Segment Information (Tables)

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

Schedule of financial information for segments

The following tables present the financial information for White Mountains’s segments:

	HG Global/BAM				Ark/WM Outrigger
Millions	HG Global		BAM (1)		Ark		WM Outrigger Re		Kudu		Other Operations		Total
Year Ended December 31, 2023
Earned insurance premiums (2)	$	26.0	$	5.2	$	1,305.4	$	104.3	$	—	$	—	$	1,440.9
Net investment income	17.1		14.6		50.4		11.0		71.0		30.1		194.2
Net investment income (expense) - BAM    Surplus Note interest	26.2		(26.2)		—		—		—		—		—
Net realized and unrealized investment gains    (losses)	13.6		13.0		85.9		—		106.1		188.5		407.1
Net realized and unrealized investment gains    (losses) from investment in MediaAlpha	—		—		—		—		—		27.1		27.1
Commission revenues	—		—		—		—		—		13.2		13.2
Other revenues	—		2.9		.8		—		—		80.5		84.2
Total revenues	82.9		9.5		1,442.5		115.3		177.1		339.4		2,166.7
Loss and loss adjustment expenses	—		—		711.2		15.6		—		—		726.8
Acquisition expenses	7.4		1.2		251.0		30.5		—		—		290.1
Cost of sales	—		—		—		—		—		40.4		40.4
General and administrative expenses	2.8		66.1		161.7		.3		19.4		182.3		432.6
Change in fair value of contingent    consideration	—		—		48.7		—		—		—		48.7
Interest expense	16.5		—		21.3		—		21.2		3.7		62.7
Total expenses	26.7		67.3		1,193.9		46.4		40.6		226.4		1,601.3
Pre-tax income (loss)	$	56.2	$	(57.8)	$	248.6	$	68.9	$	136.5	$	113.0	$	565.4

(1) BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS.

(2) Ark’s earned insurance premiums based on the location of Ark’s underwriting offices in the United Kingdom and Bermuda are $791.7 and $513.7.

	HG Global/BAM				Ark/WM Outrigger				Other Operations
Millions	HG Global		BAM (1)		Ark		Kudu				Total
Year Ended December 31, 2022
Earned insurance premiums (2)	$	27.5	$	5.8	$	1,043.4	$	—	$	—	$	1,076.7
Net investment income	10.3		11.2		16.3		54.4		32.2		124.4
Net investment income (expense) - BAM    Surplus Note interest	11.7		(11.7)		—		—		—		—
Net realized and unrealized investment gains    (losses)	(52.5)		(53.3)		(55.2)		64.1		(1.6)		(98.5)
Net realized and unrealized investment gains    (losses) from investment in MediaAlpha	—		—		—		—		(93.0)		(93.0)
Commission revenues	—		—		—		—		11.5		11.5
Other revenues	.5		4.1		5.0		—		127.2		136.8
Total revenues	(2.5)		(43.9)		1,009.5		118.5		76.3		1,157.9
Losses and loss adjustment expenses	—		—		536.4		—		—		536.4
Acquisition expenses	9.3		1.9		239.4		—		—		250.6
Cost of sales	—		—		—		—		98.6		98.6
General and administrative expenses	2.8		66.3		106.2		14.7		174.1		364.1
Change in fair value of contingent    consideration	—		—		17.3		—		—		17.3
Interest expense	8.3		—		15.1		15.0		1.9		40.3
Total expenses	20.4		68.2		914.4		29.7		274.6		1,307.3
Pre-tax income (loss)	$	(22.9)	$	(112.1)	$	95.1	$	88.8	$	(198.3)	$	(149.4)

(1)    BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS.

(2)    Ark’s earned insurance premiums based on the location of Ark’s underwriting offices in the United Kingdom and Bermuda are $638.5 and $404.9.

	HG Global/BAM				Ark/WM Outrigger				Other Operations
Millions	HG Global		BAM (1)		Ark		Kudu				Total
Year Ended December 31, 2021
Earned insurance premiums (2)	$	22.2	$	4.7	$	637.3	$	—	$	—	$	664.2
Net investment income	7.2		10.3		2.9		43.9		18.2		82.5
Net investment income (expense) - BAM    Surplus Note interest	12.0		(12.0)		—		—		—		—
Net realized and unrealized investment    gains (losses)	(13.7)		(9.2)		16.5		89.9		50.7		134.2
Net realized and unrealized investment    gains (losses) from investment in    MediaAlpha	—		—		—		—		(380.3)		(380.3)
Commission revenues	—		—		—		—		9.6		9.6
Other revenues	.5		1.0		11.8		.2		90.7		104.2
Total revenues	28.2		(5.2)		668.5		134.0		(211.1)		614.4
Loss and loss adjustment expenses	—		—		314.8		—		—		314.8
Acquisition expenses	5.7		2.6		178.0		—		—		186.3
Cost of sales	—		—		—		—		69.3		69.3
General and administrative expenses	2.0		55.1		110.0		14.8		109.7		291.6
Change in fair value of contingent    consideration	—		—		5.5		—		—		5.5
Interest expense	—		—		7.3		11.7		1.5		20.5
Total expenses	7.7		57.7		615.6		26.5		180.5		888.0
Pre-tax income (loss)	$	20.5	$	(62.9)	$	52.9	$	107.5	$	(391.6)	$	(273.6)

(1)    BAM manages its affairs on a statutory accounting basis. BAM’s statutory surplus includes the BAM Surplus Notes and is not reduced by accruals of interest expense on the BAM Surplus Notes. BAM’s statutory surplus is reduced only after a payment of principal or interest has been approved by the NYDFS.

(2)    Ark’s earned insurance premiums based on the location of Ark’s underwriting offices in the United Kingdom and Bermuda are $459.3 and $178.0.

Millions Selected Balance Sheet Data	HG Global/BAM			Ark		Kudu		Other Operations			Total
December 31, 2023:
Total investments	$	1,082.9		$	2,671.1	$	925.6	$	1,709.1		$	6,388.7
Total assets	$	1,172.0	(1)	$	4,378.6	$	959.4	$	1,875.9	(2)	$	8,385.9
Total liabilities	$	531.7	(2)	$	2,876.1	$	275.4	$	141.1		$	3,824.3
Total White Mountains’s common    shareholders’ equity	$	779.3	(2)	$	1,165.6	$	570.2	$	1,725.4	(2)	$	4,240.5
Noncontrolling interest	$	(139.0)		$	336.9	$	113.8	$	9.4		$	321.1
December 31, 2022:
Total investments	$	975.8		$	1,965.6	$	695.9	$	1,532.7		$	5,170.0
Total assets	$	1,058.5	(1)	$	3,691.4	$	825.9	$	1,813.5	(2)	$	7,389.3
Total liabilities	$	501.8	(2)	$	2,522.1	$	273.3	$	157.1		$	3,454.3
Total White Mountains’s common    shareholders’ equity	$	712.0	(2)	$	921.4	$	477.5	$	1,636.0	(2)	$	3,746.9
Noncontrolling interest	$	(155.3)		$	247.9	$	75.1	$	20.4		$	188.1

(1) As of December 31, 2023 and 2022, total assets in the HG Global/BAM segment reflected the elimination of $322.2 and $340.0 of BAM Surplus Notes issued to HG Global and its subsidiaries and $174.5 and $157.9 in accrued interest related to the BAM Surplus Notes.

(2) HG Global preferred dividends payable to White Mountains’s subsidiaries is eliminated in White Mountains’s consolidated financial statements. For segment reporting, the HG Global preferred dividends payable to White Mountains’s subsidiaries included within the HG Global/BAM segment are eliminated against the offsetting receivable included within Other Operations and therefore added back to White Mountains’s common shareholders’ equity within the HG Global/BAM segment. As of December 31, 2023 and 2022, the HG Global preferred dividends payable to White Mountains’s subsidiaries was $399.8 and $341.4.