ASE Technology Holding Co., Ltd. Announces Subsidiary ASE Semiconductor Manufacturing Inc. Acquires Factory Engineering from Marketech International Corp.

1. Name and nature of the subject matter (e.g., land located in XX Section, XX Subsection, North District, Taichung City): Factory engineering for business use 2. Date of occurrence: 115/5/19 ~ 115/6/8 3. Date of board approval: Not applicable 4. Other approval date: Approval level: Approved by General Manager June 8, 2026 (Minguo 115) 5. Transaction quantity (e.g., XX square meters, converted to XX ping), unit price, and total transaction amount: Transaction quantity: One batch Unit price: NT$793,729 thousand (excluding tax) Cumulative total transaction amount: NT$793,729 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, disclosure of name may be omitted): Counterparty: Marketech International Corp. Relationship with the company: None 7. If the counterparty is a related party, the reason for selecting the related party as the transaction counterparty, the previous owner, the relationship between the previous owner and the company and the counterparty, the date of previous transfer, and the transfer amount shall be disclosed: Not applicable 8. If the owner of the subject matter within the past five years was a related party of the company, the date and price of acquisition and disposal by the related party, and the relationship with the company at the time of the transaction shall be disclosed: Not applicable 9. Expected disposal gain or loss (not applicable for acquisition of assets) (if deferred, the recognition status shall be listed): Not applicable 10. Delivery or payment terms (including payment period and amount), contract restrictions, and other important terms: Delivery or payment terms: Payment by wire transfer or letter of credit Contract restrictions: None Other important terms: None 11. Method of decision for this transaction (e.g., tender, price comparison, or negotiation), reference basis for price determination, and decision-making unit: Method of decision and reference basis for price determination: Price comparison and negotiation Decision-making unit: According to the company's approval authority regulations 12. Name of professional appraiser firm or company and its appraisal amount: Not applicable 13. Name of professional appraiser: Not applicable 14. Professional appraiser license number: Not applicable 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. 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 license number: Not applicable 22. Broker and brokerage fee: None 23. Specific purpose or use of acquisition or disposal: For production and operation 24. Opinions of directors who expressed dissent to this transaction: Not applicable 25. Whether this transaction is a related party transaction: No 26. Date of supervisor approval or audit committee consent: Not applicable 27. Whether this transaction is the acquisition of real estate or right-of-use assets from a related party: No 28. Price evaluated in accordance with 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 in accordance with Article 17 of the same regulations: Not applicable 30. Date of previous material information announcement on the same event: Not applicable 31. Other matters to be stated: None