What is Loss Ratio?
The loss ratio is the percentage of earned premium consumed by claims — calculated as incurred losses divided by earned premium — and is the primary measure of underwriting profitability for carriers, MGAs, and reinsurers, with a combined ratio (adding expense ratio) below 100% indicating an underwriting profit.
The loss ratio is the most fundamental measure of whether an insurance book is profitable at the underwriting level. It strips out expenses and investment income to answer the core question: for every dollar of premium collected, how many cents went out the door as claims?
The calculation uses earned premium (the portion of written premium that corresponds to expired policy periods) in the denominator rather than written premium, ensuring that the metric aligns the timing of risk exposure with the timing of claims. Incurred losses in the numerator include both paid claims and changes in loss reserves — estimates of future claim payments on in-force or reported-but-not-closed losses.
A loss ratio of 60% means 60 cents of every premium dollar goes to claims, leaving 40 cents to cover expenses, profit, and investment income. The expense ratio — covering acquisition costs (commissions), administrative expenses, and overhead — typically runs 25–35% for specialty insurers. Adding the loss and expense ratios gives the combined ratio: below 100% is an underwriting profit; above 100% is a technical underwriting loss, which carriers may still absorb if their investment returns are sufficient.
Loss ratios are monitored at multiple levels of granularity: by line of business, by class of risk, by distribution channel, by geographic territory, and by individual underwriter or MGA book. This granularity is critical for delegated authority oversight — a carrier granting binding authority to an MGA will typically set loss ratio thresholds in the DUA, triggering a performance review or profit commission adjustment if the book deteriorates.
Actuaries distinguish between accident-year loss ratios (grouping losses by when the claim occurred) and calendar-year ratios (grouping by when losses were booked). For long-tail lines like professional liability or workers' compensation, accident-year development can take years to mature, making early loss ratio monitoring inherently uncertain.
Orb improves loss ratios by catching risk factors that manual underwriting misses under time pressure. Atlas Professional Lines reduced their D&O loss ratio from 58% to 52% within six months of deploying Orb — attributing the improvement to better identification of adverse disclosure risks, SEC investigation flags, and OFAC matches that were being missed in a high-volume manual review process. The structured decision memo creates an audit trail that supports post-bind analysis of which risk signals predicted adverse loss development.
Frequently asked questions
What is a good loss ratio for a specialty MGA?
Target loss ratios vary significantly by line of business. Property catastrophe books may target 40–55%; professional liability books 55–65%; general liability 55–70%. The key metric is the combined ratio — loss plus expense — which should sit below 90–95% for a healthy specialty book, though this varies by capital structure and investment strategy.
How does the loss ratio differ from the combined ratio?
The loss ratio measures only claims costs as a percentage of earned premium. The combined ratio adds the expense ratio (underwriting and administrative expenses as a percentage of written or earned premium) to give a complete picture of operating profitability at the underwriting level before investment income.
Why do loss ratios look low in early policy years?
For long-tail casualty lines, most claims are reported and reserved after the initial policy year. Early calendar-year loss ratios appear low because IBNR (incurred but not reported) reserves may be understated. Mature accident-year loss ratios — looked at five or more years after the policy year — are a more reliable measure of true profitability.