UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549 

SCHEDULE 14A 

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.          ) 

Notice of 2026

Annual General Meeting

Of Members and

Proxy Statement

LETTER FROM THE BOARD OF DIRECTORS

FROM OUR BOARD OF DIRECTORS

Dear Fellow Shareholders:

As your Board of Directors, we oversee White Mountains’s efforts to create superior growth in intrinsic value per share over long periods of time. Your Company seeks to achieve this goal by making opportunistic and value-oriented acquisitions of businesses primarily in the insurance, financial services and related sectors, operating these businesses and, if and when attractive exit valuations become available, disposing of these businesses. Since the Company’s IPO in 1985, we have delivered annualized growth in book value per share of 13% and market value per share of 12%.

2025 was an excellent year for your Company. We finished 2025 with book value per share of $2,188, up 25% for the year. The successful sale of Bamboo in December was the biggest driver, adding roughly $320 to book value per share. Total shareholder return was 7% in 2025, compared to 18% for the S&P 500 and 10% for the S&P 500 P&C Insurance Index.

Apart from Bamboo, our operating businesses generally produced solid to very good results in 2025. Ark produced excellent results while growing premiums 16%. Kudu had a good year, producing a 13% return on equity and closing three acquisitions during the year. HG Global generated premiums of $61 million, driven by strong activity in the primary and secondary markets.

Your Company also added value through capital deployment and capital management activities. During the year, we acquired a majority stake in Distinguished Programs, an MGA and program administrator for specialty property & casualty insurance, and made a strategic investment in BroadStreet Partners, a top-10 North American insurance brokerage. In April, White Mountains Partners completed its acquisition of Enterprise Solutions, a leading provider of specialty electrical contracting services. And, over the year, we repurchased roughly $200 million of shares, inclusive of our self-tender offer, at accretive prices.

The Board takes its role in the planning of thoughtful, orderly succession seriously, and we were delighted to announce Liam Caffrey’s promotion to CEO and appointment as a fellow Director effective January 1^st. Mr. Caffrey is a proven executive who brings deep insurance experience to his new role, and we are confident that owners will prosper under his leadership. We also congratulated our outgoing CEO, Manning Rountree, on his well-deserved retirement after an impactful 21-year career at White Mountains. The Company flourished during his tenure as CEO, and he left it well-positioned for the future. We are pleased that Mr. Rountree will remain employed as a Senior Advisor through January 1, 2028.

Ongoing Dialogue with Shareholders Through Proactive Engagement

Over the last year, members of the Board and management reached out to shareholders owning 75% of White Mountains’s shares outstanding and met with all shareholders--owning 31% of shares outstanding--who accepted a meeting. In years past, feedback from these shareholder discussions has informed changes to our executive compensation program and enhanced disclosures about the skills and areas of expertise of our Board, as well as improvements to our ESG, risk management and human capital management practices. This year, these shareholder discussions focused primarily on our business performance and outlook, approach to capital management, CEO and CFO succession, board composition and refreshment, compensation philosophy and corporate governance practices. Shareholders were supportive and provided valuable feedback.

Our core principles served us well in 2025 and will continue to guide us going forward. It is a privilege to serve as your Board, and we value highly your support of White Mountains.

Sincerely,

The White Mountains Insurance Group Board of Directors

April 1, 2026

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 affiliates. Within this report, the term “White Mountains” is used to refer to one or more entities within the consolidated organization, as the context requires.

White Mountains is engaged in the business of making opportunistic and value-oriented acquisitions of businesses and assets in the insurance, financial services and related sectors, operating these businesses and assets through its subsidiaries and, if and when attractive exit valuations become available, disposing of these businesses and assets.

As of December 31, 2025, White Mountains conducted its business primarily in five areas: property and casualty insurance and reinsurance, municipal bond guarantee reinsurance, capital solutions for asset and wealth management firms, specialty insurance distribution and other operations. White Mountains’s property and casualty insurance and reinsurance business is conducted through its subsidiary 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”). White Mountains’s municipal bond guarantee reinsurance business is conducted through its subsidiary HG Global Ltd. and its reinsurance subsidiary HG Re Ltd. (“HG Re”) (collectively with HG Re, “HG Global”). White Mountains provides capital solutions for asset and wealth management firms through its subsidiary Kudu Investment Management, LLC and its subsidiaries (collectively, “Kudu”). White Mountains’s specialty insurance distribution business is conducted through its subsidiary WM Phoenix Parent, L.P. and its subsidiaries d/b/a Distinguished Programs (collectively, “Distinguished”). 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 (collectively, “Bamboo”) 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”). As of December 31, 2025, White Mountains’s reportable segments were Ark/WM Outrigger, HG Global, Kudu and Distinguished, with its remaining operating businesses, holding companies and other assets included in Other Operations.

The 2026 Annual General Meeting will be confined to a shareholder vote on the proposals set forth in this Proxy Statement and on such other matters properly brought before the meeting.

For a reconciliation of non-GAAP measures used in this Proxy Statement to their most comparable GAAP measures, see Annex A.

PROXY SUMMARY

This summary highlights information contained elsewhere in this Proxy Statement. This summary does not contain all of the information that you should consider. You should read the entire Proxy Statement carefully before voting.

This Proxy Statement and the accompanying proxy card are being sent to shareholders on or about April 16, 2026.

For more information on our business and performance highlights, please refer to page 29 of the proxy statement.

* Not standing for reelection at completion of current term, which ends as of the 2026 Annual General Meeting

Governance Highlights
The Company’s commitment to strong corporate governance, effective risk management and strong independent oversight of management by the Board is reflected in our sound governance practices and policies. Our governance highlights (assuming the election of our current slate of nominees) include:
	✓     70% independent directors (7 out of 10) ✓     Commitment to board refreshment (four new directors since 2023) ✓     Average board tenure is 4.6 years ✓     Independent Chairman ✓     30% gender and 20% racial/ethnic diversity ✓     Shareholder right to call a Special Meeting at 10% ✓     Annual board and committee self-evaluations ✓     Robust director and executive officer share ownership guidelines (5x cash retainer for directors and 10x salary for CEO and EVPs)

Reflects Board composition and refreshment statistics if director nominees are elected at the 2026 Annual General Meeting. The lack of a checkmark for a particular item does not mean that the director does not possess that qualification, skill or experience, but rather the checkmark indicates that the item is a particularly prominent qualification, skill or experience that the director brings to the Board.

For more information on our corporate governance practices, please refer to page 18 of the proxy statement.

Shareholder engagement is of great importance to our Board and management team as a means to solicit feedback and to ensure accountability and responsiveness to our shareholders. Feedback from these discussions is shared with the Board each year. Our shareholder outreach highlights include:

For more information on our commitment to ongoing shareholder engagement and details of our 2025 shareholder outreach, please refer to page 18 of the proxy statement.

Our executive compensation policies are designed with the primary goal of creating superior growth in our values per share over long periods of time.  We believe that this goal is best pursued by utilizing a pay-for-performance program that closely aligns the financial interests of management with those of the Company’s shareholders.  As many of our subsidiaries are engaged in the business of insurance, we evaluate the executive compensation programs of a group of insurance company peers in terms of structure and variability of payouts in good and poor performance scenarios.  However, unlike most of our insurance company peers, a primary responsibility of our parent company’s management is allocating capital and opportunistically finding and executing value-creating acquisitions and dispositions of operating businesses.  Over the years, transaction gains have been a large driver of success in achieving our principal objective of growing our values per share.  As a result, we believe benchmarking against the peer group could result in compensation that is not competitive for our talent pool.  When recruiting and retaining talented professionals, we compete against firms whose main business is derived from transactional activity such as private equity and investment banking firms, and our compensation practices must reflect this reality.  

The Compensation/Nominating & Governance Committee is committed to ensuring that our executive compensation programs and governance practices motivate long-term value creation, align the financial interests of management with those of our shareholders, maintain competitiveness in the market for talent, and encourage appropriate, but not excessive, risk-taking.

Chief Executive Officer¹:

¹ Does not sum to 100% due to rounding.

Other Named Executive Officers (“NEOs”):

The specifics of our compensation program begin on page 28 of the proxy statement.

White Mountains’s Board and management are committed to sustainability and corporate responsibility as stewards of our owners’ capital. With the Board’s oversight, we have identified ESG priorities that align with both our Company’s business strategy as well as industry and investor expectations, as outlined below:

For more information on our ESG practices, please refer to page 24 of the proxy statement or the ESG landing page on our Company website (www.whitemountains.com/esg/).

WHITE MOUNTAINS INSURANCE GROUP, LTD.

NOTICE OF 2026 ANNUAL GENERAL MEETING OF MEMBERS

TO BE HELD MAY 21, 2026

April 1, 2026

Notice is hereby given that the 2026 Annual General Meeting of Members of White Mountains Insurance Group, Ltd. will be held on Thursday, May 21, 2026 at 8:00 am Atlantic Time at Rosewood Bermuda Hotel, 60 Tucker’s Point Drive, Hamilton Parish, Bermuda. At this meeting, you will be asked to consider and vote upon the following proposals:

The Company’s audited financial statements for the year ended December 31, 2025, as approved by the Company’s Board of Directors, will be presented at this Annual General Meeting.

Shareholders of record of common shares on the record date, Monday, March 30, 2026, (1) who are individuals, may attend and vote at the meeting in person or by proxy or (2) that are corporations or other entities, may have their duly authorized representative attend and vote at the meeting in person or by proxy. A list of all shareholders entitled to vote at the meeting will be open for public examination during regular business hours beginning on or about April 16, 2026 at the Company’s registered office located at Clarendon House, 2 Church Street, Hamilton HM 11, Bermuda.

Shareholders are invited to complete and sign the accompanying proxy card to be returned to White Mountains Insurance Group, Ltd., Proxy Services, c/o Computershare Investor Services, P.O. Box 43101, Providence, RI 02940-5067, in the envelope provided, whether or not they expect to attend the meeting. Shareholders may also vote their shares by telephone or via the internet in accordance with the instructions on your proxy card.

WHITE MOUNTAINS INSURANCE GROUP, LTD.

PROXY STATEMENT

This Proxy Statement is being furnished in connection with the solicitation of proxies on behalf of the Company’s Board of Directors (the “Board”) for the 2026 Annual General Meeting of Members (the “2026 Annual Meeting”), to be held on Thursday, May 21, 2026 at 8:00 am Atlantic Time at Rosewood Bermuda Hotel, 60 Tucker’s Point Drive, Hamilton Parish, Bermuda.

Holders of the Company’s common shares, par value $1.00 per share, as of the close of business on Monday, March 30, 2026, the record date, are entitled to vote at the meeting. The solicitation of proxies will be made primarily by mail, and the Proxy Statement and related proxy materials will be sent to registered shareholders on or about April 16, 2026.

You can ensure that your common shares are properly voted at the meeting by completing, signing, dating and returning the enclosed proxy card in the envelope provided. Shareholders may also vote their shares by telephone or via the internet in accordance with the instructions on your proxy card. Shareholders have the right to appoint another person (who need not be a shareholder) to represent the shareholder at the meeting by completing an alternative form of proxy which can be obtained from the Corporate Secretary or by notifying the Inspectors of Election (see page 62). Every shareholder entitled to vote has the right to do so either in person or by one or more persons authorized by a written proxy executed by such shareholder and filed with the Corporate Secretary. Any proxy duly executed will continue in full force and effect unless revoked by the person executing it in writing or by the filing of a subsequent proxy.

Sending in a signed proxy will not affect your right to attend the meeting and vote. If a shareholder attends the meeting and votes in person, his or her signed proxy is considered revoked.

IMPORTANT VOTING INFORMATION

If you hold your shares through a broker, bank or other financial institution, in order for your vote to be counted on any matter other than Proposal 3 (the ratification of the appointment of PwC as the Company’s independent registered public accounting firm for 2026), you must provide specific voting instructions to your broker, bank or financial institution by completing and returning the proxy card or following the instructions provided to you to vote your shares via telephone or the internet. Voting deadlines vary by institution. Please check with your broker, bank or other financial institution for the voting cut-off date for WTM.

Your Participation in Voting the Shares You Own Is Important

Voting your shares is important to ensure that you have a say in the governance of your company. Please review the proxy materials and follow the instructions on the proxy card to vote your shares. We hope you will exercise your rights and fully participate in your Company’s future.

More Information Is Available

If you have any questions about this rule or the proxy voting process in general, please contact the broker, bank or other financial institution where you hold your shares. The U.S. Securities and Exchange Commission (“SEC”) has information available on the internet at: https://www.investor.gov/shareholder-voting with more information about your voting rights as a shareholder.

PROPOSAL 1 - ELECTION OF THE COMPANY’S DIRECTORS

THE BOARD OF DIRECTORS

The Board is divided into three classes (each a “Class”). Each Class serves a three-year term.

At the 2026 Annual General Meeting, Liam P. Caffrey, Mary C. Choksi, John K. Chu and Weston M. Hicks are nominated to be elected to Class II with a term ending in 2029. In February 2026, Mr. Yi notified the Board that he would not stand for reelection as a Class II director. Of the nominees for election at the 2026 Annual General Meeting, Ms. Choksi and Mr. Hicks were previously elected by shareholders. Mr. Chu was recommended by Mr. Caffrey, the Chief Executive Officer. Messrs. Caffrey and Chu were approved for nomination to be elected at the 2026 Annual General Meeting by the Compensation/Nominating & Governance Committee.

The Board recommends a vote FOR Proposal 1 which calls for the election of the 2026 nominees.

The director nominees, continuing members of the Board and terms of each Class are set forth below:

* Not standing for reelection at completion of current term, which ends as of the 2026 Annual General Meeting.

The Board is currently comprised of seven independent directors and three non-independent directors (including the Chief Executive Officer). If Mr. Chu and the other director nominees are elected by shareholders at the 2026 Annual General Meeting, the board will have ten directors, of which seven will be independent.

Board Composition and Refreshment

The Board is committed to regularly refresh its membership to enhance the diversity of its skills, experience and backgrounds to effectively oversee the business as the Company evolves and to promote independent thinking. 

With Mr. Yi not standing for reelection at the end of his current term, the Compensation/Nominating & Governance Committee has approved Mr. Chu for nomination to be elected at the 2026 Annual General Meeting. Mr. Chu brings over thirty years of executive, financial and insurance industry experience and is the Founder and Chief Executive Officer of Bamboo Insurance.

With respect to independence, of ten current directors, seven are independent, with 100% independence on the Audit and Compensation/Nominating & Governance committees.  The Board’s overall diverse representation is 40%, of which gender diversity is 30% and racial/ethnic diversity is 20%. If the director nominees are elected by shareholders at the 2026 Annual General Meeting, the Board will continue to have ten directors, of which seven will be independent and the Board’s overall diverse representation will be 40%, of which gender diversity will be 30% and racial/ethnic diversity will be 20%.

Reflects Board composition and refreshment statistics if director nominees are elected at the 2026 Annual General Meeting

Director Skills and Qualifications

Our Board seeks Directors with a broad range of skills, experience and backgrounds in order to ensure effective oversight of the Company’s strategies and risks. The Board believes its members must be willing and able to devote adequate time and effort to Board responsibilities. In evaluating director candidates, the Compensation/Nominating & Governance Committee evaluates attributes such as independence, integrity, expertise, breadth of experience, knowledge about the Company’s business and industry and ownership in the Company. The skills matrix below highlights our Board’s key skills and qualifications that are directly relevant to our business, strategy and operations. The Board reviews this matrix and the overall Board composition periodically in order to ensure the appropriate balance of skills, experience and backgrounds.

The lack of a checkmark for a particular item does not mean that the director does not possess that qualification, skill or experience, but rather the checkmark indicates that the item is a particularly prominent qualification, skill or experience that the director brings to the Board.

Board of Directors

Class I –Term Ending in 2028

Class II –To Be Elected to a Term Ending in 2029

Class III – Term Ending in 2027

CORPORATE GOVERNANCE

We are committed to the ethical conduct of our business. This commitment is reflected in our corporate governance and in our corporate values and culture. Our corporate governance helps us to mitigate and manage risks by providing clear lines of oversight and responsibility for management and the Board. We review and seek to improve our corporate governance regularly.

The Company’s Corporate Governance Guidelines spell out our overall approach towards corporate governance. The Company also has a Code of Business Conduct that applies to all directors, officers and employees in carrying out their responsibilities to, and on behalf of, the Company. No waivers of the Code of Business Conduct were requested of, or granted by, the Board for any director or executive officer during 2025.

The Company’s Corporate Governance Guidelines and Code of Business Conduct are available on our website, www.whitemountains.com. These documents are available in print, free of charge, to any shareholder upon request.

The Board

The primary responsibility of the Board is to oversee and review management’s performance in order to advance the long-term interests of the Company and its shareholders. The day-to-day management of the Company, including preparation of financial statements and short-term and long-term strategic planning, is the responsibility of management.

In fulfilling their responsibility, directors must exercise common sense business judgment and act in what they reasonably believe to be in the best interests of the Company. Directors keep themselves informed by discussing matters with the CEO, other key executives and our principal external advisors, such as legal counsel, outside auditors and other consultants, by reading the reports and other materials that management sends them regularly, and by participating actively in Board and committee meetings. Directors are entitled to rely on the honesty and integrity of senior management and the Company’s outside advisors and auditors. However, it is the Board’s responsibility to establish that they have a reasonable basis for such reliance by ensuring that they have a strong foundation for trusting the integrity, honesty and undivided loyalty of the senior management team upon whom they are relying and the independence and expertise of outside advisors and auditors.

Mr. Hicks, an independent director, serves as Chairman of the Board. At meetings of the Board, Mr. Hicks presides over a separate session of non-management directors without Company management present. In addition to being led by an independent Board Chair, the Board is comprised of directors who, together, are knowledgeable and experienced in the Company’s business. The Board is satisfied that the current structure provides strong oversight of the Company’s affairs.

Shareholder Engagement

Shareholder engagement is of great importance to our Board and management team as a means to solicit feedback and to ensure accountability and responsiveness to our shareholders. We recognize the value of maintaining open lines of communication with our shareholders and consider our robust annual shareholder outreach program to be an important governance tool. In these meetings, we address any trends, topics or issues that participating shareholders wish to discuss with us. As part of our shareholder engagement efforts in 2025, we reached out to shareholders owning 75% of outstanding shares and met with all shareholders who accepted a meeting, who represented 31% of outstanding shares. Our Compensation / Nominating & Governance Committee Chair personally led discussions in meetings with shareholders representing 8% of outstanding shares.

These discussions centered around our business performance and outlook, capital deployment, executive compensation practices, corporate governance and ESG. More specifically, we discussed (i) our business performance in 2025, including the sale of Bamboo and capital deployments into Distinguished Programs, BroadStreet Partners and Enterprise Solutions, (ii) our approach to capital management, including the Company’s self-tender offer, (iii) the Company’s CEO and CFO succession, (iv) board composition and the alignment of directors’ skills with our businesses, (v) our board refreshment and the diversity of skills, experience and background that enable effective oversight of our business, (vi) our executive compensation program and how our rigorous performance targets align payouts with company performance, and (vii) our ESG and cybersecurity practices.

Our shareholders expressed support for our executive compensation program and its alignment of pay with performance, our ESG practices and proxy disclosures focused on board composition, and our thoughtful approach to capital deployment and value creation through effective stewardship of capital. Our shareholders were supportive of our approach in 2025.

Investors also expressed interest in our Board’s annual evaluation process. We have provided information on the Board’s annual evaluation process in the section “Board and Committee Evaluations” on page 20.

Our Annual Investor Meeting provides another opportunity for us to engage with our shareholders. The Company will hold its 2026 Annual Investor Meeting on Friday, June 5, 2026. Please refer to the Company’s website for further details.

Director Independence

The Board has determined that a majority of the Company’s current directors are independent, as defined in Section 303A of the New York Stock Exchange (“NYSE”) Listed Company Manual. Those directors determined to be independent are Messrs. Carlson, Gelston, Hicks and Tanner and Mmes. Choksi, Dillon and Shank. For a director to be independent, the Board must determine that the director has no relationship with the Company (other than being a director or shareholder of the Company or its subsidiaries) or has only immaterial relationships with the Company. The Company does not apply categorical standards as a basis for determining director independence. Accordingly, the Board considers all relevant facts and circumstances, on a case-by-case basis, in making an independence determination.

The Board notes no current relationships (other than being directors or shareholders) with Messrs. Carlson, Gelston, Hicks and Tanner or Mmes. Choksi, Dillon and Shank. In making its independence determinations, the Board would consider any such relationship in light of NYSE standards as well as the attributes it believes should be possessed by independent-minded directors. Those attributes include the relative impact of the transactions to the director’s personal finances, the perceived degree of dependence by the director or the Company upon the relationship or transactions continuing in the future and whether the transactions were on terms that were reasonable and competitive.

Board Meetings and Committees; Annual Meeting Attendance

During 2025, the following meetings of the Board were held: four meetings of the full Board, eight meetings of the Audit Committee, five meetings of the Compensation/Nominating & Governance Committee, four meetings of the Finance Committee, and two meetings of specially formed subcommittees of the Board relating to transactions. During 2025, each director attended more than 75% of the aggregate of: (1) the total number of meetings of the Board (held during the period for which he or she has been a director); and (2) the total number of meetings held by all committees of the Board on which he or she served.

It is White Mountains’s practice that all directors are invited to, receive materials for and generally attend all Committee meetings. In addition, each Committee Chair provides regular updates to the full Board regarding Committee activities. Directors are encouraged to attend the Annual General Meeting. All of the Company’s directors were in attendance at the 2025 Annual General Meeting, which was held on May 22, 2025.

Board and Committee Evaluations

We believe that a robust Board and committee evaluation process is an essential component of good governance and board effectiveness. Our Board and committees conduct annual self-evaluations covering a wide array of topics that include, among other things: governance processes; whether the Board and the committees are maintaining the proper level of oversight; Board and committee composition and function; meeting content, structure and preparation; and management’s interaction with the Board and committees. The self-evaluation process is overseen by our Compensation/Nominating & Governance Committee to ensure a rigorous assessment of Board and committee effectiveness, priorities and composition.

Committees of the Board

Interlocks and Insider Participation

No member of the Compensation/Nominating & Governance Committee was an employee of the Registrant during the last fiscal year or has served as an officer of the Registrant.

Consideration of Director Nominees

General Criteria and Process for Selection of Director Candidates. Our Compensation/Nominating & Governance Committee regularly reviews the individual and collective skills and other attributes of Board members. In identifying and evaluating director candidates, the Compensation/Nominating & Governance Committee does not set specific criteria for directors. Under its Charter, the Committee is responsible for determining desired Board skills and evaluating attributes such as independence, integrity, expertise, breadth of business and life experience, knowledge about the Company’s business and industry and ownership interest in the Company. Directors must be willing to devote adequate time and effort to Board responsibilities. As set forth in the Company’s Corporate Governance Guidelines and its Charter, the Committee is responsible for recommending director candidates to the Board.

The Compensation/Nominating & Governance Committee has the authority to retain search firms to be used to identify director candidates. We inform any director search firm that may be retained of our preference to include highly qualified candidates who have diverse identities or backgrounds in the pool of potential candidates it presents for consideration by the Board.

Consideration of Diversity in Selection of Director Candidates. We believe that a variety of perspectives, opinions, backgrounds, business and life experiences and tenure among the members of the Board enhances the Board’s ability to perform its duties and effectively oversee the Company’s business. In the selection of director candidates, we welcome a diversity of skills, backgrounds, business and life experiences, identities and viewpoints.

Consideration of Director Candidates Nominated by Shareholders. The Company has not adopted a specific policy regarding consideration of director candidates from shareholders. Shareholders who wish to recommend candidates for consideration by the Committee may submit their nominations in writing to the Corporate Secretary at the address provided in this Proxy Statement. The Committee may consider such shareholder recommendations when it evaluates and recommends candidates to the Board for submission to shareholders at each annual general meeting. In addition, shareholders may nominate director candidates for election without consideration by the Committee by complying with the eligibility, advance notice and other provisions of our Bye-laws as described below.

Procedures for Nominating Director Candidates. Under the Company’s Bye-laws, nominations for the election of directors may be made by the Board or by any shareholder entitled to vote for the election of directors (a “Qualified Shareholder”). A Qualified Shareholder may nominate persons for election as directors only if written notice of such Qualified Shareholder’s intent to make such nomination is delivered to the Corporate Secretary not later than: (1) with respect to an election to be held at an annual general meeting, 90 days prior to the anniversary date of the immediately preceding annual general meeting or not later than 10 days after notice or public disclosure of the date of the annual general meeting is given or made available to Qualified Shareholders, whichever date is earlier, and (2) with respect to an election to be held at a special general meeting for the election of directors, the close of business on the seventh day following the date on which notice of such meeting is first given to Qualified Shareholders. Each such notice shall set forth: (a) the name and address of the Qualified Shareholder who intends to make the nomination and of the person or persons to be nominated; (b) a representation that the Qualified Shareholder is a holder of record of common shares entitled to vote at such meeting and intends to appear in person or by proxy at the meeting to nominate the person or persons specified in the notice; (c) a description of all arrangements or understandings between the Qualified Shareholder and each such candidate and any other person or persons (naming such person or persons) pursuant to which the nomination or nominations are to be made by the Qualified Shareholder; (d) such other information regarding each candidate proposed by such Qualified Shareholder as would have been required to be included in a proxy statement filed pursuant to the proxy rules of the SEC had each such candidate been nominated, or intended to be nominated, by the Board; and (e) the consent of each such candidate to serve as a director of the Company if so elected.

Shareholder Communications

Shareholders, employees and others interested in communicating directly with the Board, any of the Board’s Committees or any individual member of the Board should write to the addressee, c/o the Corporate Secretary, at the address presented under “Available Information” (which appears on page 63).

Succession Planning

One of the top responsibilities of the Board is to ensure continuity in White Mountains’s senior leadership by overseeing the development of executive talent and planning for the efficient succession of the CEO and other senior executives. Among the responsibilities of the Compensation/Nominating & Governance Committee is to review, at least annually, the CEO’s short-term and long-term succession plans for the CEO and other senior management positions and report to the Board on succession planning. During 2025, and effective January 1, 2026, the Company completed an orderly succession of its CEO and its CFO roles.

In 2025, the Board held an offsite which allocated a significant portion of its agenda to talent development and succession planning. Our goal is to develop well-rounded and experienced leaders. The Company ensures that our executives have the necessary internal or external training and mentoring they need to develop professionally. Our high potential executives are regularly challenged with additional responsibilities and positioned to interact more frequently with the Board so Directors can get to know and assess them.

Risk Oversight

The Board, directly and through its Committees, plays an active role in the oversight of the Company’s risk management. The subject of risk management is a recurring agenda item, for which the Board regularly receives reports from management on capital, investments, and operations, including the risks associated with each and the steps management is taking to manage those risks. The Board discusses with management the Company’s business strategy, risk appetite and appropriate levels of risk, as well as considerations of ESG risks, such as the impact of climate change, human capital management and cybersecurity threats.

The Board’s committees are assigned oversight responsibility for particular areas of risk. For example, the Audit Committee receives a report, at least annually, on company-wide risks which considers operational, financial, legal, compliance, cyber and reputational risks, as well as climate risks and sustainability matters. The Compensation/Nominating & Governance Committee oversees risk related to executive compensation plans and implementation, corporate governance, succession planning and corporate social responsibility. The Finance Committee oversees the risks related to managing the Company’s investment portfolio. Full Board meetings and individual committee meetings are scheduled so as not to overlap and all directors are encouraged to attend all committee meetings, allowing for every director to participate and provide guidance regarding any risk concerns.

More information about the Company’s approach to risk management, including the primary frameworks used to assess risk and our approach to business continuity and the management of cybersecurity risks, is available on the ESG landing page on our Company website (www.whitemountains.com/esg/).

Our ESG Practices

White Mountains strives to create superior growth in the Company’s intrinsic value per share over long periods of time.  In order to achieve this goal, and in order to steward our owners’ capital effectively, the Board and management are committed to sustainability and corporate social responsibility. We have made this commitment an integral part of our culture and practices.

With oversight from our Board of Directors, we focus on ESG priorities that align with both our Company’s business strategy as well as industry and investor expectations. Our key areas of focus are (i) ESG principles in the Company’s investment policy, (ii) Board oversight of ESG matters, (iii) our climate change statement, and (iv) ESG in our risk management practices. In response to feedback from shareholders, we created an ESG landing page on our Company website. Our ESG priorities are based on their relevance and applicability to our businesses and their feasibility of implementation. Our ESG practices are as follows:

“Carbon dioxide and other greenhouse gases contribute to higher temperatures, sea level rise and weather events including droughts, wildfires, convective storms and hurricanes.  We do not manufacture products that produce carbon dioxide or other greenhouse gases, nor do we otherwise meaningfully impact the environment through our operations. However, as the owner and operator of a diversified group of businesses in insurance, financial services and related sectors, we are exposed to risks that are exacerbated by climate change, in particular in our property and casualty insurance/reinsurance and municipal bond reinsurance businesses.  Accordingly, in our risk management processes, we consider the potential impact of climate change on the nature of the risks we are assuming and the pricing for such risks.

We believe that we have an important role to play as a responsible corporate citizen on climate change matters. Our corporate philanthropy reflects our commitment to the environment.”

More detailed information on the practices outlined above is available on the ESG landing page on our Company website (www.whitemountains.com/esg/).

Human Capital Management

Our strength lies in our people, and we proactively support each employee’s well-being and development. Our Board receives periodic reporting on employee satisfaction and concerns and interacts with employees across our organization. We have an inclusive, team-oriented culture in which all employees are treated with respect. Under the guidelines of our Code of Business Conduct, we are firmly committed to providing equal employment opportunities. We deeply value diversity of backgrounds, experiences and ideas, which we believe fosters more engaging discussions, stronger collaboration and better company performance. In our recruiting practices at our parent company, we seek to consider a diverse slate of highly-qualified candidates for every open position. We invest in the professional development of our workforce and are committed to the long-term development of our workforce and the cultivation of our next generation of leaders. To support the advancement of our employees at the parent company, we endeavor to strengthen their qualifications by providing access to training in financial skills, effective communication and institutional knowledge. Our parent company mentoring program encourages new relationships and additional career support opportunities, and our Educational Assistance Program funds external professional development opportunities to further enhance job-related skills.

Corporate Social Responsibility

White Mountains is committed to the communities in which we live and work. Our parent company Community Engagement Program follows the lead of our employees in supporting a wide range of causes through employee matching gift programs, local volunteering events, in-kind donations and our Giving with Impact initiative, where employee-sponsored charities pitch for transformational grants from White Mountains. In our local communities, we have supported a broad range of causes including environmental sustainability and conservation.

More detailed information on our Community Engagement Program is available on the ESG landing page on our Company website (www.whitemountains.com/esg/).

VOTING SECURITIES AND PRINCIPAL HOLDERS THEREOF

Voting Rights of Shareholders

As of March 30, 2026, there were 2,476,670 common shares outstanding. Shareholders of record of common shares shall be entitled to one vote per common share, provided that if, and so long as, the votes conferred by “Controlled” common shares (as defined below) of any person constitute ten percent (10%) or more of the votes conferred by the outstanding common shares of the Company, each outstanding common share comprised in such Controlled common shares shall confer only a fraction of a vote that would otherwise be applicable according to the following formula:

[(T divided by 10)-1] divided by C

Where: “T” is the aggregate number of votes conferred by all the outstanding common shares; and “C” is the number of votes conferred by the Controlled common shares of such person.

“Controlled” common shares in reference to any person means:

The limitations set forth above do not apply to any shareholder which is a “Byrne Entity” (as defined below) for any matter submitted to the vote of shareholders, except with respect to the election of directors. “Byrne Entity” means any foundation or trust established by John J. Byrne, Patrick Byrne, and any associate or affiliate of any of them (or any group of which any of them is a part), as defined under Section 13(d) of the United States Securities Exchange Act of 1934, as amended.

If, as a result of giving effect to the foregoing provisions or otherwise, the votes conferred by the Controlled common shares of any person would otherwise represent 10% or more of the votes conferred by all the outstanding common shares, the votes conferred by the Controlled common shares of such person shall be reduced in accordance with the foregoing provisions. Such process shall be repeated until the votes conferred by the Controlled common shares of each person represent less than 10% of the votes conferred by all common shares.

Security Ownership of Certain Beneficial Owners

To the knowledge of the Company, there was no person or entity beneficially owning more than 5% of the common shares outstanding as of March 30, 2026, except as shown below.

Security Ownership of Management

The following table sets forth, as of March 30, 2026, beneficial ownership of common shares by each director, the Named Executive Officers (as defined on page 33) and all other executive officers as a group:

EXECUTIVE COMPENSATION

FROM OUR COMPENSATION/NOMINATING & GOVERNANCE COMMITTEE

Dear Fellow Shareholders:

One of our most important responsibilities as the independent Compensation/Nominating & Governance Committee (the “CNG Committee”) is to structure our executive compensation program (i) to create strong alignment of interests with shareholders and (ii) to attract, retain and motivate talented executives who create long-term value for the Company and its shareholders.

We have a long track record of seeking feedback from our shareholders on our compensation and governance practices. In 2025, we reached out to shareholders owning 75% of White Mountains’s outstanding shares, and we met with all shareholders who accepted a meeting (representing 31% of our outstanding shares). These meetings provided valuable feedback regarding our compensation and governance practices.

Compensation Program Highlights:

CEO and CFO Transitions:

Another one of our most important responsibilities is succession planning for our CEO and other senior management positions. At least annually, the Committee reviews the CEO’s short-term and long-term succession plans for the CEO and other senior management positions and reports to the Board on succession planning. This year, the Company completed a thoughtfully planned and orderly transition with Liam Caffrey’s promotion to CEO and Michael Papamichael’s promotion to CFO. We are confident that owners will continue to prosper under our new leadership.

The CNG Committee is committed to ensuring that our executive compensation programs and governance practices continue to drive long-term value creation. We welcome your continued feedback.

Sincerely,

The White Mountains Insurance Group Compensation/Nominating & Governance Committee

Philip A. Gelston, Chair | Margaret Dillon | Suzanne F. Shank

April 1, 2026

Compensation Discussion and Analysis

Executive Summary

Business Overview and 2025 Performance Highlights

White Mountains is engaged in the business of making opportunistic and value-oriented acquisitions primarily in the insurance, financial services and related sectors, operating these businesses through our subsidiaries and, if and when attractive exit valuations become available, selling these businesses for meaningful gains. Our principal focus is to grow our various book value per share metrics because we believe, based on the trading history of our stock, that over the long term our share price growth will follow our growth in these metrics (see chart and discussion on page 37). Since our IPO in 1985, including dividends, White Mountains has delivered 13% annualized growth in book value per share and 12% annualized growth in market value per share.

We finished 2025 with book value per share of $2,188, an increase of 25% from the prior year. The successful sale of Bamboo in December was the biggest driver, adding roughly $320 to book value per share. Apart from Bamboo, the performance of our operating businesses was generally solid to very good. Ark had an excellent year, producing an 83% combined ratio while growing gross written premiums by 16%. Kudu had a good year, producing a 13% return on equity and deploying almost $200 million into three new managers. HG Global generated record premiums of $61 million, driven by strong activity in the primary and secondary markets, although book value growth was more muted. Our investment portfolio was up 9%, a good absolute return, although we trailed our benchmarks. During the year, we acquired a majority stake in Distinguished Programs, an MGA and program administrator for specialty property & casualty insurance, and made a strategic investment in BroadStreet Partners, a top-10 North American insurance brokerage. White Mountains Partners completed its acquisition of Enterprise Solutions, a leading provider of specialty electrical contracting services. And, during the year, we repurchased roughly $200 million of shares at accretive prices.

Commitment to Ongoing Shareholder Engagement

As part of our ongoing commitment to better understand the views of our shareholders with respect to our business, governance and compensation practices, we continued our investor outreach efforts in 2025. Feedback was positive and reflective of the 97% support received for the prior year say-on-pay resolution.

Over the past several years, feedback received from these discussions has helped guide refinements to our executive compensation programs and governance practices, as well as enhancements to our public disclosures. A summary of these efforts in 2025, feedback received and our history of responsiveness is included below:

Compensation Peer Group

As described in more detail below, the CNG Committee reviews the compensation structures of a peer group as part of its evaluation of the Company’s compensation practices, but not for benchmarking compensation levels. As many of our subsidiaries are engaged in the business of insurance, we evaluate the executive compensation programs of a group of insurance company peers in terms of structure and variability of payouts in good and poor performance scenarios. However, unlike most of our insurance company peers, a primary responsibility of our parent company’s management is allocating capital and opportunistically finding and executing value-creating acquisitions and dispositions of operating businesses. Over the years, transaction gains have been a large driver of success in achieving our principal objective of growing our values per share.

Given our differentiated business model relative to traditional insurance companies, we do not use the peer group to benchmark compensation. We believe that benchmarking against the insurance peer group could result in compensation that is not competitive for our talent pool. We seek to structure our compensation program to be less fixed and more variable than a traditional insurance company. When recruiting and retaining talented professionals, we compete against firms whose main business is derived from transactional activity, such as private equity and investment banking firms, and our compensation practices must reflect this reality. The CNG Committee takes account of the transactional component of our business when setting pay that is competitive and tied to rigorous performance goals. We believe our executive compensation program has driven tremendous value for shareholders, as evidenced by our long-term BVPS growth. BVPS reached $2,188 in 2025, up 25% year-over-year, and its growth over the last decade has been created in meaningful part through our transactions, as shown below.

Over the Past Decade Our Transactions Have Driven Growth in BVPS

The CNG Committee believes that our compensation structure closely aligns the financial interests of management with those of our shareholders and encourages appropriate, but not excessive, risk-taking.

The CNG Committee regularly evaluates the continuing appropriateness of our peer group. See page 36 for further details on our peer group.

Compensation Program Aligned with Company Performance

The current design of our compensation program consists of three primary elements: base salary, annual incentive bonus and long-term incentive compensation. Each element is structured with the primary goal of creating incentives for superior growth in our values per share over long periods of time. For many years, the Company’s return target has been 700 basis points over the yield on the 10-year Treasury. Absent unusual circumstances, the CNG Committee has set the target level for the annual incentive bonus and long-term incentives at this level.

Highlights of our compensation program are as follows:

Elements and Structure

We believe that the goal of creating superior growth in values per share over long periods of time is best pursued by utilizing a pay-for-performance program that closely aligns the financial interests of management with those of our shareholders while rewarding appropriate risk taking. We accomplish this by emphasizing variable long-term compensation, the value of which is tied to performance over a number of years, rather than fixed entitlements. To illustrate, 83% of our CEO’s 2025 target total direct compensation was linked to long-term incentives, while approximately 8% was made up of base salary and 8% was linked to annual cash bonus opportunity (at target).

Chief Executive Officer¹:

¹ Does not sum to 100% due to rounding.

Other NEOs:

Named Executive Officers

In this CD&A, we review the philosophy of White Mountains’s executive compensation program, the compensation process, the program’s elements and the 2025 and 2026 compensation decisions for our Named Executive Officers:

2026 CEO and CFO Transitions

Manning Rountree retired as Chief Executive Officer and a member of the White Mountains Board on December 31, 2025. Mr. Rountree remains employed as a Senior Advisor through January 1, 2028. Following a thoughtful succession planning process undertaken by our Board including Mr. Rountree, Liam Caffrey was promoted to CEO and joined the White Mountains Board, effective January 1, 2026. Prior to joining White Mountains as CFO in 2022, Mr. Caffrey spent nine years at Aon PLC, where he most recently served as CEO of the Global Affinity Business. Prior to Aon, he worked at McKinsey & Company.

To replace Mr. Caffrey, the Board promoted Michael Papamichael to the CFO role, effective January 1, 2026.

Business Overview, Significant Transactions, and Performance Highlights

White Mountains is engaged in the business of making opportunistic and value-oriented acquisitions primarily in the insurance, financial services and related sectors, operating these businesses through our subsidiaries and, if and when attractive exit valuations become available, selling these businesses for meaningful gains. Our principal focus is to grow our book value per share metrics because we believe, based on the trading history of our stock, that over the long term our share price growth will follow our growth in these metrics (see chart and discussion on page 37). Since our IPO in 1985, including dividends, White Mountains has delivered 13% annualized growth in book value per share and 12% annualized growth in market value per share.

We finished 2025 with book value per share of $2,188, an increase of 25% from the prior year. The successful sale of Bamboo was the biggest driver, adding roughly $320 to book value per share. Apart from Bamboo, the performance of our other operating businesses was generally solid to very good, and absolute investment returns were good.

In 2025, Ark had an excellent year, producing an 83% combined ratio while growing gross written premiums by 16%. Kudu had a good year, producing a 13% return on equity and deploying almost $200 million into three new managers. HG Global generated record premiums of $61 million, driven by strong activity in the primary and secondary markets, although book value growth was more muted. Our investment portfolio was up 9%, a good absolute return, although we trailed our benchmarks. During the year, we acquired a majority stake in Distinguished Programs, an MGA and program administrator for specialty property & casualty insurance, and made a strategic investment in BroadStreet Partners, a top-10 North American insurance brokerage. White Mountains Partners completed its acquisition of Enterprise Solutions, a leading provider of specialty electrical contracting services. And, during the year, we repurchased roughly $200 million of shares at accretive prices.

We believe the businesses we own today and our ability to deploy capital into further opportunistic and value-oriented acquisitions position us well for the future. The Company remains focused on creating shareholder value over the long term.

Shareholder Engagement

Engaging with our owners is central to our commitment to good governance and critical to maintaining our strong corporate governance practices. Consistent with prior years, our 2025 shareholder outreach was led by the Board and senior management and also included our CNG Committee chair, Mr. Gelston, who provided a direct line of communication between the Board and our shareholders.

Our substantive conversations with our owners covered a variety of company strategy, business performance, corporate governance and executive compensation-related topics:

Shareholder feedback was positive and reflective of the 97% support for the prior year say-on-pay resolution. The feedback received from these meetings is shared with the entire Board and helps to inform the Company’s decision-making process regarding corporate governance, executive compensation, leadership succession, ESG and disclosure-related matters.

The following are the areas of discussion and feedback most consistent in our dialogue with our shareholders:

The Company’s management and Board of Directors are committed to continuing its extensive shareholder outreach program.

Compensation Philosophy

Our executive compensation policies are designed with the primary goal of creating incentives for superior growth in our values per share over long periods of time. We believe that this goal is best pursued by utilizing a pay-for-performance program that closely aligns the financial interests of management with those of our shareholders while rewarding appropriate risk taking. We accomplish this by emphasizing variable long-term compensation, the value of which is tied to performance over a number of years, rather than fixed entitlements (such as base salary, pensions, and employee benefits). To that end, the CNG Committee has established base salaries and target annual bonuses for our executives that tend to be lower than those paid by other property and casualty insurers and reinsurers, while granting the bulk of an executive's target compensation as long-term incentive compensation. To illustrate, approximately 83% of our CEO’s 2025 target total direct compensation was linked to long-term incentives, while approximately 8% was made up of base salary and 8% was target annual cash bonus opportunity.

The following principles guide and inform the CNG Committee’s efforts to deliver a highly effective executive compensation program that drives shareholder value and fosters the attraction and motivation of key talent:

Compensation Setting Process

The CNG Committee is responsible for approving our compensation programs for executive officers, and it specifically approves all compensation for our executive officers and for any employee with target annual compensation in excess of $1.5 million. Our CEO annually presents to the CNG Committee his evaluation of our executives, their individual performance, achievements and the contributions they made to the Company's accomplishments over the past year and over the most recent long-term incentive plan cycle. In connection with this evaluation, the CEO recommends to the CNG Committee appropriate compensation amounts for these executives. The CNG Committee evaluates these recommendations and also assesses the performance, responsibilities and contributions of the CEO, considers CEO succession plans and sets the CEO compensation.

With the exception of significant promotions and new hires, compensation matters are usually addressed at the first meeting of the CNG Committee each year (typically late February), following the availability of financial results for the prior year and the current year’s financial plan. This allows us to determine the results of prior period grants and to set targets for the current year and newest long-term performance cycle. Performance cycles for long-term compensation typically run for three years beginning on January 1st of the year of grant.

Compensation Peer Group

When making new long-term incentive grants, the CNG Committee assesses the impact of different performance scenarios on potential realizable compensation. Further, in order to test our beliefs about the structure and variability of the awards we make, the CNG Committee annually reviews and considers a systematic analysis of the public compensation disclosures made by other property and casualty insurers and reinsurers that the CNG Committee uses as peers.

Importantly, our compensation peer group is not used for benchmarking purposes, but rather to analyze whether our compensation programs are appropriately structured and to ensure they are less fixed and more variable than most other insurance and reinsurance peers.

As many of our subsidiaries are insurance companies, we evaluate the executive compensation programs of a group of insurance company peers in terms of structure and variability of payouts in good and poor performance scenarios. However, unlike most of our insurance company peers, a primary responsibility of our parent company’s management is allocating capital and opportunistically finding and executing value-creating acquisitions and dispositions of operating businesses. Over the years, transaction gains have been a large driver of success in achieving our principal objective of growing our values per share.

Given our differentiated model relative to insurance company peers, we do not use the peer group to benchmark compensation. We believe that benchmarking against the peer group could result in compensation that is not competitive for our talent pool. We seek to structure our compensation program to be less fixed and more variable than our insurance peers. When recruiting and retaining talented professionals, we compete against firms whose main business is derived from transactional activity, such as private equity and investment banking firms, and our compensation practices must reflect this reality. The CNG Committee takes account of the transactional component of our business when setting pay that is competitive and tied to rigorous performance goals. We believe our executive compensation program has driven tremendous value for shareholders, as evidenced by our long-term BVPS growth. BVPS reached $2,188 in 2025, up 25% year-over-year, and has grown steadily over the last decade in meaningful part through our transactions, as shown on pages 31 and 37.

In considering its analysis of compensation structure and variability, the Company uses a peer group of insurance companies that engage in business similar to the business conducted by some of our subsidiaries. The CNG Committee regularly evaluates the continuing appropriateness of this group and did so again during 2025. The companies included in the analysis presented to the CNG Committee prior to it making compensation decisions in 2025 were unchanged from the prior year.

The CNG Committee concluded that the peer analysis supported its view that the Company’s compensation programs are more variable than most other insurance and reinsurance peers, have fewer fixed elements of compensation and perquisites and do not lead to significant rewards for poor performance. The CNG Committee believes that the compensation structures that have been developed for the Company closely align the financial interests of management with those of our shareholders and encourage appropriate, but not excessive, risk taking.

Compensation Best Practices

We maintain a number of compensation governance best practices which support our overarching compensation philosophy and are fully aligned with our compensation principles, as discussed in the following section. Our compensation practices also align with input we have received from shareholders.

Superior Track Record and the Alignment of Growth in BVPS and Market Value Per Share

From our IPO in 1985 through year-end 2025, we have delivered 13% annualized growth in book value per share and 12% annualized growth in market value per share to our shareholders. Importantly, as seen in the chart below, BVPS and market value per share have generally moved in tandem over the last 40 years, despite short-term fluctuations. This is a core factor supporting the CNG Committee’s selection of incentive plan performance metrics that relate to growth in book value per share.

Compensation for 2025

The principal elements of compensation for our executives in 2025 - base salary, annual incentive bonus and long-term incentive compensation - are discussed below.

2025 Target Annual Direct Compensation Mix

¹ Does not sum to 100% due to rounding.

As discussed above under “Compensation Philosophy”, the Company’s compensation program emphasizes variable long-term incentive compensation, rather than fixed entitlements. Accordingly, we pay our executive officers salaries that we believe to be below market. In 2025, the cap on base salaries for Named Executive Officers was unchanged at $600,000, which remains generally below market.

2. Annual Incentive Bonuses

We provide annual bonus opportunities to our executive officers, which make up a relatively small percentage of each NEO’s target total annual compensation – approximately 8% for our CEO and 14% on average for the other NEOs in 2025 – as the bulk of our executive officers’ compensation opportunity is tied to long-term incentives. Each NEO participates in the annual bonus pool applicable to the parent holding companies. For 2025, the target bonus pool was $11.7 million for 64 employees.

Under our formulaic annual bonus program, the level of payout is determined by reference to the Company’s growth in CVPS, which is defined by the CNG Committee as the average of growth in BVPS and growth in “intrinsic value per share,” which is the BVPS including franchise value adjustments to reflect the fair value of certain subsidiaries/affiliates carried at book value. In choosing this metric for the annual bonus program, the CNG Committee recognized that this is the same metric as used in a portion of the Company’s long-term incentives (albeit for a different time period). The CNG Committee considered a number of other metrics but concluded that no other metric is as pertinent to our business as CVPS. CVPS is the metric that the Board and the management team focus on because it is linked to growth in book value per share metrics, which we believe is what ultimately drives growth in our share price. The 2025 annual bonus pool could range from 0% to 200% of target, based on the harvest scale of 6%-11%-16% growth in CVPS. In setting this performance scale, the CNG Committee’s goal was to set a performance target that was reasonable, but with an appropriate degree of stretch. The 11% target was roughly equal to the Company’s return target of the yield on the 10-year Treasury plus 700 basis points.

For our executive officers, the CNG Committee maintains the discretion to decrease, but not increase, the individual annual bonus payouts after the quantitative formula has been applied. Our executive officers cannot receive more than the formulaic result.

For 2025, the NEOs had base salaries which were unchanged from 2024, and target annual bonuses of 100% of salary, which were increased from 75% of salary in 2024. The CNG Committee believes that, inclusive of the bonus target change in 2025, executive officer salary and bonus target levels remain below general market practice and continue to reflect the CNG Committee’s long-standing philosophy of linking a vast majority of executives’ compensation to long-term incentives in order to align their interests with those of our shareholders, as opposed to awarding high levels of fixed cash compensation.

Based on the Company’s performance of a 22.8% increase in CVPS in 2025, the CNG Committee awarded the NEOs bonuses of 200% of target.

3. Long-Term Incentive Compensation

Long-term equity awards generally consist of an equal mix of restricted shares and performance shares, rewarding long-term value creation and aligning executives’ interests with shareholders’ interests. Restricted shares are subject to a three-year cliff-vesting provision, rather than annual vesting, in order to promote executive retention that balances incentives to redeploy capital aggressively and to remain patient for optimal opportunities for the Company and its shareholders. The number of WTM common shares earned from a grant of performance shares can range from 0%-200% of target, based on after-tax annual growth in CVPS over the three-year performance cycle.

The CNG Committee selected performance metrics that relate to growth in book value per share because it continues to believe these metrics ultimately drive growth in our share price. The market value of our shares is not included as a direct measure of performance, but it determines the ultimate value of earned performance and restricted share awards.

From year-to-year when we make new long-term incentive grants, we typically adjust the target number of shares granted to individual employees to reflect the change in CVPS during the prior year, rather than focusing on changes in market values. This is consistent with our view that the change in book value per share and related metrics provides a better view of the change in value of the Company than metrics reflecting short-term market price fluctuations.

2025 Long-Term Incentive Grants: For the CEO and each of our other NEOs, the annual 2025 long-term incentive awards were allocated 50% as performance shares and 50% as restricted shares, consistent with prior years. With respect to the total grants made to employees across the Company, the CNG Committee granted 21,340 target shares for the 2025-2027 performance cycle, which represented an approximately 6% decrease, year-over-year, in the number of shares granted. These grants totaled approximately 0.8% of the then outstanding shares. The restricted shares are subject to a three-year cliff-vesting provision based on continuous service in order to promote the retention of key executive talent. The performance shares vest in a range of 0% - 200% of target following a three-year performance period.

For the 2025-2027 performance period, the CNG Committee established a target of 11.5% annual growth in CVPS as the performance target that would result in the payout of 100% of the target performance shares. There would be no payout for annual growth of 6% or less, and annual growth of 17% or more would be required for a payout of 200%. In setting this performance scale, the CNG Committee’s goal was to set a performance target that was reasonable, but with an appropriate degree of stretch. Importantly, the 11.5% target was roughly equal to the Company’s long-term return target of the yield on the 10-year Treasury plus 700 basis points, consistent with the Company’s practice for several years.

A detailed breakdown of the 2025 grants is included in the table below:

In determining the amount of new long-term incentive compensation grants for our NEOs for 2025, the CNG Committee assessed each executive’s scope of authority and ability to impact the success of the Company. Based on the CNG Committee’s general experience, familiarity with the Company and its compensation practices and the recommendation of the CEO (for NEOs other than himself), the CNG Committee established a grant level that it believed was appropriate to reflect each such executive’s expected contribution to the Company over the next performance cycle.

Payout of 2023-2025 Performance Cycle: For the 2023-2025 performance cycle, long-term incentives were granted to the NEOs as follows: 50% as performance shares and 50% as restricted shares. For the performance shares, which matured at the end of 2025, 11% annual growth in CVPS was the performance target for a payout of 100% of the target performance shares. Annual growth of 6% or less would have resulted in no payout, and annual growth of 16% or more would have resulted in a payout of 200%. At its meeting in February 2026, based on an average annual growth in CVPS of 15.2% during the 2023-2025 performance cycle, the CNG Committee confirmed that the payout that was earned was 184% of target.

2026 Compensation Actions

2026 Annual Target Cash Compensation: Base salaries continue to be capped at $600,000 for NEOs, with target bonus opportunities remaining unchanged at 100% of salary in 2026. Mr. Papamichael’s 2026 salary was set at $550,000 following his promotion to CFO on January 1, 2026. Mr. Rountree, who transitioned from CEO to Senior Advisor on January 1, 2026, is no longer an executive officer of the Company. The CNG Committee believes the 2026 salary and bonus target levels for executive officers remain below general market practice and continue to reflect the CNG Committee’s long-standing philosophy of linking a vast majority of executives’ compensation to long-term incentives in order to align their interests with those of our shareholders, as opposed to awarding high levels of fixed cash compensation.

For many years, the Company’s return target has been 700 basis points over the yield on the 10-year Treasury. Absent unusual circumstances, the CNG Committee has set the target level for the annual bonus plan at this level. The design of our executive officers’ 2026 annual bonus plan will be the same as the plan in effect for 2025, with payouts tied to annual growth in CVPS and a harvest scale of 6%-11%-16% for threshold / target / maximum payout levels. The CNG Committee determined that 11% annual growth in CVPS is an appropriately challenging target for the annual bonus plan and is in line with the Company’s return target.

2026 Long-term Incentive Grants: In February 2026, the CNG Committee made new long-term incentive grants to the NEOs based on the same factors described above with respect to grants made in 2025 and allocated 50% as performance shares and 50% as restricted shares. With respect to the total grants made to employees across the Company, the CNG Committee granted 19,230 target shares for the 2026-2028 performance cycle, which represents a 10% decrease, year-over-year, in the number of shares granted. These grants totaled approximately 0.8% of the then outstanding shares. 

The CNG Committee set a performance target of 11% annual growth in CVPS for the 2026-2028 performance cycle. This target level is consistent with the CNG Committee’s typical practice of setting the target in line with the Company’s return target of 700 basis points over the 10-year Treasury yield. In setting the performance scale, the CNG Committee’s goal was to set a performance target that was reasonable, but with an appropriate degree of stretch, for a payout of 100% of the target performance shares. Annual growth of 6% or less would result in no payout, and annual growth of 16% or more would result in a payout of 200%.

The CNG Committee believes this target and scale properly incentivize management to manage our businesses efficiently, without taking excessive risk.

CVPS Definition Change for Calendar Years Beginning with 2025: Following the deconsolidation of BAM and the incorporation of a fair value adjustment in BVPS for the BAM Surplus Notes, the CNG Committee determined to replace growth in ABVPS with growth in BVPS in the calculation of CVPS for both annual bonus and performance shares for calendar years beginning with 2025. For example, for the 2024-2026 performance cycle, ABVPS growth would be used in the calculation for calendar year 2024, and BVPS growth would be used for calendar years 2025 and 2026.

Share Ownership Guidelines for Executive Officers

The CNG Committee has established share ownership guidelines for our executive officers. According to the guidelines, our CEO and EVPs are required to hold Company shares with a value of 10x salary, while other executive officers are required to hold Company shares with a value of 3x salary. Shares received upon vesting must be held until the executive has met the ownership threshold. Unvested restricted shares will count toward satisfaction of the guideline, while unvested performance shares will not count. As of December 31, 2025, all NEOs were in compliance with the guidelines with the exception of Mr. Harrison who joined the Company as of June 10, 2024. Mr. Harrison is required to hold all shares upon vesting until he meets the ownership threshold.

Clawback Policy

The CNG Committee adopted a recovery policy for the Company which is applicable to performance-based compensation for the Company’s current and former executive officers and complies with NYSE rules. The policy requires the recovery of performance-based compensation in the case of an accounting restatement, without regard to fault.

The Company has also adopted a clawback policy applicable to bonuses (including non-equity incentive plan compensation) and long-term incentive awards (including time-based awards). If the Company restates any financial statement included in an SEC filing as a result of an employee’s misconduct, the Board may, without prejudice to any other remedies available to the Company, seek reimbursement of any bonus or long-term incentive award received by such person that relates in whole or in part to any period for which such financial statements were restated. If the misconduct involved fraud, then in addition to other actions, the Board will mandatorily seek such reimbursement.

Other Elements of Compensation

Retirement Benefits

We have no active U.S. defined benefit pension plans. Our employees may participate in our qualified 401(k) plans and eligible employees can participate in a qualified employee stock ownership plan. We do not provide supplemental retirement benefits to any employees in connection with these plans.

Perquisites

We review the perquisites that our senior management receives. The primary perquisite is limited personal use of corporate aircraft.

We allow our NEOs to use our corporate aircraft from time to time for personal reasons. The aggregate incremental cost to the Company is included, for proxy reporting purposes, as compensation to the NEO. For tax purposes, we comply with IRS regulations. We do not “gross-up” our NEOs for their taxes associated with perquisites, including with respect to personal use of our aircraft.

Our NEOs also participate in our benefit plans on the same terms as our other employees. These plans include medical and health insurance, company paid life insurance and charitable gift matching.

Certain Board Fees

Our NEOs do not receive director fees for serving on the Company's board of directors or for serving on the boards of our wholly-owned or majority-owned subsidiaries. However, those NEOs who serve on the boards of other companies in which we have a minority interest may receive director fees from those companies. We consider those board fees when evaluating the compensation of our NEOs.

Employment Agreements; Compensation Arrangement for Mr. Rountree

We typically do not enter into employment agreements with our NEOs. From time to time we have entered into short-term arrangements with (a) newly hired executives governing their compensation and severance for a period of up to their first three years with the Company or (b) departing executives in connection with their transition into advisory roles. On September 2, 2025, the Company announced that Mr. Rountree would retire from the Chief Executive Officer position on December 31, 2025 and become a Senior Advisor to the Company. On January 1, 2026, Mr. Rountree and White Mountains Capital (“WMC”), acting with the approval of the CNG Committee, entered into an employment agreement (the “Rountree Agreement”) relating to Mr. Rountree’s service as a Senior Advisor.

Under the Rountree Agreement, Mr. Rountree will (a) be paid a base salary at the annual rate of $300,000, (b) participate in WMC’s employee benefit plans and (c) not be granted any new equity incentives during the period of the Agreement. In addition, Mr. Rountree’s existing 3,425 performance shares and 3,425 restricted shares will remain outstanding and continue to vest in accordance with their terms, except as follows. If the Company were to terminate Mr. Rountree’s employment for Cause, or if Mr. Rountree resigns voluntarily, the Company would terminate any outstanding equity incentives without any payment. If the Company were to terminate Mr. Rountree’s employment without Cause, the Company shall (i) if such termination occurs in 2026, (v) immediately accelerate the vesting of the 2024 restricted share award (“RSA”) and the 2025 RSA, (w) settle the 2024-2026 performance share award (“PSA”) at the same time and in the same amounts as if Mr. Rountree had continued employment until the normal vesting date thereof (assuming the same level of performance achievement applied to other Company executives), (x) settle the 2025-2027 PSA prior to March 15, 2027 based on the same performance achievement through the end of the Company’s 2026 fiscal year applied to other Company executives, and (ii) if such termination occurs during 2027, (x) immediately accelerate the vesting of the 2025 RSA and (y) settle the 2025-2027 PSA at the same time and in the same amounts as if Mr. Rountree had continued employment until the normal vesting date thereof (assuming the same level of performance achievement applied to other Company executives).

The Rountree Agreement also provides that Mr. Rountree will be subject to certain restrictive covenants.

Severance Agreements; Change in Control

Severance benefits, if any, for our NEOs are determined by the CNG Committee in its sole discretion. Executive officers of our operating subsidiaries participate in the severance plans, if any, generally applicable at those companies.

If any of our most senior executives decide to retire, in order to enable the Company to ensure a smooth transition, to receive a non-compete/non-solicit from the executive and to retain access to valuable knowledge, talents and relationships, our general practice has been to enter into arrangements that would permit the executive to earn some or all of such executive’s long-term incentive compensation then outstanding.

We have no standalone change in control agreements with our NEOs. However, under our long-term incentive plans, if a change in control of the Company (or a business unit, as applicable) were to occur, certain events, such as involuntary or constructive employment termination or amendments to our incentive plans which are materially adverse to its participants, may cause restricted shares to become immediately vested and performance shares and performance units to become payable in full or in part. Our plans do not provide for tax gross-ups for excess parachute payments that may result from a change in control.

Compensation/Nominating & Governance Committee Report

The Compensation/Nominating & Governance Committee of the Company has reviewed and discussed the Compensation Discussion and Analysis required by Item 402(b) of Regulation S-K with management and, based on such review and discussions, the Compensation/Nominating & Governance Committee recommended to the Board that the Compensation Discussion and Analysis be included in this Proxy Statement.

Philip A. Gelston, Chair

Margaret Dillon

Suzanne F. Shank

Summary Compensation Table

The following table presents compensation in 2025, 2024 and 2023 for the Company’s CEO, CFO and its three other most highly compensated executive officers (collectively, the “Named Executive Officers”):

All Other Compensation

The following table presents a breakout of “All Other Compensation” included in the Summary Compensation Table for 2025, 2024 and 2023:

Grants of Plan-Based Awards

The following table presents plan-based awards granted, except as otherwise noted, under the White Mountains Long-Term Incentive Plan (the “WTM Incentive Plan”) to the Named Executive Officers that received such awards during 2025:

Outstanding Equity Awards at Fiscal Year-End

The following table presents outstanding equity awards under the WTM Incentive Plan, except as otherwise noted, to the Named Executive Officers as of December 31, 2025:

Option Exercises and Stock Vested

The following table presents stock awards that vested in 2025 for each of the Named Executive Officers. No option awards were exercised by the Named Executive Officers during 2025.