White Mountains Insurance Group trades at a significant valuation premium relative to trailing earnings due to an expected 78% earnings decline — a cyclical peak reversal — while the balance sheet retains attractive peer-relative margins of 37% and an on-balance volume trend that is rising despite price weakness.
Thesis pillars
- Cyclical Earnings Peak Risk↓Deteriorating
- Best In Class Margins→Stable
- Counterparty Concentration Bam↓Deteriorating
- +1 more pillar — see the Why tab for full reasoning
Pillars as of Jul 3, 2026, based on the 10-K filed Feb 27, 2026
White Mountains Insurance Group (WTM) Stock Analysis
Financial Services · Insurance - Property & Casualty
Sell if holding. Multiple concerning factors at $2208.58: Concentration risk — Counterparty: BAM; Concentration risk — Customer: top-3 carriers (Distinguished) (61.0%).
White Mountains Insurance Group is a Bermuda-based holding company operating specialty P&C insurance and reinsurance (Ark), municipal bond guarantee reinsurance (HG Global), capital solutions for asset managers (Kudu), and specialty insurance distribution (Distinguished). Ark... Read more
Sell if holding. Multiple concerning factors at $2208.58: Concentration risk — Counterparty: BAM; Concentration risk — Customer: top-3 carriers (Distinguished) (61.0%). Chart setup: No clear chart pattern; technical signals are mixed. Score 6.6/10, high confidence.
Passes 5/9 gates (positive momentum, clean insider activity, news events none recent, semi cycle peak clear, materials cycle peak clear). Fails on earnings proximity 6d<=7d. Suitability: speculative.
About White Mountains Insurance Group
About White Mountains Insurance Group
Ark, White Mountains Insurance Group's largest segment, wrote $2,557.2 million in gross written premiums in 2025 across property, specialty, marine & energy, casualty, and accident & health lines, generated through Lloyd's syndicates in the United Kingdom ($1,404.7 million) and a Class 4 Bermuda platform ($1,152.5 million). Three additional segments—HG Global in municipal bond guarantee reinsurance, Kudu in capital solutions for asset managers, and Distinguished in specialty insurance distribution—complete the holding company's portfolio.
White Mountains generates underwriting revenue through Ark's specialty property and casualty book, where property lines produced $1,178.0 million and specialty lines $646.7 million in 2025 gross written premiums. Ark distributes primarily through insurance and reinsurance brokers and intermediaries, with Marsh & McLennan Companies producing 24.3%, Arthur J. Gallagher 15.2%, and Aon 12.4% of gross written premiums in 2025—the top five intermediaries collectively generating 64.7% of Ark's volume. Distinguished earns commissions as a managing general agent, placing approximately 61% of its premium volume with three carriers in 2025. Kudu holds participation contracts with asset and wealth managers, whose revenue depends on asset-based and performance fees tied to market conditions. HG Global's subsidiary HG Re provides reinsurance to Build America Mutual (BAM), the municipal bond insurer whose Standard & Poor's "AA/stable" rating was affirmed in July 2025.
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HG Re is licensed solely to provide reinsurance to BAM, creating a single-counterparty dependency: if BAM's S&P rating falls below "AA," BAM could be prevented from writing new policies, eliminating HG Re's entire business. White Mountains holds BAM Surplus Notes with a principal balance of $277 million and accrued interest of $214 million at nominal value, carried at fair value of $339 million as of December 31, 2025, with NYDFS approval required for any principal or interest payments—an approval that cannot be guaranteed.
See also: Financial Services · Insurance - Property & Casualty
From White Mountains Insurance Group's most recent 10-K filing, extracted June 16, 2026.
Recent developments
updated 2026-10-29Recent Developments — White Mountains Insurance Group
Latest news
- NEWS White Mountain Insur Grp Number of Employees 2026 | Employee Count & Headcount Data - Revelio Labs — Revelio Labs neutral
- NEWS White Mountains Insurance Swings to Loss in Q1, Revenue Declines - marketscreener.com — marketscreener.com negative
- NEWS Earnings Flash (WTM) White Mountains Insurance Group, Ltd. Reports Q1 Revenue $517.8M - marketscreener.com — marketscreener.com neutral
- NEWS White Mountains: Q1 Earnings Snapshot - marketscreener.com — marketscreener.com negative
- NEWS White Mountains: Q1 Earnings Snapshot - KING5.com — KING5.com neutral
Generated 2026-10-29T11:08:52Z.
Upcoming dated catalysts
Thesis
Key Metrics
Quality Signals
Concentration Risks(10-K Item 1A)
- HIGHcounterpartyBAM10-K Item 1A: 'HG Re is only licensed to provide reinsurance to BAM ... is dependent on BAM's ability to write municipal bond insurance policies.'
- HIGHCustomertop-3 carriers (Distinguished)61%10-K Item 1A: 'Distinguished placed approximately 61% of its business with its three largest carriers during the year ended December 31, 2025.'
- LOWCustomersingle largest carrier (Distinguished)22%10-K Item 1A: 'Distinguished placed approximately 22% of its business with its single largest carrier during the year ended December 31, 2025.'
Material Events(8-K, last 90d)
- 2026-05-21Item 5.02LOWDirector Steven M. Yi did not stand for re-election and completed his tenure as a Board member on May 21, 2026 at the conclusion of his term. No reason cited; no successor named.SEC filing →
Model-generated analysis — not investment advice. Not a registered investment advisor. Past performance does not guarantee future results. How we score · Editorial policy
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Rating Breakdown
1 floor-breaker·1 ceiling hit
No near-term catalyst priced in. Thesis progression will come from fundamentals grinding, not event reaction.static
Price Targets
Position Sizing
Risk Alerts
Earnings
Verdict History
Frequently Asked Questions
Sell if holding. Multiple concerning factors at $2208.58: Concentration risk — Counterparty: BAM; Concentration risk — Customer: top-3 carriers (Distinguished) (61.0%). Chart setup: No clear chart pattern; technical signals are mixed. Prior stop was $2122.62. Score 6.6/10, high confidence.
Default target: $2539.87 (+15.0% upside). Prior stop was $2122.62. Stop-loss: $2122.62.
Concentration risk — Counterparty: BAM; Concentration risk — Customer: top-3 carriers (Distinguished) (61.0%); Earnings expected to decline ~79% (cyclical peak).
White Mountains Insurance Group trades at a P/E of 5.1 (forward 24.5). TrendMatrix value score: 8.0/10. Verdict: Sell.
8 analysts cover WTM with a consensus score of 2.3/5.
What does White Mountains Insurance Group do?White Mountains Insurance Group is a Bermuda-based holding company operating specialty P&C insurance and reinsurance...
White Mountains Insurance Group is a Bermuda-based holding company operating specialty P&C insurance and reinsurance (Ark), municipal bond guarantee reinsurance (HG Global), capital solutions for asset managers (Kudu), and specialty insurance distribution (Distinguished). Ark wrote $2.6 billion in gross written premiums in 2025 across Lloyd's syndicates and a Bermuda platform.