[ASE Technology Holding] Subsidiary Siliconware Precision Industries Announces Acquisition of Plant Engineering Services

1. Type of contract: Plant engineering. 2. Date of occurrence: April 15, 2026, to April 27, 2026. 3. Date of approval by the board of directors: Not applicable. 4. Other authorization date: Authorized by the General Manager on April 27, 2026. 5. Counterparty and relationship with the company: Sheng Hui Engineering Technology Co., Ltd. Relationship: None. 6. Main content of the contract (including total amount, expected investment, and duration), restrictive clauses, and other important agreements: Total amount: NTD 1,075,137,000; Contract period: April 15, 2026, to December 31, 2027; Restrictive clauses and other important agreements: None. 7. Name of professional valuation firm or company and valuation results: Not applicable. 8. Name of real estate appraiser: Not applicable. 9. Real estate appraiser's license number: Not applicable. 10. Specific purpose of acquisition: For production and operational use. 11. Dissenting opinions from directors regarding this transaction: None. 12. Is this a related party transaction: No. 13. Date of approval by supervisor or audit committee: Not applicable. 14. Whether the appraisal report is for limited, specific, or special price: No or not applicable. 15. Whether the appraisal report has not been obtained: No or not applicable. 16. Reason for not obtaining the appraisal report: Not applicable. 17. Reasons for significant differences in appraisal results and auditor's opinion: Not applicable. 18. Name of accounting firm: Not applicable. 19. Name of accountant: Not applicable. 20. Accountant's license number: Not applicable. 21. Date of previous announcement on the same event: Not applicable. 22. Other matters to be specified: None.