Goodwill and Other Intangible Assets

9 Months Ended

Sep. 30, 2025

Goodwill and Intangible Assets Disclosure [Abstract]

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 September 30, 2025 and December 31, 2024:


$ in Millions	Weighted Average Economic Life (in years)	September 30, 2025						December 31, 2024
		Acquisition Date Fair Value		Accumulated Amortization		Net Carrying Value		Acquisition Date Fair Value		Accumulated Amortization		Net Carrying Value
Goodwill:
Ark	N/A	$	116.8	$	—	$	116.8	$	116.8	$	—	$	116.8
Kudu	N/A	7.6		—		7.6		7.6		—		7.6
Bamboo	N/A	270.4		—		270.4		270.4		—		270.4
Distinguished (1)	N/A	595.4		—		595.4		—		—		—
Other Operations (1)	N/A	102.1		—		102.1		44.4		—		44.4
Total goodwill		1,092.3		—		1,092.3		439.2		—		439.2
Other intangible assets:
Ark
Underwriting capacity	N/A	175.7		—		175.7		175.7		—		175.7








Kudu
Trade names	7.0	2.2		2.1		.1		2.2		1.8		.4
Bamboo
Trade names	10.0	23.5		4.1		19.4		23.5		2.3		21.2
Agency relationships	6.0	72.4		21.1		51.3		72.4		12.1		60.3
Developed technology	3.0	4.7		2.8		1.9		4.7		1.6		3.1
Other	0.3	.4		.4		—		.4		.4		—
Subtotal		101.0		28.4		72.6		101.0		16.4		84.6






Other Operations (1)
Trade names	11.8	22.4		7.1		15.3		13.3		5.6		7.7
Customer relationships	8.8	53.3		17.7		35.6		24.8		13.6		11.2


Other	11.7	3.1		1.8		1.3		3.1		1.6		1.5
Subtotal		78.8		26.6		52.2		41.2		20.8		20.4
Total other intangible assets		357.7		57.1		300.6		320.1		39.0		281.1
Total goodwill and other intangible assets		$	1,450.0	$	57.1	$	1,392.9	$	759.3	$	39.0	$	720.3

(1) The relative fair values of goodwill and other intangible assets recognized in connection with the Distinguished Transaction and the Enterprise Solutions Transaction had not yet been finalized. All amounts related to the Distinguished Transaction were reflected as goodwill as of September 30, 2025. See Note 2 — “Significant Transactions.”

Rollforward of Goodwill and Other Intangible Assets

The following tables present the change in goodwill and other intangible assets for the three and nine months ended September 30, 2025 and 2024:


	Three Months Ended September 30,
	2025						2024
Millions	Goodwill		Other Intangible Assets		Total Goodwill and Other Intangible Assets		Goodwill		Other Intangible Assets		Total Goodwill and Other Intangible Assets
Beginning balance	$	534.6	$	270.8	$	805.4	$	439.2	$	291.8	$	731.0
Acquisition of businesses (1)	595.4		—		595.4		—		—		—
Attribution of acquisition date fair value estimates between goodwill and other intangible assets (1)	(37.7)		37.6		(.1)		—		—		—


Amortization	—		(7.8)		(7.8)		—		(5.3)		(5.3)




Ending balance	$	1,092.3	$	300.6	$	1,392.9	$	439.2	$	286.5	$	725.7

(1) During the three months ended September 30, 2025, amounts relate to the Distinguished Transaction and the Enterprise Solutions Transaction. For the Distinguished Transaction, the relative fair values of goodwill and other intangible assets had not yet been finalized; accordingly, all amounts were reflected as goodwill as of September 30, 2025. See Note 2 — “Significant Transactions.”


	Nine Months Ended September 30,
	2025						2024
Millions	Goodwill		Other Intangible Assets		Total Goodwill and Other Intangible Assets		Goodwill		Other Intangible Assets		Total 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

Attribution of acquisition date fair value estimates between goodwill and other intangible assets (1)	(37.7)		37.6		(.1)		—		—		—

Amortization	—		(18.1)		(18.1)		—		(16.6)		(16.6)


Ending balance	$	1,092.3	$	300.6	$	1,392.9	$	439.2	$	286.5	$	725.7

(1) During the nine months ended September 30, 2025, amounts relate to the Distinguished Transaction and the Enterprise Solutions Transaction. For the Distinguished Transaction the relative fair values of goodwill and other intangible assets had not yet been finalized; accordingly, all amounts were reflected as goodwill as of September 30, 2025. During the nine months ended September 30, 2024, amounts relate to the acquisition of Bamboo, for which the relative fair values of goodwill and other intangible assets had not yet been finalized as of September 30, 2024. See Note 2 — “Significant Transactions.”

(2) Relates to acquisitions within Other Operations.

During the three and nine months ended September 30, 2025 and 2024, White Mountains did not recognize any impairments to goodwill and other intangible assets.