Tina M. Albertson - 20 Feb 2026 Form 4 Insider Report for Caribou Biosciences, Inc. (CRBU)

Role
Chief Medical Officer
Signature
/s/ Barbara G. McClung, as attorney-in-fact
Issuer symbol
CRBU
Transactions as of
20 Feb 2026
Net transactions value
-$2,089
Form type
4
Filing time
24 Feb 2026, 20:53:47 UTC
Previous filing
21 Feb 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Albertson Tina M. Chief Medical Officer C/O CARIBOU BIOSCIENCES, INC., 2929 7TH STREET, SUITE 105, BERKELEY /s/ Barbara G. McClung, as attorney-in-fact 24 Feb 2026 0001917391

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction CRBU Common Stock Award $0 +55,000 +377% $0.000000 69,589 20 Feb 2026 Direct F1
transaction CRBU Common Stock Sale $2,089 -1,066 -1.5% $1.96 68,523 24 Feb 2026 Direct F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction CRBU Option to purchase Common Stock Award $0 +247,500 $0.000000 247,500 20 Feb 2026 Common Stock 247,500 $1.80 Direct F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Explanation of Responses:

Id Content
F1 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.
F2 Reflects the number of shares of common stock that were sold in a "sell-to-cover" transaction for the sole purpose of satisfying tax withholding obligations in connection with the vesting of RSUs previously granted to the reporting person and does not represent a discretionary trade by the reporting person. This transaction was made pursuant to a Rule 10b5-1 trading plan in the form of a durable sell-to-cover instruction adopted by the reporting person on August 12, 2024. The trading plan provides for the automatic sale of shares of common stock necessary to satisfy the reporting person's tax withholding obligations incurred in connection with the vesting of RSUs.
F3 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.