---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-044062"
form_type: "8-K"
ticker: "WTM"
cik: "0000776867"
company_name: "WHITE MOUNTAINS INSURANCE GROUP LTD"
filed_at: "2025-10-03T23:59:59+00:00"
generated_at: "2026-05-17T04:52:22.773664+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# White Mountains sells ~77% of Bamboo to CVC at $1.75B enterprise value

## Summary
- White Mountains will sell ~77% equity interest in Bamboo to CVC, retaining ~15% fully-diluted stake.
- Transaction values Bamboo at $1.75 billion enterprise value; net cash proceeds expected ~$840M.
- White Mountains expects a gain of approximately $310 per share to book value from the sale.
- Closing expected Q4 2025, subject to regulatory approvals; no shareholder vote required.

## SEC filing metadata
- accession: 0001628280-25-044062
- form_type: 8-K
- ticker: WTM
- cik: 0000776867
- company_name: WHITE MOUNTAINS INSURANCE GROUP LTD
- filed_at: 2025-10-03T23:59:59+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/776867/000162828025044062/0001628280-25-044062-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/776867/000162828025044062/wtm-20251002.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-044062
- JSON: https://secwatch.observer/filing/0001628280-25-044062.json
- Plain text: https://secwatch.observer/filing/0001628280-25-044062.txt

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