The oil shock from the war in Iran has reached critical levels, and it now appears that prices over $100 per barrel are here to stay for at least the time being.With fighting potentially months away from ending, prices have risen at one of the fastest rates in recorded history as passage through the Strait of Hormuz has stranded approximately 20% of the global oil supply.Markets have reacted swiftly to the news, especially in Europe and Asia, where energy dependence is a perennial geopolitical risk. Investo ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) Bermuda 94-2708455 (State or other jurisdiction ...

Core Insights - Bishop Street Underwriters has received a strategic structured capital investment of $125 million from White Mountains Insurance Group, which will support its growth objectives in 2026 and beyond [1][5] - In its 2025 results, Bishop Street reported gross written premiums exceeding $650 million and maintained a portfolio loss ratio below 50% [2][4] - White Mountains reported gross written premiums of $268 million for its property and casualty re/insurance segment Ark/WM Outrigger, with a combined ratio of 77% for the fourth quarter of 2025 [3] Company Performance - Bishop Street's performance in 2025 included surpassing $650 million in gross written premiums and achieving industry-leading organic growth while keeping a sub-50% portfolio loss ratio [2][4] - The partnership with Kalepa, specializing in AI-powered underwriting solutions, aims to enhance support for Bishop Street's London-based managing general agents [2] Strategic Partnership - Chad Levine, CEO of Bishop Street, expressed enthusiasm about White Mountains joining as a strategic growth partner, emphasizing the momentum and commitment to backing elite underwriters [4] - White Mountains' CEO, Liam Caffrey, highlighted Bishop Street's emergence as an industry-leading MGA platform, indicating confidence in its ability to capitalize on growth opportunities [4] - The partnership is expected to leverage White Mountains' expertise in scaling successful MGAs and unlock new opportunities for Bishop Street and its operating partners [4]

Core Insights - Bishop Street Underwriters has completed a strategic structured capital investment of $125 million from White Mountains Insurance Group, marking a significant partnership aimed at accelerating growth and expanding its global footprint in 2026 [1][2]. Company Performance - In 2025, Bishop Street achieved over $650 million in gross written premium, demonstrating industry-leading organic growth and maintaining a portfolio loss ratio below 50% [2]. Strategic Partnership - The partnership with White Mountains is expected to enhance Bishop Street's capabilities, leveraging White Mountains' extensive experience in scaling Managing General Agents (MGAs) and deep knowledge of the insurance landscape [2]. - White Mountains views Bishop Street as an emerging industry leader with a strong executive team capable of capitalizing on growth opportunities in the insurance distribution sector [2]. Investment Rationale - The investment from White Mountains is seen as a long-term commitment, providing Bishop Street with the necessary resources and expertise to achieve its growth objectives in 2026 and beyond [2][5].

Exhibit 99.1 CONTACT: Rob Seelig (603) 640-2212 WHITE MOUNTAINS REPORTS FOURTH QUARTER RESULTS HAMILTON, Bermuda (February 6, 2026) - White Mountains Insurance Group, Ltd. (NYSE: WTM) reported book value per share of $2,188 as of December 31, 2025, an increase of 18% for the fourth quarter of 2025 and 25% for the year ended December 31, 2025, including dividends. Liam Caffrey, CEO, commented, "We had an excellent year, with BVPS growth of 18% in the quarter and 25% for the year. The largest contributor in b ...

Core Viewpoint - White Mountains Insurance Group, Ltd. has completed a "modified Dutch auction" tender offer, purchasing shares at a final price of $2,050.00 per share, totaling approximately $131.3 million for 64,064 shares, which represents about 2.5% of its outstanding shares as of November 19, 2025 [1][2]. Group 1 - The tender offer expired on December 19, 2025, at midnight New York City time [1]. - The company will have approximately 2,479,677 common shares outstanding after the payment for the accepted shares [2]. - Payment for the shares purchased will be made promptly following the tender offer [2]. Group 2 - Shareholders seeking additional information can contact D.F. King & Co., the information agent for the tender offer [3]. - The dealer managers for the tender offer were BofA Securities, Inc. and Barclays Capital Inc. [3]. - White Mountains is listed on the New York Stock Exchange under the symbol "WTM" and on the Bermuda Stock Exchange under "WTM-BH" [3].

Core Viewpoint - White Mountains Insurance Group, Ltd. announced the preliminary results of its modified Dutch auction tender offer to purchase up to $300 million in common shares, which expired on December 19, 2025 [1] Group 1: Tender Offer Details - A total of 67,186 shares were properly tendered at or below the purchase price of $2,050 per share, including 16,589 shares tendered by notice of guaranteed delivery [2] - The company expects to purchase all validly tendered shares for approximately $137.7 million, representing about 2.6% of White Mountains's shares outstanding as of November 19, 2025 [2] - The final number of shares to be purchased and the final purchase price will be announced after the completion of the confirmation process by the depositary [3] Group 2: Outstanding Shares and Contact Information - Following the payment for the accepted shares, the company expects to have approximately 2,476,555 common shares outstanding [4] - Shareholders seeking additional information about the tender offer can contact D.F. King & Co. or the dealer managers BofA Securities, Inc. and Barclays Capital Inc. [4]

Core Viewpoint - White Mountains Insurance Group, Ltd. has completed the sale of a controlling interest in Bamboo to affiliates of funds advised by CVC Capital Partners [1] Group 1 - The transaction marks a significant strategic move for White Mountains Insurance Group [1] - The sale involves a controlling interest, indicating a major shift in ownership and potential operational direction for Bamboo [1]

Longleaf Partners, managed by Southeastern Asset Management, released its “Small-Cap Fund” third-quarter 2025 investor letter. A copy of the letter can be downloaded here. The fund returned 2.03% in the third quarter, compared with the Russell 3000’s 8.18% and the Russell 2000’s 12.39%. For more information on the fund’s best picks in 2025, please check its top five holdings. In its third-quarter 2025 investor letter, Longleaf Partners Small-Cap Fund highlighted stocks such as White Mountains Insurance Gr ...

Core Insights - The article discusses the growing momentum around the issue of banning Congressional stock trading, highlighting that both retail investors and members of Congress are questioning the practice [1][2]. Stock Analysis - **LCI Industries (NYSE: LCII)**: This company, which manufactures components for the RV, marine, and housing industries, saw a significant stock increase of 24.2% following a trade by Congressman Tony Wied, who reported a purchase between $1 million and $5 million at an average price of $92.02. The RV industry is projected to see sales of approximately 337,000 units by the end of 2025, indicating potential growth [5][6][7]. - **LGI Homes (NASDAQ: LGIH)**: Focused on first-time homebuyers, LGI Homes' stock rose over 28% after Congressman Tim Moore purchased between $15,000 and $50,000 at an average price of $40.83. Analysts have set a consensus price target of $72.13, suggesting a potential gain of over 36% from its closing price on November 28. This aligns with signs of recovery in the housing market, although growth is limited to specific regions [8][10][11]. - **White Mountains Insurance Group (NYSE: WTM)**: This diversified insurance holding company saw its stock increase by 10.6% after Congressman Michael McCaul made two purchases between $15,000 and $50,000. The stock's performance is supported by strong earnings and a buyback plan, with the company initiating a self-tender offer to purchase up to $300 million in common shares [12][13][14].