ASE Holdings Announces Subsidiary's Board Resolution to Dispose of Equity Stake in Mainland Investment

1. Date of Fact: June 26, 2026 2. Method of New (or Reduced) Investment: Proposed disposal of shares in Universal Scientific Industrial (USI) Co., Ltd. through block trading on the Shanghai Stock Exchange 3. Board Approval Date: June 26, 2026 4. Other Approval Dates: Not applicable 5. Number of Units, Unit Price, and Total Transaction Amount: Quantity: Up to 47,778,700 shares Unit Price and Total Amount: To be announced after transaction execution 6. Name of Mainland Investee Company: Universal Scientific Industrial (USI) Co., Ltd. 7. Paid-in Capital of the Above Mainland Investee Company: RMB 2,388,935,678 8. Proposed New Capital Increase for the Above Mainland Investee Company: Not applicable 9. Main Business Activities of the Above Mainland Investee Company: Providing electronic product design and manufacturing services; producing and processing new electronic components, high-performance computer motherboards, and wireless network communication components 10. Auditor's Opinion Type for the Most Recent Financial Statements of the Above Mainland Investee Company: Unqualified opinion 11. Total Equity in the Most Recent Financial Statements of the Above Mainland Investee Company: RMB 20,721,402,493.02 12. Net Profit or Loss in the Most Recent Financial Statements of the Above Mainland Investee Company: RMB 1,853,439,277.28 13. Actual Investment Amount in the Above Mainland Investee Company to Date: USD 1,012,920,000 14. Counterparty and Its Relationship with the Company: Not applicable 15. If the Counterparty is a Related Party, Reason for Selection, Previous Owner, Relationships, Transfer Date, and Amount: Not applicable 16. If the Owner within the Last Five Years was a Related Party of the Company, Disclosure of Acquisition and Disposal Dates, Prices, and Relationship at the Time: Not applicable 17. Gain (or Loss) from Disposal: To be announced after transaction execution 18. Delivery or Payment Terms (including payment period and amount), Contractual Restrictions, and Other Important Agreements: After confirmation of transaction on the Shanghai Stock Exchange, both parties fulfill settlement and delivery obligations before receiving payment 19. Decision Method for the Transaction, Reference Basis for Pricing, and Decision-Making Unit: Based on the prevailing market price at the time of execution on the Shanghai Stock Exchange 20. Broker: None 21. Specific Purpose of Acquisition or Disposal: Group operational strategy 22. Dissenting Director's Opinion on the Transaction: None 23. Whether the Transaction is a Related-Party Transaction: No 24. Date of Supervisor Approval or Audit Committee Consent: Not applicable 25. Total Investment Amount Approved by the Investment Commission for Mainland China to Date (including this transaction): USI Company: USD 1,027,734,000 26. Ratio of the Above Total Approved Investment to the Latest Financial Statement's Paid-in Capital: 72.90% 27. Ratio of the Above Total Approved Investment to the Latest Financial Statement's Total Assets: 7.70% 28. Ratio of the Above Total Approved Investment to the Latest Financial Statement's Equity Attributable to Owners of Parent: 9.25% 29. Total Actual Investment Amount in Mainland China to Date: USI Company: USD 1,027,734,000 30. Ratio of the Above Total Actual Investment to the Latest Financial Statement's Paid-in Capital: 72.90% 31. Ratio of the Above Total Actual Investment to the Latest Financial Statement's Total Assets: 7.70% 32. Ratio of the Above Total Actual Investment to the Latest Financial Statement's Equity Attributable to Owners of Parent: 9.25% 33. Investment Gains or Losses from Mainland China in the Last Three Years: USI Company: 2023: NT$9,934,494,000 2024: NT$8,811,909,000 2025: NT$8,879,141,000 34. Profit Repatriation Amounts from Mainland China in the Last Three Years: USI Company: 2023: NT$3,571,427,000 2024: NT$2,718,463,000 2025: NT$2,840,683,000 35. Whether Accountant Issued Non-Reasonable Opinion on This Transaction: Not applicable 36. Name of Accounting Firm: Not applicable 37. Name of Accountant: Not applicable 38. Accountant's Practice Certificate Number: Not applicable 39. Previous Date of Material Information Disclosure on the Same Event: Not applicable 40. Other Explanatory Matters: 1. Huan Cheng Technology Limited currently holds 70.48% (1,683,749,126 shares) of USI, with a carrying amount (under equity method) of USD 2,317,808,298.22, with no restrictions on rights. Shareholding ratio and related information will be announced after transaction execution. 2. The proportion of securities investments (including this transaction) under Article 3 of the 'Rules for Acquisition or Disposal of Assets by Publicly Issued Companies' to the company's latest financial statement's total assets and equity attributable to owners of parent, as well as operating capital: To be announced after transaction execution. 3. Expected Disposal Period: July 21, 2026 to October 20, 2026 4. Matters that USI Co., Ltd. is required to disclose under the Shanghai Stock Exchange rules can be found on the Shanghai Stock Exchange website.