Workers comp premium audits. Why the bill changes and how to prepare

What a premium audit is

Workers compensation premium is usually set at the start of the policy using estimated payroll for each job classification. Each classification has its own rate, and the premium is calculated per one hundred dollars of payroll in that classification, then adjusted for experience and other factors.

Because the starting premium is only an estimate, most policies include a condition that lets the insurer examine your records after the policy period ends. The audit replaces the estimates with actual figures. If actual exposure was lower, you may receive a return premium. If it was higher, you receive an additional premium bill.

Audits are a normal part of how workers comp is priced. They are not an accusation and they do not mean anything went wrong. They simply settle the account for the year.

How the audit is done

Insurers use different audit methods depending on the size and complexity of the account. Smaller accounts may receive a mail or online questionnaire that asks for payroll totals by classification and copies of supporting reports. Larger or more complex accounts may have a phone or video review, or a field auditor may visit in person.

The auditor typically asks for payroll records, quarterly payroll tax filings, general ledger entries for outside labor, a list of subcontractors with their certificates of insurance, and descriptions of what employees actually do. The auditor then assigns payroll to classifications and calculates the final premium.

Respond to audit requests promptly. Many policies allow the insurer to estimate exposure, sometimes conservatively, or to take other action if the employer does not cooperate. An unanswered audit request can turn into a larger bill than the real numbers would have produced.

Why audit bills surprise employers

Most audit surprises come from a gap between the estimate used at the start of the year and how the business actually ran. Growth is the most common cause. A company that hired more staff or gave raises during the year will have more payroll than was estimated.

• Payroll grew through new hires, overtime or raises that were not reported mid term.
• Employees did work that falls in a higher rated classification than the one on the policy.
• Subcontractors could not show valid workers comp coverage for the period.
• Payments to casual labor or independent contractors were treated as payroll.
• Officers or owners were included or excluded differently than expected.
• Records were incomplete, so the auditor used broader assumptions.

Uninsured subcontractor charges

When you hire a subcontractor who does not carry its own workers compensation, your insurer may treat that subcontractor’s workers as if they were your employees. The reasoning is that if one of those workers is injured and has no other coverage, the claim may come back to your policy.

In practice the auditor will look at what you paid each subcontractor and ask for a certificate of insurance showing workers comp coverage in force for the dates of the work. If the certificate is missing, expired or shows no workers comp, the auditor may add some or all of the payment to your payroll in the classification that matches the work. Insurers differ on how much of a subcontract payment they count when labor and materials are mixed.

California adds another layer. Under California Labor Code section 2750.5, a worker performing services that require a contractor license, who does not hold that license, is generally presumed to be an employee rather than an independent contractor. Unlicensed subcontractors can therefore create both audit and legal exposure for the hiring business.

The fix is a simple routine. Collect a current certificate before any subcontractor starts work, confirm the policy dates cover the job, keep a copy with the invoice, and request an updated certificate when the old one expires.

Classification errors

Every employee’s payroll is assigned to a classification that describes the business or the type of work. In California the classification system is maintained by the Workers’ Compensation Insurance Rating Bureau of California, which publishes the classification descriptions that insurers use. Other states use systems from their own rating organizations.

Classification problems run in both directions. A policy may have been written with too low a classification at the start, which the audit corrects upward. Or an auditor may place payroll in a higher classification than the work justifies, for example by treating office staff as field staff when job duties are not clearly documented.

Many classification systems allow some payroll to be divided between classifications only when specific conditions are met, such as accurate time records showing hours spent on each type of work. Without those records, the auditor may assign all of an employee’s payroll to the highest rated classification that applies.

How to prepare for an audit

Preparation starts on the day the policy begins, not when the audit letter arrives. Keep audit records organized during the year so the review is quick and accurate.

• Keep payroll reports by employee with job titles and duties that match the policy classifications.
• Track overtime separately, since some rating systems treat the overtime premium portion differently.
• Keep a subcontractor file with contracts, invoices and certificates of insurance for every vendor.
• Document officer and owner elections or exclusions made on the policy.
• Reconcile audit payroll totals with your quarterly payroll tax filings before you send them.
• Write short duty descriptions for employees who split time between office and field work.
• Ask your broker to review the draft figures before you submit them when possible.

How to dispute an audit

Read the audit worksheet before paying an unexpected bill. It should show payroll by classification, any subcontractor costs added, and the rates applied. Compare each line with your own records.

If something looks wrong, contact the insurer in writing, explain the specific error and attach supporting documents such as corrected payroll reports, missing certificates or job descriptions. Insurers often reopen an audit when a missing certificate or a clear record is supplied. Keep copies of everything you send and note the dates.

If the insurer will not correct a classification or rating decision, formal review processes exist. In California, employers can raise disputes about classification and rating with the insurer and, if unresolved, seek further review through processes involving the Workers’ Compensation Insurance Rating Bureau and the California Department of Insurance. Deadlines and procedures apply, so confirm the current steps with your broker or the rating bureau early rather than waiting.

Avoid simply ignoring an audit bill while you dispute it. Unpaid audit premium can lead to collection activity or cancellation of a current policy. Ask the insurer whether the disputed amount can be held while the review is pending.

Reducing surprises during the year

The best way to avoid a large audit bill is to keep the estimate close to reality. If payroll grows significantly or the business starts a new type of work, tell your broker so the policy can be updated mid term. Some employers choose pay as you go billing, where premium is calculated from actual payroll each pay period, which tends to reduce the size of year end adjustments.

Review the classifications on your policy at every renewal, and ask your broker to explain any that do not match the work your team performs. A short conversation before the policy starts is far easier than a disputed audit after it ends.