---
schema_version: "secwatch.filing_event.v1"
accession: "0000776867-23-000014"
form_type: "8-K"
ticker: "WTM"
cik: "0000776867"
company_name: "WHITE MOUNTAINS INSURANCE GROUP LTD"
filed_at: "2023-10-20T23:59:59+00:00"
generated_at: "2026-06-09T19:21:09.529671+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# White Mountains to acquire ~70% of Bamboo for ~$285M; California homeowners MGA

## Summary
- White Mountains to invest approx. $285M for ~70% of Bamboo, a California homeowner MGA.
- Bamboo insures over 100,000 California policyholders; founded in 2018 by John Chu.
- John Chu and current management will continue leading the business with a significant equity stake.
- Transaction expected to close Q1 2024, subject to regulatory approvals; no financing condition.
- White Mountains' final ownership could range from 62% to 81% based on unitholder rollovers.

## SEC filing metadata
- accession: 0000776867-23-000014
- form_type: 8-K
- ticker: WTM
- cik: 0000776867
- company_name: WHITE MOUNTAINS INSURANCE GROUP LTD
- filed_at: 2023-10-20T23:59:59+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/776867/000077686723000014/0000776867-23-000014-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/776867/000077686723000014/wtm-20231019.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000776867-23-000014
- JSON: https://secwatch.observer/filing/0000776867-23-000014.json
- Plain text: https://secwatch.observer/filing/0000776867-23-000014.txt

## Key facts
- Material Agreements
  WHITE MOUNTAINS INSURANCE GROUP LTD entered into Agreement and Plan of Merger with Bamboo IDE8 Insurance Services, LLC valued at approximately $285 million in cash (effective 2023-10-19).
  - Action: entry
  - Agreement: merger
  - Counterparty: Bamboo IDE8 Insurance Services, LLC
  - Value: approximately $285 million in cash
  - Effective: 2023-10-19
  source text: On October 19, 2023, White Mountains Insurance Group, Ltd. (“ White Mountains ”) and its indirect wholly owned subsidiaries PM Holdings LLC (“ Parent ”) and WM Pierce Merger Sub LLC (“ Merger Sub ”) entered into an Agreement and Plan of Merger (the “ Merger Agreement ”) with Bamboo IDE8 Insurance Services, LLC (“ Bamboo ”) and John Chu, as the unitholders’ representative.
  evidence_url: https://www.sec.gov/Archives/edgar/data/776867/000077686723000014/0000776867-23-000014-index.htm

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