SCHEDULE 13G/A 0001999371-25-007159 0001773195 XXXXXXXX LIVE 1 Common Stock, $0.0001 par value per share 01/22/2026 0001907108 Lexeo Therapeutics, Inc. 52886X107 345 Park Avenue South Floor 6 New York NY 10010 Rule 13d-1(b) Affinity Asset Advisors, LLC DE 5217660 0 5217660 0 5217660 N 7.1 IA OO Michael Cho X1 5217660 0 5217660 0 5217660 N 7.1 IN HC Lexeo Therapeutics, Inc. 345 Park Avenue South, Floor 6, New York, New York, 10010 Affinity Asset Advisors, LLC Michael Cho 450 Park Avenue Suite 1403 New York, NY 10022 Affinity Asset Advisors, LLC is a Delaware limited liability company, and Michael Cho is an individual and is a citizen of the United States. N IA HC The securities reported herein are directly held by Affinity Healthcare Fund, LP (the "Fund"). Affinity Asset Advisors, LLC (the "Adviser") is the investment manager of the Fund and exercises voting and investment power over the securities held directly by the Fund reported herein pursuant to an investment management agreement between the Adviser, the Fund, and the general partner of the Fund. The Adviser may be deemed to beneficially own the securities reported herein held by the Fund by virtue of its position as investment manager of the Fund. Michael Cho, the managing member of the Adviser, may be deemed a beneficial owner of the securities reported herein held directly by the Fund. As of the date hereof, the Adviser and Mr. Cho (collectively, the "Reporting Persons") beneficially own 5,217,660 shares of common stock, $0.0001 par value per share ("Common Stock"), of Lexeo Therapeutics, Inc. (the "Issuer"), which amount includes 867,302 shares of Common Stock issuable upon the exercise of warrants to purchase shares of Common Stock ("Warrants") held directly by the Fund. As of December 31, 2025, the Fund and the Adviser beneficially owned 4,067,302 shares of Common Stock, which amount included 867,302 shares of Common Stock issuable upon the exercise of Warrants. As of the date hereof, the Reporting Persons beneficially own approximately 7.1% of the Common Stock outstanding. As of December 31, 2025, the Fund and the Adviser beneficially owned approximately 5.5% of the Common Stock outstanding. The percentages disclosed above are based on 72,987,327 shares of Common Stock of the Issuer outstanding as of November 3, 2025, as set forth in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on November 5, 2025, plus 867,302 shares of Common Stock issuable upon the exercise of Warrants held by the Fund. As of the date hereof, the Reporting Persons have sole power to vote or to direct the vote of 5,217,660 shares of Common Stock, which amount includes 867,302 shares of Common Stock issuable upon the exercise of Warrants. As of December 31, 2025, the Fund and the Adviser had sole power to vote or to direct the vote of 0 shares of Common Stock. As of the date hereof, the Reporting Persons have shared power to vote or to direct the vote of 0 shares of Common Stock. As of December 31, 2025, the Fund and the Adviser had shared power to vote or to direct the vote of 4,067,302 shares of Common Stock, which amount included 867,302 shares of Common Stock issuable upon the exercise of Warrants. As of the date hereof, the Reporting Persons have sole power to dispose or to direct the disposition of 5,217,660 shares of Common Stock, which amount includes 867,302 shares of Common Stock issuable upon the exercise of Warrants. As of December 31, 2025, the Fund and the Adviser had sole power to dispose or to direct the disposition of 0 shares of Common Stock. As of the date hereof, the Reporting Persons have shared power to dispose or to direct the disposition of 0 shares of Common Stock. As of December 31, 2025, the Fund and the Adviser had shared power to dispose or to direct the disposition of 4,067,302 shares of Common Stock, which amount included 867,302 shares of Common Stock issuable upon the exercise of Warrants. Y Y Y 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. Affinity Asset Advisors, LLC /s/ Andrew Weinstein 01/29/2026 Michael Cho /s/ Michael Cho 01/29/2026