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Significant Transactions | 12 Months Ended
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Dec. 31, 2025
Significant Transactions [Abstract] |
Significant Transactions | Significant Transactions Bamboo Bamboo Acquisition On January 2, 2024, White Mountains acquired a controlling financial interest in Bamboo. White Mountains paid $296.7 million of cash consideration, which included $36.0 million to retire Bamboo’s legacy credit facility and a $20.0 million contribution of primary capital to Bamboo. At closing, White Mountains owned 72.8% of Bamboo on a basic shares outstanding basis (63.7% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives), while Bamboo management owned 16.1% of basic shares outstanding (26.6% on a fully-diluted/fully-converted). White Mountains recognized total assets acquired related to the Bamboo Transaction of $479.5 million, total liabilities assumed of $91.7 million and noncontrolling interests of $111.1 million reflecting acquisition date fair values. Total assets acquired included $371.4 million of goodwill and other intangible assets. See Note 4 — “Goodwill and Other Intangible Assets.” In connection with the acquisition, White Mountains incurred transaction costs of $4.0 million in Other Operations, of which $0.3 million were expensed in the first quarter of 2024. Bamboo’s segment revenue and earnings since the acquisition are presented in Note 15 — “Segment Information.” Bamboo Sale Transaction On December 5, 2025, White Mountains completed the sale of a controlling financial interest in the Bamboo Group to affiliates of funds advised by CVC Capital Partners (“CVC”), pursuant to the terms of the securities purchase agreement dated October 2, 2025 (the “Bamboo SPA”). Under the terms of the Bamboo SPA, White Mountains sold approximately 77.3% of its equity interest in the Bamboo Group for net cash proceeds at closing of $847.9 million and retained an indirect equity interest valued at $250.0 million (the “Bamboo Sale Transaction”). The proceeds are subject to customary purchase price adjustments. At closing, $3.6 million of proceeds attributable to White Mountains were held in escrow, which are expected to be released in the first half of 2026. White Mountains reported a net gain of $816.3 million, which was comprised of an $849.3 million net gain on sale of the Bamboo Group, partially offset by $33.0 million of parent compensation costs recorded within general and administrative expenses. White Mountains’s net gain on sale of the Bamboo Group includes $188.6 million attributable to its retained interest in Bamboo based on the allocation of the equity value at closing between the percentage sold and the percentage retained. White Mountains’s noncontrolling equity interest in the Bamboo SPV is accounted for at fair value in other long-term investments within Other Operations and is valued at $250.0 million as of December 31, 2025 based on the value implied by the Bamboo Sale Transaction. As of December 31, 2025, White Mountains had a 27.9% limited partnership interest in the Bamboo SPV. As of December 31, 2025, on a look-through basis, White Mountains owned 17.2% of the basic units outstanding of Bamboo (14.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives). Distinguished On September 2, 2025, White Mountains acquired a controlling financial interest in Distinguished (the “Distinguished Transaction”). White Mountains funded the Distinguished Transaction through a combination of cash on hand and new borrowings by Distinguished. White Mountains paid $224.8 million of cash consideration, including a post-closing purchase price adjustment of $0.5 million. In addition, Distinguished borrowed $50.0 million of incremental debt and utilized $6.8 million of cash on hand as part of the transaction. At closing, White Mountains owned 55.5%, inclusive of its 1.7% previously-held interest, of Distinguished on a basic units outstanding basis (43.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives). At closing, 4.2% of the basic units outstanding are owned by Distinguished management (24.7% on a fully-diluted/fully-converted basis). As part of the Distinguished Transaction, WM Phoenix GP, LLC, an indirect wholly-owned subsidiary of the Company, became the general partner of Distinguished. As the general partner, White Mountains has control over all activities of Distinguished subject to consent rights held by certain limited partners. As a result, White Mountains will continue to control Distinguished even if its economic interest falls below 50%. See Note 16 — “Variable Interest Entities.” On September 5, 2028, the third anniversary of the closing of the Distinguished Transaction, certain noncontrolling unitholders will have the option to sell additional units representing 31.4% of Distinguished’s basic units outstanding to White Mountains at the same unit price paid in the Distinguished Transaction less aggregate per unit distributions. Noncontrolling interests with optional redemption features that are not within White Mountains’s control are classified as redeemable noncontrolling interests. See Note 13 — “Common Shareholders’ Equity and Noncontrolling Interests.” In addition, White Mountains will have the parallel option to purchase such units at 1.35 times the unit price paid in the Distinguished Transaction less aggregate per unit distributions. As of December 31, 2025, the redemption value would be $131.5 million if exercised in full. White Mountains recognized total assets acquired related to the Distinguished Transaction of $743.9 million, including goodwill and other intangible assets of $618.8 million, total liabilities assumed of $249.7 million, redeemable noncontrolling interests of $133.5 million and nonredeemable noncontrolling interests of $73.8 million, reflecting provisional acquisition date fair values. In connection with the acquisition, White Mountains incurred transaction costs of $6.8 million in Other Operations. The following presents additional details of the net assets acquired as of the September 2, 2025 acquisition date:
Millions |  | As of September 2, 2025 |
Short-term investments, at fair value |  | $ | 78.1 |
Cash (restricted $0.4) |  | 1.1 |
Premiums, commissions and fees receivable |  | 34.6 |
Other assets |  | 11.3 |
Debt |  | (100.6) |
Premiums and commissions payable |  | (72.9) |
Other liabilities |  | (52.2) |
Net tangible assets acquired (liabilities assumed) |  | (100.6) |
Goodwill |  | 420.6 |
Other intangible assets |  | 198.2 |
Deferred tax liabilities related to investment basis differences |  | (24.0) |
Net assets acquired |  | $ | 494.2 |
Net tangible assets acquired and the resulting goodwill and other intangible assets were recorded at fair value using Level 3 inputs. The majority of the tangible assets acquired and liabilities assumed were recorded at their carrying values, as their carrying values approximated fair value due to their short-term nature. The fair values of other intangible assets were internally estimated based primarily on the income approach. The income approach estimates fair value based on the present value of the cash flows that the assets are expected to generate in the future. White Mountains developed internal estimates for the expected future cash flows and discount rates used in the present value calculations. See Note 4 — “Goodwill and Other Intangible Assets.” The value of the redeemable noncontrolling interests was recorded at the acquisition date fair value based on the valuation implied in the Distinguished Transaction, adjusted for the value of the embedded put and call rights. The value of the embedded put and call rights was estimated using an option pricing approach, incorporating assumptions for expected volatility, time to exercise, risk-free interest rates and other contractual terms of the instruments. The value of the nonredeemable noncontrolling interests was recorded at the acquisition date fair value based on the valuation implied in the Distinguished Transaction. Distinguished’s segment revenues and earnings since acquisition are presented in Note 15 — “Segment Information.” On November 1, 2025, Distinguished sold a small, non-core ScaleCo program for net proceeds of $33.6 million. Goodwill of $23.6 million and other intangible assets of $9.3 million were attributed to the business sold and derecognized as a result of the sale. BroadStreet On July 18, 2025, White Mountains deployed $150.0 million into BroadStreet through the BroadStreet SPV. BroadStreet is an insurance brokerage company with a presence in all 50 U.S. states and ten Canadian provinces. BroadStreet focuses on commercial and personal property & casualty insurance and employee benefits. White Mountains’s noncontrolling equity interest in the BroadStreet SPV is accounted for at fair value using NAV as a practical expedient and is included within other long-term investments. As of December 31, 2025, the fair value of White Mountains’s interest in the BroadStreet SPV was $160.0 million. As of December 31, 2025, White Mountains had a 10.9% limited partnership interest in the BroadStreet SPV and a less than 5% ownership interest in BroadStreet on a look-through basis. See Note 16 — “Variable Interest Entities.” BAM On July 1, 2024, HG Re and BAM amended the terms of the FLRT with respect to certain governance rights held by HG Re. As a result, and in combination with other governance changes at BAM, White Mountains concluded that it no longer has the power to direct BAM’s activities that most significantly impact its economic performance and is no longer BAM’s primary beneficiary. Accordingly, effective July 1, 2024, White Mountains no longer consolidates BAM. See Note 16 — “Variable Interest Entities.” Through June 30, 2024, BAM’s results of operations were presented within the HG Global segment. Upon deconsolidation, the BAM Surplus Notes met the criteria to be accounted for under the fair value option, which White Mountains elected. Accordingly, the BAM Surplus Notes, including accrued interest receivable, were carried at a fair value of $387.4 million as of July 1, 2024 resulting in an unrealized loss on deconsolidation of $114.5 million. See Note 10 — “Municipal Bond Guarantee Reinsurance” for the valuation techniques and inputs utilized to determine the fair value of the BAM Surplus Notes. WM Outrigger Re During the fourth quarter of 2022, Ark sponsored the formation of Outrigger Re Ltd., a Bermuda company registered as a special purpose insurer and segregated accounts company, to provide reinsurance capacity to Ark. Outrigger Re Ltd. was initially capitalized with $250.0 million of preference shares for business written in the 2023 underwriting year, of which White Mountains contributed $205.0 million. The remaining capital was provided by third-party investors. Outrigger Re Ltd. entered into collateralized quota share agreements with GAIL to provide reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. The proceeds from the issuance of the preference shares were deposited into collateral trust accounts to fund any potential obligations under the reinsurance agreements with GAIL. Outrigger Re Ltd.’s obligations under the reinsurance agreements with GAIL are subject to an aggregate limit equal to the assets in the collateral trusts at any point in time. The terms of the reinsurance agreements are renewable upon the mutual agreement of Ark and the applicable preference shareholder of Outrigger Re Ltd. White Mountains owns 100% of the preference shares linked to its segregated account, WM Outrigger Re. White Mountains consolidates WM Outrigger Re’s results in its financial statements. WM Outrigger Re’s quota share reinsurance agreement with GAIL eliminates in White Mountains’s consolidated financial statements. See Note 16 — “Variable Interest Entities.” During the fourth quarter of 2023, Ark renewed Outrigger Re Ltd. for the 2024 underwriting year with $250.0 million of capital. White Mountains rolled over $130.0 million from its commitment to the 2023 underwriting year. The remaining capital was provided by third-party investors. During the fourth quarter of 2024, Ark renewed Outrigger Re Ltd. for the 2025 underwriting year with $230.0 million of capital. White Mountains’s total commitment was $150.0 million, of which $130.0 million was rolled over from its commitment to the 2024 underwriting year. The remaining capital was provided by third-party investors. The reduced capacity at Outrigger Re Ltd. was replaced by Ark through traditional quota share reinsurance agreements. During the year ended December 31, 2024, White Mountains received net distributions of $122.7 million from WM Outrigger Re, which included a net return of capital related to changes in White Mountains’s capital commitments for the 2024 and 2025 underwriting years and reinsurance profits for the 2023 underwriting year. During the year ended December 31, 2024, WM Outrigger Re commuted its reinsurance agreement with GAIL for the 2023 underwriting year. During the fourth quarter of 2025, Ark renewed Outrigger Re Ltd. for the 2026 underwriting year with $70.0 million of capital. The reduced capacity at Outrigger Re Ltd. was replaced by Ark through traditional quota share reinsurance agreements. The capital was provided entirely by third-party investors excluding White Mountains. During the year ended December 31, 2025, White Mountains received net distributions of $9.5 million from WM Outrigger Re, related primarily to reinsurance profits for the 2024 underwriting year. In January 2026, White Mountains received a distribution of $127.7 million, which included a net return of capital related to its non-renewal for the 2026 underwriting year. As of December 31, 2025 and 2024, investments of $245.7 million and $203.7 million were held in a collateral trust account required to be maintained in relation to WM Outrigger Re’s reinsurance agreement with GAIL. Enterprise Solutions On April 1, 2025, White Mountains acquired a controlling financial interest in Enterprise Solutions (the “Enterprise Solutions Transaction”). Enterprise Solutions provides specialty electrical contracting services to commercial and institutional customers. White Mountains funded the Enterprise Solutions Transaction through a combination of cash on hand and new borrowings by Enterprise Solutions. White Mountains paid $58.3 million of cash consideration, which included a post-acquisition contribution of $1.5 million, and Enterprise Solutions borrowed $15.0 million in new debt as part of the transaction. At closing, White Mountains owned 65.5% of Enterprise Solutions on a basic units outstanding basis (59.0% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives). This is the first acquisition by WTM Partners. White Mountains recognized total assets acquired related to Enterprise Solutions of $176.4 million, total liabilities assumed of $74.4 million and noncontrolling interests of $30.6 million, reflecting provisional acquisition date fair values. Total assets acquired included $57.7 million of goodwill and $37.6 million of other intangible assets, reflecting provisional acquisition date fair values. In connection with the acquisition, White Mountains incurred transaction costs of $3.0 million in Other Operations. Unaudited Supplemental Pro Forma Information White Mountains’s unaudited pro forma revenues were $3,891.4 million and $2,558.8 million for the years ended December 31, 2025 and 2024, which include revenues from Distinguished and Enterprise Solutions as if the acquisitions had occurred on January 1, 2024. The pro forma revenues are presented for comparative purposes only and are not necessarily indicative of the operating results that White Mountains would have recognized had the acquisitions actually been completed on January 1, 2024. The pro forma revenues have been calculated after applying White Mountains’s accounting policies and do not include any material, nonrecurring pro forma adjustments. Impacts to White Mountains’s unaudited pro forma earnings were not material to the amounts previously reported.

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- Definition Description of various transactions that are significant to White Mountains financial position, results of operations and/or cash flows. + References No definition available. + Details
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