ASE Holdings Announces Subsidiary's Acquisition of Operating Equipment from Related Party Advantest Technology

1. Name and nature of the subject matter (e.g., land located in Section XX, Subsection XX, North District, Taichung City): Machinery and equipment for operational use

2. Date of occurrence: October 9, 2025 ~ September 11, 2026

3. Board approval date: September 11, 2026 (Republic Era 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: Transaction quantity: One batch Unit price: NT$334,297,000 (excluding tax) Total transaction amount: NT$334,297,000 (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: Advantest Technology Co., Ltd. Relationship with the company: An equity-method associated enterprise of ASE Semiconductor Manufacturing Co., Ltd. (hereinafter referred to as "ASE")

7. If the counterparty is a related party, state the reason for selecting the related party as the transaction party, the previous transferor, the relationship among the previous transferor, the company, and the counterparty, the previous transfer date, and transfer amount: Reason for selecting related party as transaction party: Ensures stable supply of equipment for ASE’s operational needs and effectively reduces supply chain risks

Previous transferor: Not applicable Relationship among previous transferor, company, and counterparty: Not applicable Previous transfer price: Not applicable Previous acquisition date: Not applicable

8. If the ownership of the subject asset was held by a related party of the company within the past five years, disclose the acquisition and disposal dates, prices, and relationship with the company at the time: Not applicable

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

10. Delivery or payment terms (including payment period and amount), contractual restrictions, and other important agreements: Delivery or payment terms: Payment via telegraphic transfer or letter of credit Contractual restrictions: None Other important agreements: None

11. Decision method for this transaction (e.g., bidding, price comparison, or negotiation), reference basis for price determination, and decision-making unit: Transaction decision method and price determination basis: Price comparison and negotiation Decision-making unit: Implemented pursuant to the resolution of the ASE board of directors

12. Name of professional appraiser firm or company and appraisal amount: Not applicable

13. Name of professional appraiser: Not applicable

14. License number of professional appraiser: 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 result, state the reason and auditor's opinion: Not applicable

19. Name of accounting firm: Not applicable

20. Name of accountant: Not applicable

21. License number of accountant: Not applicable

22. Broker and brokerage fees: None

23. Specific purpose or use of the acquisition or disposal: For production and operational use

24. Opinion of any director who objected to this transaction: Not applicable

25. This transaction is a related-party transaction: Yes

26. Date of supervisor approval or audit committee consent: September 11, 2026 (Republic Era 115)

27. This 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 valuation under the previous item is lower than the transaction price: Not applicable

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

31. Other explanatory matters: None