【UMC】Announcement: Company's Share Buyback Exceeds NT$300 Million

1. Date when the cumulative amount of shares repurchased by the company reached 2% of total issued shares or the amount exceeded NT$300 million: 115/05/13 (May 13, 2026). 2. Number of shares repurchased in this instance (shares): 6,500,000. 3. Total amount of shares repurchased in this instance (NTD): 637,759,742. 4. Average repurchase price per share (NTD): 98.12. 5. Cumulative number of treasury shares held by the company during the repurchase period (shares): 16,751,000. 6. Percentage of cumulative treasury shares held by the company to total issued shares during the repurchase period (%): 0.13. 7. Other matters that should be specified: None. Keywords: Material Information