1457 Yee Chin: Announcement of Securities Acquisition Exceeding NT$300 Million

Release Date: July 17, 2026 Statement Date: July 16, 2026 Statement Time: 15:15:07 Company Code: 1457 Company Name: Yee Chin Subject: Announcement of cumulative acquisition of securities exceeding NT$300 million by the company and its subsidiary within one year Applicable Clause: Clause 20 Factual Date: July 16, 2026

1. Name of Security: Quanta Computer Inc. Common Stock

2. Transaction Date: March 9, 2026 – July 16, 2026

3. Board Approval Date: Not applicable

4. Other Approval Dates: Approval Level: Chairman July 16, 2026

5. Transaction Quantity, Unit Price, and Total Transaction Amount: Yee Chin: 532,000 shares, average price approximately NT$305.27 Yi Dong: 561,000 shares, average price approximately NT$304.48 Total Transaction Amount: NT$333,221,147

6. Gain (or Loss) on Disposal (not applicable for acquisition of securities): Not applicable

7. Relationship with the Target Company: None

8. Cumulative Holdings of the Subject Securities (including this transaction) to Date – Quantity, Amount, Ownership Percentage, and Restrictions (e.g., Pledge Status): (1) Cumulative holdings (including this transaction): 320,000 shares (2) Investment amount (including this transaction): NT$112,460,020 (3) Ownership percentage: 0.008%

9. Cumulative securities investments (including this transaction) under Article 3 of the “Asset Acquisition and Disposal Rules for Publicly Issued Companies” as a percentage of total assets and equity attributable to owners of the parent in the latest financial statements, and the amount of working capital in the latest financial statements: (1) Securities investment as a percentage of total assets: 11.56% (2) Securities investment as a percentage of shareholders’ equity: 19.52% (3) Working capital: NT$425,566 thousand

10. Specific Purpose of Acquisition or Disposal: To improve capital utilization efficiency

11. Dissenting Director’s Opinion on this Transaction: Not applicable

12. Whether this Transaction is a Related-Party Transaction: No

13. Counterparty and Relationship with the Company: None

14. Date of Supervisor’s Approval or Audit Committee’s Consent: Not applicable

15. Previous Date of Material Information Disclosure on the Same Event: Not applicable

16. Other Disclosures: None