Loss Ratio
Also known as: loss ratio, incurred loss ratio
The loss ratio is the single most important profitability gauge in insurance: incurred losses ÷ premiums earned, expressed as a percentage. A 60% loss ratio means the carrier paid $60 in claims for every $100 of premium it earned — before its own expenses (commissions, overhead, taxes). Add a typical ~30-35% expense ratio and you get the combined ratio; above 100% the line is unprofitable on underwriting.
Loss ratios vary enormously by line and by state, which is exactly why rates differ so much. Nationally in 2023, commercial auto ran a ~74% loss ratio with a negative underwriting result, while workers' comp ran closer to 45% — a big reason WC pricing has stayed soft while trucking rates climb. Within a single line, one state can run 30% while another runs over 100% depending on litigation climate, catastrophe exposure, and medical costs.
For a business buyer, the loss ratio is the 'why' behind your renewal: carriers file rate increases where loss ratios run hot. See how it plays out by state in our commercial auto, general liability, and BOP studies. Related but distinct: a loss cost is the per-unit claims cost a rating bureau files, whereas the loss ratio is an after-the-fact result on booked premium.
Real-world scenario
Riverside Roofing LLC, a 14-employee contractor in Ohio, buys a workers' compensation policy for an annual premium of $62,000 and a general liability policy for $18,000, so the carrier collects $80,000 of earned premium over the policy year. To decide whether to renew and at what price, the underwriter looks at the account's loss ratio — total incurred losses divided by that earned premium.
During the year two claims hit. A worker falls off a ladder: the carrier pays $41,000 in medical bills, sets a case reserve of $14,000 for future physical therapy, and books $3,500 of adjuster and legal expense — roughly $58,500 on that file. A second claim, a homeowner's damaged roof deck, settles for $9,000 after a $1,000 deductible credit, plus $2,500 in defense costs. Total incurred losses reach about $70,000.
Dividing $70,000 in losses by $80,000 in premium gives an 87.5% loss ratio. Because the carrier also spends roughly $22,000 (28%) on commissions and overhead, the combined picture runs well over 100% — a money-losing account. At renewal the underwriter quotes $96,000 instead of $80,000, a $16,000 increase, and Riverside's broker shops the risk to keep the number closer to $88,000.
How it affects your premium
Loss ratio itself is a diagnostic number, not a coverage you buy — but the ratio the carrier calculates for your account directly drives what you pay at renewal. These factors move it:
- Claim frequency and severity: A few large payouts, or many small ones, both push incurred losses up relative to premium.
- Open reserves on active claims: Carriers count case reserves for claims not yet closed, so an open injury file can inflate your ratio for years before final payout.
- Earned vs. written premium timing: The denominator is earned premium, so mid-term audits and payroll changes shift the ratio.
- Loss development and IBNR: Insurers add estimates for claims incurred but not yet reported, nudging the ratio higher than your current paid losses suggest.
- Credibility of your account size: Small accounts get blended with class averages; large accounts see their own experience weighted more heavily.
- Recovery offsets: Subrogation and salvage recoveries reduce net losses and improve the ratio.
- Loss-control and safety programs: Documented safety investments lower future frequency and help argue for a better renewal despite a bad year.
Common misconceptions
Myth: A loss ratio under 100% means my insurer made money on my account.
Reality:
Not necessarily — carriers also pay commissions and overhead. When you add the expense ratio (often 25-35%) to the loss ratio, the combined ratio can exceed 100% even if losses alone are only 80%.
Myth: My loss ratio only counts checks the insurer has actually written.
Reality:
It includes open case reserves and adjustment expense too. A single unresolved injury claim with a large reserve can keep your loss ratio elevated long before any final indemnity payment is made.
Myth: One bad year permanently ruins my rates.
Reality:
Underwriters weight several years of experience, not just one. A clean loss run in the following years, plus documented safety improvements, typically pulls the multi-year ratio back down.
Frequently asked questions
What is a good loss ratio for a business buyer?
From the insured's perspective, a lower ratio at renewal generally means better pricing power. Carriers typically target a loss ratio in the 50-70% range so there's room left for expenses and profit; accounts running above 75-80% often face rate increases or non-renewal.
How is loss ratio calculated?
Divide total incurred losses (paid claims plus reserves and adjustment expense) by earned premium for the same period, then express it as a percentage.
Does loss ratio affect my workers' comp experience mod?
They're related but different. Your loss ratio is a carrier's account-level profitability measure, while the experience modifier is a formula-driven factor comparing your losses to expected losses for your class; both reflect your claims history.
Can I lower my loss ratio?
Over time, yes — through fewer and smaller claims, aggressive claim closure to release excess reserves, and documented loss-control programs. These improvements feed the underwriting decision at renewal.
Why does my broker keep asking for my loss runs?
Because a loss run is the source document underwriters use to compute your loss ratio. Clean, complete loss runs let your broker market the account and negotiate better terms.
Sources cited
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