X0206 3 2021-07-22 0 0001619856 Caribou Biosciences, Inc. CRBU 0001871145 O'Byrne Jason C/O CARIBOU BIOSCIENCES, INC. 2929 7TH STREET, SUITE 105 BERKELEY CA 94710 0 1 0 0 See Remarks Stock Option (Right to Buy) 4.11 2031-03-29 Common Stock 437201 D Stock Option (Right to Buy) 5.27 2031-06-28 Common Stock 48966 D 1/4th of the shares subject to this option will vest on February 28, 2022 and an additional 1/48th of the aggregate number of shares subject to the option will vest on the corresponding day of each month thereafter (or if there is no such corresponding day, on the last day of such month), subject to the reporting person's continued service to the Issuer thorough the applicable vesting date. 1/4th of the shares subject to this option will vest on June 29, 2022 and an additional 1/48th of the aggregate number of shares subject to the option will vest on the corresponding day of each month thereafter (or if there is no such corresponding day, on the last day of such month), subject to the reporting person's continued service to the Issuer thorough the applicable vesting date. Chief Financial Officer Exhibit 24 - Power of Attorney. /s/ Jason V. O'Byrne 2021-07-22