Caribou Biosciences (CRBU) CEO receives large new equity grants

Rhea-AI Filing Summary

Haurwitz Rachel E. reported acquisition or exercise transactions in this Form 4 filing.

Caribou Biosciences, Inc. reported new equity awards to President and CEO Rachel E. Haurwitz. On February 20, 2026, she was granted an option to purchase 682,500 shares of common stock and 151,700 shares of common stock in the form of restricted stock units (RSUs).

According to the filing, the RSUs vest in four equal annual installments beginning on February 20, 2027, and are settled in stock within 30 days after each vesting date. The stock option vests as to 1/48 of the shares each month so that it is fully vested by February 20, 2030, in each case subject to her continued service.

The document also reports 3,369,395 shares of common stock held indirectly by The City Canyon Family Trust, of which she is a co-trustee with her spouse, in addition to directly held shares.

Insider Trade Summary

3 transactions reported

Mixed 3 txns

Insider Haurwitz Rachel E.

Role President and CEO

Type	Security	Shares	Price	Value
Grant/Award	Option to purchase Common Stock	682,500	$0.00	--
Grant/Award	Common Stock	151,700	$0.00	--
holding	Common Stock	--	--	--

Holdings After Transaction: Option to purchase Common Stock — 682,500 shares (Direct); Common Stock — 447,150 shares (Direct); Common Stock — 3,369,395 shares (Indirect, By Trust)

Footnotes (1)

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. Shares are held by The City Canyon Family Trust dated May 31, 2021, of which the Reporting Person is a Co-Trustee with her spouse. 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.

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
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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^*

Haurwitz Rachel E.

(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
X	Officer (give title below)		Other (specify below)
	President and CEO

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
Common Stock	02/20/2026		A		151,700(1)	A	$0	447,150	D
Common Stock								3,369,395	I	By Trust(2)

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		682,500		(3)	02/19/2036	Common Stock	682,500	$0	682,500	D

Explanation of Responses:

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. Shares are held by The City Canyon Family Trust dated May 31, 2021, of which the Reporting Person is a Co-Trustee with her spouse.

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.

Remarks:

The reporting person has elected, consistent with the terms of a durable sell-to-cover instruction, to pay cash to satisfy withholding tax obligations due in connection with the February 20, 2026 vesting of previously-granted RSUs.

	/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 equity awards did Caribou Biosciences (CRBU) CEO Rachel Haurwitz receive?

Rachel Haurwitz received an option to purchase 682,500 shares of Caribou Biosciences common stock and 151,700 restricted stock units. These awards increase her equity-based compensation and are subject to multi-year vesting tied to her continued service with the company.

How do the new RSUs granted to the CRBU CEO vest?

The 151,700 restricted stock units vest in four equal annual installments starting February 20, 2027. Each vested portion will be settled in common stock within 30 days after its vesting date, assuming Rachel Haurwitz continues to provide service through each applicable vesting date.

What is the vesting schedule for the 682,500 stock options reported for CRBU’s CEO?

The 682,500-share stock option vests as to 1/48 of the total shares each month after the grant date. This monthly vesting continues until February 20, 2030, when the option becomes fully vested, conditioned on Rachel Haurwitz’s continued service with Caribou Biosciences.

Did the Caribou Biosciences (CRBU) Form 4 show any stock sales by the CEO?

The Form 4 reports only equity awards and holdings, with no sales. It shows newly granted options and RSUs to Rachel Haurwitz, along with direct and indirect share ownership, but does not disclose any dispositions or open-market sales of Caribou Biosciences common stock.

What indirect shareholdings of CRBU does the CEO have through a trust?

The filing shows 3,369,395 Caribou Biosciences common shares held indirectly by The City Canyon Family Trust dated May 31, 2021. Rachel Haurwitz is a co-trustee of this trust with her spouse, reflecting significant indirect beneficial ownership alongside her directly held shares and awards.

What does the Form 4 reveal about the CRBU CEO’s total equity exposure?

The Form 4 indicates direct awards of options and RSUs plus substantial indirect holdings. It reports 682,500 option shares, 151,700 RSUs, directly held common stock, and 3,369,395 shares held by The City Canyon Family Trust, highlighting a large, equity-based exposure to Caribou Biosciences.