What triggers an IRS audit for a small business is usually not one mistake but a pattern the IRS's screening systems notice: income that does not match third-party reports, deductions far outside the norm for your industry, heavy cash activity, repeated losses, or workers paid as contractors who look like employees. Some audits are also purely random.
If an audit letter has already arrived, the priority shifts from prevention to response. Call (415) 754-0115 to schedule a free consultation, or reach us through the contact page.
How the IRS picks returns in the first place
Every return runs through automated scoring. The IRS compares your figures with statistical norms drawn from returns in similar industries and income bands, and returns that stand far outside those norms get a closer look from a human classifier. Separately, the IRS matches your return against every Form W-2, 1099 and 1098 filed under your taxpayer identification number. A return can also be pulled because it is connected to another taxpayer under examination, such as a business partner, an S corporation shareholder, or a vendor.
Being flagged is not an accusation of fraud. Many examinations close with no change, or with a small adjustment. But you should understand what drew attention, because that is where the examiner will focus.
Eight common IRS audit triggers for small businesses
1. Income that does not match 1099 and 1099-K reports
Payment processors, marketplaces and clients report what they paid you. If your gross receipts come in lower than the total of those forms, the mismatch is flagged automatically. A frequent innocent cause: income reported on both a 1099-NEC and a 1099-K for the same job, or deposits that include sales tax or refunds.
2. Deductions that are large relative to income
A business that reports modest revenue but very high travel, meals, or vehicle costs stands out. The deduction may be legitimate; the question is whether you can document it.
3. A cash-intensive business
Restaurants, salons, car washes, contractors and retailers that take cash are examined more closely because cash is easy to underreport. Examiners in these cases often reconstruct income from bank deposits and personal spending.
4. Losses year after year
Tax law presumes an activity is carried on for profit if it shows a profit in at least three of five consecutive years. A business that loses money most years may face questions about whether it is really a hobby, which would limit the deductions.
5. Worker classification
Paying people as independent contractors when you control how, when and where they work can lead to an employment tax examination. California applies its own, often stricter, classification rules for state purposes, which can compound the problem.
6. Vehicles claimed at full business use
Claiming that a car is used only for business, especially when it is the only car in the household, invites questions. Vehicle expenses require specific records, including a mileage log.
7. Round numbers and estimates
Figures that end in neat zeros suggest estimates rather than records. That can make an otherwise reasonable return look unsupported.
8. Owner compensation in an S corporation
Owners who take distributions but little or no salary may face scrutiny over whether they paid themselves reasonable compensation for the work they do.
What happens once your business is selected
The IRS begins every audit by mail. It does not start with a phone call or an email demanding payment, and scam calls often pretend otherwise. The letter will say whether the examination is:
- A correspondence audit, handled by mail and usually limited to a few items.
- An office audit, where you or your representative meets an examiner at an IRS office.
- A field audit, where a revenue agent visits your business, home or your representative's office and reviews your books in more depth.
Your first steps
- Note every deadline and the tax years named in the letter.
- Gather the return, the general ledger, bank statements and source documents for the flagged items.
- Avoid sending the IRS more than it asked for; stay within the scope of the request.
- Consider whether you want a representative to handle communications before the first contact.
If the records are incomplete
Missing receipts do not automatically mean a deduction is lost. Many expenses can be rebuilt from bank and card statements, vendor copies and calendars. Certain categories, such as vehicle, travel and gift expenses, have stricter substantiation rules, so it pays to know early which items are at risk.
Where legal help fits in
Many small business owners handle a simple mail audit on their own. Owners tend to bring in counsel when the audit covers several years, when income reconstruction is involved, when employment taxes are at issue, or when they fear the examiner will find something beyond the original questions. The Somal Law Firm, led by attorney Bob Somal, Esq., represents individuals and small businesses in Pleasanton, the Tri-Valley and across Alameda and Contra Costa Counties in IRS audits, disputes and appeals. For a broader look at the audit process in this state, read our overview of IRS audit help in California.
If the audit ends with a balance you cannot pay in full, there are collection options to consider afterward, and our guide to IRS tax debt relief options explains how they differ.
Frequently asked questions
Does filing a Schedule C increase audit risk?
Sole proprietors report income and expenses themselves with little third-party verification of expenses, so Schedule C returns tend to receive more attention than wage-only returns. Good records are the best protection.
How far back can the IRS audit my business?
Generally three years from the date the return was filed. The period extends to six years if income was substantially understated, and there is no limit if a return was never filed or was fraudulent.
Can an amended return reduce my audit risk?
Correcting a genuine error can be wise, but amending a return is a legal decision with consequences of its own. An attorney can review your situation before you file anything new.
When you contact the firm, you will be asked about the letter, the years involved and the type of business you run, and then scheduled for a free consultation to talk through a response plan. Call (415) 754-0115 first, or use the online contact form if you prefer.
Attorney Advertising. This article is general legal information for Bay Area residents, not legal advice, and does not create an attorney–client relationship. Every situation is different — please consult a licensed attorney about your specific circumstances.