[ASE Technology Holding] Announcement on behalf of subsidiary Siliconware Precision Industries Co., Ltd. regarding the acquisition of facility engineering

1. Type of contract: Facility engineering 2. Date of occurrence of the event: 2026/03/23~2026/05/15 3. Date of board of directors resolution: Not applicable 4. Date of other approval: Approval level: General Manager, May 15, 2026 5. Counterparty to the contract and its relationship with the company: Li Ming Construction Co., Ltd.; Relationship: None 6. Main content of the contract (including total amount, estimated input amount, and start/end dates), restrictive clauses and other important covenants: Total amount: NTD 1,838,600,000; Contract period: March 23, 2026, to September 30, 2027; Restrictive clauses and other important covenants: None 7. Name of the professional appraiser and its appraisal result: Not applicable 8. Name of the real estate appraiser: Not applicable 9. Practice certificate number of the real estate appraiser: Not applicable 10. Specific purpose of the acquisition: For production and operations 11. Dissenting opinions of directors to the present transaction: None 12. Is the present transaction a related party transaction: No 13. Date of approval by supervisors or the audit committee: Not applicable 14. Is the appraisal report for 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 an appraisal report: Not applicable 17. Reason for significant discrepancy with appraisal results and CPA opinion: Not applicable 18. Name of the CPA firm: Not applicable 19. Name of the CPA: Not applicable 20. Practice certificate number of the CPA: Not applicable 21. Date of previous major message regarding the same event: Not applicable 22. Other matters to be specified: None