Notice Regarding Purchase of Treasury Shares and Cancellation of Treasury Shares

Press Release

April 28, 2026 SEKISUI CHEMICAL CO., LTD.

(Acquisition of treasury shares pursuant to the provisions of the Articles of Incorporation based on the provisions of Article 165, Item 2 of the Corporate Law and cancellation of treasury shares in accordance with Article 178 of the Corporate Law)

SEKISUI CHEMICAL CO., LTD. announces that it has decided at the meeting of its board of directors held on April 28, 2025 to purchase treasury shares pursuant to the provisions of Article156 of the Corporate Law after applying the provisions of Article 165, Item 3 of the Law and to cancel the treasury shares, under the provisions of Article 178 of the Corporate Law.

1. Reasons for the acquisition and cancellation of treasury shares

   As part of shareholder returns, we will purchase and cancel our own shares.

2. Details of the acquisition

   1. Type of shares to be acquired: Common shares of SEKISUI CHEMICAL

   2. Total number of shares to be acquired: Up to 4,000,000 shares

      (Percentage of total number of issued shares (excluding treasury shares): 0.99%)

   3. Total acquisition cost: 12.0 billion yen (maximum)

   4. Acquisition period: From April 30, 2026 to March 31, 2027

   5. Acquisition method: Market purchases including pre-announcement market purchases (ToSTNeT-3)

3. Details of the cancellation

   1. Type of shares to be retired: Common shares of SEKISUI CHEMICAL

   2. Number of shares to be cancelled: 25,000,000 shares

      (5.81% of issued shares before the cancellation)

   3. Total number of shares issued after the cancellation: 405,507,285 shares

   4. Scheduled date of cancellation: May 25, 2026

(Reference) Number of treasury shares as of March 31, 2026

Total number of issued shares (excluding treasury shares): 405,092,498 Treasury shares: 25,414,787