[ASE Technology] Subsidiary SPIL Announces Facility Engineering Contract

1. Contract type: Facility engineering. 2. Date of occurrence: April 27, 2026 to May 19, 2026. 3. Board approval date: N/A. 4. Other authorization dates: Authorized by the General Manager on May 19, 2026. 5. Counterparty and relationship with the company: Acter Co., Ltd.; Relationship: None. 6. Main contract content (including total amount, expected investment, and duration): Total amount: 535,483,900 TWD; Contract duration: April 27, 2026 to July 31, 2027; Restrictions and other important terms: None. 7. Name of professional appraiser or firm and results: N/A. 8. Name of real estate appraiser: N/A. 9. Real estate appraiser license number: N/A. 10. Specific purpose of acquisition: To support production and operations. 11. Opinions of directors dissenting on this transaction: None. 12. Is this a related-party transaction: No. 13. Date of approval by supervisor or audit committee: N/A. 14. Is the appraisal report for a limited, specific, or special price: No or N/A. 15. Has the appraisal report not been obtained yet: No or N/A. 16. Reason for not obtaining appraisal report: N/A. 17. Reasons for significant discrepancies in valuation results and CPA opinion: N/A. 18. Name of accounting firm: N/A. 19. CPA name: N/A. 20. CPA license number: N/A. 21. Date of prior material announcement for the same event: N/A. 22. Other disclosures: None.