Year-End Workers Comp Audit Prep Playbook

1. 1

   Pull complete payroll registers for the policy year

   The audit's base document is your payroll. Pull:

   • Quarterly 941 returns filed with IRS
   • State unemployment quarterly returns (UI / SUTA)
   • W-2s issued for the calendar year that overlapped your policy term
   • 1099-NECs issued (auditors will ask)
   • Payroll-service summary reports (Gusto, ADP, Rippling, etc.)

   These should reconcile: 941 totals = sum of all W-2 wages = payroll service total. Discrepancies here become discrepancies the auditor magnifies.

   💡 Tip: If your payroll service is one-click for these reports (most are), do this step in 10 minutes. If you're on manual payroll, this is your wake-up call to switch services before next audit.
2. 2

   Separate payroll by NCCI class code

   WC premium is calculated as (payroll ÷ 100) × class code rate × experience mod for each NCCI class code. Different employee jobs have different class rates — a clerical employee (8810, ~$0.40/$100) vs a roofer (5551, ~$30+/$100) is a 75x difference in rate per dollar of payroll.

   Most small businesses have one or two governing class codes. If you have employees in multiple roles, you need internal records that map each W-2 employee to their NCCI class code by week or pay period. Without this, the auditor will apply your highest class rate to ALL payroll — the worst-case result.

   💡 Tip: Pull your inception declarations page and confirm what class codes your premium was based on. If your operations have shifted mid-year, this is the time to discuss reclassification with the auditor.
3. 3

   Apply state-specific payroll definitions

   Payroll definitions for WC are NOT identical to IRS payroll. State-by-state variations:

   • Overtime: most states allow excluding the OT premium portion (the "half" in time-and-a-half), counting only straight-time wages. CA allows. TX, FL, NY most also allow.
   • Bonuses: generally INCLUDED in WC payroll
   • Vacation/sick/holiday pay: generally INCLUDED
   • Employer-paid 401(k) match: most states EXCLUDED
   • Section 125 / cafeteria plan deferrals: most states INCLUDED (paid in lieu of cash wages)
   • 1099 contractors: EXCLUDED IF properly classified — uncertificated 1099s get reclassified to W-2 equivalent
   • Owner draw: handled separately per state — usually subject to minimum/maximum payroll bands

   If your auditor uses raw IRS-payroll total without applying these adjustments, the audit-bill is inflated.

   💡 Tip: Some states (CA most aggressively) cap individual employee payroll at a maximum per week. CA cap is $1,755/week for most class codes in 2026 — wages above this aren't counted. Verify whether your state has caps.
4. 4

   Verify 1099 contractor classification and collect Certificates of Insurance

   1099 contractors are excluded from WC payroll only if they meet your state's contractor test (typically: separate business, separate liability insurance, no W-2-like behavior). And only if they carry their own workers comp.

   The auditor will ask for COIs from every 1099 you paid. For contractors who:

   • Have current WC COI: excluded from your payroll
   • Don't have WC COI: reclassified into your payroll at your highest applicable class rate
   • Look like W-2 employees (one client, set hours, your equipment): reclassified regardless of COI

   This step costs the most money for small businesses that didn't collect contractor COIs throughout the year.

   💡 Tip: Before audit day, request COI from any uncertified 1099. They likely already have a GL/WC COI for other customers. See <a href="/resources/certificate-of-insurance-request-playbook">COI Request Playbook</a>.
5. 5

   Reconcile against your initial payroll estimate + budget for variance

   Compare your finalized actual payroll to the estimate at policy inception. Calculate the delta and budget for the bill before audit day so you're not surprised:

   (Actual payroll - Estimated payroll) ÷ 100 × class rate × experience mod = Estimated additional premium

   Common scenarios:

   • +50% payroll growth: expect ~50% additional premium bill
   • -25% payroll shrinkage: expect ~25% refund or credit
   • +200% growth: bill could be larger than your original annual premium — plan cashflow accordingly
6. 6

   Prepare for the audit format (physical, phone, mail)

   WC audits come in three formats. Know which you have:

   • Physical / on-site: Auditor visits your location with notice. Reserve 1-2 hours. Have all documents in a folder ready.
   • Telephone: Scheduled call (45-90 min). Have documents on hand or email-ready.
   • Mail / self-report: Carrier sends a worksheet; you complete and return with documentation copies. Read instructions twice.

   If you don't know which format you have, call your agent or the carrier 60 days before policy renewal.

   💡 Tip: Auditors are not adversaries — they're field reps following a process. Be cooperative, document-ready, and politely clarify their assumptions. A 15-minute clarification call beats a 6-month dispute.
7. 7

   Document everything; never sign the auditor's worksheet without review

   At the end of the audit, the auditor produces a worksheet showing:

   • Final classified payroll figures
   • Class code applied to each payroll bucket
   • Total premium calculation
   • Additional premium owed (or refund)

   Review carefully BEFORE signing. Common errors:

   • Wrong NCCI class code applied (your industry vs auditor's interpretation)
   • Missed contractor COIs (excludable but counted)
   • Wrong state payroll definitions (OT premium portion not excluded)
   • Math errors (rare but happen)

   If something looks wrong, do NOT sign. Mark items in dispute and request the carrier's audit-review process. You typically have 60-90 days to dispute.

   💡 Tip: Save the audit worksheet, original dec page, payroll registers, and contractor COIs together. If you switch carriers next year, the new carrier's first-year audit is easier with this packet.