Samsung Asset Management cuts stake to 2.91% from 5.04%

Report on Large Shareholding of Stocks (Abbreviated Form) Dongjin Semichem Filing date: 2026-05-12 (Abbreviated form: applies to filings under Article 147 of the Financial Investment Services and Capital Markets Act where the purpose is NOT to influence management control, and where the filer is a professional investor under the latter part of Paragraph 1 of the same Article) To: Financial Services Commission Reporting obligation trigger date: May 12, 2026 To: Korea Exchange Report preparation reference date: May 12, 2026 Filer: Samsung Asset Management [Summary Information] Classification of professional investor under reporting exception: - Issuing company: Dongjin Semichem Relationship with issuer: Shareholder Report classification: Change Number and ratio of holdings: - Previous report: 2,592,254 shares (5.04%) - This report: 1,494,087 shares (2.91%) Number and ratio of voting rights: - Previous report: - / - - This report: - / - Reason for report: Change-reporting obligation triggered by trading (includes portions entrusted to Samsung Active Asset Management) Purpose of holding: Simple investment The filer hereby confirms that, as of the report preparation reference date, the holdings of the filer and its specially-related parties have been accurately prepared in accordance with relevant laws and instructions, with no false statements or omissions of material matters. Certificate (Simple Investment Purpose): No management participation purpose - Samsung Part 1: Overview of the Report 1. Information on the Issuing Company - Company name: Dongjin Semichem - Company code: 005290 - Corporate classification: KOSDAQ-listed corporation - Total issued shares with voting rights: 51,414,494 shares 2. Information on the Large Shareholder A. Filer (1) Filer Overview - Report classification: Change / Individual - Filer classification: Financial institution - Nationality: Republic of Korea - Name (Korean): Samsung Asset Management - Name (English): SAMSUNG ASSET MANAGEMENT - Head office address: 74-gil Seocho-daero, Seocho-gu, Seoul - Business registration number: 501-81-23179 - Business: Collective investment business, etc. - Relationship with issuer: Shareholder - Contact: Fund Accounting Team 1, Senior, Park Myung-gu (Phone: 3774-7***) (2) Filer details (as of end of March 2026) - Legal nature: Corporation - Total assets (or assets under management): KRW 1,191,074,278,004 - Total liabilities: KRW 141,792,856,335 - Total equity: KRW 1,049,281,421,669 - Capital: KRW 93,430,000,000 - Representative: CEO Kim Woo-seok - Decision-making body: Management Committee - Largest shareholder: Samsung Life Insurance - Largest shareholder ownership ratio: 100% B. Specially-related parties: None C. Collective Investment Business Operator (1) Overview - Name: Samsung Asset Management - Business registration number: 501-81-23179 - Target collective investment vehicle: Collective investment vehicles and discretionary management - Nationality: Republic of Korea - Address: 11, 74-gil Seocho-daero, Seocho-gu, Seoul (2) Details - Legal nature: Corporation - Capital: KRW 93,430,000,000 - Total assets under management: KRW 465.9 trillion - Representative: CEO Kim Woo-seok - Decision-making body: Management Committee - Largest shareholder (corporate representative): Samsung Life Insurance (Hong Won-hak) - Largest shareholder ownership ratio: 100% 3. Number and Ratio of Holdings - Previous report (2026-02-06): Samsung Asset Management — 2,592,254 shares (5.04%) / Common stock 2,592,254 shares (5.04%) / Total voting shares 51,414,494 - This report (2026-05-12): Samsung Asset Management — 1,494,087 shares (2.91%) / Common stock 1,494,087 shares (2.91%) / Total voting shares 51,414,494 - Change: -1,098,167 shares (-2.13%p) 4. Reason for Change - Method of change: Purchase / Sale - Reason for change: Simple additional acquisition / disposal Part 2: Details of Large Shareholding 1. Holdings by Type — Filer and Specially-Related Parties - Filer Samsung Asset Management: Common stock 1,494,087 shares; total 1,494,087 shares (2.91%) - Specially-related parties: None - Total issued shares with voting rights (I): 51,414,494 - Potential shares held: - - Holding ratio: 2.91% - Common stock holding ratio (A/I): 2.91% * The filer's holdings include 9,947 shares (0.02%) entrusted to Samsung Active Asset Management for management. 2. Holdings by Own Account vs. Client Account (Financial Institutions Only) - Samsung Asset Management (Self): Own account - / - ; Client account 1,494,087 shares (2.91%); Total 1,494,087 shares (2.91%) - Total: 1,494,087 shares (2.91%) Part 3: Details of Large Changes Since Previous Report 1. Change Summary Table A. Change in Holdings - Filer Samsung Asset Management: Common stock -1,098,167 shares; Total -1,098,167 shares (-2.13%p) - Specially-related parties: None 2. Detailed Change History A. Detailed Change in Holdings (unit: shares, KRW) - 2026.02.09 — Other(+) — Common stock — Before: 2,592,254 / Change: +7,750 / After: 2,600,004 / Unit price: 51,400 — General fund OTC ETF redemption Other(+) - 2026.02.09 — On-market purchase(+) — Common stock — Before: 2,600,004 / Change: +371 / After: 2,600,375 / Unit price: 52,842 — On-market purchase(+) - 2026.02.09 — Other(+) — Common stock — Before: 2,600,375 / Change: +40,437 / After: 2,640,812 / Unit price: 51,500 — ETF setup Other(+) - 2026.02.09 — Other(-) — Common stock — Before: 2,640,812 / Change: -34,100 / After: 2,606,712 / Unit price: 51,500 — ETF redemption Other(-) [Translation truncated]