[ASE Technology Holding] Announcement of Factory Engineering Contract by Subsidiary Siliconware Precision Industries Co., Ltd.

1. Contract Type: Factory Engineering 2. Date of Fact Occurrence: 2026/5/5 ~ 2026/5/11 3. Board Approval Date: Not applicable 4. Other Approval Dates: Approval Level: General Manager Approval May 11, 2026 5. Contracting Party and Relationship with the Company: Sheng Yi Fa Construction Co., Ltd. Relationship with the Company: None 6. Main Contract Contents (including total contract amount, estimated investment amount, and contract start/end dates), restrictive clauses, and other important agreements: Total Amount: NTD 2,485,700,000; Contract Period: May 5, 2026, to December 31, 2026; Restrictive Clauses and Other Important Agreements: None 7. Professional Appraisal Firm or Company Name and Appraisal Results: Not applicable 8. Real Estate Appraiser Name: Not applicable 9. Real Estate Appraiser Practice Certificate Number: Not applicable 10. Specific Purpose of Acquisition: For production and operational use 11. Dissenting Board Member Opinions on this Transaction: None 12. Is this transaction a related party transaction? No 13. Supervisor's Approval or Audit Committee's Approval Date: Not applicable 14. Is the appraisal report a limited price, specific price, or special price? No or not applicable 15. Has the appraisal report not yet been obtained? No or not applicable 16. Reason for not obtaining the appraisal report: Not applicable 17. Reason for significant difference in appraisal results and accountant's opinion: Not applicable 18. Accounting Firm Name: Not applicable 19. Accountant Name: Not applicable 20. Accountant Practice Certificate Number: Not applicable 21. Date of previous material information release on the same matter: Not applicable 22. Other descriptions: None