The Premium Audit: Where Commercial Insurance Billing Goes Wrong

Every other category in this series is a price list. Somebody quoted a rate, the invoice should match it, and where it does not you have a finding you can hold up.

Commercial insurance does not work that way, and that is exactly why it goes unexamined. Your premium is not a price. It is the output of a calculation performed on data about your own business: what your people do, what you paid them, what you sold, and what has gone wrong in the past. Every input to that calculation can be wrong, and when one is, the error does not appear as an overcharge on a line. It appears as a slightly larger, entirely plausible premium.

Start with the audit, not the invoice

Most commercial policies that matter here, workers' compensation and general liability in particular, are written on an estimate. At binding, you and the carrier agree an expected exposure basis: payroll for comp, usually receipts or payroll for GL. You pay a deposit premium against that estimate.

At the end of the term the carrier performs a premium audit against what actually happened. If the real exposure was higher, you owe additional premium. If it was lower, you are owed a return. That audit, not the monthly invoice, is where the money in this category lives, and it arrives months after the period it covers, addressed to whoever opened the mail.

So the first question is simply whether anyone checked the last one. In a lot of businesses the honest answer is that it was paid.

Classification codes

Workers' compensation assigns every employee a class code describing what they do, and each code carries its own rate. The spread between codes is not small: clerical work and field work are different codes at very different rates, and the same person coded two ways produces two different premiums for identical wages.

The common errors are mundane. A business gets placed on a single governing code at inception and never revisited as roles diversified. Office staff sit inside a code meant for the shop floor. A role that genuinely changed years ago is still described the way it was described at binding.

The codes and their definitions are published by the rating bureau for your state, which is NCCI in most of the country and an independent bureau in several states including California, New York and Pennsylvania. That means this is checkable rather than arguable: you can read what a code is defined to cover and compare it to what the person actually does. Splitting a payroll across codes is permitted in some circumstances and not in others, and the rules for that are state specific, which is where your broker earns the fee.

The experience modification factor

If your policy is large enough to be experience rated, a rating bureau calculates a modification factor from your claims history against what is expected for a business of your size and class. That factor multiplies your premium. A mod of 1.15 is a 15 percent surcharge on everything, applied before most other adjustments.

It is computed from data reported by your carrier, and the inputs are frequently stale in one specific way: open reserves. A claim that is effectively finished but still carries a large reserve is counted at that reserve, not at what it will actually cost. Claims that closed for far less than reserved, claims that should be subrogated, and claims attributed to the wrong entity in a group all flow through to the same number.

There is a timing detail worth knowing: the data is captured as of a valuation date well before the mod takes effect. A claim that closes cheaply after that date does not help the current year, which is an argument for managing reserves continuously rather than discovering them at renewal. It is the same argument as auditing on a subscription rather than as an event, with a deadline attached.

The payroll basis

The exposure figure the audit runs on is a defined quantity, not simply your gross payroll, and the definition is where errors cluster.

Depending on the state and the rules in force, certain amounts may be excluded or limited when calculating comp exposure, and a widely applied example is that the premium portion of overtime, the extra half in time and a half, is often excludable so overtime is rated at straight time. Severance, some fringe benefits, and payments to certain owners and officers can also be treated differently from ordinary wages, frequently subject to state minimums and maximums.

None of that happens automatically. It requires that your payroll records be presented in a form that separates those amounts in the first place, which is a direct reason to know what your payroll system can actually report before an auditor arrives. Where it cannot, the safe assumption from the auditor's side is the larger number. Your provider's reporting is therefore part of this audit as much as it is part of the payroll invoice itself.

Subcontractors and certificates

An uninsured subcontractor can be picked up on your policy and charged as though those workers were yours. The control is a valid certificate of insurance for every sub, in force for the period they worked, collected before the work rather than hunted for after the audit.

This one is worth checking first when an audit produces a surprisingly large additional premium, because it is both the most common cause and the most fixable: a certificate that existed all along and was simply not on file at audit time is a straightforward correction.

The charges that are not premium at all

Underneath the calculated premium sits a set of charges that behave exactly like the fees in every other category in this series: policy fees, inspection or surveyor fees, broker or agency fees where separately disclosed, installment and service charges for paying monthly rather than annually, and late fees.

Then there is premium finance. If you spread the premium over the year through a finance company, that is a loan. It has an interest rate, an origination fee and a down payment requirement, and all three are negotiable in a way the premium itself is not. Businesses that would never accept an unexamined rate on a piece of equipment routinely accept one here, because it arrives bundled with the insurance and reads as part of it. Compare it to what your bank would charge for the same money, and read it alongside the treasury statement, since it is the same question about the same dollars.

The dispute window is real and it closes

Policies and state regulations set out how and by when an audit can be disputed, and the window is finite. An audit statement that arrives, sits in a pile for a quarter, and then turns out to be wrong may be wrong and final at the same time.

Treat the arrival of an audit statement as a dated event: log it, diary a review inside the window, and do the review even when the number looks unremarkable. A premium audit that comes back close to expectation is not evidence that the inputs were right. It is evidence that the estimate and the error were similar in size.

Who to take it to

Everything above is a question about data: what a code says, what a claim actually cost, what the payroll records show, whether a certificate existed. That is the part worth preparing carefully, because it is the part that decides the answer.

The correction itself goes through your broker or agent, and where a class code or a mod is genuinely contested, through the rating bureau's own process. Bring the worksheet, the payroll detail and the certificates, with the specific lines you are questioning marked. It is the same discipline as putting a contract next to a statement: the conversation goes better when the disagreement is narrow, documented and about a number rather than about a feeling that the bill went up.