SCHEDULE 13G 0001404574 XXXXXXXX LIVE American Depositary Shares, each representing five ordinary shares, nominal value of 0.003 GBP per share 12/29/2025 0001719714 Mereo BioPharma Group plc 589492107 ONE CAVENDISH PLACE FOURTH FLOOR LONDON X0 W1G 0QF Rule 13d-1(c) 683 Capital Management, LLC DE 0 65083815 0 65083815 65083815 N 8.18 IA 683 Capital Partners, LP DE 0 65083815 0 65083815 65083815 N 8.18 PN Ari Zweiman X1 0 65083815 0 65083815 65083815 N 8.18 IN Mereo BioPharma Group plc ONE CAVENDISH PLACE, FOURTH FLOOR, LONDON, UNITED KINGDOM W1G 0QF 683 Capital Management, LLC 683 Capital Partners, LP Ari Zweiman The principal business address for each of the Reporting Persons is 1700 Broadway, Suite 4200, New York, New York 10019. 683 Capital Management, LLC - DELAWARE 683 Capital Partners, LP - DELAWARE Ari Zweiman - UNITED STATES Y CUSIP 589492107 relates to the American Depositary Shares, each representing five ordinary shares, nominal value of GBP 0.003 per share. As of January 6, 2026, 683 Capital Partners, LP beneficially owned 65,083,815 Ordinary Shares represented by 13,016,763 ADS. 683 Capital Management, LLC, as the investment manager of 683 Capital Partners, LP, may be deemed to have beneficially owned the 65,083,815 Ordinary Shares beneficially owned by 683 Capital Partners, LP. Ari Zweiman, as the Managing Member of 683 Capital Management, LLC, may be deemed to have beneficially owned the 65,083,815 Ordinary Shares beneficially owned by 683 Capital Management, LLC. The following percentage is based on 795,658,504 Ordinary Shares (GBP 0.003 par value per share) outstanding as of November 7, 2025, as disclosed in the Issuer's Form 10-Q filed on November 10, 2025. As of January 6, 2026, the Reporting Persons may be deemed to have beneficially owned approximately 8.18% of the outstanding Ordinary Shares. 8.18 See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. Y Y Y N See Exhibit A. Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. JOINT FILING AGREEMENT The undersigned hereby agree that the statement on Schedule 13G with respect to the Ordinary Shares, par value 0.003 GBP per share, of Mereo BioPharma Group plc dated as of January 6, 2026 is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(2) under the Securities Exchange Act of 1934, as amended. Dated: January 6, 2026 683 CAPITAL MANAGEMENT, LLC By: /s/ Ari Zweiman Ari Zweiman, Managing Member 683 CAPITAL PARTNERS, LP By: /s/ Ari Zweiman Ari Zweiman, Authorized Person /s/ Ari Zweiman Ari Zweiman 683 Capital Management, LLC Ari Zweiman 01/06/2026 683 Capital Partners, LP Ari Zweiman 01/06/2026 Ari Zweiman Ari Zweiman 01/06/2026