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v3.25.4

Segment Information (Tables) | 12 Months Ended
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Dec. 31, 2025
Segment Reporting [Abstract] |
Schedule of financial information for segments | The following tables present White Mountains’s pre-tax financial results by segment for the years ended December 31, 2025, 2024 and 2023:
|  | Ark/WM Outrigger |  |  |  |  |  |  |  |  |  |  |  |
Millions |  | Ark |  | WM Outrigger Re |  | HG Global |  | Kudu |  | Bamboo (1) |  | Distinguished (2) |  | Other Operations |  | Total
Year Ended December 31, 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  | $ | 1,612.8 |  |  | $ | 84.6 |  |  | $ | 30.8 |  |  | $ | — |  |  | $ | 26.7 |  |  | $ | — |  |  | $ | 22.2 |  |  | $ | 1,777.1 |
Net investment income (3) |  | 97.4 |  |  | 9.1 |  |  | 27.1 |  |  | 78.7 |  |  | 2.6 |  |  | 1.0 |  |  | 32.1 |  |  | 248.0 |
Net realized and unrealized investment gains (losses) (3) |  | 124.6 |  |  | — |  |  | 23.2 |  |  | 103.5 |  |  | .6 |  |  | — |  |  | 80.0 |  |  | 331.9 |
Net realized and unrealized investment gains (losses) from investment in MediaAlpha |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 29.6 |  |  | 29.6 |
Interest income from BAM Surplus Notes |  | — |  |  | — |  |  | 29.8 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 29.8 |
Change in fair value of BAM Surplus Notes |  | — |  |  | — |  |  | (37.5) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (37.5) |
Commission and fee revenues |  | — |  |  | — |  |  | — |  |  | — |  |  | 211.4 |  |  | 56.7 |  |  | 16.4 |  |  | 284.5 |
Net gain on sale of the Bamboo Group |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 849.3 |  |  | 849.3 |
Other revenues |  | 15.3 |  |  | — |  |  | .2 |  |  | 1.2 |  |  | 5.0 |  |  | — |  |  | 200.6 |  |  | 222.3 |
Total revenues |  | 1,850.1 |  |  | 93.7 |  |  | 73.6 |  |  | 183.4 |  |  | 246.3 |  |  | 57.7 |  |  | 1,230.2 |  |  | 3,735.0 |
Loss and loss adjustment expenses |  | 818.8 |  |  | 25.4 |  |  | — |  |  | — |  |  | 18.0 |  |  | — |  |  | 20.0 |  |  | 882.2 |
Acquisition expenses |  | 371.1 |  |  | 23.1 |  |  | 8.0 |  |  | — |  |  | 9.7 |  |  | — |  |  | 8.3 |  |  | 420.2 |
Cost of sales |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 151.8 |  |  | 151.8 |
Broker commission expenses |  | — |  | — |  | — |  |  | — |  |  | — |  |  | 72.0 |  |  | 22.1 |  |  | — |  |  | 94.1 |
General and administrative expenses (4) (5) (6) |  | 205.0 |  |  | .1 |  |  | 3.1 |  |  | 17.9 |  |  | 96.8 |  |  | 47.0 |  |  | 236.7 |  |  | 606.6 |
Change in fair value of contingent consideration |  | 173.0 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 173.0 |
Interest expense |  | 17.1 |  |  | — |  |  | 17.4 |  |  | 25.9 |  |  | 9.7 |  |  | 5.1 |  |  | 3.2 |  |  | 78.4 |
Total expenses |  | 1,585.0 |  |  | 48.6 |  |  | 28.5 |  |  | 43.8 |  |  | 206.2 |  |  | 74.2 |  |  | 420.0 |  |  | 2,406.3 |
Pre-tax income (loss) |  | $ | 265.1 |  |  | $ | 45.1 |  |  | $ | 45.1 |  |  | $ | 139.6 |  |  | $ | 40.1 |  |  | $ | (16.5) |  |  | $ | 810.2 |  |  | $ | 1,328.7 |
(1) Bamboo’s results are from January 1, 2025 through December 5, 2025, the date of sale. (2) Distinguished’s results are from September 2, 2025, the date of acquisition, through December 31, 2025. (3) Net investment income and net realized and unrealized investment gains (losses) for both Bamboo and Distinguished are included in other revenues in the consolidated statement of operations. (4) Ark’s general and administrative expenses include $143.9 of other underwriting expenses. (5) Bamboo’s general and administrative expenses include $12.0 of amortization of other intangible assets. (6) Distinguished’s general and administrative expenses include $7.8 of amortization of other intangible assets.
|  | Ark/WM Outrigger |  | HG Global |  |  |  |  |  | Other Operations |  |
Millions |  | Ark |  | WM Outrigger Re |  | HG Global |  | BAM (1)(2) |  | Kudu |  | Bamboo |  |  | Total
Year Ended December 31, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  | $ | 1,499.8 |  |  | $ | 88.0 |  |  | $ | 28.9 |  |  | $ | 2.8 |  |  | $ | — |  |  | $ | 39.4 |  |  | $ | 32.7 |  |  | $ | 1,691.6 |
Net investment income (3) |  | 79.4 |  |  | 11.3 |  |  | 23.4 |  |  | 8.8 |  |  | 66.7 |  |  | 2.2 |  |  | 35.6 |  |  | 227.4 |
Net realized and unrealized investment gains (losses) (3) |  | 50.1 |  |  | — |  |  | (6.4) |  |  | (5.1) |  |  | 51.3 |  |  | — |  |  | 57.0 |  |  | 146.9 |
Net realized and unrealized investment gains (losses) from investment in MediaAlpha |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 38.0 |  |  | 38.0 |
Interest income (expense) from BAM Surplus Notes |  | — |  |  | — |  |  | 29.0 |  |  | (13.2) |  |  | — |  |  | — |  |  | — |  |  | 15.8 |
Change in fair value of BAM Surplus Notes |  | — |  |  | — |  |  | .5 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 0.5 |
Unrealized loss on deconsolidation of BAM |  | — |  |  | — |  |  | (114.5) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (114.5) |
Commission and fee revenues |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 134.6 |  |  | 14.8 |  |  | 149.4 |
Other revenues |  | 22.3 |  |  | — |  |  | .1 |  |  | 1.1 |  |  | .8 |  |  | 3.6 |  |  | 56.8 |  |  | 84.7 |
Total revenues |  | 1,651.6 |  | 1,651.6 |  | 99.3 |  |  | (39.0) |  |  | (5.6) |  |  | 118.8 |  |  | 179.8 |  |  | 234.9 |  |  | 2,239.8 |
Losses and loss adjustment expenses |  | 825.9 |  |  | 29.9 |  |  | — |  |  | — |  |  | — |  |  | 20.6 |  |  | 12.1 |  |  | 888.5 |
Acquisition expenses |  | 283.9 |  |  | 23.2 |  |  | 7.8 |  |  | .4 |  |  | — |  |  | 14.1 |  |  | 12.1 |  |  | 341.5 |
Cost of sales |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 29.6 |  |  | 29.6 |
Broker commission expenses |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 51.3 |  |  | — |  |  | 51.3 |
General and administrative expenses (4) (5) |  | 208.3 |  |  | .1 |  |  | 2.2 |  |  | 33.5 |  |  | 15.4 |  |  | 61.1 |  |  | 169.5 |  |  | 490.1 |
Change in fair value of contingent consideration |  | 61.3 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 61.3 |
Interest expense |  | 19.5 |  |  | — |  |  | 16.7 |  |  | — |  |  | 22.1 |  |  | — |  |  | 2.5 |  |  | 60.8 |
Total expenses |  | 1,398.9 |  |  | 53.2 |  |  | 26.7 |  |  | 33.9 |  |  | 37.5 |  |  | 147.1 |  |  | 225.8 |  |  | 1,923.1 |
Pre-tax income (loss) |  | $ | 252.7 |  |  | $ | 46.1 |  |  | $ | (65.7) |  |  | $ | (39.5) |  |  | $ | 81.3 |  |  | $ | 32.7 |  |  | $ | 9.1 |  |  | $ | 316.7 |
(1) Effective July 1, 2024, White Mountains no longer consolidates BAM. For the period from January 1, 2024 through June 30, 2024, BAM’s results of operations are presented within the HG Global segment. (2) BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS. (3) Bamboo’s net investment income and net realized and unrealized investment gains (losses) are included in other revenues in the consolidated statement of operations. (4) Ark’s general and administrative expenses include $136.1 of other underwriting expenses. (5) Bamboo’s general and administrative expenses include $16.4 of other underwriting expenses.
|  | Ark/WM Outrigger |  | HG Global |  |  |  |  |  | Other Operations |  |
Millions |  | Ark |  | WM Outrigger Re |  | HG Global |  | BAM (1) |  | Kudu |  |  |  |  | Total
Year Ended December 31, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  | $ | 1,305.4 |  |  | $ | 104.3 |  |  | $ | 26.0 |  |  | $ | 5.2 |  |  | $ | — |  |  |  |  | $ | — |  |  | $ | 1,440.9 |
Net investment income |  | 50.4 |  |  | 11.0 |  |  | 17.1 |  |  | 14.6 |  |  | 71.0 |  |  |  |  | 30.1 |  |  | 194.2 |
Net realized and unrealized investment gains (losses) |  | 85.9 |  |  | — |  |  | 13.6 |  |  | 13.0 |  |  | 106.1 |  |  |  |  | 188.5 |  |  | 407.1 |
Net realized and unrealized investment gains (losses) from investment in MediaAlpha |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  |  | 27.1 |  |  | 27.1 |
Interest income (expense) from BAM Surplus Notes |  | — |  |  | — |  |  | 26.2 |  |  | (26.2) |  |  | — |  |  |  |  | — |  |  | — |
Commission and fee revenues |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  |  | 13.2 |  |  | 13.2 |
Other revenues |  | .8 |  |  | — |  |  | — |  |  | 2.9 |  |  | — |  |  |  |  | 80.5 |  |  | 84.2 |
Total revenues |  | 1,442.5 |  |  | 115.3 |  |  | 82.9 |  |  | 9.5 |  |  | 177.1 |  |  |  |  | 339.4 |  |  | 2,166.7 |
Loss and loss adjustment expenses |  | 711.2 |  |  | 15.6 |  |  | — |  |  | — |  |  | — |  |  |  |  | — |  |  | 726.8 |
Acquisition expenses |  | 251.0 |  |  | 30.5 |  |  | 7.4 |  |  | 1.2 |  |  | — |  |  |  |  | — |  |  | 290.1 |
Cost of sales |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  |  | 40.4 |  |  | 40.4 |
General and administrative expenses (2) |  | 161.7 |  |  | .3 |  |  | 2.8 |  |  | 66.1 |  |  | 19.4 |  |  |  |  | 182.3 |  |  | 432.6 |
Change in fair value of contingent consideration |  | 48.7 |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  |  | — |  |  | 48.7 |
Interest expense |  | 21.3 |  |  | — |  |  | 16.5 |  |  | — |  |  | 21.2 |  |  |  |  | 3.7 |  |  | 62.7 |
Total expenses |  | 1,193.9 |  |  | 46.4 |  |  | 26.7 |  |  | 67.3 |  |  | 40.6 |  |  |  |  | 226.4 |  |  | 1,601.3 |
Pre-tax income (loss) |  | $ | 248.6 |  |  | $ | 68.9 |  |  | $ | 56.2 |  |  | $ | (57.8) |  |  | $ | 136.5 |  |  |  |  | $ | 113.0 |  |  | $ | 565.4 |
(1) BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS. (2) Ark’s general and administrative expenses include $113.6 of other underwriting expenses. The following tables present White Mountains’s revenues from external customers by country for the years ended December 31, 2025, 2024 and 2023:
|  | December 31, 2025
Millions |  | United States |  | United Kingdom |  | Bermuda |  | Other |  | Total
Earned insurance premiums |  | $ | 26.7 |  |  | $ | 1,045.3 |  |  | $ | 705.1 |  |  | $ | — |  |  | $ | 1,777.1 |
Commission and fee revenues |  | 268.1 |  |  | — |  |  | — |  |  | 16.4 |  |  | 284.5 |
Other revenues (1) |  | 198.7 |  |  | — |  |  | — |  |  | — |  |  | 198.7 |
Total |  | $ | 493.5 |  |  | $ | 1,045.3 |  |  | $ | 705.1 |  |  | $ | 16.4 |  |  | $ | 2,260.3 |
(1) Amounts include revenues from external customers related to Enterprise Solutions and certain Other Operating Businesses.
|  | December 31, 2024
Millions |  | United States |  | United Kingdom |  | Bermuda |  | Other |  | Total
Earned insurance premiums |  | $ | 2.8 |  |  | $ | 956.8 |  |  | $ | 732.0 |  |  | $ | — |  |  | $ | 1,691.6 |
Commission and fee revenues |  | 134.6 |  |  | — |  |  | — |  |  | 14.8 |  |  | 149.4 |
Other revenues (1) |  | 55.8 |  |  | — |  |  | — |  |  | — |  |  | 55.8 |
Total |  | $ | 193.2 |  |  | $ | 956.8 |  |  | $ | 732.0 |  |  | $ | 14.8 |  |  | $ | 1,896.8 |
(1) Amounts include revenues from external customers related to certain Other Operating Businesses.
|  | December 31, 2023
Millions |  | United States |  | United Kingdom |  | Bermuda |  | Other |  | Total
Earned insurance premiums |  | $ | 5.2 |  |  | $ | 791.7 |  |  | $ | 644.0 |  |  | $ | — |  |  | $ | 1,440.9 |
Commission and fee revenues |  | — |  |  | — |  |  | — |  |  | 13.2 |  |  | 13.2 |
Other revenues (1) |  | 69.0 |  |  | — |  |  | — |  |  | — |  |  | 69.0 |
Total |  | $ | 74.2 |  |  | $ | 791.7 |  |  | $ | 644.0 |  |  | $ | 13.2 |  |  | $ | 1,523.1 |
(1) Amounts include revenues from external customers related to certain Other Operating Businesses. The following table presents White Mountains’s balance sheet information by segment as of December 31, 2025 and 2024:
Millions Selected Balance Sheet Data |  | Ark/WM Outrigger |  | HG Global |  | Kudu |  |  |  | Distinguished |  |  |  | Other Operations |  |  |  |  |  | Total |
December 31, 2025: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total investments |  | $ | 3,926.5 |  |  | $ | 784.2 |  |  | $ | 1,313.3 |  |  |  |  | $ | 94.0 |  |  |  |  | $ | 2,205.9 |  | (1) |  |  |  |  | $ | 8,323.9 |  |
Total assets |  | $ | 6,354.1 |  |  | $ | 1,236.8 |  |  | $ | 1,402.3 |  |  |  |  | $ | 735.4 |  |  |  |  | $ | 2,577.9 |  | (2)(3) |  |  |  |  | $ | 12,306.5 |  |
Total liabilities |  | $ | 4,528.5 |  |  | $ | 499.5 |  | (2) | $ | 446.9 |  |  |  |  | $ | 307.1 |  |  |  |  | $ | 269.4 |  | (2)(3) |  |  |  |  | $ | 6,051.4 |  |
Redeemable noncontrolling interests |  | $ | — |  |  | $ | — |  |  | $ | — |  |  |  |  | $ | 131.5 |  |  |  |  | $ | — |  |  |  |  |  |  | $ | 131.5 |  |
Total White Mountains’s common shareholders’ equity |  | $ | 1,360.4 |  |  | $ | 755.7 |  | (2) | $ | 814.2 |  |  |  |  | $ | 223.1 |  |  |  |  | $ | 2,272.0 |  | (2) |  |  |  |  | $ | 5,425.4 |  |
Nonredeemable noncontrolling interests |  | $ | 465.2 |  |  | $ | (18.4) |  |  | $ | 141.2 |  |  |  |  | $ | 73.7 |  |  |  |  | $ | 36.5 |  |  |  |  |  |  | $ | 698.2 |  |
December 31, 2024: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total investments |  | $ | 3,139.7 |  |  | $ | 667.6 |  |  | $ | 1,041.9 |  |  |  |  | $ | — |  |  |  |  | $ | 1,568.4 |  | (4) |  |  |  |  | $ | 6,417.6 |  |
Total assets |  | $ | 5,299.0 |  |  | $ | 1,179.4 |  | (3) | $ | 1,108.4 |  |  |  |  | $ | — |  |  |  |  | $ | 2,338.8 |  | (2)(3) |  |  |  |  | $ | 9,925.6 |  |
Total liabilities |  | $ | 3,664.8 |  |  | $ | 464.1 |  | (2) | $ | 316.7 |  |  |  |  | $ | — |  |  |  |  | $ | 349.0 |  | (2)(3) |  |  |  |  | $ | 4,794.6 |  |
Total White Mountains’s common shareholders’ equity |  | $ | 1,223.8 |  |  | $ | 728.7 |  | (2) | $ | 664.1 |  |  |  |  | $ | — |  |  |  |  | $ | 1,867.1 |  | (2) |  |  |  |  | $ | 4,483.7 |  |
Nonredeemable noncontrolling interests |  | $ | 410.4 |  |  | $ | (13.4) |  |  | $ | 127.6 |  |  |  |  | $ | — |  |  |  |  | $ | 122.7 |  |  |  |  |  |  | $ | 647.3 |  |
(1) Amount excludes investments of $1.0 related to an Other Operating Business that were reclassified to assets held for sale. See Note 20 — “Held for Sale.” (2) HG Global preferred dividends payable to White Mountains’s subsidiaries is eliminated in White Mountains’s consolidated financial statements. For segment reporting, the HG Global preferred dividends payable to White Mountains’s subsidiaries included within the HG Global segment are eliminated against the offsetting receivable included within Other Operations and therefore added back to White Mountains’s common shareholders’ equity within the HG Global segment. As of December 31, 2025 and 2024, the HG Global preferred dividends payable to White Mountains’s subsidiaries was $527.2 and $462.1. (3) Amounts include held for sale balances. See Note 20 — “Held for Sale.” (4) Amounts exclude investments of $58.0 related to the Bamboo Group and $2.0 related to an Other Operating Business that were reclassified to assets held for sale. See Note 20 — “Held for Sale.”

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- Definition Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-25 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-22 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 30 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-30 + Details
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