v3.25.1
Goodwill and Other Intangible Assets
 3 Months Ended
Mar. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]  
Goodwill and Other Intangible Assets 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 other intangible assets and goodwill as of March 31, 2025 and December 31, 2024:
$ in MillionsWeighted Average Economic
 Life
(in years)		March 31, 2025December 31, 2024
Acquisition Date Fair ValueAccumulated AmortizationNet 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 
BambooN/A270.4 — 270.4 270.4 — 270.4 
Other OperationsN/A44.4 — 44.4 44.4 — 44.4 
Total goodwill439.2 — 439.2 439.2 — 439.2 
Other intangible assets:
Ark
Underwriting capacityN/A175.7 — 175.7 175.7 — 175.7 
Kudu
Trade names7.02.2 1.9 .3 2.2 1.8 .4 
Bamboo
Trade names10.023.5 2.9 20.6 23.5 2.3 21.2 
Agency relationships6.072.4 15.1 57.3 72.4 12.1 60.3 
Developed technology3.04.7 2.0 2.7 4.7 1.6 3.1 
Other 0.3.4 .4 — .4 .4 — 
Subtotal101.020.480.6101.0 16.4 84.6 
Other Operations
Trade names13.313.3 6.0 7.3 13.3 5.6 7.7 
Customer relationships11.024.8 14.3 10.5 24.8 13.6 11.2 
Other11.83.1 1.6 1.5 3.1 1.6 1.5 
Subtotal41.2 21.9 19.3 41.2 20.8 20.4 
Total other intangible assets320.1 44.2 275.9 320.1 39.0 281.1 
Total goodwill and other intangible assets
$759.3 $44.2 $715.1 $759.3 $39.0 $720.3 
Rollforward of Goodwill and Other Intangible Assets

The following table presents the change in goodwill and other intangible assets for the three months ended March 31, 2025 and 2024:
Three Months Ended March 31,
20252024
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)
— — — 270.4 101.0 371.4 
Acquisitions of intangible assets (2)
— — — — .3 .3 
Amortization— (5.2)(5.2)— (5.7)(5.7)
Ending balance$439.2 $275.9 $715.1 $439.2 $297.4 $736.6 
(1) Relates to the Bamboo Transaction. See Note 2 — “Significant Transactions.”
(2) Relates to acquisitions within Other Operations.
During the three months ended March 31, 2025 and 2024, White Mountains did not recognize any impairments to goodwill and other intangible assets.