Trust Contract Termination Report — Treasury Share Buyback of KRW 10 Billion Complete — Dongjin Semichem

Summary

Dongjin Semichem has completed the termination of a specific money trust contract established for treasury share acquisition, with the trust terminated on August 31, 2026 through Daishin Securities. A total of 234,800 common shares were purchased at an aggregate cost of approximately KRW 9.999 billion, representing 99.99% utilization of the KRW 10 billion trust contract. The minor shortfall versus the planned acquisition amount was attributable to management fees and transaction commissions paid to the trustee. Following the trust termination, the company now directly holds 234,800 treasury shares, equal to 0.46% of its total outstanding shares of 50,970,126. The buyback is now fully settled with no remaining trust balance outstanding.

Historical Impact

3 past Other events at Dongjin Semichem

Median +5d

+1.79%

Range

-4.43% to +6.16%

Positive outcomes

2/3

Filed	P₀	P₊₅	+5d
Apr 16, 2026	₩56,800	₩60,300	+6.16%
Mar 12, 2026	₩50,800	₩48,550	-4.43%

Full Translation

Trust Contract Termination Result Report To: Chairman, Financial Supervisory Service Date: September 2, 2026 Company Name: Dongjin Semichem Co., Ltd. Representative Director: Lee Joon-hyuk Headquarters: 644 Baekbeom-ro, Seo-gu, Incheon Metropolitan City Tel: 032-578-5091 Website: https://www.dongjin.com Prepared by: (Title) Executive Director (Name) Jeong Seong-yeop Tel: 02-325-9421 1. Issuer Name and Address a. Name: Dongjin Semichem Co., Ltd. b. Address: 644 Baekbeom-ro, Seo-gu, Incheon Metropolitan City 2. Details of Trust Contract Termination Report a. Date of submission of major matters report on termination: August 31, 2026 b. Name of terminating trustee: Company Name: Daishin Securities Co., Ltd. Company Registration Number: 00110893 3. Trust Contract Termination Details (Unit: KRW) Termination Date | Trust Contract Type | Contract Termination Amount August 31, 2026 | Specific Money Trust for Treasury Share Acquisition | 10,000,000,000 4. Status of Shares Acquired Through Trust Contract (Unit: KRW, shares, %) Month-End | Type | Quantity | Amount (A) | Ratio (A/B) | Month-End Trust Contract Amount (B) 2026.08.31 | Common Shares | 234,800 | 9,998,549,700 | 99.99 | 10,000,000,000 Total | 234,800 | 9,998,549,700 | 99.99 | 10,000,000,000 5. Comparison of Planned vs. Actual Acquisition Planned Acquisition Amount (KRW) | Actual Acquisition Amount (KRW) | Shortfall | Reason for Shortfall Common: 10,000,000,000 / Other: — | Common: 9,998,549,700 / Other: — | Yes | Payment of management fees and transaction commissions Note: Shares were acquired after accounting for management fees and commissions; 99.99% or more of the planned amount was acquired. 6. Treasury Share Holdings After Trust Contract Termination [As of September 2, 2026] (Unit: KRW, shares, %) Share Type | Holdings under Article 165-3 (A) | Holdings via Trust Contract under Article 165-3 (B) | Total (A+B) | Quantity | Ratio | Total Value | Quantity | Ratio | Contract Amount | Quantity | Ratio | Amount Common Shares | 234,800 | 0.46% | 9,998,549,700 | — | — | — | 234,800 | 0.46% | 9,998,549,700 Total | 234,800 | 0.46% | 9,998,549,700 | — | — | — | 234,800 | 0.46% | 9,998,549,700 Note 1: The quantity shown under 'Holdings under Article 165-3 (A)' includes treasury shares received upon termination of this trust contract. The ratio is calculated against the total issued shares of 50,970,126 shares as of the disclosure submission date.