CHTMC Announces Acquisition of Marketable Securities

1. Security Name: MediaTek Common Stock

2. Transaction Date: June 17, 2026 – June 24, 2026

3. Board Approval Date: Not applicable

4. Other Approval Date: Approval Level: Approved by Chairman June 24, 2026 (Minguo Year 115)

5. Transaction Quantity, Unit Price, and Total Amount: Quantity (in thousands of shares): 72 Unit Price (NT$): 4,402.27 Total Transaction Amount (NT$): 316,963,443

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 Security (including this transaction) to Date – Quantity, Amount, Ownership Percentage, and Restricted Rights (e.g., pledged): Balance Held: 35,000 shares, Amount: NT$152,826,542 Ownership Percentage: 0.002%, Rights Restrictions: None

9. Proportion of Marketable Securities Investment (including this transaction) under Article 3 of the 'Asset Acquisition and Disposal Rules for Publicly Issued Companies' to the Company’s Total Assets and Equity Attributable to Owners of the Parent in the Most Recent Financial Statements, and the Amount of Working Capital in the Most Recent Financial Statements: Percentage of Total Assets: 82.16% Percentage of Equity Attributable to Owners of the Parent: 117.99% Working Capital Amount: NT$8,285,327 thousand

10. Specific Purpose of Acquisition or Disposal: Investment portfolio management

11. Dissenting Director Opinions on This Transaction: None

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

13. Counterparty and Its Relationship with the Company: Not applicable

14. Date of Supervisor Acknowledgment or Audit Committee Approval: Not applicable

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

16. Other Explanatory Matters: On March 31, 2026 (Minguo Year 115), authorized traders were granted permission to conduct securities transactions in the centralized market during the second quarter of 2026.