Debt (Tables)

12 Months Ended

Dec. 31, 2025

Debt Disclosure [Abstract]

Schedule of debt outstanding

The following table presents White Mountains’s debt outstanding as of December 31, 2025 and 2024:

			Effective			Effective
$ in Millions	December 31, 2025		Rate (1)	December 31, 2024		Rate (1)
Ark 2021 Subordinated Notes Tranche 1	$	45.8		$	41.1
Ark 2021 Subordinated Notes Tranche 2	47.0			47.0
Ark 2021 Subordinated Notes Tranche 3	70.0			70.0
Unamortized issuance cost	(3.1)			(3.6)
Ark 2021 Subordinated Notes, carrying value	159.7		10.2%	154.5		11.8%
HG Global Senior Notes	150.0			150.0
Unamortized discount and issuance cost	(2.2)			(2.6)
HG Global Senior Notes, carrying value	147.8		10.8%	147.4		11.8%
Kudu Credit Facility	358.3			245.3
Unamortized issuance cost	(7.9)			(6.7)
Kudu Credit Facility, carrying value	350.4		8.9%	238.6		10.3%
Distinguished Credit Facility	131.4			—
Unamortized issuance cost	(1.5)			—
Distinguished Credit Facility, carrying value	129.9		10.3%	—		N/A
Distinguished other debt, carrying value	10.9		10.9%	—		N/A
Total Distinguished debt	140.8			—
Other Operations debt	38.7			22.4
Unamortized issuance cost	(.4)			(.4)
Other Operations debt, carrying value	38.3		8.3%	22.0		10.2%
Total debt	$	837.0		$	562.5

(1) The effective rate for years ended December 31, 2025 and 2024 includes the effect of the amortization of debt issuance costs and original issue discount, but excludes the effect of the interest rate caps, where applicable. See Note 9 — “Derivatives.”

The following table presents the change in debt under the Kudu Credit Facility for the years ended December 31, 2025, 2024 and 2023:

	Year Ended December 31,
Millions	2025		2024		2023
Kudu Credit Facility
Beginning balance	$	245.3	$	210.3	$	215.2
Borrowings	113.0		35.0		12.0
Repayments	—		—		(16.9)
Ending balance	$	358.3	$	245.3	$	210.3

The following table presents the change in debt under the Distinguished Credit Facility for the period from September 2, 2025, the date of acquisition, through December 31, 2025:

Millions	September 2, 2025 - December 31, 2025
Distinguished Credit Facility
Beginning balance (1)	$	90.2
Borrowings (2)	50.0
Repayments	(8.8)
Ending balance	$	131.4

(1) Represents the outstanding balance of the Distinguished Credit Facility assumed in the Distinguished Transaction. See Note 2 — “Significant Transactions.”

(2) Represents the $50.0 of incremental term loan drawn in connection with the closing of the Distinguished Transaction. See Note 2 — “Significant Transactions.”

Schedule of contractual repayments of debt

The following table presents a schedule of contractual repayments of White Mountains’s debt as of December 31, 2025:

Millions	December 31, 2025
Due in one year or less	$	8.1
Due in two to three years	45.1
Due in four to five years	173.3
Due after five years	625.6
Total	$	852.1