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.


$ in Millions	Weighted Average Economic Life (in years)	June 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
Other Operations (1)	N/A	139.8		—		139.8		44.4		—		44.4
Total goodwill		534.6		—		534.6		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		2.0		.2		2.2		1.8		.4
Bamboo
Trade names	10.0	23.5		3.5		20.0		23.5		2.3		21.2
Agency relationships	6.0	72.4		18.1		54.3		72.4		12.1		60.3
Developed technology	3.0	4.7		2.4		2.3		4.7		1.6		3.1
Other	0.3	.4		.4		—		.4		.4		—
Subtotal		101.0		24.4		76.6		101.0		16.4		84.6
Other Operations (1)
Trade names	13.3	13.3		6.3		7.0		13.3		5.6		7.7
Customer relationships	10.9	24.8		14.9		9.9		24.8		13.6		11.2


Other	11.8	3.1		1.7		1.4		3.1		1.6		1.5
Subtotal		41.2		22.9		18.3		41.2		20.8		20.4
Total other intangible assets		320.1		49.3		270.8		320.1		39.0		281.1
Total goodwill and other intangible assets		$	854.7	$	49.3	$	805.4	$	759.3	$	39.0	$	720.3

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


	Three Months Ended June 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	$	275.9	$	715.1	$	439.2	$	297.4	$	736.6

Acquisition of businesses (1)	95.4		—		95.4		—		—		—



Amortization	—		(5.1)		(5.1)		—		(5.6)		(5.6)




Ending balance	$	534.6	$	270.8	$	805.4	$	439.2	$	291.8	$	731.0

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


	Six Months Ended June 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)	95.4		—		95.4		270.4		101.0		371.4
Acquisitions of intangible assets (2)	—		—		—		—		.3		.3



Amortization	—		(10.3)		(10.3)		—		(11.3)		(11.3)


Ending balance	$	534.6	$	270.8	$	805.4	$	439.2	$	291.8	$	731.0

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