ASE Technology Holding Co., Ltd. Announces Subsidiary Acquisition of Machinery Equipment from Hongteng Technology Co., Ltd.

1. Name and nature of the subject matter (e.g., land located at XX Section, XX Sub-section, North District, Taichung City): Machinery equipment for business use 2. Date of occurrence: June 12, 2025 to June 8, 2026 (ROC calendar) 3. Date of board approval: Not applicable 4. Other approval date: Approval level: General Manager approval June 8, 2026 (ROC calendar) 5. Quantity (e.g., XX square meters, converted to XX ping), unit price, and total transaction amount: Quantity: One batch Unit price: NT$1,450,284 thousand (before tax) Cumulative total transaction amount: NT$1,450,284 thousand (before tax) 6. Counterparty and its relationship with the company (if the counterparty is a natural person and not a related party, disclosure of the name may be omitted): Counterparty: Hongteng Technology Co., Ltd. Relationship with the company: None 7. If the counterparty is a related party, reasons for selecting the related party and information on the previous transfer: Not applicable 8. If the owner of the subject matter within the past five years was a related party of the company, information on the related party's acquisition and disposal dates, prices, and relationship with the company: Not applicable 9. Expected disposal gain or loss (not applicable for asset acquisition): 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: Price comparison and negotiation Decision-making unit: According to the company's approval authority regulations 12. Name of professional appraisal firm and its appraisal amount: Not applicable 13. Name of professional appraiser: Not applicable 14. Professional appraiser's 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 reasons for the difference and the CPA's opinion: Not applicable 19. Name of CPA firm: Not applicable 20. Name of CPA: Not applicable 21. CPA's license number: Not applicable 22. Broker and brokerage fee: None 23. Specific purpose or use of the acquisition or disposal: For production and business operations 24. Opinions of directors who expressed dissent on this transaction: Not applicable 25. Whether this transaction is a related party transaction: No 26. Date of approval by the supervisor or audit committee: Not applicable 27. Whether this transaction involves acquiring 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. Price evaluated in accordance with Article 17 of the same regulations if the evaluation price under the preceding article is lower than the transaction price: Not applicable 30. Date of previous material announcement on the same event: Not applicable 31. Other matters: None