How to Read Loss Runs Like an Underwriter

To read a loss run, look at three numbers for each claim, all as of the same valuation date: paid (what the carrier has already paid out), reserved (the adjuster's estimate of what is still to be paid) and incurred (paid plus reserved). Incurred is the number that drives your premium. Everything else on the report, such as claim numbers, status codes and descriptions, explains how those numbers got there and whether they are still changing.

Every commercial submission includes loss runs, and too many go out exactly as they arrived. That is a pricing mistake. A reserve, the money an adjuster sets aside on a claim that is not yet settled, is priced exactly like a real loss unless someone questions it.

What is a loss run report?

A loss run is the carrier's official record of claims under a specific policy, printed from its claim system as of a particular date. Underwriters read loss runs the way lenders read a credit report: as the applicant's track record, from a source the applicant does not control. Loss runs are produced by line of business and by policy term, so a complete picture means collecting separate runs for general liability, auto, workers compensation and property from every carrier that wrote the account during the look-back period. Five years is the usual look-back, which matches the loss history section of the ACORD 125. If there was no prior policy or no claims were reported, the carrier issues a "no losses" letter instead.

What does each column on a loss run mean?

Carrier formats vary, but nearly every report uses the same core fields:

Some carriers split paid and reserved amounts into indemnity and expense, and workers compensation runs also split medical from indemnity and show the claimant's name or injured body part. That detail matters. A claim with high expense and low indemnity usually points to litigation rather than a serious injury, and an underwriter who cannot see the split will assume the worst.

Why do incurred losses change between reports?

Incurred totals change because reserves change, and reserves are opinions. The adjuster sets a reserve early, before all the facts are in, and then adjusts it as medical records, repair estimates and legal developments arrive. Each adjustment changes the incurred figure on the next report. A claim can also close below its reserve, which drops incurred down to the paid amount, or a subrogation recovery can arrive between valuation dates and reduce the net figures.

That is why underwriters insist on currently valued loss runs, meaning reports with a valuation date within about 90 days of the submission. An old report is wrong in a predictable direction: stale reserves on claims that have since closed quietly overstate the account's losses. In workers compensation, those same reserves flow into the unit statistical data behind the experience modification rate, so an inflated reserve costs the client twice: once in the underwriter's judgment and again in the mod.

How do underwriters read loss runs?

Underwriters look at the pattern first and the dollars second, and the key question is frequency versus severity. Frequency means many small claims. It signals something structural, such as weak supervision or no return-to-work program, and it predicts future losses because the behavior behind it repeats. Severity, one large claim in an otherwise clean history, is usually read as bad luck unless the details suggest it could happen again. A $150,000 total from one freak auto loss prices better than the same total spread across eighteen slip-and-fall claims.

Workers compensation rating builds that preference into its formula. The experience mod formula counts the primary portion of every loss at full weight and heavily discounts the excess portion, so ten $10,000 claims move the mod much further than one $100,000 claim. Timing matters too. A cluster of claims in the most recent year weighs more than the same number spread evenly across the years, because it suggests things are getting worse. Claims that are reported but close at zero actually help the account, because they show the insured reports incidents promptly without turning them into dollars. And costs keep rising: NCCI's 2025 State of the Line report found that indemnity and medical claim severity each rose 6% in accident year 2024, so a reserve set today tracks losses that keep getting more expensive.^[1]

How do you request loss runs?

Request loss runs in writing from each carrier, signed by the insured or sent by the broker of record, and ask for five years of currently valued runs. Agency portals produce runs from the agency's own carriers instantly, while a prior carrier's loss run department usually takes five to fifteen business days. Some states set a deadline. New York Insurance Law Section 3426(g) requires a commercial insurer to mail or deliver loss information within ten days of a written request from the first named insured or its authorized broker.^[2]

Timing is the part the broker controls. Order runs about 120 days before renewal, which leaves time to work the reserves and get a revalued report before the submission goes out. A prior carrier usually will not release runs to a broker who does not hold the account until a signed authorization from the insured is on file, so get that signature with the request, not after the first refusal. If a broker of record change is coming, or the client is leaving a carrier after a dispute, send the request before the break. The data does not get easier to obtain afterward.

How do you clean up loss runs before marketing an account?

Cleanup is the most valuable work in the pre-marketing file, and it goes in this order:

1. Order currently valued runs early

   Pull five years from every carrier about 120 days before the target marketing date, and reorder any report that will be more than 90 days old at submission.

2. Reconcile the runs against the client's records

   Flag claims the client does not recognize, claims that belong to another insured on a shared policy, and incidents that were reported but never developed.

3. Work the open claims list

   Call the adjuster on every open claim, using the claim number from the report. Ask what is keeping the file open and whether the reserve reflects the current facts, and take stale reserves to the claims supervisor with supporting documents. Expect the first request to be declined.

4. Request revalued runs after the changes post

   Reductions and closures help only if the underwriter sees them, so wait a few weeks and order a fresh report. If an agreed reduction has not posted in time, note it in the loss narrative with the adjuster's name and the agreed figure.

5. Write the loss narrative for the submission

   Summarize what happened on each significant claim, what the client changed afterward, and why the pattern will not repeat.

Incurred totals decide carrier appetite. A $60,000 reserve that should be a $9,000 closed claim can be the difference between a standard market placement and a surplus lines quote.

This guide is for educational purposes and describes common carrier and underwriting practice. Your policy's specific terms, conditions, and endorsements control. Talk to a licensed broker about your actual exposures.

Getting loss runs ready for renewal

A loss run is the carrier's record of your claims, and it is only as accurate as its valuation date. Read the three numbers for each claim (paid, reserved and incurred), find how much is still sitting in open reserves, and work those reserves down before the file goes out, because every stale reserve dollar is priced like a real loss. Order runs about 120 days before renewal, challenge the large reserves, and give the underwriter a fresh report with an explanation for each claim.