Why the audit exists at all
A workers comp policy is priced at the start of the term using estimated payroll by classification code. The audit, typically conducted after the policy period ends, compares that estimate to actual payroll records — and any difference becomes an additional premium bill or a refund.
This isn't optional or occasional; it's a standard, expected part of how workers comp is priced, built into the policy from the start.
The subcontractor certificate issue that surprises people
If a subcontractor worked for you without their own active workers comp coverage, their payment to you can be added to your payroll for audit purposes — effectively making you responsible for premium on work you didn't perform yourself.
Collecting and keeping current certificates of insurance from every subcontractor before they start work is the single most effective way to avoid this surprise.
If you're on a ghost or owner-only policy, the audit works differently
Both terms describe a workers' comp policy for a business with no other employees besides the owner — the difference is whether the owner personally has coverage under it. A ghost policy means the owner signed a waiver excluding themselves; it's a real, active policy, but it exists mainly to produce a Certificate of Insurance for a GC or licensing requirement, and it pays no benefit if the owner is hurt. An owner-only policy means the owner elected to stay covered instead of waiving — same no-other-employee situation, but with a real benefit behind it.
For an audit specifically, a ghost or owner-only policy is usually simple to reconcile — there's little or no payroll to compare against the original estimate. The real risk shows up when that changes mid-term. Since Assembly Bill 2883 (2017), California officers, LLC members and partners are covered by default unless they've actively signed a waiver, so an auditor reviewing officer/owner treatment is also effectively confirming that waiver is still accurate. Hire even one real employee while the policy still reflects an owner-excluded, no-payroll setup, and the audit is exactly where that mismatch gets caught — treated as a real coverage gap, not a rounding error.
State Fund is a common source for ghost and owner-only policies since it can't decline an eligible risk, but it isn't the only one — other carriers will write these too, depending on the specific contractor classification.
Sources for this section
How to avoid a surprise audit bill
Keep clean, classification-coded payroll records throughout the year rather than reconstructing them at audit time, collect subcontractor certificates proactively, and report material payroll or operational changes to your broker mid-term rather than waiting for renewal.
A mid-term update, when payroll is running well above the original estimate, can prevent a large one-time bill by adjusting premium gradually instead.
Three audits from our own client files
Audit problems are rarely about the rate; they are about records. A contractor who ignored an auditor's requests was billed over $30,000 on an estimate, then received a credit once we reopened the audit with actual payroll (case study 10). A dry rot contractor who couldn't show that subs were licensed or insured paid $56,000 more (case study 2). And on the general liability side, a GC who had kept every sub's certificate had an added charge of about $8,000 removed entirely (case study 11).
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Frequently asked questions
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When does a workers comp audit happen?
Typically after the policy period ends, though some carriers audit mid-term for larger accounts — the exact timing depends on your specific policy and carrier.
What happens if the audit shows I owe more premium?
You'll receive a bill for the difference between what was estimated and what actual payroll/classification supports — this is standard, not a penalty.
Can an uninsured subcontractor really affect my audit?
Yes — payments to a subcontractor without their own active workers comp coverage can be added to your payroll for audit purposes, which is why collecting current certificates matters.
How can I avoid a large audit surprise?
Keep classification-coded payroll records throughout the year, collect subcontractor certificates proactively, and tell your broker about material changes mid-term rather than waiting for the audit.
Can I request my own audit before the carrier's scheduled one?
Some carriers allow a voluntary interim audit, which can help avoid a large year-end surprise — ask your broker or carrier directly whether this option is available on your policy.
Does overtime pay count toward audited payroll the same as regular wages?
Often only the straight-time portion of overtime pay counts toward workers comp payroll, with the premium portion excluded — confirm the specific treatment with your carrier, since state rules can vary.
What records should I keep to make an audit go smoothly?
Payroll registers, certificates of insurance for all subcontractors used during the policy period, 1099s, and job cost reports are the records auditors most commonly request.
Does a ghost or owner-only workers' comp policy still go through a premium audit?
Yes, but it's usually simple — there's little or no payroll to reconcile. The real risk is mid-term: if you hire a real employee while the policy still reflects an owner-excluded, no-payroll setup, the audit is exactly where that mismatch gets caught.
If I'm covered by default under AB 2883, why would an audit even look at owner/officer treatment?
Because the auditor is confirming whether an exclusion waiver is actually on file and still accurate. Since AB 2883 (2017), officers, LLC members and partners are covered by default unless they've actively signed a waiver — the audit checks that the paperwork matches reality.