WHITE MOUNTAINS INSURANCE GROUP LTD

Note 1. Basis of Presentation and Significant Accounting Policies

Basis of Presentation

White Mountains Insurance Group, Ltd. (the “Company” or the “Registrant”) is an exempted Bermuda limited liability company whose principal businesses are conducted through its subsidiaries and other affiliates. The Company’s headquarters is located at 26 Reid Street, Hamilton, Bermuda HM 11, its principal executive office is located at 23 South Main Street, Suite 3B, Hanover, New Hampshire 03755-2053 and its registered office is located at Clarendon House, 2 Church Street, Hamilton, Bermuda HM 11. The Company’s website is www.whitemountains.com. The information contained on the Company’s website is not incorporated by reference into, and is not a part of, this report.

The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and include the accounts of the Company, its subsidiaries (collectively with the Company, “White Mountains”) and other entities required to be consolidated under GAAP.

Certain amounts in the prior period financial statements have been reclassified to conform to the current presentation.

Consolidation Principles

Under GAAP, the Company is required to consolidate any entity in which it holds a controlling financial interest. A controlling financial interest is usually in the form of an investment representing the majority of the subsidiary’s voting interests. However, a controlling financial interest may also arise from a financial interest in a variable interest entity (“VIE”) through arrangements that do not involve ownership of voting interests. The Company consolidates a VIE if it determines that it is the primary beneficiary. The primary beneficiary is defined as the entity that holds a variable interest that gives it both the power to direct the VIE’s activities that most significantly impact its economic performance and the obligation to absorb losses of, or the right to receive returns from, the VIE that could potentially be significant to the VIE. See Note 16 — “Variable Interest Entities.”

Intercompany transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Reportable Segments

As of December 31, 2025, White Mountains conducted its operations through four reportable segments: (1) Ark/WM Outrigger, (2) HG Global, (3) Kudu and (4) Distinguished, with its remaining operating businesses, holding companies and other assets included in Other Operations. White Mountains has made its segment determination based on consideration of the following criteria: (i) the nature of the business activities of each of the Company’s subsidiaries and affiliates; (ii) the manner in which the Company’s subsidiaries and affiliates are organized; (iii) the existence of primary managers responsible for specific subsidiaries and affiliates; and (iv) the organization of information provided to the Company’s chief operating decision maker (“CODM”) and its Board of Directors. See Note 15 —“Segment Information.”

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The Ark/WM Outrigger segment consists of Ark Insurance Holdings Limited and its subsidiaries (collectively, “Ark”) and Outrigger Re Ltd. Segregated Account 2023-1 (“WM Outrigger Re”) (collectively with Ark, “Ark/WM Outrigger”). Ark is a specialty property and casualty insurance and reinsurance company that offers a wide range of niche insurance and reinsurance products, including property, specialty, marine & energy, casualty and accident & health. Ark underwrites select coverages through Lloyd’s Syndicates 4020 and 3902 and Additional Central Settlement Number (“ACSN”) 3832 (collectively, the “Syndicates”) and its wholly-owned subsidiary Group Ark Insurance Limited (“GAIL”). White Mountains acquired a controlling ownership interest in Ark on January 1, 2021 (the “Ark Transaction”). As of December 31, 2025 and 2024, White Mountains owned 72.1% of Ark on a basic shares outstanding basis (61.9% after taking account of management’s equity incentives). The remaining shares are owned by current and former employees of Ark. In the future, management rollover shareholders could earn additional shares in Ark if and to the extent that White Mountains achieves certain thresholds for its multiple of invested capital (“MOIC”) return. If fully earned, these shares would represent an additional 12.3% of the shares outstanding as of December 31, 2025. The liability related to these additional shares is recorded as contingent consideration. Outrigger Re Ltd. is a Bermuda special purpose insurer and segregated accounts company that provides collateralized reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio. As of December 31, 2025 and 2024, White Mountains owned 100.0% of the preferred equity of its segregated cell, WM Outrigger Re. White Mountains consolidates WM Outrigger Re in its financial statements. See Note 2 — “Significant Transactions.”

The HG Global segment consists of HG Global Ltd. and its wholly-owned subsidiaries (collectively, “HG Global”) and, prior to its deconsolidation on July 1, 2024, the consolidated results of Build America Mutual Assurance Company (“BAM”). See Note 2 — “Significant Transactions.” HG Global was established to fund the startup of BAM and, through its reinsurance subsidiary, HG Re Ltd. (“HG Re”), to provide first-loss reinsurance protection of up to 15%-of-par outstanding for each policy assumed from BAM. HG Global, together with its subsidiaries, funded the initial capitalization of BAM through the purchase of $503.0 million of surplus notes issued by BAM (the “BAM Surplus Notes”). As of December 31, 2025 and 2024, White Mountains owned 96.9% of HG Global’s preferred equity and 88.4% of its common equity.

White Mountains does not have an ownership interest in BAM. However, through June 30, 2024, White Mountains was required to consolidate BAM’s results in its financial statements because BAM is a VIE for which White Mountains was the primary beneficiary. BAM’s results were all attributed to noncontrolling interests. On July 1, 2024, HG Re and BAM amended the terms of the first-loss reinsurance treaty (“FLRT”) with respect to certain governance rights held by HG Re. As a result, and in combination with other governance changes at BAM, White Mountains concluded that it no longer has the power to direct BAM’s activities that most significantly impact its economic performance and is no longer BAM’s primary beneficiary. Accordingly, effective July 1, 2024, White Mountains no longer consolidates BAM. Through June 30, 2024, BAM’s results of operations were presented within the HG Global segment. See Note 2 — “Significant Transactions.”

The Kudu segment consists of Kudu Investment Management, LLC and its subsidiaries (collectively, “Kudu”). Kudu provides capital solutions for boutique asset and wealth managers for a variety of purposes including generational ownership transfers, management buyouts, acquisition and growth finance and legacy partner liquidity. Kudu also provides strategic advice to managers from time to time. Kudu’s capital solutions are generally structured as noncontrolling equity interests in the form of revenue and earnings participation contracts (“Participation Contracts”) and designed to generate immediate cash yields. As of December 31, 2025 and 2024, White Mountains owned 91.2% and 90.4% of Kudu’s basic units outstanding (77.9% and 77.0% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives).

The Distinguished segment consists of WM Phoenix Parent, L.P. and its subsidiaries d/b/a Distinguished Programs (collectively, “Distinguished”). Distinguished is a full-service MGA and program administrator for specialty property and casualty insurance. Distinguished places insurance across a diversified portfolio of programs broadly grouped into two verticals. The ScaleCo vertical consists of established programs, primarily focused on real estate and hospitality end markets. The GrowthCo vertical consists of start-up programs, focused on a diversified set of specialty property and casualty insurance products across multiple industries. On behalf of its insurance carrier partners, Distinguished typically manages all aspects of the placement process, including product development, marketing, underwriting and policy issuance. Distinguished earns commissions based on the volume and profitability of the insurance that it places. Distinguished does not retain insurance risk. On September 2, 2025, White Mountains acquired a controlling financial interest in Distinguished. See Note 2 — “Significant Transactions.” As of December 31, 2025, White Mountains owned 55.5% of Distinguished on a basic units outstanding basis (43.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives).

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White Mountains’s other operations consist of the Company and its wholly-owned subsidiary, White Mountains Capital, LLC (“WM Capital”), its other intermediate holding companies, its wholly-owned investment management subsidiary, White Mountains Advisors LLC (“WM Advisors”), investment assets managed by WM Advisors, its interests in Bamboo Ide8 Insurance Services LLC (“Bamboo MGA”) and its subsidiaries through a special purpose vehicle (the “Bamboo SPV”), MediaAlpha, Inc. (“MediaAlpha”), DavidShield PassportCard Ltd. and its subsidiaries (collectively, “PassportCard/DavidShield”), BroadStreet Partners, Inc. (“BroadStreet”) through a special purpose vehicle (the “BroadStreet SPV”), Elementum Holdings LP (“Elementum”), White Mountains Partners LLC (“WTM Partners”), Enterprise Electric, LLC d/b/a Enterprise Solutions (“Enterprise Solutions”), two special purpose collateralized reinsurance vehicles that provide reinsurance capacity to Bamboo (the “Bamboo CRVs”), certain other consolidated and unconsolidated entities (“Other Operating Businesses”) and certain other assets (collectively, “Other Operations”).

Held for Sale

White Mountains recognizes assets and liabilities classified as held for sale at the lower of carrying value on the date the asset is initially classified as held for sale or fair value less costs to sell. At the time of reclassification to held for sale, White Mountains ceases recognizing depreciation and amortization on assets held for sale.

On December 5, 2025, White Mountains completed the sale of a controlling financial interest in WM Pierce Holdings, Inc. and its subsidiaries, including Bamboo MGA (collectively, the "Bamboo Group"). As a result of the sale, White Mountains deconsolidated the Bamboo Group on December 5, 2025, and Bamboo is no longer a reportable segment. Through December 5, 2025, Bamboo’s results of operations are presented within the Bamboo segment. See Note 2 — “Significant Transactions.” The Bamboo Group’s assets and liabilities have been presented as held for sale as of December 31, 2024. See Note 20 — “Held for Sale.”

Through December 5, 2025, the Bamboo segment consisted of PM Holdings LLC (“Bamboo Holdings”), Bamboo MGA and Ide8 Re, Inc. (the “Bamboo Captive”) (collectively, “Bamboo”). Bamboo is a capital-light, tech- and data-enabled insurance distribution platform providing homeowners’ insurance and related products to the residential property market in California and, beginning in the third quarter of 2025, in Texas. Bamboo operates primarily through Bamboo MGA, its full-service MGA business, where the company manages all aspects of the placement process on behalf of its fronting and reinsurance carrier partners (“Capacity Providers”), including product development, marketing, underwriting, policy issuance and claims oversight, and it earns commissions based on the volume and profitability of the insurance that it places. Bamboo MGA offers both admitted and non-admitted products.

Significant Accounting Policies

Investment Securities

As of December 31, 2025 and 2024, White Mountains’s invested assets consisted of securities and other investments held for general investment purposes. White Mountains’s portfolio of investment securities held for general investment purposes consists of fixed maturity investments, short-term investments, common equity securities, its investment in MediaAlpha and other long-term investments. Short-term investments consist of interest-bearing money market funds, certificates of deposit and other fixed maturity securities, which at the time of purchase, mature or become available for use within one year. Short-term investments are carried at fair value, which approximated amortized or accreted cost as of December 31, 2025 and 2024. Other long-term investments consist primarily of unconsolidated entities, including Kudu’s Participation Contracts, the Bamboo SPV, PassportCard/DavidShield and the BroadStreet SPV, as well as private equity funds and hedge funds, a bank loan fund and Lloyd’s of London (“Lloyd’s”) trust deposits.

White Mountains’s portfolio of fixed maturity investments, including those within short-term investments, are classified as trading securities. Trading securities are reported at fair value as of the balance sheet date. White Mountains’s portfolio of common equity securities, its investment in MediaAlpha and other long-term investments are measured at fair value. White Mountains has generally taken the fair value option for its equity method eligible investments.

Changes in net unrealized investment gains (losses) are reported pre-tax in revenues. Realized investment gains (losses) are accounted for using the specific identification method and are reported pre-tax in revenues. Premiums and discounts on all fixed maturity investments are amortized and accreted to income over the anticipated life of the investment. Income on mortgage and asset-backed securities is recognized using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When actual prepayments differ significantly from anticipated prepayments, the estimated economic life is recalculated, and the remaining unamortized premium or discount is amortized prospectively over the remaining economic life.

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Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants (an exit price) at a particular measurement date. Fair value measurements are categorized into a hierarchy that distinguishes between inputs based on market data from independent sources (observable inputs) and a reporting entity’s internal assumptions based upon the best information available when external market data is limited or unavailable (unobservable inputs). Quoted prices in active markets for identical assets have the highest priority (“Level 1”), followed by observable inputs other than quoted prices including prices for similar but not identical assets or liabilities (“Level 2”) and unobservable inputs, including the reporting entity’s estimates of the assumptions that market participants would use, having the lowest priority (“Level 3”).

Assets and liabilities carried at fair value include White Mountains’s investment portfolio and derivative instruments. Valuation of assets and liabilities measured at fair value require management to make estimates and apply judgment to matters that may carry a significant degree of uncertainty. In determining its estimates of fair value, White Mountains uses a variety of valuation approaches and inputs. Whenever possible, White Mountains estimates fair value using valuation methods that maximize the use of quoted market prices or other observable inputs. Where appropriate, assets and liabilities measured at fair value have been adjusted for the effect of counterparty credit risk.

White Mountains uses outside pricing services and brokers to assist in determining fair values. The outside pricing services White Mountains uses have indicated that they will only provide prices where observable inputs are available.

Level 1 Measurements

Investments valued using Level 1 inputs include White Mountains’s fixed maturity investments, primarily investments in U.S. Treasuries and short-term investments, which include U.S. Treasury Bills, common equity securities and its investment in MediaAlpha. For investments in active markets, White Mountains uses the quoted market prices provided by outside pricing services to determine fair value.

Level 2 Measurements

Investments valued using Level 2 inputs include fixed maturity investments which have been disaggregated into classes, including debt securities issued by corporations, municipal obligations, foreign government and agency obligations, mortgage and asset-backed securities and collateralized loan obligations. Investments valued using Level 2 inputs also include certain international listed common equity funds, which White Mountains values using the fund manager’s published net asset value (“NAV”) to account for the difference in market exchange close times, and certain derivative instruments.

In circumstances where quoted market prices are unavailable or are not considered reasonable, White Mountains estimates the fair value using industry standard pricing methodologies and observable inputs such as benchmark yields, reported trades, broker-dealer quotes, issuer spreads, benchmark securities, bids, offers, credit ratings, prepayment speeds, reference data including research publications and other relevant inputs. Given that many fixed maturity investments do not trade on a daily basis, the outside pricing services evaluate a wide range of fixed maturity investments by regularly drawing parallels from recent trades and quotes of comparable securities with similar features. The characteristics used to identify comparable fixed maturity investments vary by asset type and take into account market convention.

White Mountains’s process to assess the reasonableness of the market prices obtained from the outside pricing sources covers substantially all of its fixed maturity investments and includes, but is not limited to, the evaluation of pricing methodologies and a review of the pricing services’ quality control procedures on at least an annual basis, a comparison of invested asset prices obtained from alternate independent pricing vendors on at least a semi-annual basis, monthly analytical reviews of certain prices and a review of the underlying assumptions utilized by the pricing services for select measurements on an ad hoc basis throughout the year. White Mountains also performs back-testing of selected investment sales activity to determine whether there are any significant differences between the market price used to value the security prior to sale and the actual sale price of the security on an ad-hoc basis throughout the year. Prices provided by the pricing services that vary by more than $0.5 million and 5% from the expected price based on these assessment procedures are considered outliers, as are prices that have not changed from period to period and prices that have trended unusually compared to market conditions. In circumstances where the results of White Mountains’s review process does not appear to support the market price provided by the pricing services, White Mountains challenges the vendor provided price. If White Mountains cannot gain satisfactory evidence to support the challenged price, White Mountains will rely upon its own internal pricing methodologies to estimate the fair value of the security in question.

The valuation process described above is generally applicable to all of White Mountains’s fixed maturity investments. The techniques and inputs specific to asset classes within White Mountains’s fixed maturity investments for Level 2 securities that use observable inputs are as follows:

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Debt Securities Issued by Corporations

The fair value of debt securities issued by corporations is determined from a pricing evaluation technique that uses information from market sources and integrates relative credit information, observed market movements and sector news. Key inputs include benchmark yields, reported trades, broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including sector, coupon, credit quality ratings, duration, credit enhancements, early redemption features and market research publications.

Municipal Obligations

The fair value of municipal obligations is determined from a pricing evaluation technique that uses information from market makers, brokers-dealers, buy-side firms and analysts along with general market information. Key inputs include benchmark yields, reported trades, issuer financial statements, material event notices and new issue data, as well as broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including type, coupon, credit quality ratings, duration, credit enhancements, geographic location and market research publications.

Foreign Government and Agency Obligations

The fair value of foreign government and agency obligations is determined from a pricing evaluation technique that uses information from data sources in each respective country, including active market makers and inter-dealer brokers. Key inputs include benchmark yields, reported trades, broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, local exchange prices, foreign currency exchange rates and reference data including coupon, credit quality ratings, duration and market research publications.

Mortgage and Asset-Backed Securities and Collateralized Loan Obligations

The fair value of mortgage and asset-backed securities and collateralized loan obligations is determined from a pricing evaluation technique that uses information from market sources and leveraging similar securities. Key inputs include benchmark yields, reported trades, underlying tranche cash flow data, collateral performance, plus new issue data, as well as broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including issuer, vintage, loan type, collateral attributes, prepayment speeds, default rates, recovery rates, cash flow stress testing, credit quality ratings and market research publications.

Level 3 Measurements

Fair value estimates for investments that trade infrequently and have few or no quoted market prices or other observable inputs are classified as Level 3 measurements. Investments valued using Level 3 fair value estimates are based upon unobservable inputs and include investments in certain fixed maturity investments, common equity securities and other long-term investments where quoted market prices or other observable inputs are unavailable or are not considered reliable or reasonable.

Level 3 valuations are generated from techniques that use assumptions not observable in the market. These unobservable inputs reflect White Mountains’s assumptions of what market participants would use in valuing the investment. In certain circumstances, investment securities may start out as Level 3 when they are originally issued, but as observable inputs become available in the market, they may be reclassified to Level 2. Transfers of securities between levels are based on investments held as of the beginning of the period.

Other Long-Term Investments

As of December 31, 2025, $1,814.4 million of White Mountains’s other long-term investments were classified as Level 3 investments in the GAAP fair value hierarchy, including Kudu’s Participation Contracts, the Bamboo SPV, PassportCard/DavidShield and certain other unconsolidated entities. The determination of the fair value of these securities involves significant management judgment, and the use of valuation analyses and assumptions that are inherently subjective and uncertain.

White Mountains may use a variety of valuation techniques to determine fair value depending on the nature of the investment, including a discounted cash flow analysis, market multiple approach, cost approach and/or liquidation analysis. On an ongoing basis, White Mountains also considers qualitative changes in facts and circumstances, which may impact the valuation of its unconsolidated entities, including economic and market changes in relevant industries, changes to the entity’s capital structure, business strategy and key personnel and any recent transactions. On a quarterly basis, White Mountains evaluates the most recent qualitative and quantitative information of the business and completes a fair valuation analysis for all other long-term investments classified as Level 3 investments. Periodically, and at least on an annual basis, White Mountains uses a third-party valuation firm to complete an independent valuation analysis of significant unconsolidated entities.

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Other Long-term Investments - NAV

As of December 31, 2025, $1,110.4 million of White Mountains’s other long-term investments were measured at fair value using NAV as a practical expedient, including the BroadStreet SPV, private equity funds and hedge funds, a bank loan fund, Lloyd’s trust deposits and insurance-linked securities (“ILS”) funds. Investments for which fair value is measured using NAV as a practical expedient are not classified within the fair value hierarchy.

White Mountains employs a number of procedures to assess the reasonableness of the fair value measurements for other long-term investments measured at NAV, including obtaining and reviewing interim unaudited and annual audited financial statements as well as periodically discussing the valuations and methodologies used to value the underlying investments of each fund with fund managers. However, since fund managers do not provide sufficient information to evaluate the pricing methods and inputs for each underlying investment, White Mountains considers the valuation inputs to be unobservable. The fair value of White Mountains’s other long-term investments measured at NAV are generally determined using the fund manager’s NAV. Certain other long-term investments measured at NAV may be reported to White Mountains on a lag. In these circumstances, the NAV of such investments is adjusted to account for any applicable contributions, distributions, known transactions and/or pricing estimates provided by the fund manager through White Mountains’s reporting date.

Prior to the deconsolidation of BAM on July 1, 2024, the BAM Surplus Notes, including accrued interest receivable, were

classified as intercompany notes carried at nominal value, which eliminated in consolidation. Upon deconsolidation, White

Mountains elected the fair value option for the BAM Surplus Notes. White Mountains values the BAM Surplus Notes each quarter using a discounted cash flow analysis. The BAM Surplus Notes are classified as a Level 3 measurement. Upon election of the fair value option, White Mountains made the accounting policy election to present the interest income from the BAM Surplus Notes separately from the change in fair value of the BAM Surplus Notes. See Note 10 — “Municipal Bond Guarantee Reinsurance.”

Cash and Restricted Cash

Cash includes amounts on hand and demand deposits with banks and other financial institutions. Amounts presented in the statement of cash flows are shown net of balances acquired and sold in the purchase or sale of the Company’s consolidated subsidiaries.

Cash balances that are not immediately available for general corporate and operating purposes are classified as restricted.

Derivatives

From time to time, White Mountains holds derivative financial instruments for risk management purposes. White Mountains recognizes all derivatives as either assets or liabilities, measured at fair value, on its consolidated balance sheet. Changes in the fair value of derivative instruments that meet the criteria for hedge accounting are recognized in other comprehensive income (loss) and reclassified into current period pre-tax income (loss) when the hedged items are recognized therein. Changes in the fair value of derivative instruments that do not meet the criteria for hedge accounting are recognized in current period pre-tax income (loss).

As of December 31, 2025, White Mountains holds interest rate cap derivative instruments that do not meet the criteria for hedge accounting. See Note 9 — “Derivatives.”

Property and Casualty Insurance and Reinsurance

Ark writes a diversified portfolio of reinsurance and insurance products, including property, specialty, marine & energy, casualty and accident & health.

Ark accounts for insurance and reinsurance policies that it writes in accordance with ASC 944, Financial Services - Insurance. Ark’s premiums written comprise premiums on insurance contracts incepted during the year as well as premium adjustments related to prior underwriting years. Insurance premiums are recognized as revenues over the loss exposure or coverage period. In most cases, premiums are earned ratably over the term of the contract, with unearned premiums calculated on a monthly pro-rata basis. Catastrophe premiums are earned in proportion to the insurance protection provided. Premiums earned are presented net of amounts ceded to reinsurers. Insurance premiums receivable, representing amounts due from insureds, are presented net of an allowance for uncollectible premiums, including expected credit losses. The allowance is based upon Ark’s ongoing review of amounts outstanding, historical loss data, including delinquencies and write-offs, current and forecasted economic conditions and other relevant factors. Credit risk is partially mitigated by Ark’s ability to cancel the policy if the policyholder does not pay the premium.

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Deferred acquisition costs comprise commission and brokerage fees and taxes which are directly attributable to and vary with the production of business. These costs are deferred and amortized to the extent that they relate to successful contract acquisitions over the applicable premium recognition period as acquisition expenses. Deferred acquisition costs are limited to the amount expected to be recovered from future earned premiums and anticipated investment income. A premium deficiency is recognized if the sum of expected loss and loss adjustment expenses (“LAE”), expected dividends to policyholders, unamortized acquisition costs and maintenance costs exceeds related unearned premiums and anticipated investment income. A premium deficiency is recognized by charging any unamortized acquisition costs to expense to the extent required in order to eliminate the deficiency. If the premium deficiency exceeds unamortized acquisition costs, then a liability is accrued for the excess deficiency.

Loss and LAE are charged against income as incurred. Loss and LAE reserves, including estimates for amounts incurred but not reported (“IBNR”), are based on management’s best estimate of the ultimate costs to settle claims, including the effects of inflation and other societal and economic factors. Loss and LAE reserves are presented net of estimated salvage and subrogation recoveries, if applicable. Such estimates are regularly reviewed and updated, and any resulting adjustments are reflected in current results of operations. The process of estimating loss and LAE reserves involves a considerable degree of judgment by management, and the ultimate amount of expense to be incurred could be considerably greater than or less than the amounts currently reflected in the financial statements. See Note 5 — “Loss and Loss Adjustment Expense Reserves.”

As part of its enterprise risk management function, Ark purchases reinsurance for risk mitigation purposes. Ark utilizes reinsurance and retrocessional agreements to reduce earnings volatility, protect capital, limit concentration and accumulation risk and manage within its overall internal risk tolerances and/or those set and agreed by regulators, ratings agencies and Lloyd’s. Ark also enters into reinsurance and retrocessional agreements to reduce its exposures on individual risks and enable it to underwrite policies with higher limits where Ark believes this has a broader business benefit. Ark seeks to protect its downside risk from catastrophes and large loss events by purchasing reinsurance, including excess of loss protections, aggregate covers and industry loss warranties. Ark also considers alternative structures such as collateralized reinsurance, retrocessional reinsurance and catastrophe bonds. The purchase of reinsurance does not discharge Ark from its primary liability for the full value of its policies, and thus the collectability of balances due from Ark’s reinsurers is critical to its financial strength. Ark monitors the financial strength and ratings of its reinsurers on an ongoing basis. See Note 6 — “Third-Party Reinsurance.”

Reinsurance recoverables represent paid loss and LAE, case reserves and IBNR reserves ceded to reinsurers under reinsurance treaties. Amounts recoverable from reinsurers are estimated in a manner consistent with the associated claims liability. Ark reports its reinsurance recoverables net of an allowance for estimated uncollectible reinsurance, including expected credit losses and coverage disputes. The allowance is based upon Ark’s ongoing review of amounts outstanding, length of collection periods, changes in reinsurer credit standing, disputes, applicable coverage defenses and other relevant factors.

Municipal Bond Guarantee Reinsurance

As of July 1, 2024, White Mountains no longer consolidates BAM. Through June 30, 2024, BAM’s results of operations are presented within the HG Global segment.

The FLRT and all the contracts issued by BAM are accounted for as insurance contracts under ASC 944-605, Financial Guarantee Insurance Contracts. For capital appreciation bonds, par is adjusted to the estimated equivalent par value for current interest paying bonds. Prior to the deconsolidation of BAM, HG Re’s reinsurance balances under the FLRT eliminated in White Mountains’s consolidated financial statements. See Note 10 — “Municipal Bond Guarantee Reinsurance.”

Premiums are generally received upfront and an unearned premium reserve, equal to the amount of the premium received, is established at contract inception. Premiums are recognized in revenue over the period of the contracts in proportion to the amount of insurance protection provided using a constant rate. The constant rate is calculated based on the relationship between the par outstanding in a given reporting period compared with the sum of each of the par amounts outstanding for all periods.

HG Re’s insurance premiums receivable represents amounts due from BAM. Installment premiums are measured at the present value of contractual premiums, discounted at the risk-free rate, which is set at the inception of the insurance contract.

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HG Re’s deferred acquisition costs represent the ceding commission paid to BAM. These costs are deferred and amortized to the extent that they relate to successful contract acquisitions over the applicable premium recognition period as acquisition expenses. Deferred acquisition costs are limited to the amount expected to be recovered from future earned premiums and anticipated investment income. A premium deficiency is recognized if the sum of expected loss and LAE, expected dividends to policyholders, unamortized acquisition costs and maintenance costs exceeds related unearned premiums and anticipated investment income. A premium deficiency is recognized by charging any unamortized acquisition costs to expense to the extent required in order to eliminate the deficiency. If the premium deficiency exceeds unamortized acquisition costs, then a liability is accrued for the excess deficiency.

Loss reserves are recorded only to the extent that the present value of any payments projected to be made, net of any expected recoveries, exceeds the associated unearned premium reserve. See Note 5 — “Loss and Loss Adjustment Expense Reserves.”

Reinsurance Contracts Accounted for as Deposits

Reinsurance contracts that do not meet the risk transfer requirements necessary to be accounted for as reinsurance are accounted for using the deposit method. Under the deposit method, ceded premiums paid are not recognized through income but rather treated as a deposit.

HG Re is party to an excess of loss reinsurance agreement (the “XOLT”) with BAM. The XOLT is accounted for using deposit accounting as the agreement does not meet the risk transfer requirements necessary to be accounted for as reinsurance. Accordingly, any financing revenues related to the XOLT are recorded in other revenues. See Note 10 — “Municipal Bond Guarantee Reinsurance.”

Revenue Recognition

Kudu’s revenues are primarily generated from Participation Contracts, which are generally noncontrolling equity interests in revenue and earnings participation contracts with asset and wealth management firms. Kudu’s Participation Contracts are measured at fair value with the change therein recognized within net realized and unrealized investment gains (losses). Distributions from Kudu’s managers are recognized through investment income when Kudu’s right to receive payment has been established and can be reliably measured, which generally occurs on a quarterly basis in accordance with the terms of the Participation Contracts.

Bamboo’s revenues consist primarily of commission and fee revenues for placement of insurance policies. Commission and fee revenues are measured based on the contractual rates with insurance carriers, net of any amounts expected to be uncollectible and any amounts associated with expected policy cancellations and adjustments, and are recognized when contractual performance obligations have been fulfilled. Bamboo’s primary contractual performance obligations are generally satisfied upon the issuance of an insurance policy. Bamboo’s premiums, commissions and fees receivable consist of insurance premiums and fees receivable from customers and commissions receivable from insurance carriers, net of a provision for amounts estimated to be uncollectible and any amounts associated with expected policy cancellations and adjustments.

Distinguished’s revenues consist primarily of commission and fee revenues related to its placement of insurance policies. Commission revenues are measured based on the contractual rates with its insurance carriers, net of any amounts expected to be uncollectible and any amounts associated with expected policy cancellations and adjustments, and are recognized when contractual performance obligations have been fulfilled. Distinguished also earns fee revenues, primarily related to risk management services provided to certain insureds, which are recognized when contractual performance obligations have been fulfilled. Distinguished’s primary contractual performance obligations are generally satisfied upon the issuance of an insurance policy. Distinguished’s premiums, commissions and fees receivable consist of insurance premiums and fees receivable from insureds and commissions receivable from insurance carriers, net of a provision for amounts estimated to be uncollectible and any amounts associated with expected policy cancellations and adjustments. Premiums receivable are collected on behalf of Distinguished’s insurance carriers. Distinguished’s premiums and commissions payable consist of insurance premiums payable to insurance carriers and commissions payable to sub-agents and brokers.

Other Operations recognizes commissions and fee revenues as well as other revenues when it has satisfied its performance obligations. Enterprise Solutions’s revenues consist primarily of construction revenues from specialty electrical contracting services provided to commercial and institutional customers. Enterprise Solutions’s billings are generally based on contractual terms and may not coincide with its progress in a project. Construction revenues, which are presented within other revenues, are recognized over time using the cost-to-cost percentage of completion input method, based on the ratio of contract costs incurred to date compared to total estimated contract costs. Contract costs incurred to date and expected total contract costs are continuously monitored during the term of the contract. Enterprise Solutions records accounts receivable, which are presented within other assets, for amounts billed to the customer, net of a provision for amounts estimated to be uncollectible. If the recognized revenue is greater than the amount billed to the customer, a contract asset is recorded within other assets. Contract assets also include amounts billed under retainage provisions that cannot be collected until the contract work has been completed and approved. If the amount billed to the customer is greater than the recognized revenue, a contract liability is recorded within other liabilities.

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Broker Commission Expenses and Cost of Sales

Bamboo’s broker commission expenses consist of commissions paid to sub-agents and brokers. Broker commission expense is measured in accordance with contractual terms and recognized when incurred, which is generally at the policy issuance date.

Distinguished’s broker commission expenses consist of commissions paid to sub-agents and brokers. Broker commission expense is measured in accordance with contractual terms and recognized when incurred, which is generally at the policy issuance date.

Other Operations recognizes cost of sales consisting of salaries and related expenses, professional services and marketing and advertising expenses directly related to sales generation. These expenses are recognized as incurred.

Incentive Compensation

White Mountains’s Long-Term Incentive Plan (the “WTM Incentive Plan”) provides for grants of various types of share-based and non-share-based incentive awards to key employees of White Mountains. Non-share-based awards are recognized over the related service periods based on management’s best estimate of the amounts at which the awards are expected to be paid. Share-based compensation which is typically settled in cash, such as performance shares, is classified as a liability-type award. The compensation cost for liability-classified awards is measured initially at the grant date fair value and remeasured each reporting period until settlement. The compensation cost for equity-classified awards expected to be settled in shares, such as restricted shares, is measured at the original grant date fair value of the award. The compensation cost for all awards is recognized for the vested portion of the awards over the related service periods. See Note 12 — “Employee Share-Based Incentive Compensation Plans.”

Income Taxes

White Mountains has subsidiaries and branches that operate in various jurisdictions around the world and are subject to tax in the jurisdictions in which they operate. As of December 31, 2025, the primary jurisdictions in which the Company’s subsidiaries and branches operate and were subject to tax include Israel, Luxembourg, the United Kingdom and the United States. Income earned or losses generated by companies outside the United States are generally subject to an overall effective tax rate lower than that imposed by the United States.

Deferred tax assets and liabilities are recorded when a difference between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for tax purposes exists, or there are other temporary differences. The deferred tax asset or liability is recorded based on tax rates expected to be in effect when the difference reverses. Deferred tax assets represent amounts available to reduce income taxes payable in future periods. White Mountains records a valuation allowance against deferred tax assets if it becomes more likely than not that all or a portion of a deferred tax asset will not be realized. Changes in valuation allowances from period to period are included in income tax expense in the period of change. See Note 8 — “Income Taxes.”

Leases

White Mountains has entered into lease agreements, primarily for office space and equipment. These leases are classified as operating leases, with lease expense recognized on a straight-line basis over the term of the lease. Lease assets and liabilities are not recorded for leases with a term at inception of one year or less. Lease incentives, such as free rent or landlord reimbursements for leasehold improvements, are recognized at lease inception and amortized on a straight-line basis over the term of the lease. Lease expense and the amortization of leasehold improvements are recognized within general and administrative expenses. Lease payments related to options to extend or renew the lease term are excluded from the calculation of lease liabilities unless White Mountains is reasonably certain of exercising those options.

As of December 31, 2025 and 2024, theright-of-use assets were $51.2 million and $32.6 million, and thelease liabilities were $56.2 million and $35.5 million.

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Noncontrolling Interests

Noncontrolling interests consist of the ownership interests of noncontrolling shareholders in consolidated entities. White Mountains has both redeemable and nonredeemable noncontrolling interests. Noncontrolling interests with redemption features that are not within White Mountains’s control are classified as redeemable noncontrolling interests, which are considered temporary equity and presented as mezzanine equity on the balance sheet. Redeemable noncontrolling interests are excluded from White Mountains’s total equity. The redeemable noncontrolling interests relate to Distinguished. Noncontrolling interests that do not have any redemption features are classified as nonredeemable noncontrolling interests, which are considered permanent equity and included in White Mountains’s total equity on the balance sheet. Nonredeemable noncontrolling interests are presented separately from White Mountains’s common shareholders’ equity. See Note 13 — “Common Shareholders’ Equity and Noncontrolling Interests.”

Comprehensive income (loss) is attributable to both redeemable and nonredeemable noncontrolling interests and is presented net of related income taxes in the statements of operations and comprehensive income (loss). In addition, White Mountains recognizes an adjustment to the carrying value of the redeemable noncontrolling interests to the extent that the carrying value is below the redemption value. The adjustment for redeemable noncontrolling interests is recognized through White Mountains’s common shareholders’ equity. When calculating basic and diluted earnings per share, the adjustment for redeemable noncontrolling interests is treated as being akin to a dividend and presented as an adjustment to net income (loss) attributable to White Mountains’s common shareholders.

Foreign Currency Exchange

The functional currencies for White Mountains’s non-U.S. based subsidiaries are measured, in most instances, using currencies other than the U.S. dollar. Net foreign currency exchange gains and losses arising from the translation of functional currencies are generally reported in shareholders’ equity, in accumulated other comprehensive income (loss).

White Mountains also invests in securities denominated in foreign currencies. Assets and liabilities recorded in these foreign currencies are translated into U.S. dollars at exchange rates in effect at the balance sheet date, and revenues and expenses are converted using the weighted average exchange rates for the period.

As of December 31, 2025 and 2024, White Mountains had unrealized foreign currency translation gains (losses) of $0.8 million and $(1.7) million recorded in accumulated other comprehensive income (loss) on its consolidated balance sheet.

Fair Value Measurements

Fair value measurements are categorized into a hierarchy that distinguishes between inputs based on market data from independent sources (observable inputs) and a reporting entity’s internal assumptions based upon the best information available when external market data is limited or unavailable (unobservable inputs). Quoted prices in active markets for identical assets or liabilities have the highest priority (Level 1), followed by observable inputs other than quoted prices, including prices for similar but not identical assets or liabilities (Level 2) and unobservable inputs, including the reporting entity’s estimates of the assumptions that market participants would use, having the lowest priority (Level 3). See Note 18 — “Fair Value of Financial Instruments.”

Business Combinations

White Mountains accounts for purchases of businesses using the acquisition method, which requires the measurement of assets acquired, including other intangible assets, liabilities assumed, including contingent consideration liabilities, and any noncontrolling interests in the acquired entities at their estimated fair values as of the acquisition date. The acquisition date fair values represent management’s best estimates and are based upon established valuation techniques, reasonable assumptions and, where appropriate, valuations performed by independent third parties. In circumstances where additional information is required in order to determine the acquisition date fair value of balance sheet amounts, provisional amounts may be recorded as of the acquisition date and may be subject to subsequent adjustment throughout the measurement period, which is up to one year from the acquisition date. Measurement period adjustments are recognized in the period in which they are determined. The results of operations and cash flows of businesses acquired are included in the consolidated financial statements from the acquisition date. White Mountains accounts for purchases of other intangible assets that do not meet the definition of a business as asset acquisitions. Asset acquisitions are recognized at the amount of consideration paid, which is deemed to equal fair value.

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Goodwill and Other Intangible Assets

Under the acquisition method, White Mountains recognizes and measures the assets acquired, including other intangible assets, at their acquisition date fair values. Goodwill represents the excess of the amount paid to acquire a business over the fair value of identifiable net assets at the acquisition date.

Other intangible assets consist primarily of underwriting capacity, agency relationships, customer relationships and trade names. The acquisition date fair values of other intangible assets are estimated using income approach techniques, which use future expected cash flows to develop a discounted present value amount. The multi-period-excess-earnings method estimates fair value using the present value of the incremental after-tax cash flows attributable solely to the other intangible asset over its remaining life. This approach was used to estimate the fair value of other intangible assets associated with the underwriting capacity, agency relationships and customer relationships. The relief-from-royalty method was used to estimate fair value for other intangible assets that relate to rights that could be obtained via a license from a third-party owner. Under this method, the fair value is estimated using the present value of license fees avoided by owning rather than leasing the asset. This technique was used to estimate the fair value of trade names, patents and certain information technology platforms. The with-or-without method estimates the fair value of other intangible assets that provide an incremental benefit. Under this method, the fair value of the other intangible asset is calculated by comparing the value of the entity with and without the other intangible asset. This approach was used to estimate the fair value of non-compete agreements.

Goodwill and other intangible assets with indefinite lives are not amortized, but rather are evaluated for impairment on an annual basis, or whenever indications of potential impairment exist. In the absence of any indications of potential impairment, the evaluation of goodwill and indefinite-lived intangible assets is performed no later than the interim period in which the anniversary of the acquisition date falls. White Mountains initially evaluates goodwill and indefinite-lived intangible assets using a qualitative approach (step zero) to determine whether it is more likely than not that the implied fair value is greater than the carrying value. If the results of the qualitative evaluation indicate that it is more likely than not that the carrying value of goodwill or the indefinite-lived intangible assets exceeds the implied fair value, White Mountains performs a quantitative analysis to compare the fair value with the carrying value. If the carrying value exceeds the estimated fair value, then an impairment charge is recognized through current period pre-tax income (loss).

Other intangible assets with finite lives are initially measured at their acquisition date fair values and subsequently amortized over their economic lives. Finite-lived intangible assets are presented net of accumulated amortization on the balance sheet. Finite-lived intangible assets are reviewed for impairment when events occur or there are changes in circumstances indicating that their carrying value may exceed fair value. An impairment exists when the carrying value of a finite-lived intangible asset exceeds the fair value. See Note 4 — “Goodwill and Other Intangible Assets.”

Contingent Consideration Liabilities

The consideration for the Ark Transaction included potential future payments to management rollover shareholders, which are payable in a variable number of shares, if and to the extent that White Mountains achieves certain MOIC return thresholds. This additional consideration is generally payable in three equal tranches at MOIC thresholds of 2.0x, 2.5x and 3.0x. If fully earned, these shares would represent an additional 12.3% of the shares outstanding as of December 31, 2025. The liability related to these additional shares is recorded as contingent consideration. Contingent consideration in a business combination that is classified as a liability is measured at fair value on the acquisition date and remeasured to fair value each subsequent reporting period with changes in the fair value recognized through pre-tax income (loss). As a result of the Ark Transaction, White Mountains recognized a contingent consideration liability of $22.5 million as of January 1, 2021. During the years ended December 31, 2025, 2024 and 2023, White Mountains recognized an expense of $173.0 million, $61.3 million and $48.7 million for the change in the fair value of its contingent consideration liability. As of December 31, 2025 and 2024, White Mountains’s contingent consideration liability was $328.3 million and $155.3 million. The contingent consideration liability is a Level 3 measurement.

Recently Adopted Accounting Standards

Income Taxes

White Mountains adopted ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”) effective for its annual disclosures for the year ended December 31, 2025. ASU 2023-09 requires disclosure of disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 was adopted retrospectively, including the recasting of previously reported income tax information. See Note 8 — “Income Taxes.”

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Recently Issued Accounting Standards

Disaggregation of Income Statement Expenses

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (“ASU 2024-03”), which requires additional disclosure of the nature of expenses included in the income statement. ASU 2024-03 requires disclosures about specific types of expenses (i.e., (a) purchases of inventory, (b) employee compensation, (c) depreciation and (d) intangible asset amortization) included in the expense captions presented on the face of the income statement as well as disclosures about selling expenses. ASU 2024-03 does not change the requirements for the presentation of expenses on the income statement. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. Although ASU 2024-03 requires comparative disclosures for all periods presented, reporting entities will be permitted to begin applying the guidance prospectively with the option for retrospective application for all prior periods presented. Accordingly, the new disclosure requirements in ASU 2024-03 are initially required within White Mountains’s Annual Report on Form 10-K for the year ending December 31, 2027. White Mountains is in the process of evaluating the potential impact of adoption on its financial statements.

Note 2. Significant Transactions

Bamboo

Bamboo Acquisition

On January 2, 2024, White Mountains acquired a controlling financial interest in Bamboo. White Mountains paid $296.7 million of cash consideration, which included $36.0 million to retire Bamboo’s legacy credit facility and a $20.0 million contribution of primary capital to Bamboo. At closing, White Mountains owned 72.8% of Bamboo on a basic shares outstanding basis (63.7% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives), while Bamboo management owned 16.1% of basic shares outstanding (26.6% on a fully-diluted/fully-converted).

White Mountains recognized total assets acquired related to the Bamboo Transaction of $479.5 million, total liabilities assumed of $91.7 million and noncontrolling interests of $111.1 million reflecting acquisition date fair values. Total assets acquired included $371.4 million of goodwill and other intangible assets. See Note 4 — “Goodwill and Other Intangible Assets.”In connection with the acquisition, White Mountains incurred transaction costs of $4.0 million in Other Operations, of which $0.3 million were expensed in the first quarter of 2024.

Bamboo’s segment revenue and earnings since the acquisition are presented in Note 15 — “Segment Information.”

Bamboo Sale Transaction

On December 5, 2025, White Mountains completed the sale of a controlling financial interest in the Bamboo Group to affiliates of funds advised by CVC Capital Partners (“CVC”), pursuant to the terms of the securities purchase agreement dated October 2, 2025 (the “Bamboo SPA”). Under the terms of the Bamboo SPA, White Mountains sold approximately 77.3% of its equity interest in the Bamboo Group for net cash proceeds at closing of $847.9 million and retained an indirect equity interest valued at $250.0 million (the “Bamboo Sale Transaction”). The proceeds are subject to customary purchase price adjustments. At closing, $3.6 million of proceeds attributable to White Mountains were held in escrow, which are expected to be released in the first half of 2026.

White Mountains reported a net gain of $816.3 million, which was comprised of an $849.3 million net gain on sale of the Bamboo Group, partially offset by $33.0 million of parent compensation costs recorded within general and administrative expenses. White Mountains’s net gain on sale of the Bamboo Group includes $188.6 million attributable to its retained interest in Bamboo based on the allocation of the equity value at closing between the percentage sold and the percentage retained.

White Mountains’s noncontrolling equity interest in the Bamboo SPV is accounted for at fair value in other long-term investments within Other Operations and is valued at $250.0 million as of December 31, 2025 based on the value implied by the Bamboo Sale Transaction. As of December 31, 2025, White Mountains had a 27.9% limited partnership interest in the Bamboo SPV. As of December 31, 2025, on a look-through basis, White Mountains owned 17.2% of the basic units outstanding of Bamboo (14.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives).

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On September 2, 2025, White Mountains acquired a controlling financial interest in Distinguished (the “Distinguished Transaction”). White Mountains funded the Distinguished Transaction through a combination of cash on hand and new borrowings by Distinguished. White Mountains paid $224.8 million of cash consideration, including a post-closing purchase price adjustment of $0.5 million. In addition, Distinguished borrowed $50.0 million of incremental debt and utilized $6.8 million of cash on hand as part of the transaction. At closing, White Mountains owned 55.5%, inclusive of its 1.7% previously-held interest, of Distinguished on a basic units outstanding basis (43.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives). At closing,4.2% of the basic units outstanding are owned by Distinguished management (24.7% on a fully-diluted/fully-converted basis). As part of the Distinguished Transaction, WM Phoenix GP, LLC, an indirect wholly-owned subsidiary of the Company, became the general partner of Distinguished. As the general partner, White Mountains has control over all activities of Distinguished subject to consent rights held by certain limited partners. As a result, White Mountains will continue to control Distinguished even if its economic interest falls below 50%. See Note 16 — “Variable Interest Entities.”

On September 5, 2028, the third anniversary of the closing of the Distinguished Transaction, certain noncontrolling unitholders will have the option to sell additional units representing 31.4% of Distinguished’s basic units outstanding to White Mountains at the same unit price paid in the Distinguished Transaction less aggregate per unit distributions. Noncontrolling interests with optional redemption features that are not within White Mountains’s control are classified as redeemable noncontrolling interests. See Note 13 — “Common Shareholders’ Equity and Noncontrolling Interests.” In addition, White Mountains will have the parallel option to purchase such units at 1.35 times the unit price paid in the Distinguished Transaction less aggregate per unit distributions. As of December 31, 2025, the redemption value would be $131.5 million if exercised in full.

White Mountains recognized total assets acquired related to the Distinguished Transaction of $743.9 million, including goodwill and other intangible assets of $618.8 million, total liabilities assumed of $249.7 million, redeemable noncontrolling interests of $133.5 million and nonredeemable noncontrolling interests of $73.8 million, reflecting provisional acquisition date fair values. In connection with the acquisition, White Mountains incurred transaction costs of $6.8 million in Other Operations.

The following presents additional details of the net assets acquired as of the September 2, 2025 acquisition date:

Net tangible assets acquired and the resulting goodwill and other intangible assets were recorded at fair value using Level 3 inputs. The majority of the tangible assets acquired and liabilities assumed were recorded at their carrying values, as their carrying values approximated fair value due to their short-term nature. The fair values of other intangible assets were internally estimated based primarily on the income approach. The income approach estimates fair value based on the present value of the cash flows that the assets are expected to generate in the future. White Mountains developed internal estimates for the expected future cash flows and discount rates used in the present value calculations. See Note 4 — “Goodwill and Other Intangible Assets.”

The value of the redeemable noncontrolling interests was recorded at the acquisition date fair value based on the valuation implied in the Distinguished Transaction, adjusted for the value of the embedded put and call rights. The value of the embedded put and call rights was estimated using an option pricing approach, incorporating assumptions for expected volatility, time to exercise, risk-free interest rates and other contractual terms of the instruments.

The value of the nonredeemable noncontrolling interests was recorded at the acquisition date fair value based on the valuation implied in the Distinguished Transaction.

Distinguished’s segment revenues and earnings since acquisition are presented in Note 15 — “Segment Information.”

On November 1, 2025, Distinguished sold a small, non-core ScaleCo program for net proceeds of $33.6 million. Goodwill of $23.6 million and other intangible assets of $9.3 million were attributed to the business sold and derecognized as a result of the sale.

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On July 18, 2025, White Mountains deployed $150.0 million into BroadStreet through the BroadStreet SPV. BroadStreet is an insurance brokerage company with a presence in all 50 U.S. states and ten Canadian provinces. BroadStreet focuses on commercial and personal property & casualty insurance and employee benefits. White Mountains’s noncontrolling equity interest in the BroadStreet SPV is accounted for at fair value using NAV as a practical expedient and is included within other long-term investments. As of December 31, 2025, the fair value of White Mountains’s interest in the BroadStreet SPV was $160.0 million. As of December 31, 2025, White Mountains had a 10.9% limited partnership interest in the BroadStreet SPV and a less than 5% ownership interest in BroadStreet on a look-through basis. See Note 16 — “Variable Interest Entities.”

BAM

On July 1, 2024, HG Re and BAM amended the terms of the FLRT with respect to certain governance rights held by HG Re. As a result, and in combination with other governance changes at BAM, White Mountains concluded that it no longer has the power to direct BAM’s activities that most significantly impact its economic performance and is no longer BAM’s primary beneficiary. Accordingly, effective July 1, 2024, White Mountains no longer consolidates BAM. See Note 16 — “Variable Interest Entities.”Through June 30, 2024, BAM’s results of operations were presented within the HG Global segment.

Upon deconsolidation, the BAM Surplus Notes met the criteria to be accounted for under the fair value option, which White Mountains elected. Accordingly, the BAM Surplus Notes, including accrued interest receivable, were carried at a fair value of $387.4 million as of July 1, 2024 resulting in an unrealized loss on deconsolidation of $114.5 million. See Note 10 — “Municipal Bond Guarantee Reinsurance”for the valuation techniques and inputs utilized to determine the fair value of the BAM Surplus Notes.

During the fourth quarter of 2022, Ark sponsored the formation of Outrigger Re Ltd., a Bermuda company registered as a special purpose insurer and segregated accounts company, to provide reinsurance capacity to Ark. Outrigger Re Ltd. was initially capitalized with $250.0 million of preference shares for business written in the 2023 underwriting year, of which White Mountains contributed $205.0 million. The remaining capital was provided by third-party investors. Outrigger Re Ltd. entered into collateralized quota share agreements with GAIL to provide reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. The proceeds from the issuance of the preference shares were deposited into collateral trust accounts to fund any potential obligations under the reinsurance agreements with GAIL. Outrigger Re Ltd.’s obligations under the reinsurance agreements with GAIL are subject to an aggregate limit equal to the assets in the collateral trusts at any point in time. The terms of the reinsurance agreements are renewable upon the mutual agreement of Ark and the applicable preference shareholder of Outrigger Re Ltd.

White Mountains owns 100% of the preference shares linked to its segregated account, WM Outrigger Re. White Mountains consolidates WM Outrigger Re’s results in its financial statements. WM Outrigger Re’s quota share reinsurance agreement with GAIL eliminates in White Mountains’s consolidated financial statements. See Note 16 — “Variable Interest Entities.”

During the fourth quarter of 2023, Ark renewed Outrigger Re Ltd. for the 2024 underwriting year with $250.0 million of capital. White Mountains rolled over $130.0 million from its commitment to the 2023 underwriting year. The remaining capital was provided by third-party investors.

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During the fourth quarter of 2024, Ark renewed Outrigger Re Ltd. for the 2025 underwriting year with $230.0 million of capital. White Mountains’s total commitment was $150.0 million, of which $130.0 million was rolled over from its commitment to the 2024 underwriting year. The remaining capital was provided by third-party investors. The reduced capacity at Outrigger Re Ltd. was replaced by Ark through traditional quota share reinsurance agreements. During the year ended December 31, 2024, White Mountains received net distributions of $122.7 million from WM Outrigger Re, which included a net return of capital related to changes in White Mountains’s capital commitments for the 2024 and 2025 underwriting years and reinsurance profits for the 2023 underwriting year. During the year ended December 31, 2024, WM Outrigger Re commuted its reinsurance agreement with GAIL for the 2023 underwriting year.

During the fourth quarter of 2025, Ark renewed Outrigger Re Ltd. for the 2026 underwriting year with $70.0 million of capital. The reduced capacity at Outrigger Re Ltd. was replaced by Ark through traditional quota share reinsurance agreements. The capital was provided entirely by third-party investors excluding White Mountains. During the year ended December 31, 2025, White Mountains received net distributions of $9.5 million from WM Outrigger Re, related primarily to reinsurance profits for the 2024 underwriting year. In January 2026, White Mountains received a distribution of $127.7 million, which included a net return of capital related to its non-renewal for the 2026 underwriting year.

As of December 31, 2025 and 2024, investments of $245.7 million and $203.7 million were held in a collateral trust account required to be maintained in relation to WM Outrigger Re’s reinsurance agreement with GAIL.

Enterprise Solutions

On April 1, 2025, White Mountains acquired a controlling financial interest in Enterprise Solutions (the “Enterprise Solutions Transaction”). Enterprise Solutions provides specialty electrical contracting services to commercial and institutional customers. White Mountains funded the Enterprise Solutions Transaction through a combination of cash on hand and new borrowings by Enterprise Solutions. White Mountains paid $58.3 million of cash consideration, which included a post-acquisition contribution of $1.5 million, and Enterprise Solutions borrowed $15.0 million in new debt as part of the transaction. At closing, White Mountains owned 65.5% of Enterprise Solutions on a basic units outstanding basis (59.0% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives). This is the first acquisition by WTM Partners.

White Mountains recognized total assets acquired related to Enterprise Solutions of $176.4 million, total liabilities assumed of $74.4 million and noncontrolling interests of $30.6 million, reflecting provisional acquisition date fair values. Total assets acquired included $57.7 million of goodwill and $37.6 million of other intangible assets, reflecting provisional acquisition date fair values. In connection with the acquisition, White Mountains incurred transaction costs of $3.0 million in Other Operations.

Unaudited Supplemental Pro Forma Information

White Mountains’s unaudited pro forma revenues were $3,891.4 million and $2,558.8 million for the years ended December 31, 2025 and 2024, which include revenues from Distinguished and Enterprise Solutions as if the acquisitions had occurred on January 1, 2024. The pro forma revenues are presented for comparative purposes only and are not necessarily indicative of the operating results that White Mountains would have recognized had the acquisitions actually been completed on January 1, 2024. The pro forma revenues have been calculated after applying White Mountains’s accounting policies and do not include any material, nonrecurring pro forma adjustments. Impacts to White Mountains’s unaudited pro forma earnings were not material to the amounts previously reported.

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Note 3. Investment Securities

White Mountains’s portfolio of investment securities held for general investment purposes consists of fixed maturity investments, short-term investments, common equity securities, its investment in MediaAlpha and other long-term investments. White Mountains’s portfolio of fixed maturity investments, including those within short-term investments, is classified as trading securities. Trading securities are reported at fair value as of the balance sheet date. Short-term investments also include interest-bearing money market funds and certificates of deposit that are carried at fair value. White Mountains’s portfolio of common equity securities, its investment in MediaAlpha and other long-term investments are measured at fair value. Other long-term investments consist primarily of unconsolidated entities, including Kudu’s Participation Contracts, the Bamboo SPV, PassportCard/DavidShield and the BroadStreet SPV, as well as private equity funds and hedge funds, a bank loan fund and Lloyd’s trust deposits. White Mountains has generally taken the fair value option for its equity method eligible investments. See Note 17 — “Equity Method Eligible Investments.” Net realized and unrealized investment gains (losses) are reported in pre-tax revenues.

Effective December 5, 2025, White Mountains no longer consolidates Bamboo. Through December 5, 2025, White Mountains’s consolidated financial statements included Bamboo’s investment results. Effective July 1, 2024, White Mountains no longer consolidates BAM. Through June 30, 2024, White Mountains’s consolidated financial statements included BAM’s investment results. See Note 2 — “Significant Transactions.”

White Mountains’s portfolio of investment securities includes investments classified as assets held for sale. See Note 20 — “Held for Sale.”

Net Investment Income

White Mountains’s net investment income is comprised primarily of interest income associated with White Mountains’s fixed maturity investments and short-term investments, dividend income from common equity securities and distributions from other long-term investments.

The following table presents pre-tax net investment income for the years ended December 31, 2025, 2024 and 2023:

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Net Realized and Unrealized Investment Gains (Losses)

The following table presents net realized and unrealized investment gains (losses) for the years ended December 31, 2025, 2024 and 2023:

(1) For 2025, 2024 and 2023, includes $37.1, $(31.5) and $13.6 of net realized and unrealized investment gains (losses) related to foreign currency exchange.

For the years ended December 31, 2025, 2024 and 2023, all of White Mountains’s net realized and unrealized investment gains (losses) were recorded in the consolidated statements of operations. There were no investment gains (losses) recorded in other comprehensive income.

White Mountains recognized gross realized investment gains of $117.1 million, $139.1 million and $113.7 million and gross realized investment losses of $5.6 million, $21.1 million and $16.9 million on sales of investment securities for the years ending December 31, 2025, 2024 and 2023.

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The following table presents total net unrealized gains (losses) attributable to Level 3 investments for the years ended December 31, 2025, 2024 and 2023 for investments still held at the end of the period:

Proceeds from the sales and maturities of investments, excluding short-term investments, totaled $1.4 billion, $1.2 billion and $0.8 billion for the years ended December 31, 2025, 2024 and 2023.

Investment Holdings

The following tables present the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses) and carrying value of White Mountains’s fixed maturity investments as of December 31, 2025 and 2024:

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The weighted average duration of White Mountains’s fixed income portfolio, including short-term investments, was 1.5 years and 1.9 years as of December 31, 2025 and 2024. Excluding short-term investments, the weighted average duration of White Mountains’s fixed income portfolio was 2.5 years and 2.6 years as of December 31, 2025 and 2024.

The following table presents the cost or amortized cost and carrying value of White Mountains’s fixed maturity investments by contractual maturity as of December 31, 2025 and 2024. Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without penalties.

The following tables present the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses) and carrying value of common equity securities, White Mountains’s investment in MediaAlpha and other long-term investments as of December 31, 2025 and 2024:

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Fair Value Measurements by Level

The following tables present White Mountains’s fair value measurements for investments as of December 31, 2025 and 2024 by level. See Note 1 — “Basis of Presentation and Significant Accounting Policies.”The major security types were based on the legal form of the securities. White Mountains has disaggregated its fixed maturity investments based on the issuing entity type, which impacts credit quality, with debt securities issued by U.S. government entities carrying minimal credit risk, while the credit and other risks associated with other issuers, such as corporations, foreign governments and agencies, municipalities, entities issuing mortgage and asset-backed securities or entities issuing collateralized loan obligations vary depending on the nature of the issuing entity type. White Mountains further disaggregates debt securities issued by corporations by industry sector because investors often reference commonly used benchmarks and their subsectors to monitor risk and performance. Accordingly, White Mountains has further disaggregated this asset class into subclasses based on the similar sectors and industry classifications it uses to evaluate investment risk and performance against commonly used benchmarks, such as the Bloomberg U.S. Intermediate Aggregate Index.

(1)Consists of investments in listed funds that predominantly invest in international equities.

(2) Consists of investments in the BroadStreet SPV, private equity funds and hedge funds, a bank loan fund, Lloyd’s trust deposits and ILS funds for which fair value is measured using NAV as a practical expedient. Investments for which fair value is measured at NAV are not classified within the fair value hierarchy.

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(1)Consists of investments in listed funds that predominantly invest in international equities.

(2) Consists of investments in private equity funds and hedge funds, a bank loan fund, Lloyd’s trust deposits and ILS funds for which fair value is measured using NAV as a practical expedient. Investments for which fair value is measured at NAV are not classified within the fair value hierarchy.

Investments Held on Deposit or as Collateral

Lloyd’s trust deposits are generally required of Lloyd's syndicates to protect policyholders in non-U.K. markets and are pledged into Lloyd’s trust accounts to provide a portion of the capital needed to support obligations at Lloyd’s. As of December 31, 2025 and 2024, Ark held Lloyd’s trust deposits with a fair value of $180.4 million and $149.9 million.

The underwriting capacity of a member of Lloyd’s must be supported by providing a deposit (“Funds at Lloyd’s”) in the form of cash, securities or letters of credit in an amount determined by Lloyd’s. The amount of such deposit is calculated for each member through an annual capital adequacy determination by Lloyd’s. As of December 31, 2025 and 2024, the fair value of Ark’s Funds at Lloyd’s cash and investment deposits totaled $361.6 million and $361.5 million.

As of December 31, 2025 and 2024, Ark held additional investments on deposit or as collateral for insurance regulators and reinsurance counterparties of $257.2 million and $226.5 million.

As of December 31, 2025 and 2024, investments of $245.7 million and $203.7 million were held in a collateral trust account required to be maintained in relation to WM Outrigger Re’s reinsurance agreement with GAIL.

Ark is required to pledge collateral under its standby letters of credit. See Note 7 — “Debt.”

HG Re is required to maintain assets, including investments, in collateral trusts under the FLRT with BAM. See Note 10 — “Municipal Bond Guarantee Reinsurance - Collateral Trusts.”

HG Global is required to maintain an interest reserve account in connection with its senior notes issued in 2022. See Note 7 — “Debt.”

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Kudu is required to maintain an interest reserve account in connection with its credit facility. See Note 7 - “Debt.”

As of December 31, 2024, investments of $32.2 million were held as collateral required to be maintained in relation to the Bamboo Captive’s reinsurance agreements.

As of December 31, 2025 and 2024, investments of $25.7 million and $46.7 million were held as collateral required to be maintained in relation to the Bamboo CRVs’ reinsurance agreements.

As of December 31, 2025, investments of $56.8 million were held on deposit, primarily related to amounts held on behalf of Distinguished’s insurance carrier partners and certain insureds.

Debt Securities Issued by Corporations

The following table presents the fair values for credit ratings of debt securities issued by corporations held in White Mountains’s investment portfolio as of December 31, 2025 and 2024:

(1)Credit ratings are based upon issuer credit ratings provided by Standard & Poor’s Financial Services LLC (“Standard & Poor’s”), or if unrated by Standard & Poor’s, long-term obligation ratings provided by Moody’s Investor Service, Inc.

Mortgage and Asset-backed Securities and Collateralized Loan Obligations

The following table presents the fair value of White Mountains’s mortgage and asset-backed securities and collateralized loan obligations as of December 31, 2025 and 2024:

(1)Represents publicly traded mortgage-backed securities which carry the full faith and credit guarantee of the U.S. Government (i.e., GNMA) or are guaranteed by a government sponsored entity (i.e., FNMA, FHLMC).

As of December 31, 2025 and 2024, White Mountains’s investment portfolio included $347.0 million and $236.7 million of collateralized loan obligations that are within the senior tranches of their respective fund securitization structures. All of White Mountains’s collateral loan obligations were rated AAA or AA as of December 31, 2025 and 2024.

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Investment in MediaAlpha

White Mountains’s investment in MediaAlpha is accounted for at fair value based on the publicly traded share price of MediaAlpha’s common stock and is presented as a separate line item on the balance sheet.

During the second quarter of 2024, MediaAlpha completed a secondary offering of 7.6 million shares at $19.00 per share ($18.24 per share net of underwriting fees). In the secondary offering, White Mountains sold 5.0 million shares for net proceeds of $91.2 million. During the second quarter of 2023, White Mountains completed a tender offer to purchase 5.9 million additional shares of MediaAlpha at a purchase price of $10.00 per share.

As of December 31, 2025, White Mountains owned 17.9 million shares of MediaAlpha, representing a 27.4% basic ownership interest based on the total class A and class B common shares outstanding in MediaAlpha’s Report on Form 10-Q dated October 29, 2025. At White Mountains’s December 31, 2025 level of ownership, each $1.00 per share increase or decrease in the share price of MediaAlpha will result in an approximate $7.00 per share increase or decrease in White Mountains’s book value per share. At the December 31, 2025 share price of $12.95, the fair value of White Mountains’s investment in MediaAlpha was $231.2 million. As of December 31, 2024, White Mountains owned 17.9 million shares of MediaAlpha, representing a 26.6% basic ownership interest. At the December 31, 2024 share price of $11.29, the fair value of White Mountains’s investment in MediaAlpha was $201.6 million.

Other Long-Term Investments

The following tables present the carrying values of White Mountains’s other long-term investments by reportable segment as of December 31, 2025 and 2024:

(1)Includes White Mountains’s noncontrolling equity interests in certain preferred securities, private equity securities and limited liability company units.

(1)Includes White Mountains’s noncontrolling equity interests in certain preferred securities, limited liability company units, limited partnership units and Simple Agreement for Future Equity (“SAFE”) investments.

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Private Equity Funds and Hedge Funds

White Mountains invests in private equity funds and hedge funds, which are included in other long-term investments. The fair value of these investments is generally estimated using the NAV of the funds. As of December 31, 2025, White Mountains held investments inseventeen private equity funds andtwo hedge funds. The largest investment in a single private equity fund or hedge fund was $110.6 million and $59.2 million as of December 31, 2025 and 2024.

The following table presents the fair value of investments and unfunded commitments in private equity funds and hedge funds by investment objective and sector as of December 31, 2025 and 2024:

Investments in private equity funds are generally subject to a lock-up period during which investors may not request a redemption. Distributions prior to the expected termination date of the fund may be limited to dividends or proceeds arising from the liquidation of the fund’s underlying investments. In addition, certain private equity funds have the option to extend the lock-up period.

The following table presents investments in private equity funds that were subject to lock-up periods as of December 31, 2025:

Investors in private equity funds are generally subject to indemnification obligations outside of the capital commitment period and prior to the winding up of the fund. As of December 31, 2025 and 2024, White Mountains is not aware of any indemnification claims relating to its investments in private equity funds.

Redemption of investments in most hedge funds is subject to restrictions, including lock-up periods where no redemptions or withdrawals are allowed, restrictions on redemption frequency and advance notice periods for redemptions. Amounts requested for redemptions remain subject to market fluctuations until the redemption effective date, which generally falls at the end of the defined redemption period. White Mountains’s hedge fund investments are subject to monthly and quarterly restrictions on redemptions and advance written redemption notice period requirements that range between 45 and 90 calendar days.

Bank Loan Fund

White Mountains’s other long-term investments include a bank loan fund with a fair value of $308.5 million and $264.7 million as of December 31, 2025 and 2024. The fair value of this investment is estimated using the NAV of the fund. The bank loan fund’s investment objective is to provide, on an unleveraged basis, high current income consistent with preservation of capital and low duration. The bank loan fund primarily invests in a broad portfolio of U.S. dollar-denominated, non-investment grade, floating-rate senior secured loans and may invest in other financial instruments, such as secured and unsecured corporate debt, credit default swaps, reverse repurchase agreements, synthetic indices and cash and cash equivalents.

The investment in the bank loan fund is subject to restrictions on redemption frequency and advance notice periods for redemptions. Amounts requested for redemptions remain subject to market fluctuations until the redemption effective date, which generally falls at the end of the defined redemption period. White Mountains may redeem all or a portion of its bank loan fund investment as of any calendar month-end upon 15 calendar days advanced written notice.

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Lloyd’s Trust Deposits

White Mountains’s other long-term investments include Lloyd’s trust deposits, which consist of non-U.K. deposits and Canadian comingled pooled funds. The Lloyd’s trust deposits invest primarily in short-term government securities, agency securities and corporate bonds held in trusts that are managed by Lloyd's of London. These investments are generally required of Lloyd's syndicates to protect policyholders in non-U.K. markets and are pledged into Lloyd’s trust accounts to provide a portion of the capital needed to support obligations at Lloyd’s. The fair value of the Lloyd’s trust deposits is generally estimated using the NAV of the funds. As of December 31, 2025 and 2024, White Mountains held Lloyd’s trust deposits with a fair value of $180.4 million and $149.9 million.

ILS Funds

White Mountains’s other long-term investments include ILS fund investments. The fair value of these investments is generally estimated using the NAV of the funds. As of December 31, 2025 and 2024, White Mountains held investments in ILS funds with a fair value of $50.1 million and $74.0 million.

Investments in ILS funds are generally subject to restrictions, including lock-up periods where no redemptions or withdrawals are allowed, non-renewal clauses, restrictions on redemption frequency and advance notice periods for redemptions. From time to time, natural catastrophe, liquidity, market or other events will occur that make the determination of fair value for underlying investments in ILS funds less certain due to the potential for loss development. In such circumstances, the impacted investments may be subject to additional lock-up provisions.

ILS funds are typically subject to monthly and annual restrictions on redemptions and advance redemption notice period requirements that range between 30 and 90 calendar days. Amounts requested for redemption remain subject to market fluctuations until the redemption effective date, which is generally at the end of the defined redemption period or when the underlying investment has fully matured or been commuted.

Infrastructure Fund

In 2025, Ark made a $100.0 million commitment to invest in an open-ended pooled investment fund focused on making equity investments in essential service infrastructure assets. The fund has a 4-year lock-up period, subject to the discretion of the manager. Redemptions of all or a portion of the fund are allowable semi-annually with a 90-day written notice. Ark anticipates that the initial capital call will occur in the second quarter of 2026.

Rollforward of Level 3 Investments

Level 3 measurements as of December 31, 2025 and 2024 consist of securities for which the estimated fair value has not been determined based upon quoted market price inputs for identical or similar securities. The following table presents the changes in White Mountains’s fair value measurements for Level 3 investments for the years ended December 31, 2025 and 2024:

(1)See Note 2 — “Significant Transactions.”

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Significant Unobservable Inputs

The following tables present significant unobservable inputs used in estimating the fair value of White Mountains’s other long-term investments, classified within Level 3 as of December 31, 2025 and 2024. The tables below exclude $250.4 million and $23.4 million of Level 3 other long-term investments generally valued based on recent or expected transaction prices. As of December 31, 2025, the Bamboo SPV was measured at fair value based on the value implied in the Bamboo Sale Transaction. See Note 2 — “Significant Transactions.”The fair value of investments in the BroadStreet SPV, private equity funds and hedge funds, bank loan funds, Lloyd’s trust deposits and ILS funds are generally estimated using NAV. Investments for which fair value is measured at NAV are not classified within the fair value hierarchy.

(1) Key inputs to the discounted cash flow analysis generally include projections of future revenue and earnings, discount rates and terminal exit multiples or growth rates.

(2) Includes the net unrealized investment gains (losses) associated with foreign currency; foreign currency effects based on observable inputs.

(3) Since Kudu’s Participation Contracts are not subject to corporate taxes within Kudu Investment Management, LLC, pre-tax discount rates are applied to pre-tax cash flows in determining fair values. The weighted average discount rate and weighted average terminal cash flow exit multiple applied to Kudu’s Participation Contracts was 19% and 14 x.

(4)In 2025, Kudu contributed $201.7 into new and existing Participation Contracts.

(5) Increases (decreases) to the discount rates in isolation would result in lower (higher) fair value measurements, while increases (decreases) to the terminal cash flow exit multiples or terminal revenue growth rates in isolation would result in higher (lower) fair value measurements.

(1) Key inputs to the discounted cash flow analysis generally include projections of future revenue and earnings, discount rates and terminal exit multiples or growth rates.

(2) Includes the net unrealized investment gains (losses) associated with foreign currency; foreign currency effects based on observable inputs.

(3) Since Kudu’s Participation Contracts are not subject to corporate taxes within Kudu Investment Management, LLC, pre-tax discount rates are applied to pre-tax cash flows in determining fair values. The weighted average discount rate and weighted average terminal cash flow exit multiple applied to Kudu’s Participation Contracts was 19% and 14 x.

(4)In 2024, Kudu contributed $103.5 into new and existing Participation Contracts.

(5) Increases (decreases) to the discount rates in isolation would result in lower (higher) fair value measurements, while increases (decreases) to the terminal cash flow exit multiples or terminal revenue growth rates in isolation would result in higher (lower) fair value measurements.

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Note 4. Goodwill and Other Intangible Assets

White Mountains accounts for business combinations using the acquisition method. Under the acquisition method, White Mountains recognizes and measures the assets acquired, including other intangible assets, and liabilities assumed, including contingent consideration liabilities, at their estimated fair values as of the acquisition date. Goodwill represents the excess of the amount paid to acquire a business over the fair value of identifiable net assets at the acquisition date. The estimated acquisition date fair values, generally consisting of intangible assets and contingent consideration liabilities, may be recorded at provisional amounts in circumstances where the information necessary to complete the acquisition accounting is not available at the reporting date. Any such provisional amounts are finalized as measurement period adjustments within one year of the acquisition date.

The following table presents the economic life, acquisition date fair value, accumulated amortization and net carrying value for goodwill and other intangible assets as of December 31, 2025 and 2024:

(1) Goodwill and other intangible assets associated with Bamboo were disposed of in connection with the Bamboo Sale Transaction. See Note 2 — “Significant Transactions.”

(2)The relative fair values of goodwill and other intangible assets recognized in connection with the Distinguished Transaction and the Enterprise Solutions Transaction have not yet been finalized. See Note 2 — “Significant Transactions.”

(3) Impairment is related to an Other Operating Business.

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Rollforward of Goodwill and Other Intangible Assets

The following table presents the change in goodwill and other intangible assets for the years ended December 31, 2025 and 2024:

(1)During 2025, amounts relate to the Distinguished Transaction and the Enterprise Solutions Transaction. The relative fair values of goodwill and other intangible assets recognized in connection with the Distinguished Transaction and the Enterprise Solutions Transaction have not yet been finalized. During 2024, amounts relate to the acquisition of Bamboo. See Note 2 — “Significant Transactions.”

(2) Relates to acquisitions within Other Operations.

(3) Measurement period adjustments relate to updated information about acquisition date fair values of assets acquired and liabilities assumed. Adjustments relate to the Distinguished Transaction and the Enterprise Solutions Transaction.

(4)Impairment is related to an Other Operating Business.

(5) Relates to the Bamboo Sale Transaction and the sale of a small, non-core ScaleCo program at Distinguished. See Note 2 — “Significant Transactions.”

During the year ended December 31, 2025, White Mountains recognized an impairment of goodwill of $9.1 million and other intangible assets of $0.5 million related to an Other Operating Business. Impairment charges are presented within general and administrative expenses on the statement of operations.

During the year ended December 31, 2024, White Mountains did not recognize any impairments to goodwill and other intangible assets.

Amortization of Other Intangible Assets

Amortization expense was $28.4 million, $22.0 million and $7.2 million for the years ended December 31, 2025, 2024 and 2023.

The following table presents a schedule of White Mountains’s future amortization expense as of December 31, 2025:

(1) Excludes Ark’s indefinite-lived intangible assets of $175.7.

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Note 5. Loss and Loss Adjustment Expense Reserves

Loss and LAE reserves are typically comprised of case reserves for claims reported and reserves for losses that have occurred but for which claims have not yet been reported, referred to as IBNR reserves. IBNR reserves include a provision for expected future development on case reserves. Case reserves are estimated based on the experience and knowledge of claims staff regarding the nature and potential cost of each claim and are adjusted as additional information becomes known or payments are made. IBNR reserves are derived by subtracting paid loss and LAE and case reserves from estimates of ultimate loss and LAE. Actuaries estimate ultimate loss and LAE using various generally accepted actuarial methods applied to known losses and other relevant information. Like case reserves, IBNR reserves are adjusted as additional information becomes known or payments are made. Below is a discussion of White Mountains’s loss and LAE reserves related to the Ark/WM Outrigger, HG Global and Bamboo segments as well as Other Operations.

Ark establishes loss and LAE reserves that are estimates of amounts needed to pay claims and related expenses in the future for insured events that have already occurred. Ark’s process of estimating reserves involves a considerable degree of judgment by management and, as of any given date, is inherently uncertain.

WM Outrigger Re entered into a quota share agreement with GAIL to provide collateralized reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. Ark renewed its quota share reinsurance agreement with WM Outrigger Re for the 2024 and 2025 underwriting years. WM Outrigger Re’s quota share reinsurance agreement with GAIL, including its loss and LAE reserves, eliminates in White Mountains’s consolidated financial statements. WM Outrigger Re did not participate in the 2026 underwriting year.

Loss and LAE are categorized by the year in which the policy is underwritten (the year of account, or underwriting year) for purposes of Ark’s claims management and estimation of the ultimate loss and LAE reserves. For purposes of Ark’s reporting under GAAP, loss and LAE are categorized by the year in which the claim is incurred (the accident year).

Ultimate loss and LAE are generally determined by extrapolation of claims emergence and settlement patterns observed in the past that can reasonably be expected to persist into the future. In forecasting ultimate loss and LAE for any line of business, past experience with respect to that line of business is the primary resource, but cannot be relied upon in isolation. Ark’s own experience, particularly claims development experience, such as trends in case reserves, payments on and closings of claims, as well as changes in business mix and coverage limits, is the most important information for estimating its loss and LAE reserves. External data, available from organizations such as the Lloyd’s Market Association, consulting firms and other insurance and reinsurance companies, is used to supplement or corroborate Ark’s own experience. External data can be especially useful for estimating costs on newer lines of business. Ultimate loss and LAE for major losses and catastrophes are estimated based on the known and expected exposures to the loss event, rather than simply relying on the extrapolation of reported and settled claims.

For some lines of business, such as long-tail coverages discussed below, claims data reported in the most recent years of account are often too limited to provide a meaningful basis for analysis due to the typical delay in reporting and settling of claims. For this type of business, Ark uses an expected loss ratio method for the initial years of account. This is a standard and accepted actuarial reserve estimation method in these circumstances in which the loss ratio is selected based upon information used in pricing policies for that line of business, as well as any publicly available industry data, such as industry pricing, experience and trends.

Uncertainties in estimating ultimate loss and LAE are magnified by the time lag between when a claim actually occurs and when it is reported and eventually settled. This time lag is sometimes referred to as the “claim-tail.” The claim-tail for reinsurance and insurance obtained through brokers, MGAs and reinsurance intermediaries (collectively, the “insurance and reinsurance intermediaries”) is further extended because claims are first reported to either the original primary insurance company or the insurance and reinsurance intermediaries. The claim-tail for most property coverages is typically short (usually a few days up to a few months). Settlements for casualty/liability coverages can extend for long periods of time as claims are often reported and ultimately paid or settled years after the related loss events occur. During the long claims reporting and settlement period, additional facts regarding coverages written in prior years of account, as well as about actual claims and trends, may become known and, as a result, Ark may adjust its reserves. The inherent uncertainties of estimating loss and LAE reserves are increased by the diversity of loss development patterns among different types of reinsurance treaties, facultative contracts or direct insurance contracts, the necessary reliance on the ceding companies and insurance and reinsurance intermediaries for information regarding reported claims and the differing reserving practices among ceding companies and insurance and reinsurance intermediaries.

If management determines that an adjustment is appropriate, the adjustment is booked in the accounting period in which such determination is made. Accordingly, should reserves need to be increased or decreased in the future from amounts currently established, future results of operations would be negatively or positively impacted.

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In determining ultimate loss and LAE, the cost to indemnify claimants, provide needed legal defense and other services for insureds and administer the investigation and adjustment of claims are considered. These claims costs are influenced by many factors that change over time, such as expanded coverage definitions as a result of new court decisions, inflation in costs to repair or replace damaged property, inflation in the cost of medical services and legislated changes in statutory benefits, as well as by the unique facts that pertain to each claim. As a result, the rate at which claims arose in the past and the costs to settle them may not always be representative of what will occur in the future. The factors influencing changes in claims costs are often difficult to isolate or quantify and developments in paid and incurred losses from historical trends are frequently subject to multiple and conflicting interpretations. Changes in coverage terms or claims handling practices may also cause future experience and/or development patterns to vary from the past. A key objective of actuaries in developing estimates of ultimate loss and LAE and resulting IBNR reserves is to identify aberrations and systemic changes occurring within historical experience and accurately adjust for them so that the future can be projected more reliably. Because of the factors previously discussed, this process requires the use of informed judgment and is inherently uncertain.

Ark performs an actuarial review of its recorded loss and LAE reserves each quarter, using several generally accepted actuarial methods to evaluate its loss reserves, each of which has its own strengths and weaknesses. Management places more or less reliance on a particular method based on the facts and circumstances at the time the reserve estimates are made. These methods generally fall into one of the following categories or are hybrids of one or more of the following categories:

•Historical paid loss development methods: These methods use historical loss payments over discrete periods of time to estimate future losses. Historical paid loss development methods assume that the ratio of losses paid in one period to losses paid in an earlier period will remain constant. These methods necessarily assume that factors that have affected paid losses in the past, such as inflation or the effects of litigation, will remain constant in the future. Because historical paid loss development methods do not use case reserves to estimate ultimate losses, they can be more reliable than the other methods discussed below that look to case reserves (such as actuarial methods that use incurred losses) in situations where there are significant changes in how case reserves are established by a company’s claims adjusters. However, historical paid loss development methods are more leveraged, meaning that small changes in payments have a larger impact on estimates of ultimate losses, than actuarial methods that use incurred losses because cumulative loss payments take much longer to approach the expected ultimate losses than cumulative incurred amounts. In addition, and for similar reasons, historical paid loss development methods are often slow to react to situations when new or different factors arise than those that have affected paid losses in the past.

•Historical incurred loss development methods: These methods, like historical paid loss development methods, assume that the ratio of losses in one period to losses in an earlier period will remain constant in the future. However, instead of using paid losses, these methods use incurred losses (i.e., the sum of cumulative historical loss payments plus outstanding case reserves) over discrete periods of time to estimate future losses. Historical incurred loss development methods can be preferable to historical paid loss development methods because they explicitly take into account open cases and the claims adjusters’ evaluations of the cost to settle all known claims. However, historical incurred loss development methods necessarily assume that case reserving practices are consistently applied over time. Therefore, when there have been significant changes in how case reserves are established, using incurred loss data to project ultimate losses can be less reliable than other methods.

•Expected loss ratio methods: These methods are based on the assumption that ultimate losses vary proportionately with premiums. Expected loss ratios are typically developed based upon the information used in pricing and are multiplied by the total amount of premiums earned to calculate ultimate losses. Expected loss ratio methods are useful for estimating ultimate losses in the early years of long-tail lines of business, when little or no paid or incurred loss information is available.

•Bornhuetter-Ferguson methods: These methods are a blend of the expected loss ratio and loss development methods. The percent of incurred (or paid) loss to ultimate loss implied by the selected development pattern from the incurred (or paid) loss development method is used to determine the percentage of ultimate loss yet to be developed. Inception to date losses are added to losses yet to be developed, yielding an estimate of ultimate for each year of account.

•Adjusted historical paid and incurred loss development methods: These methods take traditional historical paid and incurred loss development methods and adjust them for the estimated impact of changes from the past in factors such as inflation, the speed of claims payment or the adequacy of case reserves. Adjusted historical paid and incurred loss development methods are often more reliable methods of predicting ultimate losses in periods of significant change, provided the actuaries can develop methods to reasonably quantify the impact of changes.

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As part of Ark’s quarterly actuarial review, Ark compares the previous quarter’s projections of incurred, paid and case reserve activity, including amounts incurred but not reported, to actual amounts experienced in the quarter. Differences between previous estimates and actual experience are evaluated to determine whether a given actuarial method for estimating loss and LAE reserves should be relied upon to a greater or lesser extent than it has been in the past. While some variance is expected each quarter due to the inherent uncertainty in estimating loss and LAE reserves, persistent or large variances would indicate that prior assumptions and/or reliance on certain actuarial methods may need to be revised going forward.

Upon completion of each quarterly review, Ark selects indicated loss and LAE reserve levels based on the results of the actuarial methods described previously, which are the primary consideration in determining management's best estimate of required loss and LAE reserves. However, in making its best estimate, management also considers other qualitative factors that may lead to a difference between held reserves and the actuarial central estimate of reserves. Typically, these qualitative factors are considered when management and Ark’s actuaries conclude that there is insufficient historical incurred and paid loss information or that trends included in the historical incurred and paid loss information are not likely to repeat in the future. Such qualitative factors include, among others, recent entry into new markets or new products, improvements in the claims department that are expected to lessen future ultimate loss costs, legal and regulatory developments or other uncertainties that may arise.

Ark Reserve Estimation by Line of Business

The process of establishing loss and LAE reserves, including amounts incurred but not reported, is complex and imprecise, as it must consider many variables that are subject to the outcome of future events. As a result, informed subjective estimates and judgments as to the ultimate exposure to losses are an integral component of the loss and LAE reserving process. Ark categorizes and tracks insurance and reinsurance reserves by “reserving class of business” for each underwriting office, London and Bermuda, and then aggregates the reserving classes by line of business, which are summarized herein as property and accident & health, specialty, marine & energy, casualty-active and casualty-runoff.

Ark regularly reviews the appropriateness of its loss and LAE reserves at the reserving class of business level, considering a variety of trends that impact the ultimate settlement of claims for the subsets of claims in each particular reserving class.

For loss and LAE reserves as of December 31, 2025, Ark considers that the impact of the various reserving factors, as described below, on future paid losses would be similar to the impact of those factors on historical paid losses.

The major causes of material uncertainty (i.e., reserving factors) generally will vary for each line of business, as well as for each separately analyzed reserving class of business within the line of business. Also, reserving factors can have offsetting or compounding effects on estimated loss and LAE reserves. In most cases, it is not possible to measure the effect of a single reserving factor and construct a meaningful sensitivity expectation. Actual results will likely vary from expectations for each of these assumptions, resulting in an ultimate claims liability that is different from that being estimated currently.

Additional causes of material uncertainty exist in most product lines and may impact the types of claims that could occur within a particular line of business or reserving class of business. Examples where reserving factors, within a line of business or reserving class of business, are subject to change include changing types of insureds (e.g., size of account, industry insured, jurisdiction), changing underwriting standards, or changing policy provisions (e.g., deductibles, policy limits, endorsements).

Following is a detailed description of the reserve factors and consideration for each of Ark’s reserving lines of business.

Property and Accident & Health

Ark’s property and accident & health reserving line of business contains short-tail exposures. As such, reserving for these classes generally involves less uncertainty given the speed of settlement.

For property reserving classes, the reserve risk is driven primarily by occasional catastrophe events, though the financial effect of these is mitigated by reinsurance and retrocessional purchases. Ark writes property business on both an insurance and reinsurance basis. The insurance business primarily consists of direct and facultative contracts. However, some business is written through line slips and MGA binding authorities, which could have a longer-tail due to the increased exposure period caused by underlying policies attaching to the binder contract. The reinsurance business can also have a longer-tail due to timing delays resulting from attachment points on excess of loss contracts.

For accident & health reserving classes, the losses emanate from a wide range of personal accident, sickness, travel and medical insurance risks. The underlying business is a mix of direct and facultative contracts, as well as some MGA and reinsurance contracts, which are typically shorter-tail lines. Certain smaller components of the accident & health business can be longer-tail. The accident & health business is also exposed to catastrophic events though not to the same degree or magnitude as the property business.

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Marine & Energy

Ark’s marine & energy reserving line of business is underwritten on both an insurance and reinsurance basis and can be broken down into physical damage on marine risks, physical damage on upstream energy platforms and marine & energy liabilities.

The marine reserving classes consist primarily of marine hull, cargo and specie risks. These all generally have some element of transportability, which mitigates the catastrophe risk exposure; for example, having the ability to move out of the path of a hurricane if provided with sufficient notice. The marine reserving classes are generally shorter-tail.

The energy platform reserving classes cover risks that are less transportable and therefore are exposed to catastrophe events similar to property reserving classes. Other energy reserving classes cover construction contracts, which often have considerably protracted exposure periods with the bulk of the risk towards the end of the coverage period. This can have the effect of increasing the tail on an otherwise short-tail reserving class.

The marine & energy liability reserving classes, which represent a smaller portion of the marine & energy business, are typically longer-tail compared to physical damage reserving classes.

Specialty

Ark’s specialty portfolio is comprised of a diverse portfolio of insurance and reinsurance subclasses of business including aviation, contingency, cyber, fine art & specie, mortgage, nuclear, political and credit, space, surety as well as terrorism and political violence. Certain subclasses of business are exposed to both natural catastrophes and large man-made loss events. Although these subclasses have different coverages and exposures, they are all short-tail in nature and have similar reserving features.

Casualty-Active and Casualty-Runoff

Ark’s casualty reserving lines of business, which include casualty–active and casualty–runoff, are long-tail classes of business. Consequently, the ultimate liability may not be known at the date of loss, which results in greater uncertainty when reserving for casualty lines.

The casualty–active line of business consists of U.S. reinsurance and insurance risks written on an excess of loss basis. The casualty–runoff line of business consists of international reinsurance risks and U.S. casualty insurance risks written through an MGA binding authority. The losses arising from these lines of business are primarily related to medical malpractice, professional liability and general liability coverages, which are long-tail lines of business.

Casualty policies are generally written on either a claims-made or occurrence basis. On a claims-made basis, the trigger of loss is based on the date that the loss is reported. On an occurrence basis, the trigger of loss is the date that the loss occurred. Due to delays between loss occurrence and loss reporting, business written on an occurrence basis can be longer-tail than business written on a claims-made basis.

There are a number of common reserving factors for casualty lines that can affect the estimated casualty reserves, including:

•Changes in claims-handling practices, both in-house and through third-party claims administrators,

•Changes in court interpretations of policy provisions,

•Sustained elevated levels of inflation and

•Trends in litigation or jury awards.

Cumulative Number of Reported Claims

Ark counts a claim for each unique combination of individual claimant, loss event and risk. A claim is still counted if the claim is closed with no payment. Bulk-coded losses are counted as one claim, as underlying claim counts are not available.

Discounting

Ark does not discount loss and LAE reserves.

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Impact of Third-Party Capital

For years of account prior to the Ark Transaction, a significant proportion of the Syndicates’ underwriting capital was provided by third-party insurance and reinsurance groups (“TPC Providers”) using whole account reinsurance contracts with Ark’s corporate member. For the years of account subsequent to the Ark Transaction, Ark is no longer using TPC Providers to provide underwriting capital for the Syndicates.

A Reinsurance to Close (“RITC”) agreement is generally put in place after the third year of operations for a year of account such that the outstanding loss and LAE reserves, including future development thereon, are reinsured into the next year of account. As a result, and in combination with the changing participation provided by TPC Providers, Ark’s participation on outstanding loss and LAE reserves reinsured into the next year of account changes. After 2023, Ark is no longer subject to changes in TPC Providers’ participation.

During 2023, an RITC agreement was executed such that the outstanding loss and LAE reserves for claims arising out of the 2020 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 42.8%, were reinsured into the 2021 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 0.0%. As a result, Ark’s net loss and LAE reserves increased by $145.4 million for the year ended December 31, 2023.

Loss and Loss Adjustment Expense Reserve Summary

The following table summarizes the loss and LAE reserve activity of the Ark/WM Outrigger segment for the years ended December 31, 2025, 2024 and 2023:

(1) The beginning reinsurance recoverable on unpaid losses includes amounts attributable to TPC Providers of $145.4 as of January 1, 2023.

(2) Amount represents the impact to net loss and LAE reserves due to a change in the TPC Providers’ participation related to the annual RITC process.

During the year ended December 31, 2025, the Ark/WM Outrigger segment experienced $112.7 million of net favorable prior year loss reserve development, driven primarily by the property and accident & health ($91.7 million) and specialty ($27.2 million) reserving lines of business, partially offset by net unfavorable development in the marine & energy ($4.7 million) and casualty-active ($4.3 million) reserving lines of business. For property and accident & health, the net favorable prior year loss reserve development was driven primarily by positive claims experience for the 2024 and 2023 accident years. For specialty, the net favorable prior year loss reserve development was driven primarily by positive claims experience for the 2023 accident year, partially offset by negative claims experience for the 2022 and 2024 accident years. In addition, the net favorable prior year loss reserve development for specialty includes $91.4 million of unfavorable development related to aviation losses from the conflict in Ukraine and Russia resulting from 2025 U.K. High Court rulings on leasing claims.

During the year ended December 31, 2024, the Ark/WM Outrigger segment experienced $58.6 million of net favorable prior year loss reserve development, driven primarily by the specialty ($34.3 million) and property and accident & health ($29.2 million) reserving lines of business, partially offset by net unfavorable development in the casualty-active ($4.5 million) reserving line of business. The net favorable prior year loss reserve development was driven primarily by positive claims experience in specialty for the 2023 and 2019 accident years and in property and accident & health for the 2023 accident year.

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During the year ended December 31, 2023, the Ark/WM Outrigger segment experienced $19.9 million of net unfavorable prior year loss reserve development, driven primarily by the property and accident & health ($41.7 million) reserving line of business, partially offset by net favorable prior year loss reserve development within the specialty ($11.9 million) and casualty–runoff ($6.0 million) reserving lines of business. The net unfavorable prior year loss reserve development in the property and accident & health reserving line of business was driven primarily by Hurricane Ian and Winter Storm Elliott within the 2022 accident year. The net favorable prior year loss reserve development in specialty and casualty-runoff was driven primarily by positive claims experience for the 2021 and 2020 accident years.

The following table summarizes the unpaid loss and LAE reserves, net of reinsurance recoverables on unpaid losses, for each of the Ark/WM Outrigger segment’s major reserving lines of business as of December 31, 2025 and 2024:

(1) The amounts exclude $5.2 and $3.1 ceded by Ark to WM Outrigger Re as of December 31, 2025 and 2024, which eliminates in White Mountains’s consolidated financial statements.

(2) The amounts exclude $29.5 and $31.8 ceded by Ark to WM Outrigger Re as of December 31, 2025 and 2024, which eliminate in White Mountains’s consolidated financial statements.

The following five tables cover each of Ark’s property and accident & health, marine & energy, specialty, casualty-active and casualty-runoff reserving lines of business and are presented net of reinsurance, which includes the impact of whole-account quota-share reinsurance arrangements related to TPC Providers. Each of the five tables includes three sections as follows:

The top section of the table presents, for each of the previous ten accident years: (1) cumulative total undiscounted incurred loss and LAE as of each of the previous ten year-end evaluations, (2) total IBNR plus expected development on reported claims as of December 31, 2025 and (3) the cumulative number of reported claims as of December 31, 2025.

The middle section of the table presents cumulative paid loss and LAE for each of the previous ten accident years as of each of the previous ten year-end evaluations. Also included in this section is a calculation of the loss and LAE reserves as of December 31, 2025, which is then included in the reconciliation to the consolidated balance sheet presented above. The total unpaid loss and LAE reserves as of December 31, 2025 are calculated as the cumulative incurred loss and LAE from the top section less the cumulative paid loss and LAE from the middle section, plus any outstanding liabilities from accident years prior to 2014.

The bottom section of the table is supplementary information about the average historical claims duration as of December 31, 2025. It shows the weighted average annual percentage payout of incurred loss and LAE by accident year as of each age. For example, the first column is calculated as the incremental paid loss and LAE in the first calendar year for each given accident year (e.g. calendar year 2025 for accident year 2025, calendar year 2024 for accident year 2024) divided by the cumulative incurred loss and LAE as of December 31, 2025 for that accident year. The resulting ratios are weighted using cumulative incurred loss and LAE as of December 31, 2025.

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As of December 31, 2025 and 2024, HG Re did not have any outstanding loss and LAE reserves. For the years ended December 31, 2025, 2024 and 2023, HG Re did not recognize any incurred loss and LAE. For the year ended December 31, 2024, HG Re recognized gross incurred loss and LAE of $0.3 million related to a delinquent payment by a reinsured BAM policyholder. Net of recoveries, HG Re recognized no incurred loss and LAE for the year ended December 31, 2024.

Bamboo

As of December 31, 2024, the Bamboo Captive recorded loss and LAE reserves of $17.8 million. For the period from January 1, 2025 to December 5, 2025, the date of the Bamboo Sale Transaction, and the year ended December 31, 2024, the Bamboo Captive recognized incurred loss and LAE of $18.0 million and $20.6 million.

As of December 31, 2025 and 2024, the Bamboo CRVs recorded loss and LAE reserves of $13.6 million and $12.1 million. For the years ended December 31, 2025 and 2024, the Bamboo CRVs recognized incurred loss and LAE of $20.0 million and $12.1 million.

Note 6. Third-Party Reinsurance

In the normal course of business, Ark may seek to limit losses that arise from catastrophes or other events by reinsuring certain risks with third-party reinsurers. Ark remains liable for risks reinsured in the event that the reinsurer does not honor its obligations under reinsurance contracts.

The following table summarizes the effects of reinsurance on written and earned premiums and on loss and LAE for the Ark/WM Outrigger segment for the years ended December 31, 2025, 2024 and 2023.

(1) The years ended December 31, 2025, 2024 and 2023 exclude written premiums of $84.2, $86.5 and $110.0 ceded by Ark to WM Outrigger Re, which eliminate in White Mountains’s consolidated financial statements.

(2) The years ended December 31, 2025, 2024 and 2023 exclude earned premiums of $84.6, $88.0 and $104.3 ceded by Ark to WM Outrigger Re, which eliminate in White Mountains’s consolidated financial statements.

(3) The years ended December 31, 2025, 2024 and 2023 exclude loss and LAE of $25.4 and $29.9 and $15.6 ceded by Ark to WM Outrigger Re, which eliminate in White Mountains’s consolidated financial statements.

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The following table presents the Ark/WM Outrigger segment’s reinsurance recoverables as of December 31, 2025 and December 31, 2024:

(1) The reinsurance recoverables on unpaid losses exclude $29.5 and $31.8 ceded by Ark to WM Outrigger Re as of December 31, 2025 and 2024, which eliminate in White Mountains’s consolidated financial statements.

(2) The reinsurance recoverables on paid losses exclude $5.2 and $3.1 ceded by Ark to WM Outrigger Re as of December 31, 2025 and 2024, which eliminates in White Mountains’s consolidated financial statements.

(3) The ceded unearned premiums exclude $3.9 and $4.3 ceded by Ark to WM Outrigger Re as of December 31, 2025 and 2024, which eliminate in White Mountains’s consolidated financial statements.

As reinsurance contracts do not relieve Ark of its obligation to its policyholders, Ark seeks to reduce the credit risk associated with reinsurance balances by avoiding over-reliance on specific reinsurers through the application of concentration limits and thresholds. Ark is selective with its reinsurers, placing reinsurance with only those reinsurers having a strong financial condition. Ark monitors the financial strength of its reinsurers on an ongoing basis.

The following table presents the Ark/WM Outrigger segment’s gross and net reinsurance recoverables by the reinsurers’ A.M. Best Company, Inc (“A.M. Best”) ratings as of December 31, 2025:

(1)A.M. Best financial strength ratings as detailed above are: “A+ or better” (Superior) “A- to A” (Excellent), “B++” (Good).

(2) Excludes $34.7 ceded by Ark to WM Outrigger Re as of December 31, 2025, which eliminates in White Mountains’s consolidated financial statements.

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Note 7. Debt

The following table presents White Mountains’s debt outstanding as of December 31, 2025 and 2024:

(1)The effective rate for years ended December 31, 2025 and 2024 includes the effect of the amortization of debt issuance costs and original issue discount, but excludes the effect of the interest rate caps, where applicable. See Note 9 — “Derivatives.”

The following table presents a schedule of contractual repayments of White Mountains’s debt as of December 31, 2025:

Ark Subordinated Notes

In the third quarter of 2021, GAIL issued $163.3 million face value floating rate unsecured subordinated notes at par in three separate transactions for proceeds of $157.8 million, net of debt issuance costs (collectively, the “Ark 2021 Subordinated Notes”). The Ark 2021 Subordinated Notes were issued in private placement offerings that were exempt from the registration requirements of the Securities Act of 1933.

On July 13, 2021, Ark issued €39.1 million ($46.3 million based upon the foreign currency exchange spot rate as of the date of the transaction) face value floating rate unsecured subordinated notes (“Ark 2021 Subordinated Notes Tranche 1”). The Ark 2021 Subordinated Notes Tranche 1, which mature in July 2041, accrue interest at a floating rate equal to the three-month Euro Interbank Offered Rate (EURIBOR) plus 5.75% per annum.

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On August 11, 2021, Ark issued $47.0 million face value floating rate unsecured subordinated notes (“Ark 2021 Subordinated Notes Tranche 2”). The Ark 2021 Subordinated Notes Tranche 2, which mature in August 2041, accrue interest at a floating rate equal to the three-month Secured Overnight Financing Rate (“SOFR”) plus a SOFR benchmark adjustment of 0.26% and a stated margin of 5.75% per annum.

On September 8, 2021, Ark issued $70.0 million face value floating rate unsecured subordinated notes (“Ark 2021 Subordinated Notes Tranche 3”). The Ark 2021 Subordinated Notes Tranche 3, which mature in September 2041, accrue interest at a floating rate equal to the three-month SOFR plus a SOFR benchmark adjustment of 0.26% and a stated margin of 6.1% per annum.

On theten-year anniversary of the issue dates, the interest rate for the Ark 2021 Subordinated Notes will increase by 1.0% per annum. Ark has the option to redeem, in whole or in part, the Ark 2021 Subordinated Notes ahead of contractual maturity at the outstanding principal amounts plus accrued interest at theten-year anniversary or any subsequent interest payment date.

All payments of principal and interest under the Ark 2021 Subordinated Notes are conditional upon GAIL’s solvency and compliance with the enhanced capital requirements of the Bermuda Monetary Authority (“BMA”). The deferral of payments of principal and interest under these conditions does not constitute a default by Ark and does not give the noteholders any rights to accelerate repayment of the Ark 2021 Subordinated Notes or take any enforcement action under the Ark 2021 Subordinated Notes.

If the payments of principal and interest under the Ark 2021 Subordinated Notes become subject to tax withholding on behalf of Bermuda or any political subdivision there, the Ark 2021 Subordinated Notes require the payment of additional amounts such that the amount received by the noteholders is the same as would have been received absent the tax withholding being imposed. The Ark 2021 Subordinated Notes Tranche 3 require the payment of additional interest of 1.0% per annum upon the occurrence of a premium load event until such event is remedied. Premium load events include the failure to meet payment obligations of the Ark 2021 Subordinated Notes Tranche 3 when due, failure of GAIL to maintain an investment grade credit rating, failure to maintain 120% of GAIL’s Bermuda solvency capital requirement, failure of GAIL to maintain a debt to capital ratio below 40%, late filing of GAIL’s or Ark’s financial information and making a restricted payment or distribution on GAIL’s common stock or other securities that rank junior or pari passu with the Ark 2021 Subordinated Notes Tranche 3 when a different premium load event exists or will be caused by the restricted payment. As of December 31, 2025, there were no premium load events.

As of December 31, 2025, the Ark 2021 Subordinated Notes Tranche 1 had an outstanding balance of €39.1 million ($45.8 million based upon the foreign currency exchange spot rate as of December 31, 2025), the Ark 2021 Subordinated Notes Tranche 2 had an outstanding balance of $47.0 million and the Ark 2021 Subordinated Notes Tranche 3 had an outstanding balance of $70.0 million.

The Ark Subordinated Notes contain various affirmative and negative covenants that White Mountains considers to be customary for such borrowings.

Ark Standby Letter of Credit Facilities

In December 2021, Ark entered into an uncommitted secured standby letter of credit facility agreement with Citibank Europe Plc (the “Citibank LOC Facility”), with capacity of $125.0 million on a collateralized basis. In September 2022, Ark entered into an additional uncommitted standby letter of credit facility agreement with Lloyds Bank Corporate Markets PLC (the “Lloyds LOC Facility”), with capacity of $100.0 million on a collateralized basis.

As of December 31, 2025, the Citibank LOC Facility had an outstanding balance of $76.1 million and cash and investments pledged as collateral of $93.8 million. As of December 31, 2025, the Lloyds LOC Facility had an outstanding balance of $27.0 million and cash and investments pledged as collateral of $30.5 million. Ark’s uncommitted secured standby letter of credit facility agreements contain various representations, warranties and affirmative and negative covenants that White Mountains considers to be customary for such borrowings.

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HG Global Senior Notes

On April 29, 2022, HG Global received the proceeds from the issuance of its $150.0 million face value floating rate secured senior notes (the “HG Global Senior Notes”). The HG Global Senior Notes, which mature in April 2032, accrue interest at a floating rate equal to the three-month SOFR plus a SOFR benchmark adjustment of 0.26% and a stated margin of 6.0% per annum. Subsequent to thefive-year anniversary of the funding date, absent the occurrence of an early amortization trigger event, HG Global will be required to make payments of principal on a quarterly basis totaling $15.0 million annually. Upon the occurrence of an early amortization trigger event, HG Global is required to use all available cash flow to repay the notes. Early amortization trigger events include scenarios in which HG Re is effectively in runoff. HG Global has the option to redeem, in whole or in part, the HG Global Senior Notes after thefive-year anniversary of the funding date at the outstanding principal amount plus accrued interest.

On June 16, 2022, HG Global entered into an interest rate cap agreement, effective on July 25, 2022, to limit its exposure to the risk of interest rate increases on the HG Global Senior Notes (the “HG Global 2022 Interest Rate Cap”). Under the HG Global 2022 Interest Rate Cap, the notional amount is $150.0 million, the maximum interest rate is 9.76% per annum and the termination date is July 25, 2025. On August 22, 2024, HG Global entered into a new interest rate cap agreement, effective upon the termination of the prior interest rate cap (the “HG Global 2024 Interest Rate Cap”). Under the HG Global 2024 Interest Rate Cap, the initial notional amount is $150.0 million, the maximum interest rate is 10.76% per annum and the termination date is July 25, 2028. See Note 9 — “Derivatives.”

The HG Global Senior Notes require HG Global to maintain an interest reserve account ofeight times the interest accrued for the most recent quarterly interest period. As of December 31, 2025 and 2024, the interest reserve account held short-term investments of $30.4 million and $29.3 million.

The HG Global Senior Notes are secured by the capital stock and other equity interests of HG Global’s subsidiaries, the interest reserve account and all cash and non-cash proceeds from such collateral. The HG Global Senior Notes contain various affirmative and negative covenants that White Mountains considers to be customary for such borrowings.

If the payment of principal and interest under the HG Global Senior Notes becomes subject to tax withholding on behalf of a relevant governmental authority for certain indemnified taxes, the HG Global Senior Notes require the payment of additional amounts such that the amount received by the noteholders is the same as would have been received absent the tax withholding being imposed. The HG Global Senior Notes require the payment of additional interest of 1.0% per annum if the HG Global Senior Notes receive a non-investment grade rating or are no longer rated. As of December 31, 2025, the HG Global Senior Notes had an investment grade rating.

As of December 31, 2025, the HG Global Senior Notes had an outstanding balance of $150.0 million.

Kudu Credit Facility

On March 23, 2021, Kudu entered into a secured revolving credit facility (the “Kudu Credit Facility”) with Mass Mutual for a maximum borrowing capacity of $300.0 million. On June 28, 2024, Kudu amended the Kudu Credit Facility to increase the total commitment from $300.0 million to $350.0 million and revise the stated margin and SOFR benchmark adjustment. The amended terms also reduced the minimum debt service coverage ratio, calculated as its trailing 12 months annualized adjusted EBITDA to its total debt service, to 2.5 times for 2024, reverting back to 3.0 times for 2025 and thereafter. On March 18, 2025, Kudu amended the Kudu Credit Facility to reduce the required interest reserve account balance and lower the minimum debt service coverage ratio to 2.5 times. On July 21, 2025, Kudu amended the Kudu Credit Facility to increase the total commitment from $350 million to $500 million, reduce the maximum loan-to-value ratio from 50% to 40% and revise the interest rate. These amendments to the Kudu Credit Facility have lowered Kudu’s borrowing costs and increased its borrowing capacity. The Kudu Credit Facility has an availability period through July 21, 2030 and matures on July 21, 2038.

Through June 30, 2024, interest on the Kudu Credit Facility accrued at a floating rate equal to the three-month SOFR plus a SOFR benchmark adjustment of 0.26% and a stated margin of 4.30% (4.56% in total) per annum. From July 1, 2024 through July 21, 2025, interest on the Kudu Credit Facility accrued at a floating rate equal to the three-month SOFR plus a stated margin of 4.45% per annum with no SOFR benchmark adjustment. Effective July 21, 2025, the Kudu Credit Facility accrues interest at the greater of (i) the fixed rate equal to the interpolated yield on U.S. Treasuries at the time of each future borrowing plus a stated margin of 3.10% and (ii)7.25%. The interest rate on the $253.3 million outstanding balance as of July 21, 2025 was reduced from a then floating rate of 8.75% to a fixed rate of 7.65%.

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On September 17, 2024, Kudu entered into an interest rate cap agreement, effective on September 30, 2024, to limit its exposure to the risk of interest rate increases on the Kudu Credit Facility (the “Kudu Interest Rate Cap”). Under the Kudu Interest Rate Cap, the notional amount is $150.0 million, the maximum interest rate is 8.95% per annum and the termination date is September 30, 2027. See Note 9 — “Derivatives.”

The Kudu Credit Facility requires Kudu to maintain an interest reserve account of two times the interest accrued for the most recent quarterly interest period. Prior to the March 18, 2025 amendment, Kudu was required to maintain an interest reserve account of four times the interest accrued for the most recent quarterly interest period. As of December 31, 2025 and 2024, the interest reserve account held short-term investments of $7.6 million and $15.1 million.

The Kudu Credit Facility requires Kudu to maintain a maximum loan-to-value ratio of the outstanding balance to the sum of the fair market value of Kudu’s other long-term investments and cash held in certain accounts (the “LTV Percentage”) for annual periods beginning on July 21, 2025 as follows:40% in years 0-6,25% in years 7-8,15% in years 9-11 and 0% thereafter. As of December 31, 2025, Kudu had a 26.8% LTV Percentage.

The Kudu Credit Facility requires Kudu to maintain a minimum debt service coverage ratio of 2.5 times for 2025 and thereafter. As of December 31, 2025, Kudu had a debt service coverage ratio of 2.6 times.

Kudu may borrow undrawn balances until July 21, 2030, subject to customary terms and conditions, to the extent that the

amount borrowed under the Kudu Credit Facility does not exceed the borrowing base, which is equal to 35% of the fair value of Kudu’s other long-term investments.

The following table presents the change in debt under the Kudu Credit Facility for the years ended December 31, 2025, 2024 and 2023:

The Kudu Credit Facility is secured by all property of the loan parties and contains various representations, warranties and affirmative and negative covenants that White Mountains considers to be customary for such borrowings.

Distinguished Credit Facility

On July 4, 2025, Distinguished entered into an amended credit facility (the “Distinguished Credit Facility”). The amendment waived certain change of control prepayment provisions and provided $50.0 million of incremental term loan principal for purposes of consummating the Distinguished Transaction. The $50.0 million of incremental term loan principal was subsequently drawn on September 2, 2025 in connection with the closing of the Distinguished Transaction. The Distinguished Credit Facility is comprised of a term loan of $141.0 million, a delayed-draw term loan of $40.0 million and a revolving credit loan commitment of $15.0 million. The Distinguished Credit Facility matures on October 10, 2029. Distinguished was required to make payments of principal on a quarterly basis totaling $0.4 million for 2025, increasing to $1.4 million annually thereafter. Distinguished may also be required to use a percentage of excess cash flows to repay outstanding principal plus accrued interest if Distinguished’s total leverage ratio rises above 3.75 times. Distinguished has the option to prepay, in whole or in part, the Distinguished Credit Facility at the outstanding principal plus accrued interest. The delayed draw term loan may be drawn on or before October 10, 2026. As of December 31, 2025, the revolving credit loan was undrawn.

Interest on the Distinguished Credit Facility accrues at a floating rate equal to the three-month SOFR plus a stated margin ranging from 5.25% to 5.5% per annum driven by Distinguished’s total leverage ratio. As of December 31, 2025, Distinguished’s total leverage ratio was 4.1 times, and the stated margin was 5.5%.

On September 16, 2025, Distinguished entered into an interest rate cap agreement to limit its exposure to the risk of interest rate increases on the Distinguished Credit Facility (the “Distinguished Interest Rate Cap”). Under the Distinguished Interest Rate Cap, the notional amount is $70.0 million, the maximum interest rate is 10.5% per annum and the termination date is September 16, 2028. See Note 9 — “Derivatives.”

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The following table presents the change in debt under the Distinguished Credit Facility for the period from September 2, 2025, the date of acquisition, through December 31, 2025:

(1) Represents the outstanding balance of the Distinguished Credit Facility assumed in the Distinguished Transaction. See Note 2 — “Significant Transactions.”

(2) Represents the $50.0 of incremental term loan drawn in connection with the closing of the Distinguished Transaction. See Note 2 — “Significant Transactions.”

The Distinguished Credit Facility is secured by all property of the loan parties and contains various representations, warranties and affirmative and negative covenants that White Mountains considers to be customary for such borrowings, including a maximum total leverage ratio of 5.5 times.

Other Operations Debt

As of December 31, 2025, White Mountains’s Other Operations had debt with an outstanding balance of $38.7 million, which consisted offive secured credit facilities (collectively, “Other Operations debt”). The increase in Other Operations debt as of December 31, 2025 was driven primarily by the Enterprise Solutions Transaction.

WTM Credit Facility

On July 16, 2025, the Company entered into a credit agreement, which established a senior unsecured revolving credit facility of up to $250.0 million that matures on July 16, 2028 (the “WTM Credit Facility”). As of December 31, 2025, the WTM Credit Facility is undrawn. White Mountains may borrow undrawn balances until July 16, 2028, subject to customary terms and conditions, including key covenants tied to White Mountains’s minimum net worth and debt to total capital ratio. Interest on any future borrowings under the WTM Credit Facility will accrue at a floating rate generally equal to the SOFR term rate plus a stated margin ranging from 1.1% to 1.5% per annum.

The WTM Credit Facility contains various representations, warranties and affirmative and negative covenants that White Mountains considers to be customary for such borrowings.

Compliance

As of December 31, 2025, White Mountains was in compliance, in all material respects, with all of the covenants under its debt instruments.

Interest

Total interest expense incurred by White Mountains for its indebtedness was $78.4 million, $60.8 million and $62.7 million for the years ended December 31, 2025, 2024 and 2023. Total interest paid by White Mountains for its indebtedness was $66.4 million, $61.0 million and $42.2 million for the years ended December 31, 2025, 2024 and 2023.

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Note 8. Income Taxes

The Company has subsidiaries and branches that operate in various jurisdictions around the world and are subject to tax in the jurisdictions in which they operate. As of December 31, 2025, the primary jurisdictions in which the Company’s subsidiaries and branches operated and were subject to tax include Israel, Luxembourg, the United Kingdom and the United States.

Certain of the Company’s subsidiaries are subject to the global minimum tax regime of the Organization for Economic Cooperation and Development (“OECD”) Pillar Two initiative, as enacted by Luxembourg and the United Kingdom in their respective domestic laws. The Pillar Two initiative includes a set of model rules that are generally designed to impose a top-up tax on a large multinational enterprise group to the extent that the group is not subject to an effective tax rate of at least 15% in each jurisdiction in which the group has a consolidated affiliate or permanent establishment. White Mountains did not incur a top-up tax for the year ended December 31, 2025.

The Company and its Bermuda-domiciled subsidiaries were not subject to income tax in Bermuda in 2025 and prior years. On December 27, 2023, Bermuda enacted a 15% corporate income tax that became effective on January 1, 2025. The Bermuda legislation defers the effective date for five years for Bermuda companies in consolidated groups that meet certain requirements. White Mountains expects to meet the requirements to be exempt from the Bermuda corporate income tax until January 1, 2030.

The Bermuda legislation also provides for an optional economic transition adjustment that can decrease or increase future years’ taxable income. Under GAAP, this economic transition adjustment was required to be recognized as a deferred tax asset or liability as of December 31, 2023 if a company intended to apply the adjustment to compute its taxable income. Accordingly, White Mountains recorded a net deferred tax asset of $68.0 million in 2023, of which $51.0 million was attributable to Ark and $17.0 million was attributable to HG Global. As of July 1, 2024, White Mountains no longer consolidates BAM. As a result of the deconsolidation of BAM, the BAM Surplus Notes were recorded at fair value, which resulted in the reversal of a $5.0 million deferred tax liability related to the economic transition adjustment, generating a $5.0 million deferred tax benefit in 2024. On December 11, 2025, Bermuda enacted legislation that changes the scope of assets and liabilities subject to the economic transition adjustment. This legislation resulted in the reversal of a $5.1 million deferred tax liability related to the economic transition adjustment, generating a $5.1 million deferred tax benefit in 2025.

As a result of legislation enacted by Luxembourg on December 17, 2025, White Mountains expects to incur a top-up tax under the Luxembourg UTPR equal to the amount of the deferred tax benefit for that year associated with the Bermuda economic transition adjustment. Consequently, White Mountains expects to derive no economic benefit from the economic transition adjustment and intends to opt out of the economic transition adjustment upon becoming subject to Bermuda corporate income tax. Accordingly, White Mountains recognized a deferred tax expense of $78.1 million in 2025 to reverse the net deferred tax asset related to the Bermuda economic transition adjustment.

The following table presents the total income tax (expense) benefit for the years ended December 31, 2025, 2024 and 2023:

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Effective Rate Reconciliation

The following table presents a reconciliation of taxes calculated for 2025, 2024 and 2023 using the 21% U.S. federal statutory rate (the tax rate at which the majority of White Mountains’s worldwide operations are taxed) to the income tax (expense) benefit on pre-tax income (loss):

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Tax Payments and Receipts

The following table presents an outline of the significant components of White Mountains’s U.S. federal, state and non-U.S. tax payments (refunds):

Deferred Tax Assets and Liabilities

Deferred taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for tax purposes.

The following table presents an outline of the significant components of White Mountains’s U.S. federal, state and non-U.S. deferred tax assets and liabilities:

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White Mountains’s deferred tax assets (liabilities) are net of U.S. federal, state and non-U.S. valuation allowances and, to the extent that they relate to non-U.S. jurisdictions, are shown at year-end exchange rates.

Valuation Allowance

White Mountains records a valuation allowance against deferred tax assets if it becomes more likely than not that all or a portion of a deferred tax asset will not be realized. Changes in valuation allowances from period to period are included in income tax expense in the period of change. In determining whether or not a valuation allowance, or change therein, is warranted, White Mountains considers factors such as prior earnings history, expected future earnings, carryback and carryforward periods and strategies that if executed would result in the realization of a deferred tax asset. It is possible that certain planning strategies or projected earnings in certain subsidiaries may not be sufficient to utilize the entire deferred tax asset, which could result in changes to White Mountains’s deferred tax assets and tax expense.

Of the $95.8 million valuation allowance as of December 31, 2025, $36.8 million related to deferred tax assets on net operating losses and net unrealized investment gains and losses in the Company’s Luxembourg subsidiary, $35.3 million related to deferred tax assets on net operating losses in U.S. subsidiaries and other federal and state deferred tax benefits, $23.6 million related to deferred tax assets on net operating losses and other deferred tax benefits in Israeli subsidiaries and $0.1 million related to deferred tax assets on net operating losses in U.K. subsidiaries. Of the $89.2 million valuation allowance as of December 31, 2024, $43.4 million related to deferred tax assets on net operating losses and net unrealized investment gains and losses in the Luxembourg subsidiary, $25.2 million related to deferred tax assets on net operating losses in U.S. subsidiaries and other federal and state deferred tax benefits and $20.6 million related to deferred tax assets on net operating losses and other deferred tax benefits in Israeli subsidiaries.

United States

For the year ended December 31, 2025, White Mountains recognized income tax expense of $10.3 million to reflect an increase in the valuation allowance on the net deferred tax assets for certain U.S. operations within Other Operations, as White Mountains does not currently anticipate sufficient taxable income to utilize the remaining deferred tax assets. For the year ended December 31, 2024, White Mountains recognized income tax expense of $8.6 million to reflect an increase in the valuation allowance on the net deferred tax assets for certain U.S. operations within Other Operations, as White Mountains did not anticipate sufficient taxable income to utilize the remaining deferred tax assets.

As of July 1, 2024, White Mountains no longer consolidates BAM. Prior to the deconsolidation, White Mountains recognized income tax expense of $5.7 million to reflect the increase in the valuation allowance on net deferred tax assets of BAM for the years ended December 31, 2024. White Mountains recognized both the tax expense related to BAM’s member surplus contributions (“MSC”) and the related changes in valuation allowance on such taxes directly through noncontrolling interest equity. For the years ended December 31, 2024, BAM had income included in equity due to MSC that was available to offset its loss from operations. For the year ended December 31, 2024, BAM recognized both the income tax benefit on MSC of $3.1 million and the offsetting expense in paid-in surplus.

Non-U.S. Jurisdictions

For the year ended December 31, 2025, White Mountains recognized income tax benefit of $6.6 million to reflect a decrease in the valuation allowance against the deferred tax assets at the Luxembourg-domiciled subsidiary. The decrease in the valuation allowance was driven by the utilization of the deferred tax assets primarily from interest income, including a $3.9 million income tax benefit for the partial release in valuation allowance related to expected future interest income. White Mountains does not currently anticipate sufficient income to utilize the remaining deferred tax assets. For the year ended December 31, 2024, White Mountains recognized income tax benefit of $4.2 million to reflect a decrease in deferred tax assets and the corresponding decrease in the full valuation allowance at the Luxembourg-domiciled subsidiary. The decrease in the deferred tax assets was driven primarily by (i) utilization from interest income and (ii) a decline in the Luxembourg tax rate. As of December 31, 2024, White Mountains did not anticipate sufficient income to utilize the remaining deferred tax assets.

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For the year ended December 31, 2025, White Mountains recognized income tax expense of $3.0 million to reflect an increase in the valuation allowance against the deferred tax assets at certain Israel-domiciled subsidiaries. The increase is due to movement of foreign currency exchange rate gains during the year, which increased the Company’s net operating loss carryforward and related deferred tax asset. White Mountains does not currently anticipate sufficient taxable income to utilize the deferred tax assets. For the year ended December 31, 2024, White Mountains recognized income tax benefit of $0.2 million to reflect a decrease in the valuation allowance against the deferred tax assets at certain Israel-domiciled subsidiaries. The decrease is due to movement of foreign currency exchange rate gains during the year, which reduced the Company’s net operating loss carryforward and related deferred tax asset. As of December 31, 2024, White Mountains did not anticipate sufficient taxable income to utilize the remaining deferred tax assets.

Net Operating Loss and Capital Loss Carryforwards

The following table presents net operating loss and capital loss carryforwards as of December 31, 2025, the expiration dates and the deferred tax assets thereon:

Included in the U.S. net operating loss carryforwards are losses of $8.2 million subject to an annual limitation on utilization under Internal Revenue Code Section 382 and $0.6 million subject to the limitation on utilization under the separate-return-limitation-year (SRLY) rules in the Internal Revenue Code. These loss carryforwards will begin to expire in 2026. As of December 31, 2025, there are U.K. foreign tax credit carryforwards available of $3.7 million, which do not have an expiration date.

Uncertain Tax Positions

Recognition of the benefit of a given tax position is based upon whether a company determines that it is more likely than not that a tax position will be sustained upon examination based upon the technical merits of the position. In evaluating the more likely than not recognition threshold, White Mountains must presume that the tax position will be subject to examination by a taxing authority with full knowledge of all relevant information. If the recognition threshold is met, then the tax position is measured at the largest amount of benefit that is more than 50% likely of being realized upon ultimate settlement.

As of December 31, 2025 and 2024, White Mountains did not have any unrecognized tax benefits.

White Mountains classifies all interest and penalties on unrecognized tax benefits as part of income tax expense. During the years ended December 31, 2025, 2024 and 2023, White Mountains did not recognize any net interest (income) expense. There was no accrued interest as of December 31, 2025, 2024 and 2023.

Tax Examinations

With few exceptions, White Mountains is no longer subject to U.S. federal, state or non-U.S. income tax examinations by tax authorities for years before 2019.

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Note 9. Derivatives

HG Global Interest Rate Caps

HG Global entered intotwo interest rate cap agreements to limit its exposure to the risk of interest rate increases on the HG Global Senior Notes.

On June 16, 2022, HG Global entered into the HG Global 2022 Interest Rate Cap, effective on July 25, 2022. The notional amount of the HG Global 2022 Interest Rate Cap was $150.0 million, and the termination date was July 25, 2025. HG Global paid an initial premium of $3.3 million for the HG Global 2022 Interest Rate Cap.

On August 22, 2024, HG Global entered into the HG Global 2024 Interest Rate Cap, which became effective upon the termination of the HG Global 2022 Interest Rate Cap on July 25, 2025. The initial notional amount of the HG Global 2024 Interest Rate Cap is $150.0 million, and the termination date is July 25, 2028. For interest periods after April 26, 2027, the notional amount of the HG Global 2024 Interest Rate Cap will decrease as the outstanding principal of the HG Global Senior Notes is paid down. HG Global paid an initial premium of $1.3 million for the HG Global 2024 Interest Rate Cap.

Under the HG Global 2022 Interest Rate Cap, if the three-month SOFR on a quarterly determination date exceeded 3.5% through July 25, 2025, HG Global received a payment from the counterparty for the difference on the subsequent settlement date. For the years ended December 31, 2025 and 2024, HG Global received $1.0 million and $2.8 million related to the periodic settlement of the HG Global 2022 Interest Rate Cap.

Under the HG Global 2024 Interest Rate Cap, if the three-month SOFR on a quarterly determination date exceeds 4.5% between July 25, 2025 and July 25, 2028, HG Global will receive a payment from the counterparty for the difference on the subsequent settlement date. As of December 31, 2025, the three-month SOFR was 3.7%. For the year ended December 31, 2025, HG Global did not receive any payments related to the periodic settlement of the HG Global 2024 Interest Rate Cap.

HG Global accounts for the HG Global Interest Rate Caps as derivatives at fair value within other assets, with changes in fair value recognized in current period earnings within interest expense. For the year ended December 31, 2025, HG Global recognized a net unrealized loss of $2.3 million related to the change in fair value of both interest rate caps within interest expense. For the year ended December 31, 2024, HG Global recognized a net unrealized loss of $1.7 million related to the change in fair value of both interest rate caps within interest expense. As of December 31, 2025, the fair value of the HG Global 2024 Interest Rate Cap was $0.2 million. As of December 31, 2024, the total fair value of both interest rate caps was $2.5 million. White Mountains classifies the HG Global Interest Rate Caps as Level 2 measurements.

Kudu Interest Rate Cap

On September 17, 2024, Kudu entered into the Kudu Interest Rate Cap, effective on September 30, 2024, to limit its exposure to the risk of interest rate increases on the Kudu Credit Facility. The notional amount of the Kudu Interest Rate Cap is $150.0 million, and the termination date is September 30, 2027. Kudu paid an initial premium of $0.9 million for the Kudu Interest Rate Cap.

Under the Kudu Interest Rate Cap, if the three-month SOFR on a quarterly determination date exceeds 4.5%, Kudu will receive a payment from the counterparty for the difference on the subsequent settlement date. As of December 31, 2025, the three-month SOFR was 3.7%. For the year ended December 31, 2025, Kudu did not receive any payments related to the periodic settlement of the Kudu Interest Rate Cap. For the year ended December 31 2024, Kudu received $0.1 million related to the periodic settlement of the Kudu Interest Rate Cap.

Kudu accounts for the Kudu Interest Rate Cap as a derivative at fair value within other assets, with changes in fair value recognized in current period earnings within interest expense. For the years ended December 31, 2025 and 2024, Kudu recognized a loss of $0.9 million and a gain of $0.4 million related to the change in fair value on the Kudu Interest Rate Cap within interest expense. As of December 31, 2025 and 2024, the fair value of the Kudu Interest Rate Cap was $0.0 million and $0.9 million. White Mountains classifies the Kudu Interest Rate Cap as a Level 2 measurement.

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Distinguished Interest Rate Cap

On September 16, 2025, Distinguished entered into the Distinguished Interest Rate Cap to limit its exposure to the risk of interest rate increases on the Distinguished Credit Facility. The notional amount of the Distinguished Interest Rate Cap is $70.0 million, and the termination date is September 16, 2028. Distinguished paid an initial premium of $0.2 million for the Distinguished Interest Rate Cap.

Under the Distinguished Interest Rate Cap, if the one-month SOFR on a monthly determination date exceeds 5.0%, Distinguished will receive a payment from the counterparty for the difference on the subsequent settlement date. As of December 31, 2025, the one-month SOFR was 3.7%.

Distinguished accounts for the Distinguished Interest Rate Cap as a derivative at fair value within other assets, with changes in fair value recognized in current period earnings within interest expense. For the period from September 2, 2025, the date of acquisition, through December 31, 2025, Distinguished recognized no gain or loss related to the change in fair value on the Distinguished Interest Rate Cap. As of December 31, 2025, the fair value of the Distinguished Interest Rate Cap was $0.1 million. White Mountains classifies the Distinguished Interest Rate Cap as a Level 2 measurement.

Note 10. Municipal Bond Guarantee Reinsurance

HG Global was established to fund the startup of BAM, a mutual municipal bond insurer. HG Global, together with its subsidiaries, provided the initial capitalization of BAM through the purchase of $503.0 million of the BAM Surplus Notes.

Reinsurance Treaties

FLRT

HG Re is a party to the FLRT with BAM, under which HG Re provides first-loss reinsurance protection of up to 15%-of-par outstanding for each policy assumed from BAM. For capital appreciation bonds, par is adjusted to the estimated equivalent par value for current interest paying bonds. HG Re is only required to provide reinsurance on policies that fall within the FLRT underwriting guidelines agreed upon by HG Re.

BAM charges an insurance premium on each municipal bond insurance policy it underwrites. Historically, approximately 55% of the total insurance premium charged by BAM has been MSC, and the remainder is a risk premium. In return for the reinsurance provided, HG Re receives approximately 60% of the risk premium charged, which is net of a ceding commission.

The FLRT is a perpetual agreement with terms that can be renegotiated every five years. For the next renegotiation period, either party may provide notice during 2028 to trigger a renegotiation that would take effect on January 1, 2030.

For the year ended December 31, 2025, HG Re recognized gross written premiums of $61.4 million and earned premiums of $30.8 million. Prior to the deconsolidation of BAM on July 1, 2024, HG Re’s reinsurance balances under the FLRT eliminated in White Mountains’s consolidated financial statements. For the period from July 1, 2024 to December 31, 2024, HG Re recognized gross written premiums of $31.9 million and earned premiums of $14.9 million.

XOLT

HG Re is party to an excess of loss reinsurance agreement (the “XOLT”) with BAM, under which HG Re provides last-dollar protection for exposures on municipal bonds insured by BAM in excess of the New York State Department of Financial Services (“NYDFS”) single issuer limits. As of December 31, 2025, the XOLT is subject to an aggregate limit equal to the lesser of $125.0 million or the assets held in the supplemental collateral trust (the “Supplemental Trust”) at any point in time. The XOLT is accounted for using deposit accounting as the agreement does not meet the risk transfer requirements necessary to be accounted for as reinsurance. Accordingly, any financing revenues related to the XOLT are recorded in other revenues.

Prior to the deconsolidation of BAM on July 1, 2024, HG Re’s reinsurance balances under the XOLT eliminated in White Mountains’s consolidated financial statements. For the year ended December 31, 2025 and for the period from July 1, 2024 to December 31, 2024, other revenues recognized by HG Re related to the XOLT were insignificant.

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Collateral Trusts

HG Re’s obligations under the FLRT are subject to an aggregate limit equal to the assets in two collateral trusts, the Supplemental Trust and the Regulation 114 Trust (together, the “Collateral Trusts”), at any point in time.

On a monthly basis, BAM deposits cash equal to ceded premiums net of ceding commissions, due to HG Re under the FLRT directly into the Regulation 114 Trust. The Regulation 114 Trust target balance is equal to HG Re’s unearned premiums and unpaid loss and LAE reserves, if any. If, at the end of any quarter, the Regulation 114 Trust balance is below the target balance, funds will be withdrawn from the Supplemental Trust and deposited into the Regulation 114 Trust in an amount equal to the shortfall. If, at the end of any quarter, the Regulation 114 Trust balance is above 102% of the target balance, funds will be withdrawn from the Regulation 114 Trust and deposited into the Supplemental Trust. The Regulation 114 Trust balance as of December 31, 2025 and 2024 was $399.4 million and $352.1 million, which consisted of cash, investments and accrued investment income.

The Supplemental Trust target balance is $603.0 million, less the amount of cash and securities in the Regulation 114 Trust in excess of its target balance (the “Supplemental Trust Target Balance”). If, at the end of any quarter, the Supplemental Trust balance exceeds the Supplemental Trust Target Balance, such excess may be distributed to HG Re. The distribution will be made first as an assignment of accrued interest on the BAM Surplus Notes and second in cash and/or fixed income securities. For the year ended December 31, 2025, HG Re received a distribution from the Supplemental Trust of $61.0 million, which consisted of an assignment of $30.1 million of accrued interest on the BAM Surplus Notes and a cash distribution of $30.9 million. For the year ended December 31, 2024, HG Re received a distribution from the Supplemental Trust of $79.7 million, which consisted of an assignment of $58.5 million of accrued interest on the BAM Surplus Notes and a cash distribution of $21.2 million.

As the BAM Surplus Notes are repaid over time, the BAM Surplus Notes will be replaced in the Supplemental Trust by cash and fixed income securities. The Supplemental Trust balance as of December 31, 2025 and 2024 was $607.1 million and $598.0 million, which included $323.3 million and $289.4 million of cash, investments and accrued investment income, $276.8 million and $300.9 million of BAM Surplus Notes at nominal value and $7.0 million and $7.7 million of accrued interest receivable on the BAM Surplus Notes at nominal value.

As of December 31, 2025 and 2024, the Collateral Trusts held total assets of $1,006.5 million and $950.1 million.

Through June 30, 2024, the interest rate on the BAM Surplus Notes was a variable rate equal to the one-year U.S. Treasury rate plus 300 basis points, set annually, with each payment applied pro rata between outstanding principal and interest. Accordingly, in 2024, the interest rate on the BAM Surplus Notes was 8.2% through June 30, 2024. Effective July 1, 2024 and through maturity, HG Global and BAM amended the interest rate on the BAM Surplus Notes to be 10.0%, with a higher proportion of each payment to be applied to outstanding principal.

Under its agreements with HG Global, BAM is required to seek regulatory approval to pay principal and interest on the BAM Surplus Notes only to the extent that its remaining qualified statutory capital and other capital resources continue to support its outstanding obligations, its business plan and its “AA/stable” rating from Standard & Poor’s. No payment of principal or interest on the BAM Surplus Notes may be made without the approval of the NYDFS.

During the year ended December 31, 2025, HG Global received cash payments of principal and interest on the BAM Surplus Notes totaling $35.0 million. Of these payments, $24.2 million was a repayment of principal held in the Supplemental Trust, $0.3 million was a payment of accrued interest held in the Supplemental Trust and $10.5 million was a payment of accrued interest held outside the Supplemental Trust.

During the year ended December 31, 2024, HG Global received cash payments of principal and interest on the BAM Surplus Notes totaling $30.0 million. Of these payments, $21.3 million was a repayment of principal held in the Supplemental Trust, $0.5 million was a payment of accrued interest held in the Supplemental Trust and $8.2 million was a payment of accrued interest held outside the Supplemental Trust.

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As of December 31, 2025 and 2024, the principal balance on the BAM Surplus Notes was $276.8 million and $300.9 million, and total interest receivable on the BAM Surplus Notes was $213.7 million and $194.8 million, all at nominal value. For the year ended December 31, 2025, White Mountains accrued $29.8 million of interest income on the BAM Surplus Notes.

Prior to the deconsolidation of BAM on July 1, 2024, the BAM Surplus Notes, including accrued interest receivable, were classified as intercompany notes carried at nominal value, which eliminated in consolidation. Upon deconsolidation, White Mountains elected the fair value option for the BAM Surplus Notes. The BAM Surplus Notes are classified as a Level 3 measurement. White Mountains values the BAM Surplus Notes each quarter using a discounted cash flow analysis. The discounted cash flow analysis used to value the BAM Surplus Notes depends on key inputs, such as projections of future revenues and earnings for BAM, expected payments on the BAM Surplus Notes through maturity and a discount rate to reflect time value and related uncertainty of the repayment pattern. The expected payments on the BAM Surplus Notes are based on management judgment, considering current performance, budgets and projected future results. These expected payments depend on BAM’s ability to generate excess cash flows from its operations, driven primarily by assumptions regarding future trends for the issuance of municipal bonds, interest rates, credit spreads, insured market penetration, competitive activity in the market for municipal bond insurance and other factors affecting the demand for and pricing of BAM’s municipal bond insurance as well as BAM’s investment returns. The discount rate considers comparably-rated companies and instruments, adjusted for risks specific to BAM and the BAM Surplus Notes. As of December 31, 2025 and 2024, White Mountains concluded that a discount rate, which is a significant unobservable input used in estimating the fair value of the BAM Surplus Notes, of 8.05% and 8.10% was appropriate. The change in the discount rate was driven primarily by a decline in market interest rates.

When making its fair value selection, White Mountains considers all available information, facts and circumstances specific to BAM’s business and industry and any infrequent or unusual results for the period. As of

December 31, 2025 and 2024, White Mountains recognized the BAM Surplus Notes at a fair value of $339.0 million and $381.7 million. The recorded fair values represent management's best estimate and are within the range of reasonable values derived from the discounted cash flow analysis.

The following table presents the changes in the nominal value and fair value of the BAM Surplus Notes for the year ended December 31, 2025:

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Insured Obligations and Premiums

The following table presents the HG Global segment’s insured obligations as of December 31, 2025 and 2024:

(1) The remaining weighted average contract period was calculated using total contractual debt service outstanding, including principal and interest.

(2) Under the FLRT, HG Re provides first-loss reinsurance protection of up to 15%-of-par outstanding for each policy assumed from BAM. For capital appreciation bonds, par is adjusted to the estimated equivalent par value for current interest paying bonds.

The following table presents the HG Global segment’s future premium revenues as of December 31, 2025:

The following tables present gross written premiums and gross earned premiums included in the HG Global segment for the years ended December 31, 2025, 2024 and 2023:

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(1) For the six months ended June 30, 2024, BAM ceded written premiums of $20.5 and earned premiums of $14.0 to HG Global, which eliminated in consolidation. Subsequent to the deconsolidation of BAM, there are no ceded premiums, such that gross written premiums and gross earned premiums are equivalent to net written premiums and net earned premiums, respectively.

(1) For the year ended December 31, 2023, BAM ceded written premiums of $50.1 and ceded earned premiums of $26.0 to HG Global, which eliminated in consolidation.

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Note 11. Earnings Per Share

White Mountains calculates earnings per share using the two-class method, which allocates earnings between common shares and unvested restricted common shares. Both classes of shares participate equally in dividends and earnings on a per share basis. Basic earnings per share amounts are based on the weighted average number of common shares outstanding adjusted for unvested restricted common shares.

The following table presents the Company’s computation of earnings per share for the years ended December 31, 2025, 2024 and 2023.

(1)White Mountains recognizes an adjustment to the carrying value of the redeemable noncontrolling interests to the extent that the carrying value is below the redemption value. When calculating basic and diluted earnings per share, the adjustment for redeemable noncontrolling interests is treated as being akin to a dividend and presented as an adjustment to net income (loss) attributable to White Mountains’s common shareholders.

(2)Restricted shares issued by White Mountains receive dividends, and therefore, are considered participating securities.

(3)Restricted shares outstanding vest upon a stated date. See Note 12 — “Employee Share-Based Incentive Compensation Plans.”

The following table presents the undistributed net earnings (losses) for the years ended December 31, 2025, 2024 and 2023.

(1) Restricted shares issued by White Mountains receive dividends, and therefore, are considered participating securities.

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Note 12. Employee Share-Based Incentive Compensation Plans

White Mountains’s share-based incentive compensation plans are designed to incentivize key employees to maximize shareholder value over long periods of time. White Mountains believes that this is best pursued by utilizing a pay-for-performance program that closely aligns the financial interests of management with those of its shareholders while rewarding appropriate risk taking. White Mountains accomplishes this by emphasizing variable long-term compensation that is contingent on performance over a number of years rather than fixed entitlements. White Mountains expenses all its share-based compensation. As a result, White Mountains’s calculation of its owners’ returns includes the expense of all outstanding share-based compensation awards.

The WTM Incentive Plan provides for grants of various types of share-based and non-share-based incentive awards to key employees and directors of White Mountains. As of December 31, 2025 and 2024, White Mountains’ share-based incentive compensation awards consist of performance shares and restricted shares.

Performance Shares

Performance shares are designed to reward employees for meeting company-wide performance targets. Performance shares are conditional grants of a specified maximum number of common shares or an equivalent amount of cash. Awards generally vest at the end of athree-year service period, are subject to the attainment of pre-specified performance goals, and are valued based on the market value of common shares at the time awards are paid. Performance shares earned under the WTM Incentive Plan are typically paid in cash but may be paid in common shares. Compensation expense is recognized for the vested portion of the awards over the related service periods. The level of payout ranges from zero totwo times the number of shares initially granted, depending on White Mountains’s financial performance. Performance shares become payable at the conclusion of a performance cycle (typically three years) if pre-defined financial targets are met.

The performance measure used for determining performance share payouts is the growth in compensation value per share (“CVPS”). Prior to 2025, CVPS was calculated as the average of the growth in adjusted book value per share and the growth in intrinsic value per share. Intrinsic value per share is calculated by adjusting White Mountains’s book value per share for differences between the book value of certain assets and liabilities and White Mountains’s estimate of their underlying intrinsic value. Following the deconsolidation of BAM, White Mountains has replaced growth in adjusted book value per share with growth in book value per share in the calculation of CVPS for calendar years beginning with 2025. For example, for the 2023-2025 performance cycle, adjusted book value per share growth would be used in the calculation of CVPS for calendar years 2023 and 2024, and book value per share growth would be used for calendar year 2025.

The following table presents performance share activity for the years ended December 31, 2025, 2024 and 2023 for performance shares granted under the WTM Incentive Plan:

(1)WTM performance share payments for the 2022-2024 performance cycle were made in March 2025 at 200% of target. WTM performance share payments for the 2021-2023 performance cycle were made in March 2024 at 188% of target. WTM performance share payments for the 2020-2022 performance cycle were made in March 2023 at 200% of target.

(2)Amounts include changes in assumed forfeitures, as required under GAAP.

During 2025, White Mountains granted 10,670 performance shares for the 2025-2027 performance cycle. During 2024, White Mountains granted 11,405 performance shares for the 2024-2026 performance cycle. During 2023, White Mountains granted 10,895 performance shares for the 2023-2025 performance cycle.

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For the 2022-2024 performance cycle, the Company issued common shares for 30 performance shares earned, and all other performance shares earned were settled in cash. For the 2021-2023 performance cycle, the Company issued common shares for 100 performance shares earned, and all other performance shares earned were settled in cash. For the 2020-2022 performance cycle, all performance shares earned were settled in cash. If all outstanding performance shares had vested on December 31, 2025, the total additional compensation cost to be recognized would have been $36.5 million, based on accrual factors as of December 31, 2025 (common share price and payout assumptions).

The following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of December 31, 2025 for each performance cycle:

For the 2025-2027 performance cycle, the targeted performance goal for full payment of outstanding performance shares granted under the WTM Incentive Plan is 11.5% average annual growth in CVPS. Average annual growth of 6% or less would result in no payout, and average annual growth of 17% or more would result in a payout of 200%.

For the 2024-2026 performance cycle, the targeted performance goal for full payment of outstanding performance shares granted under the WTM Incentive Plan is 11% average annual growth in CVPS. Average annual growth of 6% or less would result in no payout, and average annual growth of 16% or more would result in a payout of 200%.

For the 2023-2025 performance cycle, the targeted performance goal for full payment of outstanding performance shares granted under the WTM Incentive Plan is 11% average annual growth in CVPS. Average annual growth of 6% or less would result in no payout, and average annual growth of 16% or more would result in a payout of 200%.

Restricted Shares

Restricted shares are grants of a specified number of common shares that generally vest at the end of a 34-month service period. The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the years ended December 31, 2025, 2024 and 2023:

During 2025, White Mountains issued 10,670 restricted shares that vest on January 1, 2028. During 2024, White Mountains issued 11,405 restricted shares that vest on January 1, 2027. During 2023, White Mountains issued 10,895 restricted shares that vest on January 1, 2026. The unamortized issue date fair value as of December 31, 2025 is expected to be recognized ratably over the remaining vesting periods.

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Note 13. Common Shareholders’ Equity and Noncontrolling Interests

Common Shares Repurchased and Retired

The Company’s Board of Directors has authorized it to repurchase its common shares from time to time, subject to market conditions. Shares may be repurchased on the open market or through privately negotiated transactions. The repurchase authorizations do not have a stated expiration date. As of December 31, 2025, White Mountains may repurchase an additional 269,594 shares under these board authorizations. In addition, from time to time White Mountains has also repurchased its common shares through self-tender offers that were separately authorized by its Board of Directors.

During 2025, the Company repurchased 100,581 common shares for $202.5 million at an average share price of $2,013.67, which included 31,420 common shares repurchased under the board authorizations for $59.2 million at an average share price of $1,884.27 and 5,097 common shares repurchased to satisfy employee income tax withholding pursuant to employee benefit plans. In addition, on December 24, 2025, White Mountains completed a “modified Dutch auction” self-tender offer, through which it repurchased 64,064 of its common shares at a purchase price of $2,082.60 per share ($2,050.00 excluding expenses) for a total cost of approximately $133.4 million, including expenses.

During 2024, the Company repurchased 5,269 common shares for $7.9 million at an average share price of $1,505.01. The common shares were repurchased to satisfy employee income tax withholding pursuant to employee benefit plans.

During 2023, the Company repurchased 24,165 common shares for $32.7 million at an average share price of $1,354.88, which included 19,536 common shares repurchased under the board authorizations for $26.2 million at an average share price of $1,340.79 and 4,629 common shares repurchased to satisfy employee income tax withholding pursuant to employee benefit plans.

Common Shares Issued

During 2025, the Company issued a total of 12,110 common shares, which consisted of 10,670 restricted shares issued to key personnel and 1,440 shares issued to directors of the Company.

During 2024, the Company issued a total of 13,100 common shares, which consisted of 11,405 restricted shares issued to key personnel and 1,695 shares issued to directors of the Company.

During 2023, the Company issued a total of 12,461 common shares, which consisted of 10,895 restricted shares issued to key personnel and 1,566 shares issued to directors of the Company.

Dividends on Common Shares

For the years ended December 31, 2025, 2024 and 2023, the Company declared and paid cash dividends totaling $2.6 million, $2.5 million and $2.6 million (or $1.00 per common share).

Noncontrolling Interests

Noncontrolling interests consist of the ownership interests of noncontrolling shareholders in consolidated entities. White Mountains has both redeemable and nonredeemable noncontrolling interests. Noncontrolling interests with optional redemption features that are not within White Mountains’s control are classified as redeemable noncontrolling interests, which are considered temporary equity and presented as mezzanine equity on the balance sheet. Noncontrolling interests that do not have any redemption features are classified as nonredeemable noncontrolling interests, which are considered permanent equity and included in White Mountains’s total equity on the balance sheet. Nonredeemable noncontrolling interests are presented separately from White Mountains’s common shareholders’ equity.

Redeemable Noncontrolling Interests

On September 5, 2028, the third anniversary of the closing of the Distinguished Transaction, certain noncontrolling unitholders will have the option to sell additional units representing 31.4% of Distinguished’s basic units outstanding to White Mountains at the same unit price paid in the Distinguished Transaction less aggregate per unit distributions. As of December 31, 2025, the carrying value of the redeemable noncontrolling interests was $131.5 million, and the redemption value would be $131.5 million if exercised in full.

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Nonredeemable Noncontrolling Interests

The following table presents the balance of noncontrolling interests included in White Mountains’s total equity and the related percentage of each consolidated entity’s total equity owned by noncontrolling shareholders as of December 31, 2025 and 2024:

(1) The noncontrolling percentage represents the basic ownership interests held by noncontrolling shareholders with the exception of HG Global, for which

the noncontrolling percentage represents the preferred share ownership held by noncontrolling shareholders.

(2) As of December 31, 2025 and 2024, Ark’s noncontrolling equity includes $58.6 and $42.9 related to management’s equity incentives.

(3) As of December 31, 2025 and 2024, Kudu’s noncontrolling equity includes $52.3 and $47.9 related to management’s equity incentives.

(4) As of December 31, 2025, Distinguished’s nonredeemable noncontrolling interests include $33.3 related to management’s equity incentives.

Note 14. Statutory Capital and Surplus

White Mountains’s insurance operations are subject to regulation and supervision in each of the jurisdictions where they are domiciled and licensed to conduct business. Generally, regulatory authorities have broad supervisory and administrative powers over such matters as licenses, standards of solvency, premium rates, policy forms, investments, security deposits, methods of accounting, form and content of financial statements, minimum capital and surplus requirements, dividends and other distributions to shareholders, periodic examinations and annual and other report filings. In general, such regulation is for the protection of policyholders rather than shareholders.

The Insurance Act 1978 of Bermuda and related regulations, as amended (the “Insurance Act”), regulates the insurance business of Bermuda-domiciled insurers. Under the Insurance Act, insurers are required to maintain available statutory capital and surplus at a level equal to or in excess of its enhanced capital requirement which is established by reference to either a Bermuda Solvency Capital Requirement (“BSCR”) model or an approved internal capital model. Generally, the BMA has broad supervisory and administrative powers over such matters as licenses, standards of solvency, investments, methods of accounting, form and content of financial statements, minimum capital and surplus requirements and annual and other report filings.

Ark

The Syndicates are subject to oversight by the Council of Lloyd’s. Ark Syndicate Management Limited is authorized by the U.K.’s Prudential Regulation Authority (the “PRA”) and regulated by the Financial Conduct Authority under the Financial Services and Markets Act 2000. The underwriting capacity of a Member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit in an amount determined under the capital adequacy regime of the PRA. This amount is determined by Lloyd’s and is based on each syndicate’s solvency and capital requirement as calculated through its internal model. In addition, if the Funds at Lloyd’s are not sufficient to cover all losses, the Lloyd’s Central Fund provides an additional discretionary level of security for policyholders. As of December 31, 2025, the fair value of Ark’s Funds at Lloyd’s cash and investment deposits totaled $361.6 million.

GAIL is subject to regulation and supervision by the BMA. As of December 31, 2025, GAIL had statutory capital and surplus of $1,700.2 million. GAIL’s minimum statutory capital and surplus requirement established by the BMA was $578.1 million as of December 31, 2025.

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WM Outrigger Re is a special purpose insurer under Bermuda insurance regulations and is subject to regulation and supervision by the BMA. As of December 31, 2025, WM Outrigger Re had statutory capital and surplus of $231.8 million. As a special purpose insurer, Outrigger Re Ltd. has a nominal minimum regulatory capital requirement of $1.

HG Re is a special purpose insurer under Bermuda insurance regulations and is subject to regulation and supervision by the BMA. As of December 31, 2025, HG Re had statutory capital and surplus of $731.7 million. As a special purpose insurer, HG Re has a nominal minimum regulatory capital requirement of $1.

Dividend Capacity

There are no restrictions under Bermuda law or the law of any other jurisdiction on the payment of dividends from retained earnings by White Mountains, provided that after the payment of any dividend, the Company would continue to be able to pay its liabilities as they become due and the realizable value of the Company’s assets would remain greater that its liabilities. Following is a description of the dividend capacity of White Mountains’s insurance and reinsurance subsidiaries:

Ark

During any 12-month period, GAIL, a class 4 licensed Bermuda insurer, has the ability to (i) make capital distributions of up to 15% of its total statutory capital per the previous year’s statutory financial statements or (ii) make dividend payments of up to 25% of its total statutory capital and surplus per the previous year’s statutory financial statements, without prior approval of Bermuda regulatory authorities. Accordingly, GAIL will have the ability to pay a dividend of up to $425.1 million during 2025, which is equal to 25% of its statutory capital and surplus of $1,700.2 million as of December 31, 2025, subject to meeting all appropriate liquidity and solvency requirements and the filing of its December 31, 2025 statutory financial statements. During 2025, GAIL did not pay any dividends to its immediate parent.

HG Re is a special purpose insurer subject to regulation and supervision by the BMA. HG Re does not require regulatory approval to pay dividends; however, its dividend capacity is limited to amounts held outside of the Collateral Trusts pursuant to the FLRT with BAM. As of December 31, 2025, HG Re had $3.9 million of net unrestricted cash and short-term investments. As of December 31, 2025, HG Re had $178.5 million of accrued interest on the BAM Surplus Notes held outside the Collateral Trusts. As of December 31, 2025, HG Re had $731.7 million of statutory capital and surplus and $1,006.5 million of assets held in the Collateral Trusts.

Note 15. Segment Information

As of December 31, 2025, White Mountains conducted its operations through four reportable segments: (1) Ark/WM Outrigger, (2) HG Global, (3) Kudu and (4) Distinguished, with its remaining operating businesses, holding companies and other assets included in Other Operations. White Mountains has made its segment determination based on consideration of the following criteria: (i) the nature of the business activities of each of the Company’s subsidiaries and affiliates; (ii) the manner in which the Company’s subsidiaries and affiliates are organized; (iii) the existence of primary managers responsible for specific subsidiaries and affiliates; and (iv) the organization of information provided to the Company’s CODM and the Board of Directors. The Company’s CODM is its Chief Executive Officer. The CODM utilizes each segment's pre-tax income (loss) in assessing each segment's performance and allocating resources. Other measures of segment profitability are also reviewed by the CODM. Significant intercompany transactions among White Mountains’s segments have been eliminated herein.

During the fourth quarter of 2022, Ark sponsored the formation of Outrigger Re Ltd. to provide collateralized reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. Ark renewed its quota share reinsurance agreement with Outrigger Re Ltd. for the 2024, 2025 and 2026 underwriting years. White Mountains consolidates its segregated account of Outrigger Re Ltd., WM Outrigger Re, in its financial statements. WM Outrigger Re’s quota share reinsurance agreement with GAIL eliminates in White Mountains’s consolidated financial statements. WM Outrigger Re exclusively provides reinsurance protection to Ark. As a result, WM Outrigger Re was aggregated with Ark within the Ark/WM Outrigger segment starting in 2023. See Note 2 — “Significant Transactions.”

Effective July 1, 2024, White Mountains no longer consolidates BAM. Through June 30, 2024, BAM’s results of operations are presented within the HG Global segment. See Note 2 — “Significant Transactions.”

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On December 5, 2025, White Mountains completed the Bamboo Sale Transaction. As a result, White Mountains deconsolidated the Bamboo Group on December 5, 2025, and Bamboo is no longer a reportable segment. Through December 5, 2025, Bamboo’s results of operations are presented within the Bamboo segment. White Mountains’s noncontrolling equity interest in the Bamboo SPV is accounted for at fair value in other long-term investments within Other Operations. See Note 2 — “Significant Transactions.”

On September 2, 2025, White Mountains completed the Distinguished Transaction. As a result, White Mountains began consolidating Distinguished in its financial statements on September 2, 2025. See Note 2 — “Significant Transactions.”

The following tables present White Mountains’s pre-tax financial results by segment for the years ended December 31, 2025, 2024 and 2023:

(1)Bamboo’s results are from January 1, 2025 through December 5, 2025, the date of sale.

(2)Distinguished’s results are from September 2, 2025, the date of acquisition, through December 31, 2025.

(3)Net investment income and net realized and unrealized investment gains (losses) for both Bamboo and Distinguished are included in other revenues in the consolidated statement of operations.

(4)Ark’s general and administrative expenses include $143.9 of other underwriting expenses.

(5)Bamboo’s general and administrative expenses include $12.0 of amortization of other intangible assets.

(6)Distinguished’s general and administrative expenses include $7.8 of amortization of other intangible assets.

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(1)Effective July 1, 2024, White Mountains no longer consolidates BAM. For the period from January 1, 2024 through June 30, 2024, BAM’s results of operations are presented within the HG Global segment.

(2)BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS.

(3) Bamboo’s net investment income and net realized and unrealized investment gains (losses) are included in other revenues in the consolidated statement of operations.

(4)Ark’s general and administrative expenses include $136.1 of other underwriting expenses.

(5)Bamboo’s general and administrative expenses include $16.4 of other underwriting expenses.

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(1)BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS.

(2)Ark’s general and administrative expenses include $113.6 of other underwriting expenses.

The following tables present White Mountains’s revenues from external customers by country for the years ended December 31, 2025, 2024 and 2023:

(1)Amounts include revenues from external customers related to Enterprise Solutions and certain Other Operating Businesses.

(1)Amounts include revenues from external customers related to certain Other Operating Businesses.

(1)Amounts include revenues from external customers related to certain Other Operating Businesses.

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The following table presents White Mountains’s balance sheet information by segment as of December 31, 2025 and 2024:

(1) Amount excludes investments of $1.0 related to an Other Operating Business that were reclassified to assets held for sale. See Note 20 — “Held for Sale.”

(2)HG Global preferred dividends payable to White Mountains’s subsidiaries is eliminated in White Mountains’s consolidated financial statements. For segment reporting, the HG Global preferred dividends payable to White Mountains’s subsidiaries included within the HG Global segment are eliminated against the offsetting receivable included within Other Operations and therefore added back to White Mountains’s common shareholders’ equity within the HG Global segment. As of December 31, 2025 and 2024, the HG Global preferred dividends payable to White Mountains’s subsidiaries was $527.2 and $462.1.

(3) Amounts include held for sale balances. See Note 20 — “Held for Sale.”

(4) Amounts exclude investments of $58.0 related to the Bamboo Group and $2.0 related to an Other Operating Business that were reclassified to assets held for sale. See Note 20 — “Held for Sale.”

Note 16. Variable Interest Entities

Under GAAP, White Mountains is required to consolidate any entity in which it holds a controlling financial interest. A controlling financial interest is usually in the form of an investment representing the majority of the subsidiary’s voting interests. However, a controlling financial interest may also arise from a financial interest in a VIE through arrangements that do not involve ownership of voting interests. A VIE is a legal entity that (i) does not have sufficient equity at risk to finance its activities without additional financial support; (ii) is structured such that equity investors, as a group, lack the power, through voting or similar rights, to direct the activities that most significantly impact the entity’s economic performance; (iii) is structured such that the equity investors lack the obligation to absorb losses of, or the right to receive returns from, the entity; or (iv) is structured with non-substantive voting rights. White Mountains determines whether an entity is a VIE at the inception of its variable interest in the entity and upon the occurrence of certain reconsideration events.

White Mountains consolidates a VIE if it determines that it is the primary beneficiary. The primary beneficiary is defined as the entity that holds a variable interest that gives it both the power to direct the VIE’s activities that most significantly impact its economic performance and the obligation to absorb losses of, or the right to receive returns from, the VIE that could potentially be significant to the VIE. The identification of the primary beneficiary of a VIE may require significant assumptions and judgment. When White Mountains determines it has a variable interest in a VIE, it determines whether it is the primary beneficiary of that VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the identification of the activities that most significantly impact the VIE’s economic performance; (iv) the governance provisions and other contractual arrangements between the VIE and its variable interest holders and other parties involved with the VIE; and (v) related party relationships. At inception of its variable interest in the VIE as well as on an ongoing basis, White Mountains performs qualitative assessments of its VIEs to determine whether White Mountains is the primary beneficiary of a VIE.

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As of December 31, 2025, White Mountains owned 100.0% of WM Outrigger Re’s preferred equity. White Mountains has determined that Outrigger Re Ltd. and its segregated accounts, including WM Outrigger Re, are VIEs. White Mountains is not the primary beneficiary of Outrigger Re Ltd. or its third-party segregated accounts. White Mountains is the primary beneficiary of WM Outrigger Re, as it has both the power to direct the activities that most significantly impact WM Outrigger Re’s economic performance and the obligation to absorb losses, or the right to receive returns, that could potentially be significant to WM Outrigger Re. As a result, White Mountains consolidates WM Outrigger Re’s results in its financial statements. The assets of WM Outrigger Re can only be used to settle the liabilities of WM Outrigger Re, and there is no recourse to the Company for any creditors of WM Outrigger Re. WM Outrigger Re’s obligations under its reinsurance agreement with GAIL are subject to an aggregate limit equal to the assets in its collateral trust at any point in time. As of December 31, 2025, investments of $245.7 million were held in its collateral trust account.

BAM

BAM is the first and only mutual municipal bond insurance company in the United States. HG Global, together with its subsidiaries, funded the initial capitalization of BAM through the purchase of $503.0 million of BAM Surplus Notes and, through its reinsurance subsidiary HG Re, provides first-loss reinsurance protection of up to 15%-of-par outstanding for each policy assumed from BAM. As a mutual insurance company, BAM is owned by and operated for the benefit of its members, the municipalities whose debt issuances are insured by BAM. White Mountains has determined that BAM is a VIE.

BAM’s underwriting process was determined to be the activity that most significantly impacts BAM’s economic performance. BAM’s underwriting guidelines define the types of credits that BAM may insure. Pursuant to the original FLRT, BAM’s underwriting guidelines could only be amended with the consent of HG Re. As a result, White Mountains concluded at inception and through June 30, 2024 that it had the power to direct BAM’s activities that most significantly impacted BAM’s economic performance and it was the primary beneficiary. Accordingly, White Mountains was required to consolidate BAM’s results in its financial statements. Since BAM is owned by its members, its equity and results of operations were included in noncontrolling interests.

On July 1, 2024, HG Re and BAM amended the terms of the FLRT with respect to certain governance rights held by HG Re. Under the amended FLRT, HG Re no longer has approval rights over changes to BAM’s underwriting guidelines; however, HG Re is only required to provide reinsurance on policies that fall within the FLRT underwriting guidelines agreed upon by HG Re. In conjunction with the amendments to the FLRT, HG Global and BAM increased the interest rate on the BAM Surplus Notes to 10.0%, with a higher proportion of each payment to be applied to outstanding principal prospectively. As a result, and in combination with other governance changes at BAM, White Mountains concluded that it no longer has the power to direct BAM’s activities that most significantly impact its economic performance and is no longer BAM’s primary beneficiary. Accordingly, effective July 1, 2024, White Mountains no longer consolidates BAM.

BAM’s assets can only be used to settle BAM’s obligations, and general creditors of BAM have no recourse to the Company or HG Global. HG Re’s obligations to BAM under the FLRT are subject to an aggregate limit equal to the assets in the Collateral Trusts at any point in time. As of December 31, 2025, the Collateral Trusts held assets of $1,006.5 million.

As of December 31, 2025, White Mountains had a 55.5% limited partnership interest in Distinguished. White Mountains has determined that Distinguished is a VIE. As a limited partnership, Distinguished is a VIE because the limited partnership interests do not have substantive kick-out rights or participating rights. White Mountains is the primary beneficiary of Distinguished, as it has both the power to direct the activities that most significantly impact Distinguished’s economic performance through its control of Distinguished’s general partner and the obligation to absorb losses, or the right to receive returns, that could potentially be significant to Distinguished through its basic units owned. As a result, White Mountains consolidates Distinguished’s results in its financial statements. The assets of Distinguished can only be used to settle the liabilities of Distinguished, and there is no recourse to the Company for any creditors of Distinguished.

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Bamboo SPV

As of December 31, 2025, White Mountains had a 27.9% limited partnership interest in the Bamboo SPV. White Mountains has determined that the Bamboo SPV is a VIE but that White Mountains is not the primary beneficiary and therefore does not consolidate the Bamboo SPV. White Mountains’s ownership interest gives White Mountains the ability to exert significant influence over the significant financial and operating activities of the Bamboo SPV. Accordingly, the Bamboo SPV meets the criteria to be accounted for under the equity method. White Mountains has taken the fair value option for its investment in the Bamboo SPV. Changes in the fair value of the Bamboo SPV are recorded in net realized and unrealized investment gains (losses). As of December 31, 2025, White Mountains’s maximum exposure to loss on its limited partnership interest in the Bamboo SPV is the carrying value of $250.0 million.

As of December 31, 2025, White Mountains’s ownership interest in PassportCard/DavidShield was 53.8%. White Mountains has determined that PassportCard/DavidShield is a VIE but that White Mountains is not the primary beneficiary and therefore does not consolidate PassportCard/DavidShield. The governance structure for PassportCard/DavidShield was designed to give White Mountains and its co-investor equal power to make the decisions that most significantly impact its operations. White Mountains does not have the unilateral power to direct the operations of PassportCard/DavidShield and does not hold a controlling financial interest. White Mountains’s ownership interest gives White Mountains the ability to exert significant influence over the significant financial and operating activities of PassportCard/DavidShield. Accordingly, White Mountains’s investment in PassportCard/DavidShield meets the criteria to be accounted for under the equity method. White Mountains has taken the fair value option for its investment in PassportCard/DavidShield. Changes in the fair value of PassportCard/DavidShield are recorded in net realized and unrealized investment gains (losses). As of December 31, 2025, White Mountains’s maximum exposure to loss on its equity investment in PassportCard/DavidShield and the non-interest-bearing loan to its co-investor is the total carrying value of $180.1 million.

As of December 31, 2025, White Mountains had a 10.9% limited partnership interest in the BroadStreet SPV. White Mountains has determined that the BroadStreet SPV is a VIE but that White Mountains is not the primary beneficiary and therefore does not consolidate the BroadStreet SPV. White Mountains’s ownership interest gives White Mountains the ability to exert significant influence over the significant financial and operating activities of the BroadStreet SPV. Accordingly, the BroadStreet SPV meets the criteria to be accounted for under the equity method. White Mountains has taken the fair value option for its investment in the BroadStreet SPV, which is measured at NAV as a practical expedient. Changes in the fair value of the BroadStreet SPV are recorded in net realized and unrealized investment gains (losses). As of December 31, 2025, White Mountains’s maximum exposure to loss on its limited partnership interest in the BroadStreet SPV is the carrying value of $160.0 million.

Elementum

As of December 31, 2025, White Mountains had a 26.6% limited partnership interest in Elementum. White Mountains has determined that Elementum is a VIE but that White Mountains is not the primary beneficiary and therefore does not consolidate Elementum. White Mountains’s ownership interest gives White Mountains the ability to exert significant influence over the significant financial and operating activities of Elementum. Accordingly, Elementum meets the criteria to be accounted for under the equity method. White Mountains has taken the fair value option for its investment in Elementum. Changes in the fair value of Elementum are recorded in net realized and unrealized investment gains (losses). As of December 31, 2025, White Mountains’s maximum exposure to loss on its limited partnership interest in Elementum is the carrying value of $35.0 million.

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Bamboo CRVs

As of December 31, 2025, White Mountains owned 100.0% of each of the Bamboo CRV’s preferred equity. White Mountains has determined that the Bamboo CRVs are VIEs. White Mountains is the primary beneficiary of the Bamboo CRVs, as it has both the power to direct the activities that most significantly impact the Bamboo CRVs’ economic performance and the obligation to absorb losses, or the right to receive returns, that could potentially be significant to the Bamboo CRVs. As a result, White Mountains consolidates the Bamboo CRVs’ results in its financial statements. The assets of each of the Bamboo CRVs can only be used to settle the respective vehicle’s liabilities, and there is no recourse to the Company for any creditors of the Bamboo CRVs. As of December 31, 2025, the Bamboo CRVs’ obligations under its reinsurance agreements are subject to an aggregate limit of approximately $10.0 million.

Limited Partnerships

White Mountains’s investments in limited partnerships are generally considered VIEs because the limited partnership interests do not have substantive kick-out rights or participating rights. White Mountains does not have the unilateral power to direct the operations of these limited partnerships, and therefore White Mountains is not the primary beneficiary and does not consolidate the limited partnerships. White Mountains has taken the fair value option for its investments in limited partnerships, which are generally measured at NAV as a practical expedient. As of December 31, 2025, White Mountains’s maximum exposure to loss on its investments in limited partnerships is the carrying value of $251.2 million.

Note 17. Equity Method Eligible Investments

White Mountains’s equity method eligible investments includes those in which White Mountains has the ability to exert significant influence over the investee’s operating and financial policies. Under GAAP, equity method eligible investments are considered related parties. White Mountains has generally taken the fair value option for its equity method eligible investments.

The following table presents the ownership interests and carrying values of White Mountains’s equity method eligible investments as of December 31, 2025 and 2024:

(1)Ownership interest references basic ownership interest with the exception of Kudu’s Participation Contracts, which are generally noncontrolling equity interests in the form of revenue and earnings participation contracts.

(2) MediaAlpha’s ownership interest as of December 31, 2025 is based on the total class A and class B common shares outstanding in MediaAlpha’s Report on Form 10-Q dated October 29, 2025.

(3) Includes certain other unconsolidated entities, private equity funds and an ILS fund.

For the years ended December 31, 2025, 2024 and 2023, White Mountains received dividend and income distributions from equity method eligible investments of $81.8 million, $71.4 million and $67.0 million, which were generally recorded within net investment income in the consolidated statements of operations.

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The following tables present aggregated summarized financial information for White Mountains’s investments in equity method eligible unconsolidated entities:

(1) Financial data for White Mountains’s equity method eligible investees is generally reported on a one-quarter lag.

(1) Financial data for White Mountains’s equity method eligible investees is generally reported on a one-quarter lag.

Note 18. Fair Value of Financial Instruments

White Mountains records its financial instruments at fair value with the exception of debt obligations which are recorded as debt at face value less unamortized debt issuance costs and original issue discount. See Note 7 — “Debt.”

The following table presents the fair value and carrying value of these financial instruments as of December 31, 2025 and 2024:

The fair value estimates for White Mountains’s debt obligations have been determined based on discounted cash flow analyses and are considered to be Level 3 measurements.

For the fair value measurements associated with White Mountains’s investment securities see Note 3 — “Investment Securities.” For the fair value measurements associated with White Mountains’s derivative instruments see Note 9 — “Derivatives.”For the fair value measurements associated with the BAM Surplus Notes see Note 10 — “Municipal Bond Guarantee Reinsurance.”

Note 19. Commitments and Contingencies

Legal Contingencies

White Mountains, and the insurance industry in general, is routinely subject to claims related litigation and arbitration in the normal course of business, as well as litigation and arbitration that do not arise from, nor are directly related to, claims activity. White Mountains’s estimates of the costs of settling matters routinely encountered in claims activity are reflected in the reserves for unpaid loss and LAE. See Note 5 — “Loss and Loss Adjustment Expense Reserves.”

White Mountains considers the requirements of ASC 450 when evaluating its exposure to non-claims related litigation and arbitration. ASC 450 requires that accruals be established for litigation and arbitration if it is probable that a loss has been incurred and it can be reasonably estimated. ASC 450 also requires that litigation and arbitration be disclosed if it is probable that a loss has been incurred or if there is a reasonable possibility that a loss may have been incurred. White Mountains does not have any current non-claims related litigation that may have a material adverse effect on White Mountains’s financial condition, results of operations or cash flows.

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Note 20. Held for Sale

On December 5, 2025, White Mountains completed the Bamboo Sale Transaction. See Note 2 — “Significant Transactions”on page F-19. As a result, the Bamboo Group’s assets and liabilities have been presented as held for sale as of December 31, 2024. The following table summarizes the Bamboo Group’s assets and liabilities classified as held for sale as of December 31, 2024:

In addition, White Mountains reported assets and liabilities held for sale related to the pending sale of an Other Operating Business. As of December 31, 2025 and 2024, amounts held for sale related to this Other Operating Business included $5.0 million and $6.5 million of short-term investments, cash and other assets, as well as $3.6 million and $5.9 million of other liabilities.

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MANAGEMENT’S RESPONSIBILITY FOR FINANCIAL STATEMENTS

Management is responsible for the preparation and fair presentation of the financial statements included in this report. The financial statements have been prepared in conformity with GAAP in the United States. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

The Audit Committee of the Board, which is comprised entirely of independent, qualified directors, is responsible for the oversight of our accounting policies, financial reporting and internal control including the appointment and compensation of our independent registered public accounting firm. The Audit Committee meets periodically with management, our independent registered public accounting firm and our internal auditors to ensure they are carrying out their responsibilities. The Audit Committee is also responsible for performing an oversight role by reviewing our financial reports. Our independent registered public accounting firm and internal auditors have full and unlimited access to the Audit Committee, with or without management present, to discuss the adequacy of internal control over financial reporting and any other matters which they believe should be brought to their attention.

MANAGEMENT’S ANNUAL REPORT ON INTERNAL CONTROL OVER FINANCIAL REPORTING

Management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) under the Securities Exchange Act of 1934. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

We assessed the effectiveness of White Mountains’s internal control over financial reporting as of December 31, 2025. Our assessment did not include an assessment of the internal control over financial reporting for certain recent acquisitions. These acquisitions were Enterprise Solutions and Distinguished. The total assets and total revenues excluded from our assessment related to these acquisitions represent approximately 1% and 1%, respectively, of White Mountains’s total assets as of December 31, 2025 and approximately 4% and 2%, respectively, of White Mountains’s total revenues for the year ended December 31, 2025. In making our assessment, we used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control-Integrated Framework (2013). Based on this assessment, we have concluded that White Mountains maintained effective internal control over financial reporting as of December 31, 2025.

PricewaterhouseCoopers LLP, the Company’s independent registered public accounting firm, has audited the effectiveness of White Mountains’s internal control over financial reporting as of December 31, 2025 as stated in their report which appears on page F-81.

February 27, 2026

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