ASE Holding Announces Subsidiary's Acquisition of Lukang Factory and Facilities

1. Name and nature of the subject property (e.g., land located in Section XX, Subsection XX, Beitun District, Taichung City): Factory and related facilities located at No. 9, Luko 3rd Road, Luzhu District, Kaohsiung City

2. Date on which the event occurred: 115/7/30 ~ 115/7/30

3. Board approval date: July 30, 2026 (Minguo Year 115)

4. Other approval dates: Not applicable

5. Quantity of transaction units (e.g., XX square meters, equivalent to XX ping), unit price, and total transaction amount: Total building area: 96,571.82 square meters (equivalent to 29,212.98 ping) Total transaction amount: NT$6.3 billion (excluding tax)

6. Counterparty and its relationship with the company (if the counterparty is an individual and not a related party of the company, name disclosure may be omitted): Counterparty: AU Optronics Corporation (hereinafter "AUO") Relationship with the company: None

7. If the counterparty is a related party, state the reason for selecting the related party as the counterparty, the previous transferor, the relationship among the previous transferor, the company, and the counterparty, the previous transfer date, and the transfer amount: Not applicable

8. If the ownership of the subject asset was held by a related party of the company within the past five years, state the related party’s acquisition and disposal date, price, and relationship with the company at the time: Not applicable

9. Estimated gain (or loss) on disposal (not applicable for asset acquisition) (for deferred gains, provide a table showing recognition schedule): Not applicable

10. Delivery or payment terms (including payment periods and amounts), contractual restrictions, and other important agreements: Delivery or payment terms: As per contractual terms Contractual restrictions and other important agreements: None

11. Method of determining the transaction (e.g., bidding, comparison, negotiation), basis for price determination, and decision-making unit: Transaction determination method and price basis: Price negotiated with AUO, referencing valuation reports from two professional appraisal firms Decision-making unit: Board of Directors of ASE Semiconductor Manufacturing Co., Ltd.

12. Name of professional appraisal firm and its valuation amount: Appraisal firm: Cushman & Wakefield Taiwan Appraisers; Valuation: NT$6.327 billion Appraisal firm: Colliers International Taiwan Appraisal Joint Office; Valuation: NT$6.263 billion

13. Names of professional appraisers: A: Cushman & Wakefield Taiwan Appraisers: Hu Chun-Chun B: Colliers International Taiwan Appraisal Joint Office: Ko Feng-Ju

14. License numbers of professional appraisers: A: (100) Taipei City Appraisal No. 000175 B: (103) Taipei City Appraisal No. 000203

15. Whether the appraisal report is for a limited price, specific price, or special price: No or not applicable

16. Whether the appraisal report has not yet been obtained: No or not applicable

17. Reason for not yet obtaining the appraisal report: Not applicable

18. Reasons for significant differences in appraisal results and auditor's opinion: Not applicable

19. Name of auditor firm: Not applicable

20. Name of auditor: Not applicable

21. Auditor license number: Not applicable

22. Broker and brokerage fees: None

23. Specific purpose or use of the acquisition or disposal: To expand the advanced packaging capacity of ASE's Kaohsiung facility

24. Dissenting director's opinion on the transaction: Not applicable

25. Whether the transaction is a related-party transaction: No

26. Date of supervisor approval or audit committee consent: Not applicable

27. Whether the transaction involves acquiring real estate or right-of-use assets from a related party: No

28. Valuation price under Article 16 of the "Asset Acquisition and Disposal Rules for Publicly Issued Companies": Not applicable

29. Valuation price under Article 17 of the same rules if the price under the previous item is lower than the transaction price: Not applicable

30. Previous date of material information announcement regarding the same event: Not applicable

31. Other explanatory matters: To accelerate the handover of the subject property, both parties have agreed that AUO will expedite the dismantling, relocation, and removal of manufacturing equipment and specific facility equipment under mutually agreed conditions. ASE will compensate AUO for the associated removal costs, estimated at approximately NT$500 million (excluding tax).