Seiyo and Parent Company Yodogawa Steel Sign Equity Transfer Agreement with Hebei Xinjin Wanli New Material Technology Co., Ltd.

Announcement Date: June 26, 2026 Release Time: 12:00:06 Company Code: 2029 Company Name: Seiyo

Subject: Announcement of Equity Transfer Agreement Signed by the Company and Its Parent, Yodogawa Steel Corporation of Japan, with Hebei Xinjin Wanli New Material Technology Co., Ltd.

Compliance Clause: Item 10 Factual Date: June 26, 2026

Details: 1. Factual Date: June 26, 2026 2. Counterparty: Hebei Xinjin Wanli New Material Technology Co., Ltd. 3. Relationship with the Company: None 4. Contract Period: June 26, 2026 – December 25, 2026 5. Main Content: - Transfer of 95% equity in Dianchuan Seiyo (Hefei) High-Tech Steel Plate Co., Ltd. to Hebei Xinjin Wanli New Material Technology Co., Ltd. - Yodogawa Steel Corporation transfers 74.09% (RMB 181,522,705) - Seiyo transfers 20.91% (RMB 51,227,295) 6. Restrictive Clauses: As stipulated in the contract 7. Commitments: As stipulated in the contract 8. Other Important Provisions: As stipulated in the contract 9. Impact on Company's Financials and Operations: No significant impact on the company's financials or operations 10. Purpose: To strategically allocate and concentrate management resources for overseas operations and enhance corporate value through the equity transfer 11. Other Matters to be Disclosed: None

This announcement may qualify as a material event under Article 7, Clause 8 of the Enforcement Rules of the Securities and Exchange Act, if the subject entity is a publicly listed company. However, no such matters are currently applicable.