What is White Mountains Insurance Group's casualty-runoff — 5?

White Mountains Insurance Group (WTM) reported casualty-runoff — 5 of 8.5% in Q4 2025.

How has White Mountains Insurance Group's casualty-runoff — 5 changed year-over-year?

White Mountains Insurance Group's casualty-runoff — 5 decreased by 0.0% year-over-year, from 8.5% to 8.5%.

What does casualty-runoff — 5 mean?

This metric measures the operating expenses incurred in the administration and settlement of casualty runoff claims. It provides insight into the cost-efficiency of the claims handling process for legacy books of business. Lower administrative costs relative to the liability base indicate operational effectiveness.

White Mountains Insurance Group (WTM) Casualty-Runoff — 5

Screener

Other product segments

Casualty-Active

10%+5.3%

Marine & Energy

6.4%+30.6%

Specialty

6.3%-13.7%

Property and Accident & Health

2.9%+3.6%

Similar metrics at other companies

HIPOCasualty Lines — 5

4%—

HGBermuda - Casualty — 5

11%-1.0pp

HGInternational - Casualty — 5

8%+2.0pp

FRHCCivil Liability — 5

9%+5.6pp

FRHCMotor Vehicle — 5

0%—

FRHCProperty Damage — 5

6%-1.0pp

Other financials

Income statement

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Revenue$844.6M+22.5%

Gross profit$764.5M+18.2%

Net income$199.5M+62.3%

Balance sheet

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Total debt$932.5M+34.2%

Total equity$5.4B+16.0%

Total assets$13.8B+16.4%

Cash flow

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Operating cash flow-$55.5M-131%

Valuation

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Market cap$5.3B+15.6%

P/E4.7×—

P/S1.4×-0.5×

Profitability

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Gross margin94.1%-3.2pp

Net margin29.3%—

Returns & leverage

See full

Return on equity22.4%—

Debt / equity0.2×0.0×

Where this comes from

Reported directly by White Mountains Insurance Group in its filing.

Tagged under the XBRL concept us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive.

The source filing: White Mountains Insurance Group’s 10-K, filed February 27, 2026.

Filed: Feb 27, 2026, 9:21 AM EST
Fiscal year: FY2025
Accession: 0001628280-26-012603

Casualty-Runoff	Casualty-Runoff / Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Casualty-Runoff / Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Casualty-Runoff / Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Casualty-Runoff / Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance	Average Annual Percentage Payout of Incurred Loss and LAE by Age, Net of Reinsurance
Years	1	2	3	4	5	6	7	8	9	10
	8.8%	13.9%	15.3%	14.8%	8.5%	6.7%	5.9%	4.2%	3.2%	2.2%

Item 16. Form 10-K Summary.

FAQ

What is White Mountains Insurance Group's casualty-runoff — 5?: White Mountains Insurance Group (WTM) reported casualty-runoff — 5 of 8.5% in Q4 2025.
How has White Mountains Insurance Group's casualty-runoff — 5 changed year-over-year?: White Mountains Insurance Group's casualty-runoff — 5 decreased by 0.0% year-over-year, from 8.5% to 8.5%.
What does casualty-runoff — 5 mean?: This metric measures the operating expenses incurred in the administration and settlement of casualty runoff claims. It provides insight into the cost-efficiency of the claims handling process for legacy books of business. Lower administrative costs relative to the liability base indicate operational effectiveness.