Workers comp audit guide for insurance agents

Workers compensation premium audits are one of the most common sources of client surprise and frustration in commercial insurance. A business that paid $8,000 in estimated premium during the policy year may receive an audit bill for an additional $4,000 — seemingly out of nowhere. Understanding how audits work and preparing clients in advance is a high-value service that prevents unpleasant surprises and positions you as a trusted advisor.

How workers comp premiums work

Workers comp premiums are estimated at the beginning of the policy period based on projected payroll. Carriers use workers comp class codes and rates to estimate what the premium should be, then charge that estimated premium during the policy year.

At the end of the policy period, the carrier performs a premium audit to reconcile the estimated premium against what it should have been based on actual payroll. If actual payroll was higher than projected — which happens when businesses grow, add employees, or pay more overtime than expected — the insured owes an additional "audit premium." If actual payroll was lower, the carrier owes a refund.

What auditors examine

A workers comp audit examines the business's payroll records in detail. Auditors typically review:

• Federal payroll tax returns (941s, 940s)
• State unemployment tax filings
• Payroll journals and summaries
• Certificates of insurance from subcontractors
• Cash disbursements for labor (1099 payments, cash payments)
• General ledger accounts for labor costs

Auditors are looking for uninsured exposures: payroll that was not reported, additional employees who were added during the year, subcontractors without their own workers comp who may be reclassified as employees, and class code misclassifications.

The subcontractor trap

One of the most common sources of unexpected audit bills involves subcontractors. If a business hires a subcontractor who doesn't have their own workers comp insurance, the carrier may treat those subcontractor payments as "uninsured labor" and add them to the audit payroll — often at a rate that's significantly higher than the base class code rate.

The solution: collect and track certificates of insurance from every subcontractor before they start work. The COI should show workers comp coverage that is active for the period the sub is working. Clients who collect COIs consistently have audit bills that match expectations. Those who don't can face significant surprises.

Building subcontractor COI collection into your client's renewal conversation — and making sure it's tracked — is a high-value advisory service. See our guide to certificates of insurance for the full picture.

Class code classification

Workers comp premiums are heavily influenced by which class codes apply to which employees. Class codes reflect the risk level of the work being performed — a clerical worker (code 8810) is rated at a fraction of a roofing worker (code 5551). Auditors may reclassify employees if their actual duties don't match the class code under which they were insured.

Common reclassification scenarios:

• An "office manager" who also does site visits is reclassified from clerical to a higher-hazard code
• A "salesperson" who actually performs installation work is reclassified to the installation class
• A construction company that added a new trade (e.g., started doing electrical when they previously only did general construction) and didn't update their class codes

Preparing clients for the audit

The best audit preparation happens before the audit. At policy inception and renewal, advise clients to:

• Track payroll by class code throughout the year — many payroll systems can be configured for this
• Collect and file COIs from every subcontractor before work begins
• Notify you of significant changes in headcount or operations mid-year — a large hiring surge in month 3 might warrant increasing the deposit premium to avoid a large audit bill
• Keep 1099s and subcontractor records organized separately from employee payroll

When the auditor arrives, remind clients to cooperate fully — audit avoidance or non-cooperation can result in estimated premium that is less favorable than what actual records would show.

Disputing audit findings

Audit results can be disputed if the auditor made an error — reclassified employees incorrectly, included excluded payroll (overtime premiums above the straight-time rate are often excludable), or included subcontractor COIs that should have been accepted. The dispute process varies by carrier, but generally involves submitting documentation and requesting a review. Agents who stay involved in the audit process can catch errors early and protect clients from overbilling.

Proactive audit preparation is one of the services that separates a transactional agent from a trusted commercial advisor. It's also directly tied to retention — clients who get unexpected $5,000 audit bills without warning look for a new agent at renewal.

Track payroll and subcontractor COIs at intake

AgencyAssist captures payroll by class code and subcontractor details during client intake — setting up a clean audit trail from day one.