[Hong Shuo] Announcement regarding endorsement guarantee by major subsidiary 'Hong Shuo Precision Electronics (Suzhou)' to 'Hong Shuo Precision Electronics (Hubei)'

1. Date of event: 2026/06/03 (Note: 115/06/03 converted to Gregorian) 2. Endorsed company: (1) Company name: Hong Shuo Precision Electronics (Hubei) Co., Ltd. (2) Relationship: A wholly-owned subsidiary of Hong Shuo Precision Electronics (Suzhou) Co., Ltd. (3) Limit of guarantee (in thousands of TWD): 819,959 (4) Previous balance of guarantee (in thousands of TWD): 641,532 (5) Additional guarantee amount this time (in thousands of TWD): 97,272 (6) Total balance of guarantee as of this event (in thousands of TWD): 738,804 (7) Actual amount utilized by the endorsed company (in thousands of TWD): 234,592 (8) Reason for additional guarantee: Long-term working capital requirements, provided by the parent company as guarantor. 3. Collateral provided: (1) Description: None (2) Value (in thousands of TWD): 0 4. Latest financial statements of the endorsed company: (1) Capital (in thousands of TWD): 1,018,380 (2) Accumulated profit/loss (in thousands of TWD): -512,447 5. Conditions for releasing the guarantee: (1) Condition: Maturity of the loan agreement (2) Date: Maturity of the loan agreement 6. Total guarantee limit (in thousands of TWD): 2,699,688 7. Total balance of guarantee as of this event (in thousands of TWD): 1,940,617 8. Ratio of guarantee balance to net worth of the listed company in the latest financial report: 143.77% 9. Ratio of total balance of guarantees, long-term investments, and fund loans to net worth of the listed company in the latest financial report: 191.12% 10. Other notes: Approved by the Board of Directors of Hong Shuo (Suzhou) on June 3, 2026.