Chang Hsin Announces Board Approval of Investment in Mainland China and Proxy Announcement for Key Subsidiary

1. Date of Event: August 7, 2026 (Republic Era Year 115) 2. Method of New (or Reduced) Investment: Establishment of a new plant directly invested by Chang Hsin (China) Investment Co., Ltd., a key subsidiary of the Company. Total investment amount: CNY 170 million, with the Company holding 70% equity. 3. Board Approval Date: August 7, 2026 (Republic Era Year 115) 4. Other Approval Dates: Not applicable 5. Number of Units, Unit Price, and Total Transaction Amount: CNY 119 million 6. Name of Investee Company in Mainland China: Newly established subsidiary, name not yet determined 7. Paid-in Capital of the Above-mentioned Mainland Investee Company: Not applicable (newly established) 8. Proposed Additional Capital for the Above-mentioned Mainland Investee Company: CNY 170 million 9. Primary Business Activities of the Above-mentioned Mainland Investee Company: Production of photocurable materials, including acrylic monomers 10. Auditor Opinion Type for the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: Not applicable (newly established) 11. Total Equity in the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: Not applicable (newly established) 12. Net Income/Loss in the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: Not applicable (newly established) 13. Cumulative Actual Investment in the Above-mentioned Mainland Investee Company to Date: Not applicable (newly established) 14. Counterparty and Relationship with the Company: Long-term equity investment accounted for using the equity method 15. If the counterparty is a related party, state the reason for selection, previous transferor, relationship among parties, transfer date, and amount: Not applicable 16. If the ownership of the subject asset was held by a related party of the Company within the past five years, disclose acquisition/disposal date, price, and relationship at the time: Not applicable 17. Gain (or loss) on disposal: Not applicable 18. Delivery or payment terms (including schedule and amounts), contractual restrictions, and other important agreements: Implementation according to progress after approval by competent authorities 19. Decision-making process for this transaction, reference basis for pricing, and decision-making unit: Approved by the Board of Directors 20. Broker: Not applicable 21. Specific Purpose of Acquisition or Disposal: Long-term equity investment 22. Dissenting Director Opinions on this Transaction: None 23. Is this transaction a related-party transaction? No 24. Date of Supervisor Acknowledgment or Audit Committee Approval: August 6, 2026 (Republic Era Year 115) 25. Cumulative Approved Investment in Mainland China by the Investment Commission (including this case): USD 956,496,252 (NTD 29,839,246 thousand) 26. Ratio of Cumulative Approved Investment in Mainland China to the Latest Financial Statement’s Paid-in Capital: 254.55% 27. Ratio of Cumulative Approved Investment in Mainland China to the Latest Financial Statement’s Total Assets: 63.91% 28. Ratio of Cumulative Approved Investment in Mainland China to the Latest Financial Statement’s Equity Attributable to Owners of Parent: 95.87% 29. Cumulative Actual Investment in Mainland China to Date: USD 653,758,930 (NTD 20,070,396 thousand) 30. Ratio of Cumulative Actual Investment in Mainland China to the Latest Financial Statement’s Paid-in Capital: 171.21% 31. Ratio of Cumulative Actual Investment in Mainland China to the Latest Financial Statement’s Total Assets: 42.99% 32. Ratio of Cumulative Actual Investment in Mainland China to the Latest Financial Statement’s Equity Attributable to Owners of Parent: 64.48% 33. Recognized Investment Gains/Losses from Mainland China Operations in the Past Three Years: Year 112: NTD 1,271,914 thousand Year 113: NTD 1,235,833 thousand Year 114: NTD 1,490,283 thousand 34. Profit Repatriation Amounts from Mainland China in the Past Three Years: Year 112: NTD 1,209,584 thousand Year 113: NTD 2,586,672 thousand Year 114: NTD 1,879,700 thousand 35. Has the auditor issued an adverse opinion on this transaction? Not applicable 36. Name of Accounting Firm: Not applicable 37. Name of Accountant: Not applicable 38. Accountant License Number: Not applicable 39. Previous Material Information Disclosure Date for the Same Event: Not applicable 40. Other Explanatory Matters: None