Loss runs are the carrier-issued claim history underwriters lean on hardest at every commercial renewal. Five years, currently valued, with stale reserves cleaned up and recoveries documented, can move pricing more than the quote itself.

A loss run is the carrier-issued report that lists every reported claim under a commercial insurance policy — date of loss, claim type, amount paid, amount reserved, and current open/closed status — and it is the single document underwriters use most to decide whether they will quote your business and at what price. Most owners have never read their own loss runs in detail; the underwriters competing for their account read them line by line.

At Avanti Group, we order, clean, and present loss runs as part of every commercial submission. Done well, a clean five-year loss-run package is the difference between three carriers competing on price and one reluctant carrier offering a take-it-or-leave-it renewal. Done badly, an open reserve nobody bothered to chase down can quietly cost an Iowa contractor or trucking fleet five figures in extra premium for the next three years. This article explains what loss runs are, why five years matters, how to order them, what to clean up before going to market, and how reserves on open claims warp renewal pricing.

What is a loss run in commercial insurance?

A loss run, also called a claims history report or claims experience report, is a document issued by an insurance carrier listing every claim filed against a specific policy or set of policies during a defined period. Each line typically shows the policy number, claimant name (or claim number), date of loss, type of loss, a short description, the amount the carrier has paid to date, the amount it has reserved (set aside but not yet paid), and whether the file is open or closed.

Loss runs exist because commercial insurance is rating-by-experience. The single best predictor of next year’s losses is the last five years of losses. That is true for workers’ compensation, general liability, and commercial auto — the three lines where loss runs do the most work in renewal pricing. They also feed the experience modification factor (the “mod”) used in workers’ compensation rating, which the National Council on Compensation Insurance (NCCI) calculates from carrier-reported loss data.

Why do underwriters require five years of loss runs?

Five years is the underwriting standard for two reasons. First, it covers the typical mod-calculation window for workers’ compensation, where the most recent three complete policy years (excluding the year that just ended) drive the experience modification factor. Second, claims that look small on day one can develop for years; a back injury reported in 2022 with a $2,000 reserve can balloon to $180,000 by 2026 if surgery and lost time follow. Five years lets the underwriter see development.

A submission with only one or two years of loss runs reads as either a brand-new business (acceptable) or a buyer hiding something (not acceptable). When a renewal market sees three years of loss runs from one carrier and a gap before that, the underwriter assumes the worst about the missing period. Pull the missing years before submitting, even if it takes a week.

How do you order loss runs?

Loss runs are ordered by written request to each carrier (or its agent) that has insured the business in the relevant period, and most carriers are required to produce them within ten business days. The request typically goes to the underwriting or claims department and includes the policy number, the policy period, and the named insured. Many carriers now have a self-service portal; some still require a signed broker-of-record letter or a written request from the insured.

A clean loss-run package for a commercial submission contains:

• Currently valued loss runs from each carrier the business used in the last five years, dated within the last 60 days.
• Continuity coverage: dates of cancellation or non-renewal explained, with no unexplained gaps.
• A short narrative for any claim over a material threshold (often $10,000 or $25,000) explaining what happened, what was paid, and what the business changed afterward.

If the business changed entities, was acquired, or merged in the period, loss runs for the predecessor entity are also required. An underwriter will not assume a new EIN washes the prior history.

What should you clean up before going to market?

Most loss-run packages can be improved materially before submission without changing a single underlying claim. The work is administrative, but it moves rates.

1. Close out claims that should be closed. A claim that has been paid in full and inactive for two years should not still show “Open” on the loss run. Have the carrier review and close. Each open file with a reserve attached is treated as if the reserve will be paid.
2. Confirm reserves are current. Carriers periodically over- or under-reserve. A workers’ comp claim with a $75,000 reserve where the claimant returned to full duty 18 months ago is overstating the cost of the program. Ask the carrier (or a claims-advocacy partner) to revisit the reserve.
3. Document recoveries and subrogation. A $40,000 auto claim where the carrier recovered $30,000 from the at-fault driver should net to $10,000 in the underwriter’s view, but only if the recovery is shown on the loss run. If it is not, request a corrected report.
4. Annotate large losses. A single severe claim five years ago does not have to define the next five renewals if the business can show what changed — a new safety program, a new fleet policy, a hiring change, a new general contractor agreement.
5. Reconcile against your own records. Loss runs occasionally contain claims that do not belong to the business or miss claims that were closed in error. Catch the errors before the underwriter does.

Why do open claims hurt renewal pricing more than closed ones?

An open claim with a reserve is treated by underwriters as if the full reserved amount has already been paid. A claim closed at $5,000 paid is a $5,000 loss; the same claim still showing $5,000 paid plus a $35,000 reserve is, for pricing purposes, a $40,000 loss. That is why aging open claims with stale reserves quietly inflate renewal premium.

The effect is amplified on workers’ compensation through the experience mod. Reserves on open indemnity claims feed directly into the mod calculation, and a mod above 1.00 raises premium proportionally for the next three years. Closing a claim or right-sizing a reserve before the unit-statistical filing date can move the mod by enough to matter on the next renewal.

How does Iowa context change the loss-run review?

Iowa businesses face two specific dynamics. First, Iowa workers’ compensation is governed by Iowa Code Chapter 85, and Iowa is an NCCI state for class codes and experience rating, which means most workers’ comp loss runs flow into the standard NCCI mod calculation. Second, Iowa’s commercial-auto and trucking markets have hardened materially since 2023; underwriters in those classes are reading loss runs more aggressively, weighting severity over frequency, and pricing nuclear-verdict exposure into renewal quotes. Loss-run hygiene matters more in a hard market than a soft one because the underwriter is looking for reasons to decline.

The Business Risk Diagnostic™

Avanti Group treats loss-run review as a structured step inside the Business Risk Diagnostic™ — the pre-quote due diligence we run before going to market. The Diagnostic pulls five years of loss runs from every carrier in the period, reconciles them against the insured’s own claim records, identifies open files with stale reserves, drafts the large-loss narratives, and produces a clean submission package the market will actually compete on. For most accounts, this work alone changes which carriers will quote and at what attachment.

If your last renewal felt like the market quoted what you handed them rather than what your business actually looks like, the loss runs are usually where to start. For broader context on how exposures are mapped before any quote, see the business insurance hub.

Frequently asked questions

What is a loss run in insurance?

A loss run is a carrier-issued report listing every claim filed under a commercial insurance policy during a defined period, with date of loss, claim type, amounts paid, amounts reserved, and open/closed status. It is the primary document underwriters use to evaluate a renewal or a new submission.

How many years of loss runs do underwriters require?

The commercial-insurance standard is five years of currently valued loss runs from every carrier in the period. Five years covers the workers’ compensation experience-mod window and gives underwriters time to see how older claims developed. Submissions with fewer years often read as incomplete and price worse.

How do you order loss runs from a carrier?

Submit a written request to the carrier’s underwriting or claims department (or its agent of record) identifying the named insured, policy number, and policy period. Many carriers offer a self-service portal; most are required to produce the report within ten business days of a valid request.

Why do open claims affect commercial insurance pricing?

Underwriters treat open claims as if the carrier-set reserve has already been paid. A $5,000 paid claim with a $35,000 open reserve is priced as a $40,000 loss. Closing claims that should be closed and right-sizing stale reserves before renewal can lower the loss picture used for pricing without changing what actually happened.

Can errors on a loss run be corrected?

Yes. Loss runs occasionally contain claims that do not belong to the business or omit recoveries (subrogation, salvage, deductible reimbursement) that should reduce the net loss. Reconcile each loss run against your own records and request corrected reports from the carrier before submitting to market.

Related reading

Other articles in the Commercial Foundations series:

• Captive vs Guaranteed Cost vs Large Deductible: Risk Financing Compared — Three risk financing structures side by side—when each one fits and when it stops making sense.
• Why the Cheapest Commercial Quote Is Usually the Most Expensive Policy — Three Iowa-style scenarios where the lowest premium hid the largest gap.
• Coinsurance Penalties on Commercial Property: The Clause That Quietly Cuts Claim Checks — How the coinsurance formula trims a claim check when valuation drifts.