A premium audit is the year-end true-up of your workers compensation and general liability premiums to your actual payroll, sales, and class codes (they were priced on estimates at the start of the term). If your actuals came in higher, you owe more; if lower, you may get money back. The way to avoid a surprise is accurate class-code and payroll classification, keeping subcontractor certificates of insurance on file, and reporting changes during the year — uninsured subs and misclassification are the most common causes of a big audit bill.
Many business owners are blindsided by an audit bill months after renewal. This guide explains why the audit happens, what records you will need, and how to avoid the surprises — so the audit is a formality, not a shock. It is general education, not advice for your specific policy; work the details with your carrier or agent.
Why the audit happens
Workers compensation and general liability premiums are based on exposures that are not known for sure until the term is over — your payroll (for WC) and your sales or payroll (for GL). At the start of the policy, the carrier charges an estimated premium; at the end, it audits your actual figures and adjusts:
- Actuals higher than estimated — you owe additional premium.
- Actuals lower than estimated — you may receive a return premium.
- Class codes — the audit also confirms your work was classified correctly; a wrong class can move your rate substantially.
What records you will need
- Payroll records — by employee and, where allowed, split by class of work.
- Tax forms — 941s, state filings, and 1099s.
- Sales/revenue — for general liability audits.
- Certificates of insurance from subcontractors — an uninsured sub can be added to your payroll base and charged to your policy. See certificate of insurance.
- Descriptions of job duties — to support the class codes claimed.
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A few quick questions. No phone calls. No contact info.
How to avoid a surprise bill
- Classify accurately from the start — the right class code and payroll estimate keep the audit boring.
- Collect subcontractor COIs — keep current certificates for every sub so their payroll is not charged to you.
- Separate payroll by class where allowed — clean records can lower the charge when duties span classes.
- Report changes during the year — if payroll or operations change a lot, tell your agent rather than waiting for the audit.
- Do not misclassify to lower the estimate — the audit corrects it with back-charges, and it can be treated as fraud. See how to lower your cost honestly.
If the audit is wrong
Audits can contain errors — misapplied class codes, subcontractors counted despite valid COIs, or clerical mistakes. You generally have the right to dispute an audit: gather your records, identify the specific error, and submit a correction request to the carrier. An agent can help you contest an incorrect audit.
Frequently Asked Questions
What is a business insurance premium audit?
It is the year-end true-up of your workers comp and general liability premiums to your actual payroll, sales, and class codes. Your initial premium was based on estimates; the audit adjusts it to reality.
Why did I get a bill after my policy ended?
Because your actual payroll or sales came in higher than the estimate used to price the policy, so you owe additional premium. If your actuals were lower, you may receive a return premium instead.
How do I avoid a surprise audit bill?
Classify your work and payroll accurately from the start, collect certificates of insurance from every subcontractor, separate payroll by class where allowed, and report significant changes during the year rather than waiting for the audit.
Why are my subcontractors on my audit?
An uninsured subcontractor — one without a valid certificate of insurance — can have their payroll added to your base and charged to your policy. Keeping current COIs on file prevents this.
Can I dispute a premium audit?
Yes. Audits can contain errors such as misapplied class codes or subs counted despite valid COIs. Gather your records, identify the specific error, and submit a correction request; an agent can help you contest it.
Does misclassifying payroll lower my cost?
Not really — it is corrected at audit with back-charges and can be treated as fraud. Accurate classification is the honest way to keep your premium fair.
Quick glossary
- Premium audit
- The year-end true-up of estimated premium to actual payroll, sales, and class codes.
- Class code
- The classification describing your work that drives your rate; verified at audit.
- Additional / return premium
- The amount owed or refunded after the audit adjusts your premium.
- Uninsured subcontractor
- A sub without a valid COI, whose payroll can be charged to your policy at audit.