An IDES audit is an Illinois Department of Employment Security review of your payroll records to check that you reported wages and paid unemployment insurance contributions correctly. Most of the money in these audits comes from one question, whether people you paid as independent contractors were employees under Illinois law. If IDES issues an assessment, you have 20 days to file a written protest, and after that the assessment is final. Victory Tax Lawyers helps Illinois employers prepare for the audit, test their classification position honestly, and respond before the protest window closes.
Contact us today and let us look at your IDES audit notice.
Victory Tax Lawyers, LLP is a California-licensed firm. Our attorneys are admitted in California and to the United States Tax Court, not in Illinois. We help with the audit and records work, and where a hearing or court review needs an Illinois-admitted attorney, we coordinate with Illinois counsel.
What Is an IDES Audit?
IDES runs a field audit program. Its Guide to the Illinois Unemployment Insurance Act describes it as a program "to monitor the accuracy of the employer's wage reports and assist in the collection of employer contributions." A Department representative visits and examines "the payroll records to verify the accuracy of the wage reports." The Guide notes that an audit can produce additional contributions or, sometimes, a refund.
The reports being checked are the quarterly wage reports on Form UI-3/40. IDES says they are due, with contributions, on or before April 30, July 31, October 31, and January 31. For 2026, IDES lists a taxable wage base of $14,250 per worker, a standard rate for most new employers of 3.350%, and experience rates from 0.750% to 7.050%.
IDES unemployment tax is separate from Illinois income tax withholding, which the Illinois Department of Revenue collects. An IDES audit will not look at your IL-941 filings, but a classification finding in one agency often raises questions in the other.
What Triggers an IDES Audit?
IDES does not publish how it chooses employers for field audits. What its Guide does describe are the checks that surface problems.
- The wage and claims crossmatch. IDES matches each employer's quarterly wage report against its own benefit payment records. A worker who files for unemployment benefits and has no reported wages from you raises an obvious question.
- Random claim reviews. Each week IDES selects a sample of benefit claims for review, which includes verifying the employer's wage records.
- Misclassification complaints. The Illinois Department of Labor says complaints filed through its misclassification system are shared with IDES.
In our experience, the most common starting point is a former worker you treated as a contractor filing an unemployment claim. The claim itself is not the audit, but it tells IDES where to look.
How Does the Illinois ABC Test Decide Worker Classification?
Illinois uses its own three-part test for unemployment insurance. Under 820 ILCS 405/212, services performed for pay are employment unless it is proven that all three of these are true:
- The worker has been and will continue to be free from control or direction over the performance of the services, both under the contract and in fact.
- The service is either outside the usual course of your business, or performed outside all of your places of business.
- The worker is engaged in an independently established trade, occupation, profession, or business.
Fail any one, and the worker is an employee for unemployment insurance purposes. The burden is on the business. IDES restates the test on its employee misclassification page.
The second part is worth reading closely, because it differs from California's version. Illinois lets a business satisfy it by showing the work was done outside all of its places of business, even if the work is in the usual course of the business. A remote bookkeeper for an accounting firm may pass that part in Illinois where the same arrangement would fail in California. That does not settle the other two parts, and a contract calling someone a contractor settles nothing on its own.
Construction has an additional law. The Employee Classification Act, 820 ILCS 185/10, applies its own test to construction contractors and is enforced by the Illinois Department of Labor. The Department of Labor lists fines of up to $1,000 per violation in a first audit and up to $2,000 per repeat violation within five years.
What Happens If IDES Finds Unreported Wages?
IDES issues a determination and assessment for the unpaid contributions, and the costs stack up quickly.
| Rule | What it means for an employer | Source |
|---|---|---|
| 4-year assessment window | IDES generally cannot assess wages paid more than four years back; the limit does not apply to willful evasion, knowingly false statements, or failure to disclose | 820 ILCS 405/2207 |
| Interest at 2% per month | Late contributions accrue interest daily at 2% a month; IDES may waive interest for good cause | 820 ILCS 405/1401 |
| Late report penalties | Penalties for late wage reports, with a $50 minimum | 820 ILCS 405/1402 |
| Fraud penalty | 60% of the contribution, at least $400, for willful non-payment with intent to defraud | 820 ILCS 405/1402 |
| Personal liability | Officers or employees who willfully fail to report or pay can be assessed personally | 820 ILCS 405/2405 |
Two items in that table surprise business owners most. Interest at 2% a month is 24% a year, which IDES itself cites on its misclassification page. And personal liability works through the same process the Illinois Department of Revenue uses for unpaid trust taxes, so forming a corporation or LLC does not automatically protect the person who ran payroll.
How Do You Contest an IDES Assessment?
The deadline is short. Under 820 ILCS 405/2200, a determination and assessment becomes final 20 days after service of the notice unless you file a written protest and a petition for a hearing. IDES's Guide says the protest can be delivered in person, postmarked, or filed on MyTax Illinois within that time.
Here is how the process runs after a timely protest:
- A hearing officer, acting as the Director's Representative, holds a telephone or in-person hearing. The assessment is presumed correct, and the burden is on the employer.
- The Director's Representative files a report with a recommended decision. You have 20 days from its mailing to file specific objections.
- If no objections are filed, the recommendation becomes the Director's final decision.
- A final decision can be reviewed by the circuit court of the county where the hearing was held, under the Administrative Review Law.
There is a second route. You can pay the contributions and file a refund claim within three years, then petition for a hearing within 20 days of a denial. IDES's Guide also notes that free legal help is available at Department hearings for small employers with fewer than 20 employees, which is worth knowing before you hire anyone.
How Should You Respond to an IDES Audit Notice?
What happens before the auditor arrives often decides the result. These are the steps we recommend.
Step 1: Calendar Every Date
Note the audit appointment and any document deadline. If an assessment has already issued, the 20-day protest date comes before everything else.
Step 2: Gather the Payroll File
IDES requires employers to keep wage records for five years. Pull the UI-3/40 reports, payroll registers, 1099s, W-2s, contractor agreements, and invoices for the audit period.
Step 3: Test Each Contractor Relationship Honestly
Run every worker paid on a 1099 through all three parts of the Illinois test. Separate the defensible relationships from the ones that are not, so the strategy fits the facts.
Step 4: Answer What Is Asked
Respond fully and on time, and keep the response to the records requested. Volunteering unrelated material can widen the audit to new workers or new quarters.
Step 5: Get Help Before the Interviews
An auditor who hears the working relationship described badly will write it down that way. Preparing for those conversations is usually worth more than arguing about them later.
Step 6: Review the Assessment Line by Line
Check the workers included, the wages counted against the $14,250 wage base, the quarters, and the rate applied. Errors in the math are common and easy to miss.
Step 7: Protest Within 20 Days
If the assessment is wrong, file the written protest and hearing petition on time. A separate sworn application can ask IDES to waive interest or penalties for good cause, and it has its own 30-day deadline.
How Does Victory Tax Lawyers Help With IDES Audits?
We start with exposure. That means the audit notice, the quarters at issue, and the list of workers, followed by an honest classification analysis so you know the realistic range before anything goes to IDES.
We then organize the payroll response, so it is complete and limited to the request, and we help you prepare for the auditor's questions about how your workers operate. Where the audit has produced an assessment, we review the calculation, help assemble the protest within the 20-day window, and coordinate with Illinois counsel if the case goes to a hearing or to circuit court and needs an Illinois-admitted attorney.
IDES findings rarely stay with IDES. A worker reclassified for unemployment insurance can lead the IRS to ask about federal employment taxes for the same people. Our payroll tax page covers the federal side, which is our core practice, and our Illinois tax attorney page explains how we divide state and federal work. For the California version of this audit, see our EDD audit representation page.
Ready to Talk About Your IDES Audit?
The two dates that matter are the audit's document deadline and the 20-day protest window, and the second one does not move. Bring the IDES notice, your UI-3/40 reports, and any contractor agreements to a free consultation. We can walk you through where the exposure sits and what a defensible position looks like.
Reach out to Victory Tax Lawyers today to review your IDES audit.
Frequently Asked Questions
These are the questions Illinois employers ask most often when IDES opens an audit.
What Does an IDES Audit Examine?
It examines your payroll records to verify that your quarterly wage reports were accurate and that you paid the right unemployment insurance contributions. Most audits turn on whether workers paid as independent contractors were employees under Illinois law.
What Is the Illinois ABC Test for Unemployment Insurance?
It is the three-part test in 820 ILCS 405/212. A worker is an employee unless the business proves the worker is free from its control, the work is outside its usual course of business or outside all of its places of business, and the worker has an independently established business.
How Far Back Can IDES Assess Contributions?
Generally four years after the last day of the month following the quarter in which the wages were paid. That limit does not apply to willful evasion, knowingly false statements, or failure to disclose.
Can I Be Held Personally Liable for Unpaid IDES Contributions?
Yes. An officer or employee responsible for filing reports and paying contributions who willfully fails to do so can be assessed personally, through the same process the Illinois Department of Revenue uses for unpaid trust taxes.
How Long Do I Have to Protest an IDES Assessment?
20 days from service of the notice of determination and assessment. You file a written protest and a petition for a hearing, and if you miss the deadline the assessment becomes final.
Legal Disclaimer: The information on this page is provided for general educational purposes and is not legal or tax advice. IDES audit procedures, contribution rates, wage bases, penalty and interest rules, and protest deadlines change over time and depend on the facts of each matter. Worker classification turns on the particular working relationship, and no general description can determine how the Illinois test applies to your workers. Victory Tax Lawyers, LLP attorneys are licensed in California and admitted to the United States Tax Court; they are not admitted to practice law in Illinois, and matters that require an Illinois-admitted attorney are handled with Illinois counsel. Reading this page does not create an attorney-client relationship. Past results do not guarantee future outcomes.
