex-rights/ex-dividend (please enter 'ex-rights', 'ex-dividend', or 'ex-rights and ex-dividend'): ex-dividend 3. Type and amount of dividend distribution: Cash dividend of NT$0.35 per share (NT$350 per 1,000 shares), totaling NT$73,495,118 4. Ex-rights/ex-dividend trading day: N/A 5. Last transfer date: July 10, 115 (2026) 6. Start date of transfer suspension: July 11, 115 (2026) 7. End date of transfer suspension: July 15, 115 (2026) 8. Ex-dividend reference date: July 15, 115 (2026) 9. Other disclosures: Estimated cash dividend payment date: August 5, 115 (2026)