[Steel Union] Announcement of Consolidated Self-Audited Profit and Loss for April 2026

1. Date of occurrence of the event: 2026/05/07 2. Company name: Taiwan Steel Union Co., Ltd. 3. Relationship with the company (please enter "the company" or "subsidiary"): The company 4. Mutual shareholding ratio: Not applicable 5. Reason for occurrence:

(Unit: NT$ thousand) April 2026 April 2025 Jan-Apr 2026 Jan-Apr 2025 Consolidated net operating revenue 372,826 242,274 807,912 735,055 Consolidated self-audited operating profit (loss) 201,702 104,769 369,785 294,057 Consolidated self-audited pre-tax profit (loss) 198,059 103,485 366,174 282,934 This data represents the company's consolidated self-compiled figures and has not yet been audited by an accountant.

The company's revenue primarily comes from the sale of zinc oxide and revenue from customer waste recycling. Customer waste recycling revenue is recognized based on the actual recycled volume. In addition, the shipment volume of zinc oxide is as follows, and its revenue recognition is handled in accordance with the regulations for preparing financial reports by securities issuers: 2026 2025 4-month shipment volume (tons) 4,375 4,326 Jan-Apr shipment volume (tons) 16,143 18,269

The company's self-compiled revenue for April 2026 was announced on May 7, 2026, on the Market Observation System. 6. Countermeasures: Not applicable. 7. Other matters that need to be specified (If the subject of the event or resolution is a public offering company or above, this material information also complies with Article 7, Paragraph 9 of the Enforcement Rules of the Securities and Exchange Act regarding matters that have a material impact on shareholders' equity or securities prices): None.