Yao-Deng Provides New Endorsement Guarantee of NT$193.86 Million to Vietnamese Subsidiary

Disclosure Date: August 7, 2026 Statement Date: August 6, 2026 Statement Time: 4:23:05 Company Code: 3138 Company Name: Yao-Deng Subject: The Company Announces Matters Pursuant to Article 25, Paragraph 1, Clause 4 of the Handling Principles for Loans and Endorsements by Publicly Issued Companies

Applicable Clause: Clause 22 Event Date: August 5, 2026

Explanation: 1. Event Date: 08/05/2026

2. Endorsed Entity: (1) Company Name: AUDEN TECHNO VIETNAM CO.,LTD. (2) Relationship with Guarantor: Grandchild company indirectly holding 100% equity (3) Endorsement Limit (in thousand NTD): 528,833 (4) Previous Endorsement Balance (in thousand NTD): 0 (5) Amount of New Endorsement This Time (in thousand NTD): 193,860 (6) Endorsement Balance as of Event Date (in thousand NTD): 193,860 (7) Actual Amount Drawn by Endorsed Company (in thousand NTD): 26,336 (8) Reason for New Endorsement: Working capital requirement

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

4. Latest Financial Statements of Endorsed Company: (1) Capital (in thousand NTD): 199,266 (2) Accumulated Profit/Loss (in thousand NTD): -35,562

5. Conditions for Release of Endorsement Liability: (1) Condition: As per contractual terms (2) Date: As per contractual terms

6. Total Endorsement Limit (in thousand NTD): 1,057,666

7. Total Endorsement Balance as of Event Date (in thousand NTD): 355,410

8. Ratio of Endorsement Balance to Net Equity of the Publicly Issued Company Based on Most Recent Financial Statement as of Event Date: 13.44%

9. Combined Ratio of Endorsement, Long-Term Investment, and Loan Balances to Net Equity of the Publicly Issued Company Based on Most Recent Financial Statement as of Event Date: 29.07%

10. Other Disclosures: Net equity calculated using exchange rate from Q2 2026 financial report: 1 USD = 31.85 TWD Endorsement amount converted using end-of-July exchange rate: 1 USD = 32.31 TWD