Most small business audits are not random. The IRS selects returns because specific, identifiable patterns in a return deviate from statistical norms the agency has built over decades. Understanding those patterns is the first step to reducing audit risk. Owners who want defensible filings can also work with a professional who has untangled these situations before.
Table of Contents
- How does the IRS decide which returns to audit?
- What are the most common red flags on a small business return?
- Do large deductions or big changes in expenses increase audit risk?
- Are cash businesses and certain industries audited more often?
- How likely is an audit, and who gets audited the most?
- What should an owner do if they are selected for an audit?
- What happens if an audit finds a problem?
- How can a business owner reduce the risk of an audit?
- Key Takeaways
- References
How does the IRS decide which returns to audit?
The IRS uses computer screening that compares every return against "norms" for similar returns. Those norms come from a statistically valid random sample of returns studied under the National Research Program, according to the IRS.
Returns can also be selected through related examinations. If a business partner or investor has a return selected for audit, the IRS may examine transactions involving other taxpayers connected to that return.
All returns pass through automated and human review layers. A flagged return is not always an audit. Some flags are identity verification checks, not examinations of income or deductions, according to TurboTax.
The IRS notifies taxpayers by mail, never by telephone. Audits are conducted by mail or through an in-person interview at an IRS office, the taxpayer's home, or the place of business.
What are the most common red flags on a small business return?
Unreported income is the easiest trigger to avoid and the easiest to overlook. The IRS receives copies of W-2s and 1099s, and its systems automatically compare that data against the amounts reported on a return, according to Empower. A 1099 that does not appear on the return can trigger further review.
Claiming 100% business use of a vehicle draws attention. If the owner has no other personal vehicle registered in their name, the claim becomes nearly impossible to support, according to Empower.
Business travel and meal expenses face scrutiny because of past abuse. The IRS expects records showing who attended and the specific business purpose, not just a receipt, according to Empower.
Reporting a loss year after year can lead the IRS to question whether the activity is a business or a hobby, according to The Hartford.
Do large deductions or big changes in expenses increase audit risk?
Yes. The IRS compares itemized deductions against the average total deductions claimed by other taxpayers in the same income range. Deductions that exceed those averages may be scrutinized, according to Empower.
A drastic change in expenses from one year to the next can raise flags. Charging all meals during the workday as business expenses when that pattern did not exist before is one example, according to The Hartford.
A legitimate business expense must be both ordinary and necessary. Ordinary means common and accepted in the trade. Necessary means helpful and appropriate for the trade, according to The Hartford.
The home office deduction is only valid if a portion of the home is used regularly and exclusively for business, according to Empower.
Are cash businesses and certain industries audited more often?
Yes. The IRS has extensive experience auditing self-employed taxpayers who operate primarily in cash. Restaurants, beauty salons, and barbershops face higher audit risk because income is easier to underreport, according to The Hartford.
Misreporting income on Schedule C increases the chance of being selected. That includes rounding up income, averaging income, or not reporting all income, according to The Hartford.
Employee misclassification is a specific trigger. The IRS defines an independent contractor as someone who controls what work gets done and how. The payer only dictates the result of the work, according to The Hartford.
The IRS also runs a compliance campaign focused on cryptocurrency transactions. Virtual currency activity is under increased scrutiny, according to Empower.
How likely is an audit, and who gets audited the most?
From 2020 to 2023, less than 0.50% of individual returns were selected for audit. That is the lowest published audit rate since 1950, and audit rates have fallen by two-thirds since 2010, according to Empower.
The IRS is allocating more audit resources to higher-income, higher-complexity taxpayers. Most audits target individuals earning more than $200,000 or corporations with more than $10 million in assets, according to TurboTax.
A refund does not trigger an audit. Filing an amended return does not affect the selection process of the original return, though the amended return itself goes through screening, according to the IRS.
The statute of limitations for the IRS to review a return is generally three years from the due date or the filing date, whichever is later, according to Empower.
What should an owner do if they are selected for an audit?
The IRS requires taxpayers to keep all records used to prepare a return for at least three years from the filing date. For mail audits, a one-time automatic 30-day extension is generally available upon written request, according to the IRS.
A Notice of Deficiency changes the timeline. The IRS cannot grant additional time to submit documents, and the window to petition the U.S. Tax Court is limited to 90 days, according to the IRS.
Spencer Accounting Group helps business owners facing multi-state sales tax exposure or who are behind on filings. The same discretion applies to audit support. Their Sales Tax Resolution service covers nexus review, exposure quantification, voluntary disclosure, and getting current with each state.
This article is general information, not tax advice for a specific situation. An owner facing an audit should consult a qualified professional.
What happens if an audit finds a problem?
If the IRS finds errors, the outcome depends on what was misreported. The process can result in additional tax owed, interest, and penalties, but the specific result depends on the facts of the return.
The IRS watches Earned Income Tax Credit claims closely to prevent fraud, according to Empower. Errors in that area carry their own scrutiny.
An audit does not automatically mean fraud. Many findings are simple mismatches or record-keeping gaps that can be resolved with proper documentation.
The IRS conducts audits by mail or through an in-person interview. The interview can be at an IRS office, the taxpayer's home, or the place of business, according to the IRS.
How can a business owner reduce the risk of an audit?
The most effective step is accurate reporting of all income. Third-party information returns make discrepancies easy for the IRS to spot, according to Empower.
Keep documentation for deductions. For travel and meals, that includes the business purpose and who attended. Avoid claiming 100% business use of a vehicle unless it is strictly true.
Report a profit in at least three of every five years to support that an activity is a business rather than a hobby, according to Empower.
Clean, reliable books maintained year round remove the guesswork at filing time. Spencer Accounting offers Bookkeeping and Tax Filing services that keep the numbers usable for decisions and defensible in a review.
Key Takeaways
- Less than 0.50% of individual returns were audited from 2020 to 2023, the lowest rate since 1950.
- The IRS compares every return against statistical norms developed from a random sample of returns.
- Unreported income is the most common and most avoidable audit trigger because the IRS automatically matches W-2s and 1099s.
- Claiming 100% business use of a vehicle is a red flag unless there is a separate personal vehicle.
- The IRS defines a deductible business expense as both ordinary and necessary.
- Cash-intensive businesses face higher audit risk because income is easier to underreport.
- The IRS generally has three years from the due date or filing date to audit a return.
References
- IRS audits — Internal Revenue Service — date unknown
- IRS audit triggers — Empower — published 2025-11-17
- Top 4 Red Flags That Trigger an IRS Audit — TurboTax — updated 2026-08-04
- 6 Small Business Tax Audit Triggers — The Hartford — date unknown