UMC to Host 2026 Second Quarter Earnings Conference Call

Announcement Date: July 15, 115 Speaking Date: July 14, 115 Speaking Time: 14:01:35 Company Code: 2303 Company Name: UMC Purpose: Announcement of the 2026 Second Quarter Earnings Conference Call Applicable Clause: Clause 12 Factual Date: July 29, 115

Details: Complies with Clause 4, Sub-clause XX: 12 Factual Date: 7/29/115

1. Date of Earnings Conference Call: 7/29/115 2. Time of Earnings Conference Call: 5:00 PM 3. Location: Online Conference 4. Summary of Conference: Financial and operational report for UMC's 2026 second quarter. 5. Other Disclosures: None

For complete financial and business information, please visit the 'Earnings Conference' section or the 'Investor Presentation' tab on Taiwan's Public Information Observation System.