Caribou Biosciences Inc.

02/24/2026 | Press release | Distributed by Public on 02/24/2026 19:54

Statement of Changes in Beneficial Ownership (Form 4)

FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0287
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(Print or Type Responses)
1. Name and Address of Reporting Person *
MCCLUNG BARBARA G
2. Issuer Name and Ticker or Trading Symbol
Caribou Biosciences, Inc. [CRBU]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Legal Officer
(Last) (First) (Middle)
C/O CARIBOU BIOSCIENCES, INC., 2929 7TH STREET, SUITE 105
3. Date of Earliest Transaction (Month/Day/Year)
02/20/2026
(Street)
BERKELEY, CA 94710
4. If Amendment, Date Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City) (State) (Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 02/20/2026 A 45,000(1) A $ 0 488,502 D
Common Stock 02/24/2026 S(2) 6,938(2) D $1.96 481,564 D
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Option to purchase Common Stock $1.8 02/20/2026 A 202,500 (3) 02/19/2036 Common Stock 202,500 $ 0 202,500 D

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
MCCLUNG BARBARA G
C/O CARIBOU BIOSCIENCES, INC.
2929 7TH STREET, SUITE 105
BERKELEY, CA 94710
Chief Legal Officer

Signatures

/s/ Barbara G. McClung 02/24/2026
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) 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.
(2) 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 prior to the 2023 amendments to Rule 10b5-1. 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.
(3) 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.
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.
Caribou Biosciences Inc. published this content on February 24, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on February 25, 2026 at 01:55 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]