[CMC] Announcement of the acquisition of securities by the company

1. Name of securities: LandMark Optoelectronics Common Stock 2. Transaction date: March 26, 2027 to April 27, 2027 3. Date of board approval: Not applicable 4. Other authorization date: Level of authorization: Chairman's approval on April 27, 2027 5. Transaction volume, unit price, and total amount: Transaction volume (thousand shares): 184 Unit price (TWD): 2,424.93 Total amount (TWD): 446,187,649 6. Gain (or loss) from disposal (not applicable to acquisition): Not applicable 7. Relationship with the transaction target company: None 8. Cumulative holding of the transaction securities to date (including this transaction): volume, amount, shareholding ratio, and rights restrictions: Balance held: 105,000 shares; Amount: 278,834,990 TWD Shareholding ratio: 0.11%; Rights restrictions: None 9. Ratio of total investment in securities to total assets and equity attributable to owners of the parent company as listed in the latest financial statements, and working capital amount: Ratio to total assets: 76.43% Ratio to equity attributable to owners of the parent: 107.06% Working capital amount: 8,285,327 thousand TWD 10. Specific purpose of acquisition or disposal: Investment portfolio 11. Opinions of dissenting directors for this transaction: None 12. Is this transaction a related party transaction: No 13. Counterparty and relationship with the company: Not applicable 14. Date of supervisor's acknowledgment or audit committee's approval: Not applicable 15. Date of previous announcement on the same event: Not applicable 16. Other stated matters: Authorized the designated trader on March 31, 2027, to conduct securities transactions in the centralized exchange market during the second quarter of 2027.