Every Form 4 that Caribou Biosciences, Inc. (CRBU) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow CRBU and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full CRBU filings page.
Caribou Biosciences, Inc. Chief Technology Officer Timothy P. Kelly reported an open-market sale of 6,228 shares of common stock at $1.93 per share. After this February 25, 2026 transaction, he directly owns 73,125 shares of Caribou Biosciences common stock.
Caribou Biosciences Chief Technology Officer Timothy P. Kelly reported a mix of equity awards and a small tax-related share sale. He received 45,000 restricted stock units that vest in four equal annual installments beginning on February 20, 2027, settling in stock within 30 days after each vesting date.
He was also granted an option to buy 202,500 shares of common stock, vesting monthly so the option is fully vested by February 20, 2030. Separately, 3,147 shares of common stock were sold at $1.96 per share under a mandatory sell‑to‑cover policy to satisfy tax withholding when previously granted RSUs vested, and this did not represent a discretionary trade. After these transactions, Kelly directly holds 79,353 shares of common stock and 202,500 option shares.
Caribou Biosciences Chief Legal Officer Barbara G. McClung reported both equity grants and a small share sale. She received a grant of options to purchase 202,500 shares of common stock and a separate grant of 45,000 restricted stock units, both awarded on February 20, 2026.
The options vest in equal monthly installments over 48 months until February 20, 2030, and the RSUs vest in four equal annual installments beginning February 20, 2027, contingent on continued service. On February 24, 2026, 6,938 shares were sold at $1.96 per share solely to cover tax withholding on previously vested RSUs under an existing Rule 10b5-1 sell-to-cover plan, leaving her with 481,564 common shares directly owned.
Caribou Biosciences Chief Business Officer Ruhi Ahmad Khan reported a mix of equity grants and a small tax-related share sale. On February 24, 2026, Khan sold 6,938 shares of common stock at $1.96 per share in an open-market transaction, leaving 104,998 shares held directly. A footnote explains this was a sell-to-cover trade executed under a Rule 10b5-1 plan solely to satisfy tax withholding on vesting RSUs, not a discretionary sale.
On February 20, 2026, Khan received a grant of 45,000 restricted stock units that vest in four equal annual installments beginning on February 20, 2027, with shares delivered within 30 days after each vesting date. On the same date, Khan was granted options for 202,500 shares of common stock, vesting monthly over 48 months so that the option is fully vested by February 20, 2030, contingent on continued service.
Caribou Biosciences Chief Medical Officer Tina M. Albertson reported a mix of equity grants and a small tax-related sale. She received 55,000 shares of common stock as restricted stock units that vest annually over four years starting on February 20, 2027. She was also granted an option for 247,500 shares of common stock, vesting monthly so that it is fully vested by February 20, 2030.
Separately, 1,066 common shares were sold at $1.96 per share in a sell-to-cover transaction to satisfy tax withholding on previously vested RSUs under a pre-established Rule 10b5-1 trading plan. After these transactions, she directly holds 68,523 common shares.
Caribou Biosciences director Zheng Ran received an option grant for 45,000 shares of common stock. The option was awarded at an exercise price of $0.00 per share, reflecting a compensatory equity award rather than a market purchase.
According to the vesting terms, one-twelfth of the option shares vest on each monthly anniversary of the February 20, 2026 grant date, so the award will be fully vested by February 20, 2027, as long as Zheng Ran continues providing services to Caribou Biosciences through each vesting date.
Caribou Biosciences, Inc. reported that director Nancy Whiting received a grant of options to purchase 45,000 shares of common stock. The options have an exercise price of $0.00 per share, representing a compensatory award rather than a cash purchase.
According to the terms, one-twelfth of the option grant vests on each monthly anniversary of the grant date and will be fully vested by February 20, 2027, as long as she continues providing service to the company through each vesting date.
Sacks Natalie reported acquisition or exercise transactions in this Form 4 filing.
Caribou Biosciences, Inc. reported that director Natalie Sacks received an option grant to purchase 45,000 shares of common stock. The option was awarded at a price of $0.00 per share, reflecting a no-cost equity award rather than an open-market purchase.
According to the vesting terms, one-twelfth of the option shares will vest on each monthly anniversary of the grant date, so the award will be fully vested by February 20, 2027, assuming she continues providing service to the company through each vesting date.
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.
JOHNSON DAVID LEE reported acquisition or exercise transactions in this Form 4 filing.
Caribou Biosciences, Inc. reported that director David Lee Johnson received a grant of 45,000 options to purchase common stock. The options were awarded for no cash consideration and are held directly by Johnson.
According to the vesting terms, one-twelfth of the option shares vest on each monthly anniversary of the February 20, 2026 grant date, so the award will be fully vested by February 20, 2027, as long as Johnson continues providing service to the company through each vesting date.
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.
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.
Caribou Biosciences, Inc. Chief Financial Officer Sriram Ryali reported equity awards consisting of stock options and restricted stock units. He was granted an option to purchase 247,500 shares of common stock at an exercise price of $0.00 per share.
The option vests over time, with 1/48 of the shares vesting monthly so that it is fully vested by February 20, 2030, contingent on continued service. He also received 55,000 shares of common stock in the form of RSUs that vest in four equal annual installments beginning on February 20, 2027, also subject to continued service, and will be settled in stock within 30 days after each vesting date.
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.