Combined Ratio

The combined ratio is the single most important measure of an insurance company's underwriting profitability — whether its core business of pricing and selling insurance actually makes money, before any investment returns. It brings together the cost of claims and the cost of running the business into one clear figure. This guide explains what the combined ratio is, how it's calculated, how to interpret it, and why it matters — in plain language. It builds on the loss ratio and is a relevant topic in finance and insurance qualifications.

What is the combined ratio?

The combined ratio measures an insurer's total underwriting costs — claims plus expenses — as a proportion of the premiums it earns. In effect, it answers the central question of the insurance business: for every pound of premium taken in, how much goes out in claims and running costs? Because it captures both of an insurer's main outflows in a single number, it's the headline gauge of how profitable the underwriting operation is, separate from the money an insurer also makes by investing its reserves.

How the combined ratio is calculated

The combined ratio is the sum of two component ratios:

• The loss ratio — claims incurred divided by premiums earned. This is usually the larger component.
• The expense ratio — the insurer's operating expenses (commissions, administration, marketing and so on) divided by premiums.

Added together, they give the combined ratio:

Combined ratio = Loss ratio + Expense ratio

For example, an insurer with a 60% loss ratio and a 30% expense ratio has a combined ratio of 90%. That means 90 pence of every premium pound went on claims and expenses, leaving a 10 pence underwriting profit.

The crucial 100% line

The combined ratio is read against a simple, decisive benchmark — the 100% mark:

• Below 100%: the insurer is making an underwriting profit — premiums more than cover claims and expenses. A combined ratio of 95% means a 5% underwriting profit.
• Above 100%: the insurer is making an underwriting loss — claims and expenses exceed premiums. A ratio of 105% means the insurer loses 5 pence on every premium pound from its core business.

Importantly, an insurer can run a combined ratio above 100% and still be profitable overall, because it also earns investment income on the premiums it holds before paying claims. But a persistently high combined ratio signals that the underwriting itself is unprofitable and reliant on investment returns — a riskier position.

A worked example

Suppose an insurer earns £100m in premiums over a year. It pays £55m in claims (a 55% loss ratio) and spends £35m on commissions, salaries and other running costs (a 35% expense ratio). Its combined ratio is 55% + 35% = 90%, an underwriting profit of £10m. Now imagine a bad year of storms pushes claims to £75m: the loss ratio jumps to 75%, the combined ratio rises to 110%, and the insurer makes a £10m underwriting loss — which it would need investment income to offset. The same business can swing from profit to loss purely on the claims experience, which is why insurers watch this ratio so closely.

Why the combined ratio matters

The combined ratio is the clearest single indicator of how well an insurer runs its core operation. It strips away investment performance to show whether the fundamental business — pricing risk and controlling costs — is sound. Analysts, investors and regulators watch it closely, and compare it across insurers and over time, because an insurer that consistently underwrites at a profit has a far more sustainable, less market-dependent business than one that relies on investment income to cover underwriting losses.

Why it matters for finance professionals

For anyone analysing or working in insurance, the combined ratio is essential. It distils a complex business into one comparable figure and makes plain whether an insurer is genuinely good at its job. Understanding how it's built from the loss and expense ratios, and how to read it against the 100% line, is fundamental to insurance analysis and a practical example of ratio analysis in action.

Frequently asked questions

What is the combined ratio?

An insurance metric measuring total underwriting costs — claims plus expenses — as a proportion of premiums earned. It's the headline gauge of underwriting profitability, before investment income.

How is the combined ratio calculated?

By adding the loss ratio (claims ÷ premiums) to the expense ratio (operating costs ÷ premiums). A 60% loss ratio plus a 30% expense ratio gives a 90% combined ratio.

What does a combined ratio above 100% mean?

That claims and expenses exceed premiums — an underwriting loss. The insurer may still be profitable overall thanks to investment income, but its core insurance business is losing money.

Why is the combined ratio important?

It shows whether an insurer's core operation is profitable, independent of investment returns. A consistently sub-100% ratio indicates a sustainable, well-run underwriting business.

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The combined ratio is central to understanding insurance profitability. Learnsignal's tutor-led courses, including ACCA, develop the financial-analysis understanding that metrics like this build on — with clear teaching that connects the numbers to what they reveal about a business.