---
schema_version: "secwatch.filing_event.v1"
accession: "0001619856-22-000039"
form_type: "8-K"
ticker: "CRBU"
cik: "0001619856"
company_name: "Caribou Biosciences, Inc."
filed_at: "2022-12-16T23:59:59+00:00"
generated_at: "2026-06-21T03:21:36.993709+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.1
calibrated_materiality_score: 0.1
confidence: "high"
source: SEC EDGAR
---

# Caribou appoints CFO Jason O'Byrne as principal accounting officer; controller Fischesser cedes role

## Summary
- Jason V. O'Byrne, CFO, appointed principal accounting officer effective Dec 15, 2022.
- Ryan Fischesser steps down as principal accounting officer but remains VP of Finance and Controller.
- Fischesser is no longer an officer for Section 16 purposes as of Dec 15, 2022.
- No new arrangements, family relationships, or material transactions tied to the change.

## SEC filing metadata
- accession: 0001619856-22-000039
- form_type: 8-K
- ticker: CRBU
- cik: 0001619856
- company_name: Caribou Biosciences, Inc.
- filed_at: 2022-12-16T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.1
- calibrated_materiality_score: 0.1
- confidence: high
- sec_items: 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1619856/000161985622000039/0001619856-22-000039-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1619856/000161985622000039/crbu-20221215.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001619856-22-000039
- JSON: https://secwatch.observer/filing/0001619856-22-000039.json
- Plain text: https://secwatch.observer/filing/0001619856-22-000039.txt

## Key facts
- Executive change
  Ryan Fischesser changed role as principal accounting officer at Caribou Biosciences, Inc..
  - Action: ceased to serve as
  - Role: principal accounting officer
  source text: The Company’s Vice President of Finance and Controller, Ryan Fischesser, who was previously serving as the Company’s principal accounting officer, will continue serving as the Company’s Vice President of Finance and Controller but not as the Company’s principal accounting officer, effective as of December 15, 2022.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1619856/000161985622000039/0001619856-22-000039-index.htm
- Executive change
  Jason V. O'Byrne was appointed as principal accounting officer at Caribou Biosciences, Inc..
  - Action: appointed
  - Role: principal accounting officer
  source text: On December 15, 2022, Caribou Biosciences, Inc. (the “Company”) appointed Jason V. O’Byrne, its Chief Financial Officer, as the Company’s principal accounting officer.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1619856/000161985622000039/0001619856-22-000039-index.htm

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