[ASE Technology Holding] Announces Subsidiary Siltronic Precision Industrial Co., Ltd. Acquired Facility Engineering Services

1. Contract Type: Facility Engineering 2. Date of Fact Occurrence: 2026/02/23 ~ 2026/04/15 3. Date of Board Resolution: Not applicable 4. Date of Other Approvals: Approval Level: General Manager Approval April 15, 2026 5. Counterparty to Contract and Relationship with Company: Sung Feng Engineering Technology Co., Ltd. Relationship with Company: None 6. Main Content of Contract (including total contract amount, planned investment amount, and contract period), restrictive clauses, and other important agreements: Total Amount: NT$1,165,769,000; Contract Period: February 23, 2026, to December 31, 2027; Restrictive Clauses and Other Important Agreements: None 7. Name of Professional Appraisal Firm or Company and its Appraisal Result: Not applicable 8. Name of Real Estate Appraiser: Not applicable 9. Real Estate Appraiser's 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. Date of Supervisor's Approval or Audit Committee's Consent: Not applicable 14. Is the Appraisal Report Based on a Limited Price, Specific Price, or Special Price: No or Not applicable 15. Has an Appraisal Report Not Yet Been Obtained: No or Not applicable 16. Reason for Not Yet Obtaining Appraisal Report: Not applicable 17. Reason for Significant Difference in Appraisal Result and Accountant's Opinion: Not applicable 18. Name of Accounting Firm: Not applicable 19. Name of Accountant: Not applicable 20. Accountant's Practice Certificate Number: Not applicable 21. Date of Previous Material Information Announcement for the Same Event: Not applicable 22. Other Matters to be Noted: None