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

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

RLICasualty — Operating Expenses

$16.73M+7.4%

ACGLCasualty — Incurred losses and allocated loss adjustment expenses, net of reinsurance

521,000,000,000%+447,600,000,000pp

WRBCasualty — Loss and loss expenses incurred, net of reinsurance

$4.01B+736%

RNRCasualty and Specialty — Underwriting expense ratio

30.3%-4.7pp

RNRCasualty and Specialty — Loss Ratio

70.1%-6.0pp

RNRCasualty and Specialty — Combined Ratio

100.4%-10.7pp

Other financials

Income statement

See full

Revenue$517.8M-10.4%

Gross profit$475.1M-16.7%

Net income-$27.2M-180%

Balance sheet

See full

Total debt$834.8M+23.5%

Total equity$5.4B+19.2%

Total assets$13.2B+19.7%

Cash flow

See full

Operating cash flow$30.5M+176%

Valuation

See full

Market cap$4.99B+9.8%

Profitability

See full

Gross margin94.9%-3.7pp

Net margin28.4%—

Returns & leverage

See full

Return on equity21.2%—

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 official record: White Mountains Insurance Group’s 10-K, filed February 27, 2026, on SEC EDGAR. View the filing →

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Questions, answered.

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.