X0609 4 2026-09-24 0001907108 Lexeo Therapeutics, Inc. LXEO 0002109299 Bhalla Narinder Pal false C/O LEXEO THERAPEUTICS, INC. 345 PARK AVENUE SOUTH, 6TH FLOOR NEW YORK NY 10010 false true false false Chief Medical Officer 0 Common Stock 2026-09-14 5 A 0 2714 3.579 A 84908 D Stock Option (right to buy) 3.39 2026-09-24 4 A 0 54750 0 A 2036-09-23 Common Stock 54750 54750 D The reporting person is voluntarily reporting the acquisition of shares of the Issuer's common stock pursuant to the Lexeo Therapeutics, Inc. 2023 Employee Stock Purchase Plan. This transaction is exempt under both Rule 16b-3(c) and Rule 16b-3(d). Includes 49,500 Restricted Stock Units. 25% of the shares underlying the option vest and become exercisable on September 24, 2027, and 1/48th of the shares underlying the option shall vest in monthly installments thereafter, subject to the Reporting Person's continuous service. /s/ Youjin Choi, Attorney-in-Fact 2026-09-28