[GSEO] Announcement of Ex-Dividend Record Date and Payment Date for Cash Dividends

1. Date of Board of Directors, Shareholders' Meeting resolution or company decision: 2026/05/22 (Year 115) 2. Type of Ex-Rights/Ex-Dividends: Ex-Dividend 3. Type and amount of cash dividends for common stock: Cash dividend of 1,916,632,071 NTD, 17 NTD per share. 4. Ex-Dividend trading date: 2026/06/08 (Year 115) 5. Last transfer date: 2026/06/09 (Year 115) 6. Start date of transfer suspension: 2026/06/10 (Year 115) 7. End date of transfer suspension: 2026/06/14 (Year 115) 8. Ex-Dividend record date: 2026/06/14 (Year 115) 9. Last date for bond conversion application: N/A 10. Start date of bond conversion suspension: N/A 11. End date of bond conversion suspension: N/A 12. Common stock cash dividend payment date: 2026/07/08 (Year 115) 13. Other notes: None