Treasury share acquisition: results report

What happened

Treasury Share Acquisition Results Report (Form 6.0) Dongnam Chemical Co., Ltd. Treasury Share Acquisition Results Report To the Commissioner of the Financial Supervisory Service July 7, 2026

Company Name: Dongnam Chemical Co., Ltd. Representative Director: Park Mi-ryeong Head Office Address: 80-61 Tancheon Industrial Complex-gil, Tancheon-myeon, Gongju-si, Chungcheongnam-do (Phone) 041-840-3100 (Website) http://www.dongnamchem.com Preparer: (Title) Division Head (Name) Seo Won-cheol (Phone) 031-472-7619

1. Name and Address of the Issuer (a) Name: Dongnam Chemical Co., Ltd. (b) Address: 80-61 Tancheon Industrial Complex-gil, Tancheon-myeon, Gongju-si, Chungcheongnam-do

2. Details of the Acquisition Report (a) Date the material event report was filed: May 4, 2026 (b) Acquisition period: from May 6, 2026 to August 5, 2026 (*) The above dates are based on trade execution dates.

3. Details of Acquisition (Unit: KRW, shares) Date: 2026-05-06; Share type: common shares; Order quantity: 400; Acquired quantity: 400; Price per share (KRW): 30,900; Total acquisition amount (KRW): 12,360,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-07; Share type: common shares; Order quantity: 400; Acquired quantity: 400; Price per share (KRW): 31,150; Total acquisition amount (KRW): 12,460,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-08; Share type: common shares; Order quantity: 400; Acquired quantity: 400; Price per share (KRW): 31,000; Total acquisition amount (KRW): 12,400,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-11; Share type: common shares; Order quantity: 400; Acquired quantity: 400; Price per share (KRW): 30,950; Total acquisition amount (KRW): 12,380,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-12; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,450; Total acquisition amount (KRW): 15,225,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-13; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,350; Total acquisition amount (KRW): 15,175,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-14; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,300; Total acquisition amount (KRW): 15,150,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-15; Share type: common shares; Order quantity: 500; Acquired quantity: 216; Price per share (KRW): 29,950; Total acquisition amount (KRW): 6,469,200; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-18; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,450; Total acquisition amount (KRW): 15,225,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-19; Share type: common shares; Order quantity: 400; Acquired quantity: 400; Price per share (KRW): 30,550; Total acquisition amount (KRW): 12,220,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-20; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,050; Total acquisition amount (KRW): 15,025,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-21; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,600; Total acquisition amount (KRW): 14,800,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-22; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,750; Total acquisition amount (KRW): 14,875,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-26; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,600; Total acquisition amount (KRW): 14,800,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-27; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,500; Total acquisition amount (KRW): 14,750,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-28; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 28,950; Total acquisition amount (KRW): 14,475,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-05-29; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 28,900; Total acquisition amount (KRW): 14,450,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-01; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 28,800; Total acquisition amount (KRW): 14,400,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-04; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 28,550; Total acquisition amount (KRW): 14,275,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-09; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,350; Total acquisition amount (KRW): 19,845,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-10; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,300; Total acquisition amount (KRW): 19,810,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-11; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,750; Total acquisition amount (KRW): 20,125,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-12; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,000; Total acquisition amount (KRW): 20,300,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-15; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,100; Total acquisition amount (KRW): 20,370,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-16; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,900; Total acquisition amount (KRW): 20,230,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-17; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,700; Total acquisition amount (KRW): 20,090,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-18; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,000; Total acquisition amount (KRW): 20,300,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-19; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,900; Total acquisition amount (KRW): 20,930,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-22; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,550; Total acquisition amount (KRW): 20,685,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-23; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 29,550; Total acquisition amount (KRW): 20,685,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-24; Share type: common shares; Order quantity: 700; Acquired quantity: 700; Price per share (KRW): 28,850; Total acquisition amount (KRW): 20,195,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-25; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,900; Total acquisition amount (KRW): 14,950,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-26; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,300; Total acquisition amount (KRW): 14,650,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-29; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 28,650; Total acquisition amount (KRW): 14,325,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-06-30; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,550; Total acquisition amount (KRW): 14,775,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-07-01; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 30,250; Total acquisition amount (KRW): 15,125,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-07-02; Share type: common shares; Order quantity: 500; Acquired quantity: 500; Price per share (KRW): 29,500; Total acquisition amount (KRW): 14,750,000; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Date: 2026-07-03; Share type: common shares; Order quantity: 378; Acquired quantity: 378; Price per share (KRW): 28,950; Total acquisition amount (KRW): 10,943,100; Brokerage: NH Investment & Securities; Financial investment firm ID: 00120182 Total: Order quantity 20,778; Acquired quantity 20,494; Average price per share (KRW) 29,472; Total acquisition amount (KRW) 603,997,300 (*) The above dates are based on trade execution dates; the total acquisition amount does not include brokerage fees.

4. Whether the Planned and Actual Acquisition Amounts Match Planned acquisition amount (KRW): common shares 604,000,000; other shares - Total acquisition amount (KRW): common shares 603,997,300; other shares - Whether the planned amount was underachieved: common shares -; other shares - Reason if underachieved: - (*) The planned acquisition amount is based on the closing price on April 30, 2026, the trading day immediately before the board resolution to acquire treasury shares.

5. Status of Treasury Shares Held After Acquisition [as of July 7, 2026] (Unit: KRW, shares, %) Share type: Common shares Holdings under Article 165-3 (A): Quantity 170,780; Ratio 4.88%; Total value (KRW) 5,858,207,947 Holdings under trust contract per Article 165-3 (B): Quantity -; Ratio -; Contract amount - Total (A+B): Quantity 170,780; Ratio 4.88%; Total value (KRW) 5,858,207,947 Overall total: Quantity 170,780; Ratio 4.88%; Amount (KRW) 5,858,207,947

6. Changes in the Largest Shareholder's Holdings Before and After Acquisition [as of July 7, 2026] (Unit: shares) Name: Miwon Holdings Co., Ltd.; Share type: common shares; Holdings on the acquisition report date: 1,480,000; Holdings on the acquisition end date: 1,480,000; Reason for change: - Subtotal (common shares): 1,480,000 / 1,480,000 / - Grand total: 1,480,000 / 1,480,000 / -