SCHEDULE 13G/A 0001104659-25-078711 0001472322 XXXXXXXX LIVE 1 American Depositary Shares, each representing one ordinary share, par value of GBP 0.008 per share 09/30/2025 0001816590 COMPASS Pathways plc 20451W101 33 Broadwick Street London X0 W1F 0DQ Rule 13d-1(b) Nantahala Capital Management, LLC MA 0.00 3484315.00 0.00 3484315.00 3484315.00 N 3.57 IA Wilmot B. Harkey X1 0.00 3484315.00 0.00 3484315.00 3484315.00 N 3.57 HC Daniel Mack X1 0.00 3484315.00 0.00 3484315.00 3484315.00 N 3.57 HC COMPASS Pathways plc 33 Broadwick Street London, UNITED KINGDOM, W1F 0DQ (1) Nantahala Capital Management, LLC ("Nantahala") (2) Wilmot B. Harkey (3) Daniel Mack (together the "Reporting Persons") 130 Main St. 2nd Floor, New Canaan, Connecticut 06840 (1) Nantahala is a Massachusetts limited liability company. (2) Each of Messrs. Harkey and Mack is a citizen of the United States of America. N IA HC As of September 30, 2025, Nantahala may be deemed to be the beneficial owner of 3,484,315 Shares held by funds and separately managed accounts under its control, and as the managing members of Nantahala, each of Messrs. Harkey and Mack may be deemed to be a beneficial owner of those Shares. As of September 30, 2025, each of the Reporting Persons may be deemed to be the beneficial owner of the following percentage of the total number of Shares outstanding: (1) Nantahala Capital Management, LLC ("Nantahala") : 3.57% (2) Wilmot B. Harkey: 3.57% (3) Daniel Mack: 3.57% (1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares. (2) Wilmot B. Harkey: 0 Shares. (3) Daniel Mack: 0 Shares. (1) Nantahala Capital Management, LLC ("Nantahala") : 3,484,315 Shares. (2) Wilmot B. Harkey: 3,484,315 Shares. (3) Daniel Mack: 3,484,315 Shares. (1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares. (2) Wilmot B. Harkey: 0 Shares. (3) Daniel Mack: 0 Shares. (1) Nantahala Capital Management, LLC ("Nantahala") : 3,484,315 Shares. (2) Wilmot B. Harkey: 3,484,315 Shares. (3) Daniel Mack: 3,484,315 Shares. N Y Y N Each of Messrs. Harkey and Mack is filing this Schedule 13G as a control person in respect of shares beneficially owned by Nantahala, an investment adviser as described in ss. 240.13d-1(b)(1)(ii)(E). See Item 4(a). Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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. Nantahala Capital Management, LLC /s/ Taki Vasilakis 11/14/2025 Wilmot B. Harkey /s/ Wilmot B. Harkey 11/14/2025 Daniel Mack /s/ Daniel Mack 11/14/2025