Riso Kagaku : Notice Regarding the Status of Purchase of Treasury Stock

December 1, 2025

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)

Notice Regarding the Status of Purchase of Treasury Stock

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

RISO KAGAKU CORPORATION (the “Company”) announced the status of treasury stock 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.

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

2. Number of shares purchased: 175,000 shares

3. Total purchase cost: 213,445,000 yen

4. Purchase period: From November 19, 2025 to November 30, 2025 (based on commitment)

5. Purchase method: Purchased on the Tokyo Stock Exchange

Details of purchase determined by the Board’s resolution dated November 5, 2025

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

2. Number of shares to be purchased: Up to 470,000 shares

   (Ratio against the total number of issued shares (excluding treasury stock):0.74%)

3. Total purchase cost: Up to 500,000,000 yen

4. Purchase period: From November 19, 2025 to December 23, 2025 (based on commitment)

5. Purchase method: Purchased on the Tokyo Stock Exchange