Caribou Biosciences (CRBU) director receives stock options for 45,000 shares

Rhea-AI Filing Summary

Caribou Biosciences, Inc. director Andrew Guggenhime received a grant of options to purchase 45,000 shares of the company’s common stock. The options were awarded at an exercise price of $0.00 per share as a form of equity compensation.

According to the vesting terms, one-twelfth of the option grant vests on each monthly anniversary of the grant date, so the entire 45,000-share option will be fully vested by February 20, 2027, as long as Guggenhime continues to provide services to the company through each vesting date.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider GUGGENHIME ANDREW

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^*

GUGGENHIME ANDREW

(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 Andrew Guggenhime?

Caribou Biosciences reported that director Andrew Guggenhime received an option grant for 45,000 shares of common stock. This equity award is structured as stock options with a $0.00 exercise price, aligning his compensation with the company’s long-term performance.

How many Caribou Biosciences (CRBU) shares are covered by Guggenhime’s new stock option?

The new stock option granted to Andrew Guggenhime covers 45,000 shares of Caribou Biosciences common stock. This entire amount reflects his holdings from this specific award following the transaction, subject to the described vesting schedule and continued service requirements.

What is the vesting schedule for Andrew Guggenhime’s Caribou Biosciences (CRBU) option grant?

One-twelfth of Guggenhime’s 45,000-share option vests on each monthly anniversary of the grant date. The award will be fully vested by February 20, 2027, provided he continues to provide services to Caribou Biosciences through each applicable vesting date.

When will Andrew Guggenhime’s Caribou Biosciences (CRBU) option grant be fully vested?

The option grant to Andrew Guggenhime is scheduled to be fully vested on February 20, 2027. Vesting occurs monthly, with one-twelfth of the 45,000 total option shares vesting on each monthly anniversary of the original grant date.

Is Andrew Guggenhime’s Caribou Biosciences (CRBU) option grant a direct ownership position?

Yes, the reported option grant to Andrew Guggenhime is classified as directly owned. The filing labels the nature of ownership as direct, meaning the option award is attributed to him personally rather than through an intermediary entity or indirect structure.

What type of security was granted to Andrew Guggenhime by Caribou Biosciences (CRBU)?

Andrew Guggenhime received an “Option to purchase Common Stock” from Caribou Biosciences. This derivative security gives him the right to acquire 45,000 shares of common stock, subject to the stated vesting conditions and a reported exercise price of $0.00 per share.