---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-21-227378"
form_type: "8-K"
ticker: "CRBU"
cik: "0001619856"
company_name: "Caribou Biosciences, Inc."
filed_at: "2021-07-28T23:59:59+00:00"
generated_at: "2026-06-30T01:40:23.684180+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Caribou Biosciences completes $304M IPO; sells 19M shares at $16 each

## Summary
- Gross proceeds of $304M before underwriting discounts; underwriters have 30-day option for up to 2.85M additional shares.
- All outstanding preferred stock (Series A, A-1, B, C) converted into 26,234,654 common shares automatically prior to IPO close.
- Director Jeffrey Long-McGie resigned effective July 27, 2021, in connection with the IPO closing; no disagreement cited.
- Adopted 2021 Equity Incentive Plan and 2021 Employee Stock Purchase Plan; entered amended employment agreements with four named officers.
- Filed amended and restated certificate of incorporation and bylaws effective July 27, 2021.

## SEC filing metadata
- accession: 0001193125-21-227378
- form_type: 8-K
- ticker: CRBU
- cik: 0001619856
- company_name: Caribou Biosciences, Inc.
- filed_at: 2021-07-28T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 3.02, 5.02, 5.03, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1619856/000119312521227378/0001193125-21-227378-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1619856/000119312521227378/d189230d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-21-227378
- JSON: https://secwatch.observer/filing/0001193125-21-227378.json
- Plain text: https://secwatch.observer/filing/0001193125-21-227378.txt

## Key facts
- Executive change
  Jeffrey Long-McGie resigned as Director at Caribou Biosciences, Inc..
  - Action: resigned
  - Role: Director
  source text: Effective as of July 27, 2021, Mr. Jeffrey Long-McGie resigned from the Company’s board of directors in connection with the closing of the Offering.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1619856/000119312521227378/0001193125-21-227378-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.