Combined Ratio (Insurance)

The combined ratio is the single most important metric for evaluating the underwriting performance of a property and casualty insurance company. It compresses the two primary cost categories — losses paid on claims and the operational expenses of running the insurance business — into a single percentage that immediately reveals whether the core insurance operation is generating profit or loss independent of investment income.

The loss ratio portion divides incurred losses (claims paid plus changes in reserves for reported but unpaid claims) by earned premiums. An insurer that collects $10 billion in premiums and pays $7 billion in claims has a 70% loss ratio. The expense ratio divides underwriting expenses — commissions, administrative costs, marketing, and other overhead — by premiums. If those expenses are $2.5 billion against the same premium base, the expense ratio is 25%. The combined ratio is 95%, indicating that the company earns 5 cents of underwriting profit for every dollar of premium.

A combined ratio above 100% signals an underwriting loss. The insurer is paying out more in claims and expenses than it collects in premiums. Property and casualty insurers can still be profitable in these circumstances if investment income from the float — the pool of premiums collected before claims are paid — is sufficient to offset the underwriting deficit. Warren Buffett has highlighted this dynamic extensively in Berkshire Hathaway letters: GEICO and other Berkshire insurance subsidiaries generate investment income from the float that has historically more than compensated for modest underwriting losses in difficult years.

Catastrophe losses — from hurricanes, wildfires, flooding, and earthquakes — are the most significant driver of combined ratio volatility in property insurance. Insurers that write homeowners policies in high-risk coastal or wildfire-prone regions face unpredictable spikes in the loss ratio following major weather events. Reinsurance contracts help offset these losses, but the cost of reinsurance is itself rising as climate-related losses increase.

Progressive, Travelers, and Allstate all report combined ratios as central earnings metrics. Analysts compare the combined ratio to the prior year, to industry benchmarks, and to the company's own historical track record of underwriting discipline. Consistent combined ratios below 100% across multiple years are the hallmark of a disciplined underwriter. Ratios that drift above 100% for extended periods suggest pricing inadequacy, adverse selection, or insufficient claims management.

The accident-year combined ratio, which attributes losses to the policy year in which the underlying claim occurred rather than the year it was reported or paid, provides a cleaner view of underlying performance and removes the noise created by favorable or adverse development on prior-year reserves.