Common Shareholders’ Equity and Noncontrolling Interests (Tables)

12 Months Ended

Dec. 31, 2025

Equity [Abstract]

Schedule of noncontrolling interest

The following table presents the balance of noncontrolling interests included in White Mountains’s total equity and the related percentage of each consolidated entity’s total equity owned by noncontrolling shareholders as of December 31, 2025 and 2024:

	December 31, 2025				December 31, 2024
$ in Millions	Nonredeemable Noncontrolling Percentage (1)		Nonredeemable Noncontrolling Equity		Nonredeemable Noncontrolling Percentage (1)		Nonredeemable Noncontrolling Equity
Nonredeemable noncontrolling interests:
Ark (2)	27.9	%	$	465.2	27.9	%	$	410.4
HG Global	3.1	%	(18.4)		3.1	%	(13.4)
Kudu (3)	8.8	%	141.2		9.6	%	127.6
Bamboo	—	%	—		27.2	%	113.6
Distinguished (4)	13.1	%	73.7		—		—
Other	various		36.5		various		9.1
Total nonredeemable noncontrolling interests			$	698.2			$	647.3

(1) The noncontrolling percentage represents the basic ownership interests held by noncontrolling shareholders with the exception of HG Global, for which

the noncontrolling percentage represents the preferred share ownership held by noncontrolling shareholders.

(2) As of December 31, 2025 and 2024, Ark’s noncontrolling equity includes $58.6 and $42.9 related to management’s equity incentives.

(3) As of December 31, 2025 and 2024, Kudu’s noncontrolling equity includes $52.3 and $47.9 related to management’s equity incentives.

(4) As of December 31, 2025, Distinguished’s nonredeemable noncontrolling interests include $33.3 related to management’s equity incentives.