Century Steel Corrects Disclosure Details of Endorsement Guarantees for April, May, and June 2026

1. Date of Event: 115/07/23 2. Company Name: Century Steel Structure Co., Ltd. 3. Relationship with Company (Please enter '本公司' or 'Subsidiary'):本公司 (Parent Company) 4. Cross-shareholding Ratio: Not applicable 5. Reason for Occurrence: Correction of the disclosure details for endorsement guarantees in April, May, and June 2026 6. Items/Report Names Subject to Correction: Disclosure Details of Endorsement Guarantees - April 2026 Disclosure Details of Endorsement Guarantees - May 2026 Disclosure Details of Endorsement Guarantees - June 2026 7. Amounts/Content/Page Numbers Before Correction: None 8. Amounts/Content/Page Numbers After Correction: April 2026: Endorser Company Name: Century Steel Structure Co., Ltd. Guarantee Recipient: PT CENTURY INDONESIA WIND ENERGY Guarantee Limit per Single Entity: 1,111,157 thousand NT dollars Cumulative Maximum Balance to Date: 791,500 thousand NT dollars Monthly Increase/Decrease Amount for Individual Subsidiary: 0 thousand NT dollars End-of-Period Guarantee Balance: 791,500 thousand NT dollars Amount Actually Drawn: 216,065 thousand NT dollars Guarantee Amount Secured by Property: 0 thousand NT dollars Ratio of Cumulative Guarantee Amount to Net Worth in Latest Financial Statements: 7.12 Maximum Endorsement Guarantee Limit: 5,555,786 thousand NT dollars

May 2026: Endorser Company Name: Century Steel Structure Co., Ltd. Guarantee Recipient: PT CENTURY INDONESIA WIND ENERGY Guarantee Limit per Single Entity: 1,146,797 thousand NT dollars Cumulative Maximum Balance to Date: 783,875 thousand NT dollars Monthly Increase/Decrease Amount for Individual Subsidiary: 0 thousand NT dollars End-of-Period Guarantee Balance: 783,875 thousand NT dollars Amount Actually Drawn: 213,984 thousand NT dollars Guarantee Amount Secured by Property: 0 thousand NT dollars Ratio of Cumulative Guarantee Amount to Net Worth in Latest Financial Statements: 6.84 Maximum Endorsement Guarantee Limit: 5,733,987 thousand NT dollars

June 2026: Endorser Company Name: Century Steel Structure Co., Ltd. Guarantee Recipient: PT CENTURY INDONESIA WIND ENERGY Guarantee Limit per Single Entity: 1,146,797 thousand NT dollars Cumulative Maximum Balance to Date: 796,250 thousand NT dollars Monthly Increase/Decrease Amount for Individual Subsidiary: 0 thousand NT dollars End-of-Period Guarantee Balance: 796,250 thousand NT dollars Amount Actually Drawn: 217,362 thousand NT dollars Guarantee Amount Secured by Property: 0 thousand NT dollars Ratio of Cumulative Guarantee Amount to Net Worth in Latest Financial Statements: 6.94 Maximum Endorsement Guarantee Limit: 5,733,987 thousand NT dollars

9. Response Measures: Corrected information has been re-uploaded to the Public Information Observation Station 10. Other Matters to be Disclosed: None