Caribou director granted option for 45,000 shares

Caribou Biosciences, Inc. director Dara Richardson-Heron reported receiving an option grant to purchase 45,000 shares of common stock.

Rhea-AI Filing Summary

Caribou Biosciences, Inc. director Dara Richardson-Heron reported receiving an option grant to purchase 45,000 shares of common stock. The option was awarded at an exercise price of $0.0000 per share, reflecting a typical compensatory equity award rather than an open-market transaction.

According to the vesting terms, one-twelfth of the shares subject to this option vest on each monthly anniversary of the February 20, 2026 grant date. The option will be fully vested by February 20, 2027, as long as Richardson-Heron continues to provide service to Caribou Biosciences through each monthly vesting date.

Insider Trade Summary

Grant/Award: 45,000 shares

Grant/Award 1 txn

Insider Richardson-Heron Dara

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Option to purchase Common Stock	45,000	$0.00	$0.00

Holdings After Transaction: Option to purchase Common Stock — 45,000 contracts (Direct)

Footnotes (1)

1. F1. One-twelfth of the 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, 2027, subject to the reporting person continuing to provide service to the Issuer through each such vesting date.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did Caribou Biosciences (CRBU) report for Dara Richardson-Heron?

Caribou Biosciences reported that director Dara Richardson-Heron received an option grant for 45,000 shares of common stock. This compensatory award gives her the right to purchase shares under specified terms rather than reflecting an open-market stock purchase or sale.

How many Caribou Biosciences (CRBU) shares are covered by Dara Richardson-Heron’s new option?

The new option grant to Dara Richardson-Heron covers 45,000 shares of Caribou Biosciences common stock. These shares become exercisable over time as they vest according to the monthly vesting schedule tied to continued service with the company.

What is the exercise price of Dara Richardson-Heron’s Caribou Biosciences (CRBU) stock option?

The option granted to Dara Richardson-Heron has an exercise price of $0.0000 per share. This nominal exercise price indicates a compensatory equity award structure rather than a market-priced option, aligning director incentives with Caribou Biosciences’ long-term performance.

How does Dara Richardson-Heron’s Caribou Biosciences (CRBU) option vest over time?

One-twelfth of the option’s 45,000 shares vest on each monthly anniversary of the February 20, 2026 grant date. The option will be fully vested on February 20, 2027, provided she continues to serve Caribou Biosciences throughout the entire vesting period.

When will Dara Richardson-Heron’s Caribou Biosciences (CRBU) option be fully vested?

The option grant to Dara Richardson-Heron will be fully vested by February 20, 2027. Monthly vesting occurs in equal one-twelfth installments from the February 20, 2026 grant date, contingent on her continued service with Caribou Biosciences during the vesting period.

Is Dara Richardson-Heron’s Caribou Biosciences (CRBU) Form 4 transaction a stock purchase or sale?

The Form 4 reports an option grant to acquire 45,000 shares, not a stock purchase or sale. It reflects a compensatory award of derivative securities, with shares becoming exercisable over time as they vest while she remains in service to the company.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 02/20/2026 - 05:27 PM EST Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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
Estimated average burden
hours per response:			0.5

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 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). See Instruction 10.

1. Name and Address of Reporting Person^*

Richardson-Heron Dara

(Last) (First) (Middle)

C/O CARIBOU BIOSCIENCES, INC.

2929 7TH STREET, SUITE 105

(Street)

BERKELEY CA 94710

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Caribou Biosciences, Inc. [ CRBU ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
02/20/2026

4. If Amendment, Date of 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

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

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 Securities Underlying Derivative Security (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: 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		45,000		(1)	02/19/2036	Common Stock	45,000	$0	45,000	D

Explanation of Responses:

1. One-twelfth of the 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, 2027, subject to the reporting person continuing to provide service to the Issuer through each such vesting date.

Remarks:

	/s/ Barbara G. McClung, as attorney-in-fact	02/20/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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 Number.