SCHEDULE III SUPPLEMENTARY INSURANCE INFORMATION

12 Months Ended

Dec. 31, 2022

SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]

Schedule III - Supplementary Insurance Information

WHITE MOUNTAINS INSURANCE GROUP, LTD.

SUPPLEMENTARY INSURANCE INFORMATION

	Column A	Column B		Column C		Column D		Column E		Column F		Column G		Column H		Column  I		Column J		Column K
	Millions Segment	Deferred Acquisition Costs		Future Policy Benefits, Losses, Claims and Loss Expenses		Unearned Premiums		Other Policy Claims and Benefits Payable		Premiums Earned		Net Investment Income		Benefits, Claims, Losses and Settlement Expenses		Amortization of Deferred Acquisition Costs		Other Operating Expenses		Premiums Written
Years ended:
December 31, 2022
	HG Global/BAM	$	36.0	$	—	$	298.3	$	—	$	33.3	$	21.5	$	—	$	11.2	$	.4	$	65.1
	Ark	127.2		1,296.5		623.2		—		1,043.4		16.3		536.4		238.3		78.7		1,195.2
December 31, 2021
	HG Global/BAM	33.1		—		266.3		—		26.9		17.5		—		8.3		.4		55.8
	Ark	100.8		894.7		495.9		—		637.3		2.9		314.8		111.3		64.6		859.1
December 31, 2020
	HG Global/BAM	27.8		—		237.5		—		22.8		19.5		—		7.0		.4		61.7

Schedules of the Registrant should be read in conjunction with the Consolidated Financial Statements and Notes.