---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-049888"
form_type: "8-K"
ticker: "WTM"
cik: "0000776867"
company_name: "WHITE MOUNTAINS INSURANCE GROUP LTD"
filed_at: "2025-11-06T23:59:59+00:00"
generated_at: "2026-05-17T00:05:45.503524+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# White Mountains Q3 BVPS $1,851 (+3%); sells 77% of Bamboo to CVC for ~$325/share boost

## Summary
- Book value per share $1,851, up 3% in Q3 and 6% YTD including dividends; pro-forma BVPS $2,176 after Bamboo sale.
- Ark combined ratio 76% in Q3 (vs 79% prior year); gross written premiums $2.3B YTD, up 18%.
- Bamboo sale to CVC: White Mountains sells ~77% stake; expected Q4 close adds ~$325 to BVPS.
- Kudu pre-tax income $44M, adjusted EBITDA $15M; trailing 12-month ROE 9%.
- Distinguished acquired for $224M cash on Sep 2; contributed $1M ScaleCo adjusted EBITDA in stub period.

## SEC filing metadata
- accession: 0001628280-25-049888
- form_type: 8-K
- ticker: WTM
- cik: 0000776867
- company_name: WHITE MOUNTAINS INSURANCE GROUP LTD
- filed_at: 2025-11-06T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/776867/000162828025049888/0001628280-25-049888-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/776867/000162828025049888/wtm-20251106.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-049888
- JSON: https://secwatch.observer/filing/0001628280-25-049888.json
- Plain text: https://secwatch.observer/filing/0001628280-25-049888.txt

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