Haurwitz Rachel E. 4

What Happened Rachel E. Haurwitz, President, CEO and a director of Caribou Biosciences (CRBU), was granted two compensation awards on February 20, 2026: 151,700 restricted stock units (RSUs) and 682,500 derivative awards (stock option-type award). Both awards were reported as acquired at $0.00 (i.e., no cash paid). These are grants/awards (compensation), not open-market purchases or sales.

Key Details

• Transaction date: 2026-02-20; acquisition price reported: $0.00 for both grants.
• Award amounts: 151,700 RSUs (F1) and 682,500 derivative awards (F3).
• Vesting: RSUs (151,700) vest in four equal annual installments beginning Feb 20, 2027; each vested RSU will be settled in stock within 30 days after each vesting date (F1). The derivative award vests monthly at 1/48 of the grant each month, fully vesting on Feb 20, 2030 (F3).
• Shares held: filing notes certain shares are held by The City Canyon Family Trust (reporting person is co-trustee) (F2). The filing does not state total shares owned by Ms. Haurwitz after these grants.
• Tax withholding remark: the reporting person elected to pay cash to satisfy withholding tax obligations related to RSUs that vested on Feb 20, 2026 (filing remark).
• Timeliness: Filing date and report date are both Feb 20, 2026 — appears timely (no late filing indicated).

Context These entries are compensation awards (RSUs and derivative awards/options) typically granted to executives as part of long-term incentive programs. They do not represent an immediate purchase or sale of existing shares; value to the executive depends on future vesting and any applicable exercise. The RSUs are settled in shares upon vesting, and the derivative award vests monthly over four years. This is routine executive compensation reporting rather than an indication of an open-market trade.