The IRS isn't reading your return. A computer is.
WHAT THE IRS LOOKS FOR IN AN AUDIT
The IRS isn't reading your tax return.
Not at first. A computer scores it.
Every return filed in America gets a DIF score (Discriminant Function). The algorithm compares your deductions, income, and expense ratios against statistical norms for your industry and income level. Returns that deviate from the pattern get flagged.
The IRS also runs targeted campaigns and occasional random pulls, but for most small business returns the first gatekeeper is a score, not a person.
If your return looks like the other clean returns in your lane, you're less interesting. If it doesn't, a human takes a closer look.
The audit rate for individual filers in the $100K–$500K income range is 0.1%. 1 in 1,000. The odds of being selected are low. But 9 out of 10 people who do get audited walk out owing more money. The question isn't whether you'll get selected. It's whether you're ready if you are.
It's part science, part art. The science is the scoring algorithm. The art is that your return has to look normal for your income level and industry.
Here's where returns stop looking normal.
THE THREE TRIGGERS THAT FLAG RETURNS
1. Income mismatches
This is the most common trigger and the least glamorous.
The IRS receives copies of every 1099-NEC, 1099-K, and W-2 issued to you. They match those figures to your return.
No human involved.
If a client paid you $47,000 and issued a 1099-NEC but your return shows $40,000 in revenue, a computer flags it before an examiner ever sees the file.
Miss one 1099 and the IRS assumes the full amount was taxable with no additional deductions, then sends a CP2000 proposing extra tax. This isn't an audit. It's a math correction. But it generates the same letter, the same bill, and the same panic. Ignore it, and it escalates like any other IRS balance.
If the CP2000 is wrong, respond with your records. The IRS will adjust it. But you have to respond.
2. Expense ratios outside your industry norm
Reporting $80,000 in expenses against $100,000 in revenue on a Schedule C isn't suspicious on its own. It depends on your industry.
A staffing business at 75% expense ratio looks normal. A consulting business at 75% raises a flag.
The IRS has industry benchmarks and knows what margins look like for your business type. The DIF score doesn't know your whole story. It knows you don't look like the other consultants in your revenue range.
The deductions themselves aren't the problem. The ratio is. If the ratio looks wrong, the documentation has to be airtight.
Large vehicle deductions under Section 179 or bonus depreciation, client and business meals claimed at 100% instead of 50%, and home office claims that don't match declared square footage are common deduction-level flags.
These surface as correspondence audits (a letter requesting specific documentation), not a field exam.
3. S-Corp salary mismatches
This one is where the real money is at stake.
Between Social Security wage data and Bureau of Labor Statistics surveys, the IRS knows what your role pays in your geography. When an S-Corp owner reports $400,000 in profit and pays themselves $30,000, the algorithm knows that's not a defensible market rate for any profession.
The examiner's move: recharacterize the distributions as wages. Assess back payroll taxes plus penalties and interest.
In more serious payroll tax cases, they pursue trust fund penalties against you. That liability follows you, not the business.
On a $250,000 profit with a $30,000 salary, the back payroll tax exposure alone in a case like this runs $25,000 to $35,000. With penalties and interest, it clears $40,000.
WHAT AN EXAMINER ASKS FOR
Most small business owner audits at this level start as correspondence audits.
You get a letter. It names a specific tax year, a specific issue, and a list of documents to provide. The notice tells you how long you have. Plan on 30 to 60 days depending on the notice type. Send a complete, organized response on time. Many audits stop right there.
The IRS is not coming to your office. They want documentation for the specific items they flagged.
The burden of proof is on you. Every number on your return, you have to substantiate. The IRS doesn't prove you're wrong. You prove you're right. No documentation means no deduction.
For a vehicle deduction: your mileage log, the odometer reading at start of year, and documentation of business purpose for each trip.
For a home office: square footage of the office, total square footage of the home, proof the space is used regularly and exclusively for business.
For a contractor expense: the 1099-NEC you issued, the contract, and evidence of services rendered.
The audit lives or dies on whether those documents exist and match the return.
Most audits that result in additional tax don't end because the deduction was wrong. They end because the documentation wasn't there. An examiner who can't see the mileage log disallows the deduction.
The math on getting caught is brutal: a $20,000 deduction that doesn't hold up costs $40,000 by the time tax, penalties, and interest are done.
THE HOME OFFICE MYTH
The most expensive misunderstanding in my client base: business owners skipping the home office deduction because they've heard it triggers audits.
By itself, it doesn't trigger audits.
Claiming a home office that doesn't qualify triggers audits. Claiming 800 square feet when your office is 180 triggers audits. Claiming a room your kids use for homework triggers audits.
A dedicated room, used regularly and exclusively for business, documented with square footage and photographs, with a calculation of the home office percentage applied to rent or mortgage interest and utilities. That's a routine deduction.
A solo consultant with a 200-square-foot dedicated office in a 2,000-square-foot home has a 10% home office allocation. If that home costs $3,500 per month in rent and utilities, the deduction is $4,200 per year.
Skipping it out of fear costs $4,200. Every year. $21,000 over five years.
Take the deduction. Document the deduction. Those are not the same thing.
THE FIX IS DOCUMENTATION, NOT FEWER DEDUCTIONS
$380,000 in distributions. $40,000 salary. Two years of S-Corp filings.
The IRS sent a letter. We spent eight months on a response and wrote a $52,000 check.
The documentation existed. He hadn't made the case before the IRS made it for him.
The goal isn't to claim less. It's to document more.
Three things to have before your return is filed:
- A mileage log with dates, destinations, and business purpose. Not an estimate, not a reconstruction from memory in March. The IRS knows what reconstructed logs look like.
- A home office measurement and photo on file. One time. Five minutes.
- A reasonable compensation analysis for your S-Corp salary. Not a formula you found online. A documented market rate for your role and geography, pulled from BLS.gov or RCReports.com, with a written record of how you landed on your number.
SO WHAT SHOULD YOU DO?
Pull your salary-to-distribution ratio today. Not this quarter. Today.
If your salary is a fraction of what you'd pay someone else to do your job full-time, that's a red flag worth fixing. If your salary doesn't match what the market pays for your role and your distributions are carrying the load, the ratio doesn't matter. The salary doesn't hold up. Your CPA should be able to tell you in 30 minutes whether your number is defensible.
If you're on Schedule C with expenses over 60% of revenue, open your mileage log right now. Check that it has dates, destinations, and business purpose for every trip. Not a total mileage number and a blank column.
If you've been skipping the home office deduction, measure the room. Take a photo. Write down the square footage. Do it this week, not in March.
A 30-minute call with Visor will tell you whether your salary is defensible, what the documentation gaps are, and whether there's money worth going after.
Schedule the call today. It’s money in your pocket.