---
schema_version: "secwatch.filing_event.v1"
accession: "0000874501-24-000137"
form_type: "8-K/A"
ticker: "OSG"
cik: "0000874501"
company_name: "OCTAVE SPECIALTY GROUP INC"
filed_at: "2024-06-05T23:59:59+00:00"
generated_at: "2026-06-01T06:24:36.530011+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Ambac agrees to sell Ambac Assurance to American Acorn for $420M; shareholder vote required

## Summary
- Purchase price of $420M plus adjustment amount for 100% of Ambac Assurance Corporation shares.
- Buyer American Acorn Corp. also gets a warrant for 9.9% of fully diluted Ambac common stock.
- Transaction requires stockholder approval under DGCL Section 271; board unanimously recommends.
- Closing subject to regulatory approvals, other conditions; sponsor equity commitment letter in place.
- Transition services and employment agreements with key employees effective at closing.

## SEC filing metadata
- accession: 0000874501-24-000137
- form_type: 8-K/A
- ticker: OSG
- cik: 0000874501
- company_name: OCTAVE SPECIALTY GROUP INC
- filed_at: 2024-06-05T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/874501/000087450124000137/0000874501-24-000137-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/874501/000087450124000137/ambc-20240604.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000874501-24-000137
- JSON: https://secwatch.observer/filing/0000874501-24-000137.json
- Plain text: https://secwatch.observer/filing/0000874501-24-000137.txt

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