Goodwill and Other Intangible Assets
    White Mountains accounts for business combinations using the acquisition method. Under the acquisition method, White Mountains recognizes and measures the assets acquired, including other intangible assets, and liabilities assumed, including contingent consideration liabilities, at their estimated fair values as of the acquisition date. Goodwill represents the excess of the amount paid to acquire a business over the fair value of identifiable net assets at the acquisition date. The estimated acquisition date fair values, generally consisting of intangible assets and contingent consideration liabilities, may be recorded at provisional amounts in circumstances where the information necessary to complete the acquisition accounting is not available at the reporting date. Any such provisional amounts are finalized as measurement period adjustments within one year of the acquisition date.
The following table presents the economic life, acquisition date fair value, accumulated amortization and net carrying value for goodwill and other intangible assets as of December 31, 2025 and 2024:
$ in MillionsWeighted Average Economic
 Life
(in years)
December 31, 2025December 31, 2024
Acquisition Date Fair ValueAccumulated Amortization
Impairments (3)
Net Carrying ValueAcquisition Date Fair ValueAccumulated AmortizationNet Carrying Value
Goodwill:
ArkN/A$116.8 $ $ $116.8 $116.8 $— $116.8 
KuduN/A7.6   7.6 7.6 — 7.6 
Bamboo (1)
N/A    270.4 — 270.4 
Distinguished (2)
N/A396.7   396.7 — — — 
Other OperationsN/A102.1  9.1 93.0 44.4 — 44.4 
Total goodwill623.2  9.1 614.1 439.2 — 439.2 
Other intangible assets:
Ark
Underwriting capacityN/A175.7   175.7 175.7 — 175.7 
Kudu
   Trade names7.02.2 2.1  .1 2.2 1.8 .4 
Bamboo (1)
   Trade namesN/A    23.5 2.3 21.2 
   Agency relationshipsN/A    72.4 12.1 60.3 
Developed technologyN/A    4.7 1.6 3.1 
OtherN/A    .4 .4 — 
      Subtotal    101.0 16.4 84.6 
Distinguished (2)
   Trade names
10.024.3 .8  23.5 — — — 
   Agency relationships
8.0127.9 2.0  125.9 — — — 
Developed technology5.036.6 5.0  31.6 — — — 
      Subtotal
188.8 7.8  181.0    
Other Operations (2)
   Trade names11.722.4 7.7 .2 14.5 13.3 5.6 7.7 
Customer relationships8.853.3 19.4 .3 33.6 24.8 13.6 11.2 
Other11.83.1 1.9  1.2 3.1 1.6 1.5 
Subtotal78.8 29.0 .5 49.3 41.2 20.8 20.4 
Total other intangible assets445.5 38.9 .5 406.1 320.1 39.0 281.1 
Total goodwill and other intangible assets
$1,068.7 $38.9 $9.6 $1,020.2 $759.3 $39.0 $720.3 
(1) Goodwill and other intangible assets associated with Bamboo were disposed of in connection with the Bamboo Sale Transaction. See Note 2 — “Significant Transactions.”
(2) The relative fair values of goodwill and other intangible assets recognized in connection with the Distinguished Transaction and the Enterprise Solutions Transaction have not yet been finalized. See Note 2 — “Significant Transactions.”
(3) Impairment is related to an Other Operating Business.
Rollforward of Goodwill and Other Intangible Assets

The following table presents the change in goodwill and other intangible assets for the years ended December 31, 2025 and 2024:
December 31, 2025December 31, 2024
MillionsGoodwillOther Intangible AssetsTotal Goodwill and Other Intangible AssetsGoodwillOther Intangible AssetsTotal Goodwill and Other Intangible Assets
Beginning balance$439.2 $281.1 $720.3 $168.8 $201.8 $370.6 
Acquisitions of businesses (1)
690.8  690.8 270.4 101.0 371.4 
Acquisitions of intangible assets (2)
   — .3 .3 
Measurement period adjustments (3)
23.1  23.1 — — — 
Attribution of acquisition date fair value estimates
   between goodwill and other intangible assets (1)
(235.6)235.6  — — — 
Amortization (28.4)(28.4)— (22.0)(22.0)
Impairments (4)
(9.1)(.5)(9.6)— — — 
Dispositions (5)
(294.3)(81.7)(376.0)— — — 
Ending balance$614.1 $406.1 $1,020.2 $439.2 $281.1 $720.3 
(1) During 2025, amounts relate to the Distinguished Transaction and the Enterprise Solutions Transaction. The relative fair values of goodwill and other intangible assets recognized in connection with the Distinguished Transaction and the Enterprise Solutions Transaction have not yet been finalized. During 2024, amounts relate to the acquisition of Bamboo. See Note 2 — “Significant Transactions.”
(2) Relates to acquisitions within Other Operations.
(3) Measurement period adjustments relate to updated information about acquisition date fair values of assets acquired and liabilities assumed. Adjustments relate to the Distinguished Transaction and the Enterprise Solutions Transaction.
(4) Impairment is related to an Other Operating Business.
(5) Relates to the Bamboo Sale Transaction and the sale of a small, non-core ScaleCo program at Distinguished. See Note 2 — “Significant Transactions.”

During the year ended December 31, 2025, White Mountains recognized an impairment of goodwill of $9.1 million and other intangible assets of $0.5 million related to an Other Operating Business. Impairment charges are presented within general and administrative expenses on the statement of operations.
During the year ended December 31, 2024, White Mountains did not recognize any impairments to goodwill and other intangible assets.

Amortization of Other Intangible Assets

Amortization expense was $28.4 million, $22.0 million and $7.2 million for the years ended December 31, 2025, 2024 and 2023.
The following table presents a schedule of White Mountains’s future amortization expense as of December 31, 2025:
MillionsAmortization Expense
2026$35.5 
202734.1 
202833.2 
202932.8 
203029.3 
2031 and years after65.5 
Total (1)
$230.4 
(1) Excludes Ark’s indefinite-lived intangible assets of $175.7.

Historical Timeline

Fiscal YearFiled
2025Feb 27, 2026Showing above
2024Feb 28, 2025
2023Feb 26, 2024
2022Feb 27, 2023
2021Feb 28, 2022
2020Feb 26, 2021
2019Mar 2, 2020
2018Feb 27, 2019
2017Feb 28, 2018
2016Feb 27, 2017
2015Feb 29, 2016

About Goodwill & Intangibles Disclosures

Goodwill and intangible asset disclosures reveal the premium paid in acquisitions and how management assesses whether that premium retains its value. Since goodwill is no longer amortized under US GAAP, the annual impairment test is the only mechanism that adjusts carrying values downward — making the assumptions behind that test critically important for investors.

Key signals: a history of goodwill impairments suggests management consistently overpays for acquisitions. Watch the gap between reporting unit fair value and carrying amount — when fair value exceeds carrying amount by less than 10-20%, a small decline in business performance could trigger a write-down. For finite-lived intangibles, examine useful life assumptions across customer relationships, technology, and trade names; aggressive estimates inflate near-term earnings. Compare total intangibles-to-total-assets ratios against peers to assess acquisition dependency. Rising goodwill as a percentage of equity can signal balance sheet fragility.