UMC Announces Disposal of Novatek Microelectronics Corp. Securities

1. Name and nature of the subject matter (for preferred shares, specify issuance terms such as dividend rate): Ordinary shares of Novatek Microelectronics Corp.

2. Date of occurrence: June 17–18, 115 (2026)

3. Board approval date: Not applicable

4. Other approval dates: Approval level: Not applicable June 18, 115 (2026)

5. Transaction quantity, unit price, and total amount: Number of units: 2,896,036 shares Unit price: NT$479.8 Total amount: NT$1,389,518,072

6. Counterparty and its relationship with the company (if the counterparty is a natural person and not a related party, name disclosure may be omitted): Conversion exercised by holders of exchangeable bonds

7. If the counterparty is a related party, state the reason for selecting the related party, the previous transferor, relationships among the previous transferor, the company, and the counterparty, transfer date, and amount: Not applicable

8. If the owner of the subject matter was a related party of the company within the past five years, disclose the date, price, and relationship with the company at the time of acquisition and disposal: Not applicable

9. Matters related to the disposal of receivables (including types of collateral attached to the disposed receivables; if receivables from related parties, disclose names and book amounts): Not applicable

10. Gain (or loss) from disposal (not applicable for acquisition of securities) (if previously deferred, explain recognition status): Impact on retained earnings: NT$1,007,168,830 (no impact on profit or loss)

11. Delivery or payment terms (including payment period and amount), contractual restrictions, and other important agreements: Exchangeable bondholders converted into Novatek ordinary shares. Contractual restrictions: None Other important agreements: None

12. Method of transaction decision, reference basis for price determination, and decision-making unit: Transaction decision method: As per the prospectus Price determination basis: Conversion at exchange price

13. Net asset value per share of the securities-issuing company: NT$118.20

14. Cumulative holdings of the securities involved in this transaction (including this transaction) as of now, including quantity, amount, ownership percentage, and any restrictions on rights (e.g., pledge status): Quantity: 12,373,857 shares Amount: NT$5,980,931,747 Ownership percentage: 2.03% Rights restriction status: None

15. Ratio of securities investments (including this transaction) under Article 3 of the "Asset Acquisition and Disposal Rules for Publicly Issued Companies" to total assets and equity attributable to owners of the parent in the company's latest financial statements, and the amount of operating capital in the latest financial report (Note 2): Ratio to total assets: 41.91% Ratio to shareholders' equity: 57.37% Operating capital in latest financial report: NT$44,980,640 thousand

16. Broker and brokerage fees: Broker: None Brokerage fees: None

17. Specific purpose or use of the acquisition or disposal of securities: Conversion of exchangeable bonds

18. Dissenting directors' opinions on this transaction: Not applicable

19. Whether this transaction is a related-party transaction: No

20. Date of auditor's acknowledgment or audit committee approval: Not applicable

21. Whether the accountant issued a non-reasonableness opinion on this transaction: Not applicable

22. Name of accounting firm: Not applicable

23. Name of accountant: Not applicable

24. Accountant's license number: Not applicable

25. Whether it involves a change in business model: No

26. Explanation of business model change: Not applicable

27. Transaction status with the counterparty in the past year and expected in the next year: Not applicable

28. Source of funds: Not applicable

29. Previous date of material information disclosure regarding the same event: Not applicable

30. Other explanatory matters: None