5546 Yung Ku-KY Announces Additional Endorsement Guarantee for Subsidiary

Announcement Date: August 7, 2026 Statement Date: August 6, 2026 Statement Time: 18:53:04 Company Code: 5546 Company Name: Yung Ku-KY Subject: Announcement by subsidiary Chongqing Lari Yung Ku Concrete Co., Ltd. regarding a newly added endorsement guarantee that meets the disclosure criteria under Article 25, Paragraph 1, Clause 3 of the Handling Principles for Loans and Endorsement Guarantees by Publicly Issued Companies. Applicable Clause: Clause 22 Factual Event Date: August 6, 2026

Details: 1. Factual Event Date: 08/06/2026

2. Guaranteed Party: (1) Company Name: Chongqing Dongzhao Changsheng New Building Materials Co., Ltd. (2) Relationship with Guarantee Provider: Both companies are wholly-owned (100%) subsidiaries directly held by the same group. (3) Endorsement Guarantee Limit (in thousand NTD): 8,733,255 (4) Previous Endorsement Guarantee Balance (in thousand NTD): 38,216 (5) Amount of Newly Added Guarantee (in thousand NTD): 47,292 (6) Endorsement Guarantee Balance as of Factual Event Date (in thousand NTD): 85,508 (7) Actual Amount Drawn by Guaranteed Party (in thousand NTD): 38,216 (8) Reason for New Guarantee: Approved by the board of directors to support a subsidiary’s loan facility application. Disclosure required as threshold was met at announcement time.

3. Collateral Provided by Guaranteed Party: (1) Description: None (2) Value (in thousand NTD): 0

4. Latest Financial Statement Data of Guaranteed Party: (1) Capital (in thousand NTD): 92,210 (2) Accumulated Profit/Loss (in thousand NTD): -13,410

5. Conditions for Release from Guarantee Liability: (1) Condition: Guarantee liability will be released once the subsidiary cancels its borrowing facility with the bank. (2) Date: Upon fulfillment of above condition.

6. Total Endorsement Guarantee Limit (in thousand NTD): 51,859,259

7. Total Endorsement Guarantee Balance as of Factual Event Date (in thousand NTD): 1,088,487

8. Ratio of Endorsement Guarantee Balance Provided by Party A to Net Equity in Latest Financial Statements of Public Company: 56.98%

9. Combined Ratio of Endorsement Guarantees, Long-Term Investments, and Fund Lending to Net Equity in Latest Financial Statements: 117.85%

10. Other Disclosures: Exchange rates used: RMB 4.777, USD 32.245 per unit, as of August 6, 2026.