Caribou Biosciences (CRBU) director receives 45,000 stock options vesting by 2027

Rhea-AI Filing Summary

Caribou Biosciences, Inc. reported that director Scott Braunstein received a grant of options to purchase 45,000 shares of common stock at an exercise price of $0.00 per share. One-twelfth of the options vest monthly and will be fully vested by February 20, 2027, assuming continued service.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Braunstein Scott

Role Director

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

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

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

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^*

Braunstein Scott

(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.

FAQ

What insider transaction did Caribou Biosciences (CRBU) report for Scott Braunstein?

Caribou Biosciences reported that director Scott Braunstein received an option grant for 45,000 shares of common stock. The options were awarded at an exercise price of $0.00 per share, representing a compensatory equity grant rather than an open-market stock purchase or sale.

How many Caribou Biosciences (CRBU) options were granted to Scott Braunstein?

Scott Braunstein was granted options to purchase 45,000 shares of Caribou Biosciences common stock. All 45,000 options were acquired in a single grant, increasing his derivative holdings to 45,000 options immediately following the reported transaction according to the Form 4 data.

What is the vesting schedule for Scott Braunstein’s CRBU stock options?

The 45,000 Caribou Biosciences stock options vest in equal monthly installments. One‑twelfth of the options vest on each monthly anniversary of the grant date, so the entire grant will be fully vested by February 20, 2027, if Braunstein continues providing service.

Was the Caribou Biosciences (CRBU) option grant to Scott Braunstein a purchase or a compensatory award?

The Form 4 classifies the transaction as a grant or award acquisition, not an open‑market purchase. The transaction code is “A” for an option award, and the reported price per share is $0.00, indicating compensatory equity rather than a cash-funded share purchase.

How did Scott Braunstein’s Caribou Biosciences (CRBU) holdings change after this Form 4 transaction?

After the transaction, Scott Braunstein held 45,000 derivative securities in the form of stock options. The Form 4 shows total options following the transaction equal to 45,000, reflecting the entire grant, all held as direct beneficial ownership under his name.

What does transaction code “A” mean in Scott Braunstein’s CRBU Form 4 filing?

Transaction code “A” indicates a grant, award, or other acquisition of derivative securities. In this case, Caribou Biosciences granted Scott Braunstein stock options, rather than him buying or selling shares in the market, consistent with typical director or executive equity compensation.