ASE Holdings Announces Subsidiary SPIL's Acquisition of Facility Engineering Project

1. Type of Contract: Facility Engineering 2. Date of Event: June 17, 2026 to June 29, 2026 (Minguo Year 115) 3. Board Approval Date: Not applicable 4. Other Approval Dates: Approval Level: Approved by General Manager Date: June 29, 2026 (Minguo Year 115) 5. Counterparty and Relationship with Company: Chung Yuan Mechanical & Electrical Consultants Inc. Relationship with Company: None 6. Main Contents of Contract (including total contract value, estimated investment amount, contract start and end dates, restrictive clauses, and other important terms): Total Amount: NT$597,795,100 Contract Period: June 17, 2026 (Minguo Year 115) to December 30, 2028 (Minguo Year 117) Restrictive Clauses and Other Important Terms: None 7. Name of Professional Appraiser Firm or Company and Appraisal Result: Not applicable 8. Name of Real Estate Appraiser: Not applicable 9. License Number of Real Estate Appraiser: Not applicable 10. Specific Purpose of Acquisition: For production and operational use 11. Dissenting Director Opinions on This Transaction: None 12. Is This a Related-Party Transaction: No 13. Date of Supervisor Approval or Audit Committee Consent: Not applicable 14. Is the Appraisal Report 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 Obtaining 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 Auditor: Not applicable 20. Auditor's License Number: Not applicable 21. Previous Date of Material Information Disclosure for the Same Event: Not applicable 22. Other Statements: None