A practical guide for California contractors with crews, payroll and subcontractors.
When a workers’ comp audit bill comes in high, six things are worth checking first: payroll that came in above the estimate, payroll moved to a different class code, a payroll split the records don’t support, dual-wage employees placed in the higher-rated class, subcontractor charges, or overtime and other pay adjustments. This guide walks through each check, then a payroll reconciliation and a worksheet you can use with your own records.
The final premium and the balance due are different numbers. The final premium is the policy’s cost after audit. The balance due is what remains after payments and credits are applied. A large balance does not identify the cause—or establish whether the calculation is correct.
Paying every installment on time does not guarantee that the estimated premium covered the final amount. California’s Department of Insurance explains this reconciliation in its workers’ compensation guide.
Ask for the final audit detail by class, the policy and endorsements, and a ledger showing payments and credits. Confirm the policy number and dates. If the audit uses estimated exposure because records were missing, identify what the carrier needs to complete it.
For the broader premium calculation, see our workers’ compensation guide for contractors. Here, work through the six checks below with your own records.
Six checks that help explain a high workers’ comp audit
1. Compare estimated, reported and actual payroll
Build three columns for each month and class: the policy estimate, what you submitted to the carrier, and the amount supported by your records. Added crews, raises and more work can explain legitimate growth. A missed reporting period, duplicate entry or year-to-date total entered as one month can explain a reporting difference.
Start with employee-level detail, including off-cycle checks and corrections. Do not compare a calendar-year total with a policy covering different dates. Follow the reconciliation steps below before deciding that a difference is an error.
Question to resolve: Which month, employee or class accounts for the increase?
2. Identify payroll that changed classifications
Compare the estimated and audited class codes, payroll assigned to each, and the carrier’s rates. The same total payroll can cost more when its distribution changes.
Ask which duties or operations support each change. A job title such as “project manager” does not establish the classification. Office work also has specific eligibility rules; a desk does not automatically qualify an employee for clerical treatment. See WCIRB’s classification inspection and audit guidance.
Question to resolve: What work did the employee perform, and what classification wording did the auditor apply?
3. Test whether your records support a permitted payroll split
When a construction payroll division is allowed, records must show the employee’s remuneration separately by operation, supported by original time cards or time book entries. Trace one pay period from the work record to the class totals. A percentage estimated after the year ends is not a substitute.
Records do not make every split permissible. If required records are missing, the employee’s entire remuneration can be assigned to the highest-rated classification applicable to any part of that employee’s work. Check WCIRB’s division-of-payroll explanation and time-card rules.
Question to resolve: Can you connect the employee, operation, time worked and pay without reconstructing a percentage from memory?
4. Check dual wage employee by employee
Certain California construction trades have companion classifications based on regular hourly wage. Use the trade’s threshold applicable to the audited policy’s effective date. Do not apply today’s threshold automatically to an older policy. WCIRB publishes the approved 2026 threshold changes.
Meeting the threshold and proving it are separate requirements. For nonsalaried employees using time records, those records must include operations, daily hours, and the start and end of each work period. A qualifying collective bargaining agreement with the required employee roster offers another verification route. Salaried employees have separate calculation rules.
The overtime premium does not count toward the regular-hourly-wage test. If wage verification is insufficient, the affected payroll cannot receive the high-wage classification. Review each employee; do not assume one missing record disqualifies the whole crew. See WCIRB’s wage-verification requirements.
For scale, WCIRB’s approved advisory pure premium rates for policies effective on or after Sep 1, 2026 are $20.827 per $100 of payroll for roofing classification 5552 and $12.112 for 5553. Pure premium is not the carrier’s billed rate; your policy’s rates and adjustments determine the premium. The gap shows why wage verification matters, without predicting your bill.
Question to resolve: Was the applicable threshold met under the rule’s calculation, and can the required records establish it?
5. Examine every subcontractor charge
Create a list of subs paid during the policy period. Beside each payment, record the work performed, license information, contract, invoices and workers’ comp coverage dates. Match the insured business name to the subcontractor and confirm coverage for the work dates. A general liability certificate is not proof of workers’ comp coverage, and a 1099 does not settle employment status.
Uninsured or unlicensed labor may generate premium, but the treatment depends on the facts and applicable policy rules. State Fund describes this as a case-by-case audit determination. WCIRB itself does not determine employee versus independent-contractor status.
If a charge appears, ask for its basis and calculation. Provide available actual payroll and separately identified labor, materials and equipment costs; ask how the governing rule treats them. Do not assume every invoice dollar is payroll, or that a claimed exemption automatically removes the charge.
Question to resolve: Why was this sub included, and how was the exposure amount calculated?
6. Review overtime and other remuneration adjustments
The straight-time component of overtime stays in workers’ comp payroll. The additional overtime premium can be excluded when records satisfy the rule, showing the required breakdown by employee and in summary by operation. At a $30 regular rate, a time-and-a-half hour pays $45: $30 remains and $15 is the potential exclusion. Removing the entire $45 would be wrong.
Bonuses and vacation, holiday and sick pay generally count. Expense reimbursements and benefit contributions require their own rule review; a tax deduction is not automatically an insurance exclusion. WCIRB explains the treatment of payroll components.
For owners and officers, check coverage status, the entity and role, any required waiver or election, and its effective date. For covered individuals, verify applicable payroll minimums or maximums. Ownership alone does not answer the audit question.
Question to resolve: Can the auditor show the calculation from gross earnings through each supported adjustment to auditable remuneration?
Reconcile payroll without forcing the tax forms to match
Form 941, DE 9 and DE 9C are useful cross-checks. They do not define workers’ comp remuneration. WCIRB expressly distinguishes insurance payroll from IRS payroll.
- Set the period and entity. Write down the policy dates, insured entities and locations. Export detailed payroll for the term and the surrounding tax quarters. Identify checks crossing the policy boundary and document earned-versus-paid timing with the auditor; do not simply add four quarters.
- Establish the gross-earnings total. Include regular pay, overtime, bonuses, paid leave, manual checks, voids and corrections. Tie the payroll register to the general ledger and explain exceptions. Keep subcontractor disbursements in a separate schedule.
- Reconcile the federal return by wage definition. Form 941 line 2 reports wages, tips and other compensation corresponding to W-2 box 1. Social Security wages on line 5a are subject to a wage-base limit; Medicare wages on line 5c use a different basis. Do not add those overlapping wage lines together or treat any one as universal audit payroll. Use the IRS Form 941 instructions.
- Reconcile California quarterly reports. DE 9 is the quarterly contribution return; DE 9C supplies employee wage detail. Compare corresponding subject-wage totals, and separately explain differences involving personal income tax (PIT) wages. Subject wages, capped UI taxable wages and PIT wages are not interchangeable. Use EDD’s wage definitions and the DE 9 and DE 9C guidance.
- Build the insurance adjustment schedule. Starting from gross earnings for the correct period, list each inclusion, exclusion, owner/officer adjustment and any separately determined subcontractor exposure. Attach the amount, reason, governing rule and supporting record. Then allocate the resulting remuneration to supported classifications.
- Compare with the portal and final audit. Reconcile month by month and class by class. Preserve original submissions and corrections. Ask the payroll professional about actual tax-return errors; do not amend tax filings merely to make them equal the audit.
A sample reconciliation
Illustration only: invented figures for one employee group in one policy period. This is not a client case, a tax-return calculation or a premium quote. Assume no adjustments other than the documented overtime premium.
| Reconciliation line | Amount | What supports it |
|---|---|---|
| Gross earnings for the policy term | $300,000 | Payroll register, including $24,000 total time-and-a-half earnings |
| Less qualifying overtime premium | ($8,000) | $24,000 ÷ 3 applies only because these earnings were paid at time-and-a-half; records meet the overtime rule. Do not use one-third for double-time or mixed-rate pay. |
| Auditable employee remuneration | $292,000 | $300,000 − $8,000; straight-time overtime remains |
| Payroll originally estimated | $250,000 | Policy estimate on the same remuneration basis |
| Increase over the estimate | $42,000 | $292,000 − $250,000; this is payroll, not premium |
The $42,000 difference is not a $42,000 bill. Its premium effect depends on class allocation, carrier rates and applicable policy adjustments. Reconcile payments and credits separately after confirming the final premium.
Your audit review worksheet
Copy this worksheet into your review file. Keep employee identifiers and financial records in your secure records system.
Policy number: __________ Policy period: __________ Audit notice received: __________
Bill due date: __________ Formal response or appeal date, if applicable: __________
Final premium: __________ Payments and credits: __________ Balance due: __________
| Check | Record the difference | Evidence and next action |
|---|---|---|
| 1. Payroll | Estimate ___ / reported ___ / reconciled ___ | Months or employees affected ___; payroll and tax bridge ___ |
| 2. Class codes | Original code ___ / audited code ___ | Duties ___; auditor’s written reason ___ |
| 3. Payroll split | Employee ___ / operations ___ | Time record ___; pay-period trace ___ |
| 4. Dual wage | Trade ___ / threshold ___ / wage ___ | Policy effective date ___; wage proof ___ |
| 5. Subcontractors | Sub ___ / charge ___ / work dates ___ | Coverage and license evidence ___; calculation basis ___ |
| 6. Adjustments | Gross ___ / additions ___ / exclusions ___ | Overtime detail ___; owner or benefit documents ___ |
For each unresolved item, add: amount questioned, document filename, question sent, person responsible, response due, and resolution. Keep “confirmed,” “needs explanation” and “correction requested” distinct.
Send a specific question and preserve your deadlines
Send the auditor or broker the exact audit line, the amount you question and the supporting records. For example: “The portal total for this month includes the same payroll batch twice. Attached are the register and submission receipts. Please reconcile this line and confirm the revised balance, if a correction is warranted.”
Calendar the bill’s due date and all dispute notices while the records are being reviewed. Do not assume an informal email suspends payment obligations or preserves formal appeal rights; obtain written confirmation of any payment arrangement or hold.
For California’s formal process, a Complaint and Request for Action to the insurer or WCIRB precedes an appeal to the Insurance Commissioner. The CDI identifies a 30-day appeal period after service of specified rejections or decisions—not simply 30 days from the audit bill. If a timely written decision is not served, different limits apply: 120 days after service of the complaint, or 60 business days after service of a reconsideration request. Follow the applicable notice and CDI appeal instructions promptly.
Frequently asked questions
Can I owe more even if I paid every installment?
Yes. Installments may have been based on estimated exposure. Confirm the audited calculation, then check that all payments and credits reached the correct policy.
Should my workers’ comp payroll equal Form 941 or DE 9C?
Not necessarily. Reconcile the period, entity and wage definitions, then document the insurance adjustments. An explained difference is more useful than a forced match.
Can payroll be split between office and field work?
Do not assume so. Standard Exception classifications have restrictions; WCIRB generally prohibits splitting one employee’s payroll between a Standard Exception and another class within the policy period, except for a single permanent job reassignment. See its Standard Exception rule explanation.
Does a subcontractor’s certificate guarantee exclusion?
No. Check workers’ comp coverage, business identity, work dates, license and employment-status facts. Ask the auditor what evidence resolves that particular charge.
Does finding a discrepancy guarantee a lower bill?
No. A correction may lower or increase premium, or leave it unchanged. The purpose is an accurate calculation supported by the records.
Put the completed worksheet beside the audit and review the open items with your broker and payroll professional. For common audit mistakes and how to prepare, see Payroll Audits: What Contractors Get Wrong. For help organizing next year’s records, the Contractor Report Library includes Unique Risk’s Workers’ Comp Premium Audit Guide.
Workers' Comp Premium Audit Guide
Scott Henricks is the founder of Unique Risk Management and Insurance Services, a commercial insurance brokerage specializing in California contractors and trades. He has been in the commercial insurance industry since 2003. Unique Risk is licensed in California, Florida, Minnesota, Utah, and New Jersey. 949.305.5577 (Mission Viejo, CA) · 772.254.9221 (Port St. Lucie, FL) · scott@uniquerisk.com · CA Lic #0F56527
This guide provides general education. Policy terms, applicable California rules and the facts of the account determine the result.