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

Disclosure Date: 1150629 Statement Date: 1150628 Statement Time: 182714 Company Code: 3711 Company Name: ASE Holding Subject: Announcement on Behalf of Subsidiary USI Enterprise Limited Regarding Board Resolution to Dispose of Equity in Mainland China Investment Compliance Clause: Item 20 Event Date: 1150626

1. Event Date: From 115/6/26 to 115/6/26

2. Method of Investment Change (Increase/Decrease): Proposed disposal of shares in Universal Scientific Industrial Co., Ltd. via block trading on the Shanghai Stock Exchange

3. Board Approval Date: June 26, 115 (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 Investee Company in Mainland China: Universal Scientific Industrial Co., Ltd.

7. Paid-in Capital of the Above-mentioned Mainland Investee Company: RMB 2,388,935,678

8. Proposed Additional Capital for the Above-mentioned Mainland Investee Company: Not applicable

9. Main Business of the Above-mentioned Mainland Investee Company: Providing electronic product design and manufacturing services, producing and processing new electronic components, high-performance computer motherboards, wireless network communication components, etc.

10. Auditor's Opinion Type for the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: Unqualified opinion

11. Total Equity in the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: RMB 20,721,402,493.02

12. Net Profit/Loss in the Most Recent Financial Statements of the Above-mentioned Mainland Investee Company: RMB 1,853,439,277.28

13. Cumulative Actual Investment Amount in the Above-mentioned Mainland Investee Company: USD 1,012,920 thousand

14. Counterparty and Its Relationship with the Company: Not applicable

15. If the Counterparty is a Related Party, Explanation of Selection Reason, Previous Owner, Relationships Among Parties, Previous Transfer Date and Amount: Not applicable

16. If the Owner of the Subject Asset Was a Related Party Within the Last Five Years, Disclosure of Acquisition/Disposal Date, Price, and Relationship with the Company 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. Transaction Decision Method, Pricing Reference Basis, and Decision-Making Unit: Based on the prevailing market price at the time of transaction on the Shanghai Stock Exchange

20. Broker: None

21. Specific Purpose of Acquisition or Disposal: Group operational strategy

22. Dissenting Director Opinions on This Transaction: None

23. Is This a Related-Party Transaction? No

24. Date of Supervisor Approval or Audit Committee Consent: Not applicable

25. Cumulative Investment Amount Approved by the Investment Commission for Mainland China (Including This Transaction): Huan Electric Company: USD 1,027,734 thousand

26. Ratio of Cumulative Approved Mainland Investment to Latest Financial Statement's Paid-in Capital: 72.90%

27. Ratio of Cumulative Approved Mainland Investment to Latest Financial Statement's Total Assets: 7.70%

28. Ratio of Cumulative Approved Mainland Investment to Latest Financial Statement's Equity Attributable to Owners of Parent: 9.25%

29. Cumulative Actual Investment Amount in Mainland China: Huan Electric Company: USD 1,027,734 thousand

30. Ratio of Cumulative Actual Mainland Investment to Latest Financial Statement's Paid-in Capital: 72.90%

31. Ratio of Cumulative Actual Mainland Investment to Latest Financial Statement's Total Assets: 7.70%

32. Ratio of Cumulative Actual Mainland Investment to Latest Financial Statement's Equity Attributable to Owners of Parent: 9.25%

33. Recognized Investment Gains/Losses in Mainland China for the Past Three Years: Huan Electric Company: Year 112: NT$9,934,494 thousand Year 113: NT$8,811,909 thousand Year 114: NT$8,879,141 thousand

34. Profit Repatriation Amounts from Mainland China for the Past Three Years: Huan Electric Company: Year 112: NT$3,571,427 thousand Year 113: NT$2,718,463 thousand Year 114: NT$2,840,683 thousand

35. Non-Reasonable Opinion Issued by Accountant for This Transaction: Not applicable

36. Name of Accounting Firm: Not applicable

37. Name of Accountant: Not applicable

38. Accountant's License Number: Not applicable

39. Previous Material Information Disclosure Date for the Same Event: Not applicable

40. Other Explanatory Matters: 1. Huan Cheng Technology Limited currently holds 70.48% of USI shares (1,683,749,126 shares), with a carrying amount (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 'Asset Acquisition and Disposal Rules for Publicly Issued Companies' to the latest financial statements' total assets and equity attributable to owners of parent, as well as the amount of working capital, will be announced after transaction execution. 3. Expected disposal period: From July 21, 115 (2026) to October 20, 115 (2026) 4. Matters required to be disclosed by Universal Scientific Industrial Co., Ltd. under the Shanghai Stock Exchange regulations can be found on the Shanghai Stock Exchange website.