Major Shareholding Report: CEO Stake Diluted to 54.20% After CB Conversion — Cheonbo

Summary

Largest shareholder and CEO Lee Sang-ryul filed an updated major shareholding report as of June 12, 2026. While he and related parties acquired 491 additional shares, the total holding ratio fell sharply from 64.04% to 54.20% (-9.84pp) because the total issued shares ballooned from 10,000,000 to 12,253,025 following convertible bond (CB) conversion into common stock. Voting-right ratio also dropped from 55.42% to 45.24% (-10.18pp), meaning the controlling group now holds less than half of voting rights. The number of special-related parties increased from 12 to 14. The filing reaffirms management-control purpose, but the dilution from CB conversion is a meaningful overhang for minority shareholders.

Historical Impact

6 past Large Holding Report (5%+) · ≈ Schedule 13D/G events at Cheonbo

Median +5d

-1.95%

Range

-6.78% to -0.37%

Positive outcomes

0/6

Filed	P₀	P₊₅	+5d
Jun 26, 2026	₩37,800	₩36,600	-3.17%
Jun 22, 2026	₩42,800	₩39,900	-6.78%

Full Translation

Report on Mass Holdings of Stocks, Etc. (General) Version 6.0 Cheonbo Co., Ltd. Report on Mass Holdings of Stocks, Etc. (General form: Reports under Article 147 of the Financial Investment Services and Capital Markets Act, for the purpose of 'influencing management control') To: Financial Services Commission Reporting obligation date: June 11, 2026 To: Korea Exchange Report preparation reference date: June 12, 2026 Reporter: Lee Sang-ryul [Summary] Issuer: Cheonbo Co., Ltd. Relationship with issuer: Largest shareholder Report classification: Change Number and ratio of shares held: - Previous report: 7,938,213 shares (64.04%) - Current report: 7,938,704 shares (54.20%) Major contract shares: None (previous and current) Voting rights and ratio: - Previous report: 5,542,602 (55.42%) - Current report: 5,543,093 (45.24%) Reason for reporting: - Stock purchase by related party - Change in total issued shares due to conversion of convertible bonds into common stock The reporter confirms that, as of the report reference date, the shareholding status of the reporter and special related parties has been accurately prepared in accordance with relevant laws and disclosure guidelines, and that there are no false statements or omissions of material information. Part 1: Overview of Report 1. Issuer Information - Company name: Cheonbo Co., Ltd. - Company code: 278280 - Corporate classification: KOSDAQ-listed company - Total issued shares with voting rights: 12,253,025 2. Mass Holder Information A. Reporter (1) Reporter overview - Report classification: Change - Reporter type: Individual (domestic) - Nationality: Republic of Korea - Name: Lee Sang-ryul (李相律 / LEE SANG RYUL) - Address: Jungangtap-myeon, Chungju-si, Chungcheongbuk-do - Date of birth: 1961.10.21 - Occupation: CEO of Cheonbo Co., Ltd. - Relationship with issuer: Largest shareholder - Business contact: Yoon Hong-hwan, Deputy General Manager, Management Team, Cheonbo Co., Ltd. B. Special Related Parties 14 individuals/entities are listed, including: 1. Seo Ja-won (CEO, major shareholder) 2-10. Relatives (Lee Seul-ji, Lee Hyun-ji, Lee Young-seok, Choi Byung-min, Shin Su-il, Lee Sang-eun, Joo Hye-shin, Joo Hye-yeon, Lee Un-jong) 11. Cheonbo Precision Co., Ltd. (affiliated company) 12. Solique Investment Co., Ltd. (affiliated company) 13. Woo Dong-hee (registered executive) 14. Lee Geun-pil (registered executive) Details on key affiliates (in million KRW): - Cheonbo Precision: Total assets 35,446; Liabilities 9,305; Equity 26,141; Capital 200; CEO Lee Sang-ryul; Largest shareholder Lee Sang-ryul (47.5%) - Solique Investment: Total assets 22,394; Liabilities 32; Equity 22,362; Capital 200; CEO Ryu Si-myung; Largest shareholder Cheonbo Precision (50.9%) 3. Number and Ratio of Shares Held - Previous report (Nov 20, 2024): Lee Sang-ryul + 12 related parties, 7,938,213 shares (64.04%), 5,542,602 voting rights (55.42%), total issued voting shares 10,000,000 - Current report (Jun 12, 2026): Lee Sang-ryul + 14 related parties, 7,938,704 shares (54.20%), 5,543,093 voting rights (45.24%), total issued voting shares 12,253,025 - Change: +491 shares, -9.84pp ratio, +491 voting rights, -10.18pp voting ratio, +2,253,025 total issued shares 4. Holding Purpose Influence over management control, covering: (1) appointment/dismissal/suspension of directors and auditors; (2) amendments to articles of incorporation relating to corporate organs; (3) changes in capital; (4) dividend decisions; (5) mergers, splits, and split-mergers; (6) comprehensive stock exchange/transfer; (7) transfer of all business or material parts thereof; (8) disposal of all or material parts of assets; (9) leases or management delegation of all business, or contracts sharing all business profits/losses; (10) dissolution of the company. The reporter states he exercises de facto influence over all such matters and will make decisions consistent with the company's management objectives. 5. Reasons for Change - Method of change: Share purchase by special related party; change in total issued shares due to conversion of convertible bonds to common stock - Reason: Same as above Part 2: Mass Holdings Detail 1. Holdings by Reporter and Special Related Parties A. Holdings by share type (partial): - Reporter Lee Sang-ryul (1961.10.21): 3,300,000 common shares + 958,244 convertible-bond-related (convertible into voting shares) = 4,258,244 shares (29.07%) - Special related party Seo Ja-won (1962.08.09): 1,037,065 common shares (7.08%) - Lee Seul-ji (1994.07.02): 535,000 common + 287,474 conversion-related = 822,474 (5.61%) - Lee Hyun-ji (1995.12.07): 515,000 common + 958,244 conversion-related = 1,473... [Translation truncated]