Riso Kagaku : Notice Regarding the Results of Purchase and the Termination of Purchase of Treasury Stock

September 11, 2026

Company name: RISO KAGAKU CORPORATION

Listing: Tokyo Stock Exchange Prime Market

Stock code: 6413

Representative: Akira Hayama, President & CEO

Inquiries: Yoshiomi Narumiya, Director and General Manager of Corporate Headquarters TEL: +81-3-5441-6611 (from overseas)

(Purchase of treasury stock pursuant to the provisions of Article 165, Paragraph 2 of the Corporate Law)

RISO KAGAKU CORPORATION (the “Company”) announced that it purchased treasury stock from the market as shown below, pursuant to Article 156 of the Corporate Law of Japan as applied pursuant to Article 165, Paragraph 3 of the same Law.

It also announced the completion of the share purchase executed in compliance with the Board’s resolution dated July 31, 2026.

1. Type of shares purchased: Common stock of the Company

2. Number of shares purchased: 284,600 shares

3. Total purchase cost: 309,348,700 yen

4. Purchase period: From September 1, 2026 to September 10, 2026 (based on commitment)

5. Purchase method: Purchased on the Tokyo Stock Exchange

   • Details of purchase determined by the Board’s resolution dated July 31, 2026

1. Type of shares to be purchased: Common stock of the Company

2. Number of shares to be purchased: Up to 660,000 shares

   (Ratio against the total number of issued shares (excluding treasury stock): 1.05%)

3. Total purchase cost: Up to 600,000,000 yen

4. Purchase period: From August 21, 2026 to September 18, 2026 (based on commitment)

5. Purchase method: Purchased on the Tokyo Stock Exchange

   • Cumulative shares purchased pursuant to the resolution above (as of September 10, 2026)

1. Number of shares purchased: 536,600 shares

2. Total purchase cost: 599,965,100 yen