Rachel E. Haurwitz - Feb 20, 2024 Form 4 Insider Report for Caribou Biosciences, Inc. (CRBU)

Role: President and CEO, Director
Signature: /s/ Barbara G. McClung, as attorney-in-fact
Stock symbol: CRBU
Transactions as of: Feb 20, 2024
Transactions value $: $0
Form type: 4
Date filed: 2/22/2024, 05:18 PM
Previous filing: Jun 16, 2023
Next filing: Jun 14, 2024

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CRBU	Common Stock	Award	$0	+119K	+296.75%	$0.00	159K	Feb 20, 2024	Direct	F1
holding	CRBU	Common Stock						3.35M	Feb 20, 2024	By Trust	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	CRBU	Option to purchase Common Stock	Award	$0	+547K		$0.00	547K	Feb 20, 2024	Common Stock	547K	$6.81	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	This reflects restricted stock units ("RSUs") that vest in four equal annual installments beginning on February 20, 2025, subject to the reporting person's continued services to the Issuer through the applicable vesting dates. The RSUs will be settled in stock within 30 days after each vesting date.
F2	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.
F3	25% of the options will vest upon the one-year anniversary of the grant date, February 20, 2025, and 1/48th will vest monthly thereafter over the 36-month period following the one-year cliff, subject to the reporting person's continued service to the Issuer through the applicable vesting dates.