X0508 4 2026-02-20 0 0001619856 Caribou Biosciences, Inc. CRBU 0001762893 Ryali Sriram C/O CARIBOU BIOSCIENCES, INC. 2929 7TH STREET, SUITE 105 BERKELEY CA 94710 0 1 0 0 Chief Financial Officer 0 Common Stock 2026-02-20 4 A 0 55000 0 A 72360 D Option to purchase Common Stock 1.80 2026-02-20 4 A 0 247500 0 A 2036-02-19 Common Stock 247500 247500 D This reflects restricted stock units ("RSUs") that vest in four equal annual installments beginning on February 20, 2027, subject to the reporting person continuing to provide service to the Issuer through the applicable vesting dates. The RSUs will be settled in stock within 30 days after each vesting date. 1/48 of the total number of shares subject to this option will vest on each monthly anniversary of the grant date such that the option will be fully vested on February 20, 2030, subject to the reporting person continuing to provide service to the Issuer through each such vesting date. /s/ Barbara G. McClung, as attorney-in-fact 2026-02-20