Caribou Biosciences shareholders reject officer exculpation amendment at annual meeting

Proposal 4 - Approval of the Adjournment of the 2026 Annual Meeting to a Later Date or Dates, if Necessary, to Permit Further Solicitation and Voting of Proxies in the Event There are not Sufficient Votes in Favor of Proposal 3 or if There are not Sufficient Shares Present to Establish a Quorum. The stockholders approved the adjournment of the 2026 annual meeting, if necessary, by the following votes: Votes For Votes Against Votes Abstain Broker Non-Votes 37,615,389 3,418,004 106,383 27,098,425

Proposal 3 - Approval of an Amendment to the Company's Amended and Restated Certificate of Incorporation to Provide for Exculpation of Officers from Certain Breaches of Fiduciary Duty to the Fullest Extent Permitted by the General Corporation Law of the State of Delaware The stockholders did not approve the above-referenced amendment to the Company's amended and restated certificate of incorporation. The voting results on this proposal were as follows: Votes For Votes Against Votes Abstain Broker Non-Votes 37,483,637 3,513,785 142,354 27,098,425

Proposal 1 - Election of Three Class II Directors Each of the following nominees was elected to serve as a Class II director, to hold office until the Company’s 2029 annual meeting of stockholders and until their respective successor is duly elected and qualified or until their earlier death, resignation, or removal. The voting results on this proposal were as follows: Nominee Votes For Votes Withheld Broker Non-Votes Andrew Guggenhime, M.B.A. 31,554,511 9,585,265 27,098,425 David Johnson, M.B.A. 31,725,652 9,414,124 27,098,425 Nancy Whiting, Pharm.D. 31,694,175 9,445,601 27,098,425

Proposal 2 - Ratification of Selection of Independent Registered Public Accounting Firm The stockholders ratified the selection by the Audit Committee of the Company’s Board of Directors of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026, by the following votes: Votes For Votes Against Votes Abstain Broker Non-Votes 67,457,482 337,911 442,808 0