Welcome to our dedicated page for White Mountains SEC filings (Ticker: WTM), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
The White Mountains Insurance Group, Ltd. (WTM) SEC filings page on Stock Titan provides direct access to the company’s U.S. regulatory disclosures, including Forms 10‑K, 10‑Q and 8‑K. As a Bermuda‑domiciled financial services holding company with common shares listed on the New York Stock Exchange and the Bermuda Stock Exchange, White Mountains files detailed reports describing its property and casualty insurance and reinsurance activities, municipal bond reinsurance operations, capital solutions for asset and wealth management firms, insurance distribution platforms and other investments.
In its annual reports on Form 10‑K and quarterly reports on Form 10‑Q, White Mountains presents consolidated financial statements, segment information for businesses such as Ark/WM Outrigger, HG Global, Kudu, Bamboo, Distinguished and Other Operations, and discussions of book value per share, comprehensive income and risk factors. These filings also describe exposures to catastrophic events, reserve adequacy considerations, investment portfolio performance and the impact of holdings such as MediaAlpha.
Current reports on Form 8‑K capture material events affecting WTM. Recent examples include the renewal of Outrigger Re Ltd., a collateralized reinsurance sidecar providing quota share protection on a portion of Ark Bermuda’s global property catastrophe portfolio; the entry into and closing of transactions to acquire a controlling interest in Distinguished Programs; the sale of a controlling financial interest in the Bamboo Group to affiliates of funds advised by CVC Capital Partners while retaining an indirect equity interest; announcements of quarterly results and non‑GAAP segment metrics; and disclosures regarding executive leadership changes.
On Stock Titan, these filings are updated as they are posted to EDGAR and are accompanied by AI‑powered summaries that highlight key points, such as segment performance, transaction terms, capital deployment, and changes in book value per share. Users can quickly scan 10‑K and 10‑Q reports for segment‑level trends, review 8‑K filings for acquisitions, dispositions, tender offers and governance changes, and examine how White Mountains describes risks related to catastrophes, reinsurance capacity, rating agency actions and regulatory developments. The platform also surfaces insider‑related disclosures contained in periodic and current reports, helping investors understand how management and the board respond to evolving conditions in the insurance and financial services markets.
White Mountains Insurance Group Ltd filed a Form 13F reporting institutional holdings. The filing lists 2 holdings with a combined reported market value of $261,929,551. The report is signed by Michaela J. Hildreth, Managing Director and Chief Accounting Officer.
Morgan Stanley has filed an amended Schedule 13G/A reporting its beneficial ownership in White Mountains Insurance Group Ltd. common stock as of 12/31/2025. The firm reports beneficial ownership of 76,817 shares, representing 3.0% of the outstanding common stock.
Morgan Stanley reports 0 shares with sole voting or dispositive power, 53,289 shares with shared voting power, and 76,817 shares with shared dispositive power. It states that it has ceased to be the beneficial owner of more than five percent of this class and that the shares are held in the ordinary course of business, not to influence control of the issuer.
White Mountains Insurance Group reported strong fourth-quarter and full-year 2025 results, driven primarily by the sale of Bamboo and solid insurance and investment performance. Book value per share reached $2,188 as of December 31, 2025, up 18% in the quarter and 25% for the year including dividends.
For 2025, net income attributable to common shareholders was $1.11 billion, helped by an $816 million net gain on the Bamboo transaction. Bamboo was sold to CVC Capital Partners for $848 million in cash, with White Mountains retaining a 15% fully diluted equity interest valued at $250 million.
Ark delivered a full-year combined ratio of 83% on $2.6 billion of gross written premiums, up 16%. Excluding MediaAlpha, the investment portfolio returned 2.0% in the quarter and 8.9% for the year. The company repurchased $203 million of shares in 2025 at about 92% of year-end book value per share, and reported roughly $1.0 billion of undeployed capital including a January distribution from Outrigger Re.
White Mountains Insurance Group Ltd. reported that investment firms Neuberger Berman Group LLC and Neuberger Berman Investment Advisers LLC have filed a Schedule 13G for its common shares as of 12/31/2025.
Neuberger Berman Group LLC may be deemed to beneficially own 129,654 shares, or 5.1% of the class, all through shared voting or investment authority. Neuberger Berman Investment Advisers LLC may be deemed to beneficially own 125,524 shares, or 4.9%. The filing explains that these shares are held in various fiduciary and advisory accounts for unrelated clients, who retain the economic interest in the securities.
The Neuberger entities state that the holdings were acquired and are held in the ordinary course of business and are not intended to change or influence control of White Mountains. No single client has more than 5% of the issuer’s shares.
White Mountains Insurance Group, Ltd. reported that its specialty property and casualty subsidiary, Ark Insurance Holdings Limited, has renewed Outrigger Re Ltd., a reinsurance sidecar, for business incepting during calendar year 2026 on terms similar to 2025. Outrigger has again entered into a quota share with Ark to provide collateralized reinsurance protection on a portion of Ark Bermuda’s global property catastrophe portfolio.
For the 2026 underwriting year, Outrigger deployed $70 million of total investor capital, all provided by third-party investors and excluding White Mountains. The filing notes that Outrigger’s size was reduced compared with the prior year because Ark increased its use of traditional quota share reinsurance for 2026.
White Mountains Insurance Group executive MD & Chief Accounting Officer reported a routine change in holdings. On January 1, 2026, 600 restricted common shares became unrestricted, and 274 common shares were withheld by the company to cover the reporting person's tax obligations. This withholding is shown as a disposition transaction.
After this event, the reporting person beneficially owned 2,491 common shares and 1,225 restricted common shares directly, plus 20 common shares held indirectly through a 401(k) plan.
White Mountains Insurance Group Ltd. Chief Financial Officer, a reporting officer and insider of the company, reported a routine equity transaction. On January 1, 2026, 400 restricted common shares became unrestricted. To cover tax obligations related to this vesting, 131 common shares were withheld by the company, coded as an "F" transaction for tax withholding. After this event, the reporting person beneficially owns 772 common shares directly, 700 restricted common shares directly, and 12 common shares indirectly through the White Mountains Retirement Plan.
White Mountains Insurance Group Ltd reported the initial holdings of its Chief Financial Officer in a Form 3 dated as of 01/01/2026. The filing shows direct ownership of 503 Common Shares and 1,100 Common Shares (Restricted), as well as indirect ownership of 12 Common Shares held through the White Mountains Retirement Plan. The indirect position is based on a plan report dated as of December 22, 2025.
White Mountains Insurance Group executive vice president and general counsel reported changes in his holdings of the company’s common shares. On January 1, 2026, 1,000 restricted common shares became unrestricted, and 398 of those shares were withheld by the company to cover tax obligations at a reported value of $2,078.03. Following this transaction, he beneficially owns 17,907 common shares directly, 1,725 restricted common shares directly, 4 common shares indirectly through his wife and dependent children, and 583 common shares indirectly through the White Mountains Retirement Plan, which includes an accumulation of 3 shares since his prior report as of a plan statement dated December 22, 2025.
White Mountains Insurance Group Chief Executive Officer Wesley C. Bell reported changes in his shareholdings in the company. On January 1, 2026, 1,250 restricted common shares became unrestricted, and 425 common shares were withheld by the company to cover his tax obligations at a reported price of $2,078.03. After this transaction, he directly held 1,655 restricted common shares and 2,150 common shares, and indirectly held 8 common shares through the WTM Retirement Plan. The filing is made by a single reporting person in his capacity as Chief Executive Officer.