White Mountains Insurance Group (WTM) Stock Price & How to Invest
Last updated July 2026
Short answer
White Mountains is a Bermuda-domiciled holding company that buys, builds and sells whole insurance and financial businesses, so it gets judged on book value per share rather than on any revenue or earnings multiple. At roughly $2,141 a share against ~$2,258 of book value at June 30, 2026, it changes hands just under book, and that ratio is the yardstick to follow.
WTM stock price
As of 2026-08-25, White Mountains Insurance Group (WTM) last closed at $2,141.20, up 16.6% over the past year. Over the past 52 weeks it has traded between $1,650.50 and $2,319.41.
Prices are daily closing prices from Yahoo Finance and may be delayed. For the live quote, check your broker or White Mountains Insurance Group's investor relations page. Walnut is informational, not investment advice.
What does White Mountains Insurance Group (WTM) do?
White Mountains Insurance Group is a holding company, not an insurer that happens to own a few other things. Its capital sits in four reported segments: Ark and the WM Outrigger sidecar, which underwrite specialty insurance and reinsurance largely at Lloyd's; Kudu Investment Management, which buys minority stakes in boutique asset and wealth managers and collects a share of their revenue; HG Global, the reinsurance arm behind municipal bond insurer BAM; and Distinguished, a specialty program manager placing more than ~$550 million of premium a year, majority-acquired in 2025 for ~$230 million. The business everybody still asks about, Bamboo, is mostly gone: White Mountains agreed in October 2025 to sell control of the California homeowners MGA to CVC funds at a ~$1.75 billion valuation, taking ~$840 million of net cash and keeping roughly 15%. Liam Caffrey became chief executive on January 1, 2026, after four years as chief financial officer.
Book value per share reached ~$2,258 at June 30, 2026, up ~4% in the quarter and ~3% for the first half including dividends, on ~$5.39 billion of common equity spread across only ~2.39 million shares. Because businesses get bought and sold whole, reported revenue and earnings jump around: the first half produced ~$172 million of net income to common shareholders, nearly all of it in the second quarter. Repurchasing stock is a working part of the model, with ~91,000 shares retired in the second quarter for ~$191 million at about 93% of book value, and roughly 12% of the company bought back since the 2016 authorization. At ~0.95 times book, the market is paying close to what the balance sheet says the pieces are worth, which puts the whole argument on the future: whether the Bamboo cash and the rest of the holding company's capital get deployed at returns above what they earn sitting still.
What's driving White Mountains Insurance Group (WTM)?
1. Redeploying the Bamboo proceeds
The Bamboo sale turned a fast-growing California MGA into roughly $840 million of cash plus a retained stake of about 15%. What that cash becomes is the single largest determinant of book value growth over the next few years. The Distinguished purchase in 2025 shows the preferred shape: majority control of a fee-based specialty distributor rather than more balance sheet risk.
2. Ark and WM Outrigger in a softer market
Ark wrote ~$778 million of gross premium in the second quarter and ~$1.87 billion in the first half, at combined ratios of 84% and 88%. Property rates have come off their 2023 peak, so premium growth is slowing while margins are still good. WM Outrigger is the sidecar that lets White Mountains take extra property catastrophe risk on its own book when pricing justifies it, and pull back when it does not.
3. Kudu's cash yield
Kudu earned ~$109 million of pre-tax income in the first half of 2026 at a trailing twelve month return on equity of ~15%. Its participations pay out of the revenue of boutique asset and wealth managers, which makes the cash steadier than a carried-interest business. It is still keyed to markets and to net flows at dozens of small firms, and the stakes are illiquid.
4. A shrinking share count
With only ~2.39 million shares outstanding, every repurchase moves the arithmetic. Management has bought at or slightly below book rather than waiting for deep discounts, and about 12% of the company has been retired since the 2016 authorization. The dividend stays token at roughly $1 a share a year, which keeps capital available for whichever use looks better.
What are the risks to White Mountains Insurance Group (WTM)?
Catastrophe is the clearest one. Ark and WM Outrigger carry real property exposure, and the first half of 2025 ran thirteen points of catastrophe losses on the California wildfires against five points in the first half of 2026, driven mostly by the war in Iran. Kudu's stakes are illiquid and internally marked, so a drawdown in small-manager assets would reach book value with a lag and without a market price to argue against. HG Global sits behind municipal bond insurance, a business that is quiet for years at a time and then suddenly is not. The mundane risk matters as much: a large holding company cash balance earns a money market return until it is spent, and an overpriced acquisition made with it is close to impossible to undo.
Is WTM a buy or a sell?
We give no verdict on White Mountains Insurance Group. Both cases are real, which is why the question is contested at all, so here is the strongest version of each.
The case for buying. Redeploying the Bamboo proceeds. The Bamboo sale turned a fast-growing California MGA into roughly $840 million of cash plus a retained stake of about 15%.
The case against. Catastrophe is the clearest one.
Read the full bull and bear case on WTM, including what would have to change to break either one. Walnut is not an investment adviser.
How is White Mountains Insurance Group (WTM) valued? (approximate, August 2026)
A simple financial snapshot. These are approximations and refresh quarterly; for current figures see White Mountains Insurance Group's investor relations page or your broker.
- Book value per share (June 30, 2026): ~$2,258
- Price to book: ~0.95x
- Book value per share growth: ~4% in Q2 2026, ~3% for the first half including dividends
- Common shareholders' equity: ~$5.39 billion
- Net income to common shareholders: ~$200 million in Q2 2026, ~$172 million for the first half
- Shares outstanding: ~2.39 million, down ~12% since the 2016 buyback authorization
White Mountains retired its adjusted book value per share measure in 2025, so plain GAAP book value per share is now the headline figure and the one management is scored on. Price to book, not a price to earnings or price to sales multiple, is the relevant comparison, because reported revenue moves with whichever subsidiaries were consolidated that year. The repurchase price is a useful cross-check: the company paid about 93% of book value for its own stock in the second quarter of 2026.
Who competes with White Mountains Insurance Group (WTM)?
Insurance-based holding companies
Berkshire Hathaway, Markel, Fairfax Financial, Loews and Boston Omaha run the same basic design, using insurance cash flow to fund the purchase of whole operating businesses. All of them get valued on book value or sum of the parts rather than on an earnings multiple, and all of them depend on the acquisition record of a small group of people.
Specialty insurers and Lloyd's underwriters
Beazley, Hiscox, Lancashire, Conduit Re, RenaissanceRe, Arch Capital and Everest Group compete with Ark for the same specialty and property catastrophe business. Their combined ratios are the fair benchmark for Ark's 88% first half result, and their rate commentary is the best available read on where Ark's premium growth goes next.
Capital providers to asset managers
Kudu competes with Blue Owl's GP stakes arm, Goldman Sachs Petershill, Bonaccord and P10 for minority positions in investment managers. Kudu aims at smaller boutiques than most of them, which means less competition per deal and thinner liquidity if it ever wants out of one.
What stocks are similar to White Mountains Insurance Group (WTM)?
Other names that sit close to WTM: same theme, named as a direct competitor, or held beside it in the same funds. Each entry says which. Worth a look if you are thinking about diversification within a thesis rather than concentration on one ticker.
How to invest in White Mountains Insurance Group (WTM)
There are three common ways to get WTM exposure. Buy shares (or fractional shares) directly at any major broker. Hold an ETF that includes it, which spreads the position across many companies. Or build it into a focused thematic portfolio, so WTM sits alongside other stocks that express the same thesis.
Walnut takes the portfolio route. Describe a thesis where WTM fits (for example “AI infrastructure” or “dividend-growth large-caps”) and the AI proposes 5 to 6 constituents with target weights. You review the plan and fund it through your own broker when you're ready.
New to this? Start with how to invest in stocks, see how to analyze a stock with AI, or compare the best AI stock analyzers.
The bottom line on White Mountains Insurance Group (WTM)
WTM is a book value compounder whose case rests on whether management keeps turning sale proceeds into businesses worth more than what was paid for them.
More on White Mountains Insurance Group (WTM)
Whether WTM is worth buying today depends more on your time horizon and what you already hold than on any single call. We walk through valuation, what would have to go right, and the risks in is WTM a buy or a sell?, and where the stock could go from here in the WTM stock forecast.
For income investors, whether WTM pays a dividend and how the payout looks is covered in does WTM pay a dividend? And to weigh WTM against a peer, read the full side-by-side comparisons: WTM vs BRK-B and WTM vs MKL.
Wondering how WTM fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in White Mountains Insurance Group with AI
Connect the broker you already use and ask Walnut's AI how WTM fits what you actually hold: whether you own it already through a fund, what it would do to your concentration, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What does White Mountains actually own?
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Four reported segments as of 2026: Ark and WM Outrigger (specialty insurance and reinsurance written largely at Lloyd's), Kudu Investment Management (minority revenue stakes in boutique asset and wealth managers), HG Global (reinsurance support for municipal bond insurer BAM) and Distinguished (a specialty program manager placing more than ~$550 million of premium a year). Everything else, including the retained ~15% of Bamboo and the holding company's cash, falls into Other Operations. The mix changes by design, because buying and selling whole businesses is the business.
Does White Mountains still have California wildfire exposure through Bamboo?
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Much less than it did. In October 2025 the company agreed to sell control of Bamboo, the California homeowners MGA, to CVC funds at a ~$1.75 billion valuation, taking ~$840 million of net cash and an expected gain of roughly $310 per share to book value while retaining about 15%. Bamboo was an MGA throughout, meaning it distributed and administered policies rather than carrying most of the underwriting risk, although White Mountains had also funded a collateralized reinsurance vehicle behind it, cut from $30 million in 2024 to $10 million in 2025. Wildfire risk now reaches the group mainly through the Ark and WM Outrigger property book.
It is a Bermuda company listed on the NYSE. What does that mean for a US investor?
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At the trading level, very little. WTM has its primary listing on the New York Stock Exchange, prices in US dollars, and White Mountains files the same 10-K, 10-Q and proxy statements as a US domestic issuer, so there is no ADR, no currency conversion and no special account type. Bermuda domicile is a tax and regulatory structure common across the reinsurance industry, and Bermuda applies no withholding tax on dividends, though the annual dividend is a token ~$1 a share. Tax treatment of a foreign-domiciled corporation can still differ from a US one depending on the account and the holder, which is a question for a tax professional rather than a stock screener.
Why does book value matter more than earnings for this company?
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A holding company that buys and sells whole businesses reports lumpy earnings by construction: one sale creates a large gain in a single quarter and nothing the next, and revenue rises or falls with which subsidiaries are consolidated. Book value per share collects all of that into one running total, which is why management, the proxy statement and long-term holders all cite it. The figure was ~$2,258 at June 30, 2026, up ~4% in the quarter and ~3% for the first half including dividends, on ~$5.39 billion of common equity. One wrinkle: the company stopped publishing adjusted book value per share in 2025, so older commentary quoting an adjusted figure refers to a measure that no longer exists.
How much stock has the company bought back?
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Roughly 91,000 shares in the second quarter of 2026 for ~$191 million, at about 93% of book value, and ~104,000 shares for ~$217 million across the first half. Since the current authorization was put in place in late 2016, about 12% of the shares outstanding have been retired, leaving ~2.39 million. Repurchasing below book adds to book value per share arithmetically, which is why the price paid relative to book gets disclosed next to the share count each quarter.
Is there an active securities-fraud class action against White Mountains?
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A review of company filings and the usual shareholder-litigation trackers found no active securities-fraud class action against White Mountains as of August 2026. The company files as a US domestic issuer, shareholders backed the board, the compensation plan and PwC as auditor at the 2026 annual meeting, and the litigation it does carry is the ordinary claims and coverage kind any underwriting group faces. Legal status can change, so current SEC filings are the place to verify before relying on it.
What would most likely break the story?
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A very large catastrophe year at Ark and WM Outrigger, which take property risk on purpose and priced it well in 2026 at an 88% first half combined ratio but absorbed thirteen points of wildfire losses a year earlier. Next, a poor use of the Bamboo cash, since a holding company sitting on a large balance eventually has to spend it and an overpriced deal is nearly irreversible. Then the slower grind: Kudu's boutique managers losing assets, or repurchases stopping because the stock no longer trades near book. Liquidity is thin as well, with only ~2.39 million shares outstanding, so the quote can move on modest volume.
Walnut is informational, not investment advice. Financial figures on this page are approximations; always verify current numbers with White Mountains Insurance Group's investor relations page or your broker before making investment decisions.