---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-051169"
form_type: "8-K"
ticker: "OSG"
cik: "0000874501"
company_name: "OCTAVE SPECIALTY GROUP INC"
filed_at: "2025-11-10T23:59:59+00:00"
generated_at: "2026-05-16T22:49:17.376377+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.55
calibrated_materiality_score: 0.55
confidence: "high"
source: SEC EDGAR
---

# Ambac rebrands to Octave Specialty Group, new ticker OSG starting Nov 20

## Summary
- Name changed to Octave Specialty Group, Inc. effective Nov 10, 2025; AMBC ticker to OSG on Nov 20.
- Subsidiaries rebranded: Cirrata Group becomes Octave Partners, Beat Capital Partners becomes Octave Ventures.
- Legacy financial guarantee business sold; company now focused on building MGA platform across U.S., U.K., Bermuda.
- CEO Claude LeBlanc says rebrand marks culmination of transformation into a diversified specialty insurance enterprise.

## SEC filing metadata
- accession: 0001628280-25-051169
- form_type: 8-K
- ticker: OSG
- cik: 0000874501
- company_name: OCTAVE SPECIALTY GROUP INC
- filed_at: 2025-11-10T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.55
- calibrated_materiality_score: 0.55
- confidence: high
- sec_items: 5.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/874501/000162828025051169/0001628280-25-051169-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/874501/000162828025051169/ambc-20251110.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-051169
- JSON: https://secwatch.observer/filing/0001628280-25-051169.json
- Plain text: https://secwatch.observer/filing/0001628280-25-051169.txt

## Key facts
- Governance Changes
  OCTAVE SPECIALTY GROUP INC: Amended certificate of incorporation to change company name to 'Octave Specialty Group, Inc.' (effective 2025-11-10).
  - Change: charter amendment
  - Effective: 2025-11-10
  source text: On November 10, 2025, the Company filed with the Secretary of State of the State of Delaware a certificate of amendment to its certificate of incorporation, changing the Company’s name to “Octave Specialty Group, Inc.” (the “Name Change”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/874501/000162828025051169/0001628280-25-051169-index.htm
- Governance Changes
  OCTAVE SPECIALTY GROUP INC: Amended and restated bylaws to reflect the company name change (effective 2025-11-10).
  - Change: bylaw amendment
  - Effective: 2025-11-10
  source text: In connection with the Name Change, the bylaws of the Company were amended and restated in their entirety to reflect the Name Change.
  evidence_url: https://www.sec.gov/Archives/edgar/data/874501/000162828025051169/0001628280-25-051169-index.htm

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