---
schema_version: "secwatch.filing_event.v1"
accession: "0001293971-24-000090"
form_type: "8-K"
ticker: null
cik: "0001293971"
company_name: "bluebird bio, Inc."
filed_at: "2024-12-13T23:59:59+00:00"
generated_at: "2026-05-29T03:21:02.333499+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# bluebird bio effects 1-for-20 reverse stock split; shares trade split-adjusted Dec 13

## Summary
- Effective Dec 12, 2024 at 5:00 p.m. ET; new CUSIP 09609G 209.
- Every 20 pre-split shares convert to 1 share; no fractional shares issued.
- Authorized shares and par value unchanged; trading symbol remains BLUE.
- Split approved by stockholders Dec 4, 2024; board chose 1-for-20 ratio.

## SEC filing metadata
- accession: 0001293971-24-000090
- form_type: 8-K
- cik: 0001293971
- company_name: bluebird bio, Inc.
- filed_at: 2024-12-13T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 5.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1293971/000129397124000090/0001293971-24-000090-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1293971/000129397124000090/blue-20241212.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001293971-24-000090
- JSON: https://secwatch.observer/filing/0001293971-24-000090.json
- Plain text: https://secwatch.observer/filing/0001293971-24-000090.txt

## Key facts
- Governance Changes
  bluebird bio, Inc.: Effected a 1-for-20 reverse stock split of common stock via a Certificate of Amendment to the Amended and Restated Certificate of Incorporation (effective 2024-12-12).
  - Change: charter amendment
  - Effective: 2024-12-12
  source text: On December 12, 2024, bluebird bio, Inc. (the "Company") filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, as amended (the "Charter Amendment") with the Secretary of State of the State of Delaware to effect a 1-for-20 reverse stock split (the "Reverse Stock Split") of the Company's common stock, par value $0.01 per share (the "Common Stock"), effective December 12, 2024 at 5:00 p.m., Eastern Time (the "Effective Time")
  evidence_url: https://www.sec.gov/Archives/edgar/data/1293971/000129397124000090/0001293971-24-000090-index.htm

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