【ASE Technology Holding】Announcement on behalf of its subsidiary ASE Semiconductor Manufacturing Co., Ltd. regarding the acquisition of factory engineering services for operational use from Chang Ding Engineering Co., Ltd.

1. Name and nature of the subject matter (e.g., land in XX section, XX subsection, Beitun District, Taichung City): Factory engineering services for operational use 2. Date of occurrence of the event: 2025/12/17~2026/4/29 3. Date of approval by the Board of Directors: Not applicable 4. Other approval dates: Approval level: General Manager's approval April 29, 2026 5. Quantity of transaction units (e.g., XX square meters, equivalent to XX ping), unit price, and total transaction amount: Transaction quantity: One batch Unit price: NT$418,883 thousand (excluding tax) Cumulative total transaction amount: NT$418,883 thousand (excluding tax) 6. Counterparty and its relationship with the company (if the counterparty is a natural person and not a related party of the company, their name may be omitted): Counterparty: Chang Ding Engineering Co., Ltd. Relationship with the company: None 7. If the counterparty is a related party, the reason for selecting the related party as the transaction object, the previous owner, the relationship between the previous owner and the company and the counterparty, the previous transfer date, and the transfer amount should also be announced: Not applicable 8. If the ownership of the transaction subject has been a related party of the company within the last five years, the acquisition and disposal dates, prices, and the relationship with the company at the time of the transaction of the related party should also be announced: Not applicable 9. Estimated disposal profit (or loss) (not applicable for asset acquisition) (for deferred items, a table should be provided to explain the recognition status): Not applicable 10. Delivery or payment terms (including payment period and amount), contract restriction clauses, and other important agreements: Delivery or payment terms: Wire transfer or letter of credit payment Contract restriction clauses: None Other important agreements: None 11. Method of determining this transaction (e.g., bidding, price comparison, or negotiation), basis for price determination, and decision-making unit: Method of determining the transaction and basis for price determination: Price comparison and negotiation Decision-making unit: Handled according to the company's approval authority regulations 12. Name of professional appraiser's firm or company and its appraisal amount: Not applicable 13. Name of professional appraiser: Not applicable 14. Professional appraiser's license number: Not applicable 15. Is the appraisal report a limited price, specific price, or special price: No or not applicable 16. Has the appraisal report not yet been obtained: No or not applicable 17. Reason for not yet obtaining the appraisal report: Not applicable 18. If there is a significant difference in the appraisal results, the reason for the difference and the accountant's opinion: Not applicable 19. Name of accounting firm: Not applicable 20. Name of accountant: Not applicable 21. Accountant's license number: Not applicable 22. Broker and brokerage fees: None 23. Specific purpose or use of acquisition or disposal: For production and operational use 24. Opinions of directors who expressed dissent to this transaction: Not applicable 25. Is this transaction a related party transaction: No 26. Date of approval by supervisors or Audit Committee: Not applicable 27. Is this transaction the acquisition of real estate or its right-of-use assets from a related party: No 28. Price evaluated according to Article 16 of the "Regulations Governing the Acquisition and Disposal of Assets by Public Companies": Not applicable 29. If the price evaluated in the preceding item is lower than the transaction price, the price evaluated according to Article 17 of the same regulations: Not applicable 30. Date of previous material information announcement regarding the same event: Not applicable 31. Other matters to be specified: None