WHITE MOUNTAINS INSURANCE GROUP LTD

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders of White Mountains Insurance Group, Ltd.

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of White Mountains Insurance Group, Ltd. and its subsidiaries (the "Company") as of December 31, 2025 and 2024, and the related consolidated statements of operations, of comprehensive income (loss), of shareholders' equity and of cash flows for each of the three years in the period ended December 31, 2025, including the related notes and financial statement schedules listed in the index appearing before page F-1 (collectively referred to as the "consolidated financial statements"). We also have audited the Company's internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Basis for Opinions

The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Annual Report on Internal Control over Financial Reporting. Our responsibility is to express opinions on the Company’s consolidated financial statements and on the Company's internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

As described in Management’s Annual Report on Internal Control over Financial Reporting, management has excluded Enterprise Electric, LLC (“Enterprise Solutions”) and WM Phoenix Parent, L.P. and its subsidiaries (“Distinguished”) from its assessment of internal control over financial reporting as of December 31, 2025, because they were acquired by the Company in purchase business combinations during 2025. We have also excluded Enterprise Solutions and Distinguished from our audit of internal control over financial reporting. Enterprise Solutions and Distinguished are majority-owned subsidiaries whose total assets and total revenues excluded from management’s assessment and our audit of internal control over financial reporting represent approximately 1% and 1% of total assets, respectively and approximately 4% and 2% of total revenues, respectively, of the related consolidated financial statement amounts as of and for the year ended December 31, 2025.

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Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

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.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that (i) relate to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Valuation of Certain Other Long-Term Investments

As described in Notes 1 and 3 to the consolidated financial statements, as of December 31, 2025, the Company's other long-term investments consisted primarily of unconsolidated entities, and the fair values of the most significant of these investments consist of DavidShield PassportCard Ltd. and its subsidiaries (“PassportCard/DavidShield”) for $170.0 million and certain participation contracts of Kudu Investment Management, LLC and its subsidiaries (“Kudu”), representing a portion of the total of Kudu's Participation Contracts of $1,285.0 million.

Management uses a discounted cash flow analysis to determine the fair value of these other long-term investments. Key inputs to the discounted cash flow analysis generally include (i) projections of future revenues and earnings, discount rates, and terminal revenue growth rates for PassportCard/DavidShield and (ii) projections of future revenues and earnings of Kudu's investees, discount rates, and terminal cash flow exit multiples for certain of Kudu's Participation Contracts.

The principal considerations for our determination that performing procedures relating to the valuation of certain other long-term investments is a critical audit matter are (i) the significant judgment by management when developing the fair value estimates of these other long-term investments; (ii) a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management's significant assumptions related to (a) projections of future revenues and earnings, discount rates, and terminal revenue growth rates for PassportCard/DavidShield and (b) projections of future revenues and earnings of Kudu's investees, discount rates and terminal cash flow exit multiples for certain of Kudu's Participation Contracts; and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the valuation of certain other long-term investments, including controls over the Company's determination of significant assumptions. These procedures also included, among others, (i) testing the completeness and accuracy of the underlying data provided by management; (ii) evaluating the reasonableness of management's significant assumptions related to (a) projections of future revenues and earnings and terminal revenue growth rates for PassportCard/DavidShield and (b) projections of future revenues and earnings of Kudu's investees and terminal cash flow exit multiples for certain of Kudu's Participation Contracts; and (iii) the involvement of professionals with specialized skill and knowledge to assist in developing an independent fair value range for each of the aforementioned investments using independently determined assumptions related to discount rates and comparing the independent fair value range to management's estimate.

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Valuation of Loss and Loss Adjustment Expense (“LAE”) Reserves - Ark

As described in Notes 1 and 5 to the consolidated financial statements, loss and LAE reserves, including estimates for amounts incurred but not reported, 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. The Company's loss and LAE reserves as of December 31, 2025 for Ark Insurance Holdings Limited and its subsidiaries ("Ark") were $2,481.0 million. Management estimates the ultimate loss and LAE using various generally accepted actuarial methods applied to known losses and other relevant information. Ultimate loss and LAE are generally determined by extrapolation of claim emergence and settlement patterns observed in the past that can reasonably be expected to persist in the future. Management considers the Company's own experience, particularly claims development experience, such as trends in case reserves, payments on and closing of claims, as well as changes in business mix and coverage limits as the most important information for estimating its reserves. External market data is used to supplement or corroborate the Company's own experience. Ultimate loss and LAE for major losses and catastrophes are estimated based on the known and expected exposures to the loss event. Incurred but not reported reserves are adjusted as additional information becomes known or payments are made.

The principal considerations for our determination that performing procedures relating to the valuation of the loss and LAE reserves for Ark is a critical audit matter are (i) the significant judgment by management when developing the estimates of loss and LAE reserves; (ii) a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management's actuarial methods and significant assumptions related to trends in case reserves, payments on and closing of claims, and changes in business mix and coverage limits; and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the valuation of the loss and LAE reserves, including controls over management's actuarial methods and development of significant assumptions. These procedures also included, among others, (i) testing the completeness and accuracy of the underlying data provided by management and the relevance and reliability of the industry data and (ii) the involvement of professionals with specialized skill and knowledge to assist in evaluating the reasonableness of management's estimates by performing one or a combination of procedures, including (a) developing an independent estimate of the reserves for loss and LAE on a sample basis and comparing the independent estimate to management's actuarially determined reserves; (b) evaluating the appropriateness of management's actuarial methods and the reasonableness of management's significant assumptions related to trends in case reserves, payments on and closing of claims and changes in business mix and coverage limits by considering historical data, loss development patterns, industry data and other benchmarks; and (c) evaluating the consistency of management's actuarial methods period-over-period.

Valuation of Build America Mutual (“BAM”) Surplus Notes

As described in Notes 2 and 10 to the consolidated financial statements, on July 1, 2024 HG Re Ltd. (“HG Re”) and BAM amended the terms of the first loss reinsurance treaty with respect to certain governance rights held by HG Re. As a result, and in combination with other governance changes at BAM, the Company no longer consolidates BAM as of July 1, 2024. Upon deconsolidation, the Company elected the fair value option for the surplus notes issued by BAM (the "BAM Surplus Notes"). As of December 31, 2025, the estimated fair value of the BAM Surplus Notes was $339.0 million. Management estimates the fair value of the BAM Surplus Notes using a discounted cash flow analysis which 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 the 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. The discount rate considers comparably-rated companies and instruments, adjusted for risks specific to BAM and the BAM Surplus Notes.

The principal considerations for our determination that performing procedures relating to the valuation of the BAM Surplus Notes is a critical audit matter are (i) the significant judgment by management when developing the fair value estimate of the BAM Surplus Notes; (ii) a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management's significant assumptions related to projections of future revenues and earnings for BAM, expected payments on the BAM Surplus Notes through maturity and the discount rate; and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

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Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the valuation of the BAM Surplus Notes, including controls over the Company's determination of significant assumptions. These procedures also included, among others, (i) testing the completeness and accuracy of the underlying data provided by management; (ii) evaluating the reasonableness of the significant assumptions used by management related to projections of future revenues and earnings for BAM, as well as expected payments on the BAM Surplus Notes through maturity, by considering BAM's historical performance, current performance, budgets, and projected future results; and (iii) the involvement of professionals with specialized skill and knowledge to assist in developing an independent fair value range for the BAM Surplus Notes using independently determined assumptions related to the discount rate and comparing the independent fair value range to management's estimate.

/s/ PricewaterhouseCoopers LLP

Atlanta, Georgia

February 27, 2026

We have served as the Company’s auditor since 1999.

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