IRS Audit Red Flags: What I Looked for as a Revenue Agent

IRS Audit Red Flags: What I Looked for as a Revenue Agent

I spent twelve years wearing an IRS badge. Not the scary kind you see in movies—just a government ID that got me into federal buildings and made taxpayers nervous when I pulled it out. I audited hundreds of returns. I know what triggers the algorithms. I know what catches an examiner's eye. And I know how to avoid both.

Here is what I looked for, and what the IRS still looks for today.

Red Flag 1: Schedule C Losses Three Years Running

You claim your "business" lost money in 2023, 2024, and 2025. The IRS sees a hobby, not a business. The hobby loss rule (Section 183) says you must show a profit in three of five years to be presumed legitimate. Fail that, and the burden shifts to you to prove profit motive.

I audited a "horse breeder" once who lost $45,000 annually for six years. Beautiful ranch. No customers. No marketing. No profit motive. Deductions denied. All of them. He owed $180,000 plus penalties. "It is my passion," he said. The IRS does not care about passion. It cares about profit potential.

Red Flag 2: Home Office Deductions Over 20%

Claiming 40% of your home as office space is a neon sign. I have been in enough homes to know what 40% looks like. It looks like a commercial building, not a residence. The exclusive use rule is strict. Break it, and the entire deduction fails.

A real estate agent I audited claimed 35% of her loft. Walked in: treadmill, yoga mat, kids' art supplies. "I work out here sometimes." Deduction denied. $8,400 in back taxes.

Red Flag 3: Charitable Donations Over 10% of Income

Generosity is admirable. But if you earn $50,000 and claim $8,000 in charitable donations, the IRS wonders where that money came from. Cash donations without receipts are audit bait. Non-cash donations over $500 require Form 8283. Over $5,000 requires an appraisal.

I audited a teacher who claimed $12,000 in charitable donations on $48,000 income. No receipts. "I give to my church every Sunday." How much? "Whatever I have in my wallet." We allowed $1,200. She owed $2,800 plus penalty.

Red Flag 4: Business Miles Equal to Total Miles

You claim 28,000 business miles on a car with 30,000 total miles. That means you only drove 2,000 miles personally all year. Possible? Sure. Probable? The IRS doubts it. Mileage logs are required. GPS apps count. Estimates do not.

A contractor I audited claimed 24,000 business miles. His odometer showed 26,000 total. "I do not drive much personally," he said. But his Facebook showed vacation photos from Colorado, Florida, and California. We cross-referenced. Personal miles: 8,400. Deduction reduced. Penalty applied.

Red Flag 5: Round Numbers Everywhere

Business expenses of exactly $500, $1,000, $2,500? Real expenses do not round that neatly. I saw a return with "supplies: $5,000," "travel: $3,000," "meals: $2,000." All round. All suspicious. We dug in. Actual expenses: $2,100, $1,400, $800. The taxpayer had "estimated" to save time.

Red Flag 6: Income Mismatch

Your W-2 says $85,000. Your return says $82,000. The IRS matches every W-2, 1099, K-1, and 1098 against your return. Mismatches generate automatic CP2000 notices. These are not audits—they are automated underreporter contacts. But they feel like audits, and they cost money.

Crypto is the new frontier here. Exchanges now issue 1099-B and 1099-DA. If you do not report, the IRS knows. I had a client get a CP2000 for $47,000 in unreported crypto gains. He thought he was "trading" not "selling." Every trade is a taxable event. Every. Single. One.

Red Flag 7: Claiming 100% Business Use of a Vehicle

Unless you have a dedicated work vehicle that never leaves the job site, 100% business use is almost impossible. I audited a plumber who claimed 100% business use of his Ford F-150. His wife's car was a Honda Civic. Three kids. Soccer practice. Grocery store. "We use my wife's car for everything personal," he said. But his toll transponder showed trips to the mall, movies, and restaurants. We allowed 78% business. He owed $4,200.

Red Flag 8: Large Deductions for "Consulting" or "Management Fees"

These are classic income-shifting schemes. You pay your kids, your spouse, or a shell company "management fees" to move income to lower brackets. The IRS scrutinizes these heavily. Reasonable compensation documentation is required. Arm's-length transaction proof is required.

I audited a dentist who paid his 12-year-old son $18,000 in "consulting fees." The son's "consultation" consisted of occasionally answering the phone. We reclassified it as gift. Gift tax applied. Income tax recaptured. Penalties. It was ugly.

The Audit Lottery: Odds and Reality

In 2025, the IRS audited 0.4% of individual returns overall. But Schedule C filers? 2.1%. Earn over $500,000? 2.4%. Claim the EITC? 1.2%. The odds are low, but the consequences are high. Average additional tax assessed: $6,700. Plus penalties. Plus interest. Plus the eight hours of your life you will never get back.

My Advice: Be Boring

The best tax return is boring. Round numbers are suspicious. Extreme percentages are suspicious. Massive charitable donations are suspicious. Be reasonable. Be documented. Be prepared.

I tell every client: "Pretend you are explaining this deduction to a skeptical IRS agent in a windowless room. Can you? If not, do not claim it."

I used to be that skeptical agent in that windowless room. Now I help people avoid ever meeting someone like me. It is the best career change I ever made. Cooper agrees—he gets way more walks now that I am not driving to audit sites three days a week.

About the author: Michael spent 12 years at the IRS before opening his CPA practice in Austin. He has two kids who think taxes are "boring" and a dog who does not care.

The EITC Audit Risk

The Earned Income Tax Credit is one of the most audited provisions in the tax code. Why? Because it is refundable—if the credit exceeds your tax liability, you get the difference as a refund. And because eligibility rules are complex: income limits, qualifying children, residency requirements, investment income limits.

In 2025, the IRS audited 1.2% of EITC returns vs 0.4% overall. The average EITC audit took 5 hours of taxpayer time and cost $200 in documentation. For a credit worth $600-7,430, that is a heavy burden.

Common EITC errors: claiming children who do not meet residency requirements (must live with you more than half the year), claiming children who do not meet relationship tests, exceeding investment income limits ($11,600 for 2026), underreporting income to stay under thresholds.

I had a client audited for EITC in 2019. She claimed her niece, who lived with her for four months while the niece's mother was in rehab. The niece did not meet the 6+ month residency test. Credit denied: $3,600. Penalty: $720. "I was helping family," she said. The IRS does not care about intentions. They care about rules.

The Foreign Account Reporting Trap

If you have foreign bank accounts with aggregate balances exceeding $10,000 at any point during the year, you must file FinCEN Form 114 (FBAR). Failure to file carries penalties up to $10,000 per violation (non-willful) or 50% of account balance (willful). Criminal penalties possible.

If you have foreign financial assets exceeding certain thresholds, you must file Form 8938 with your tax return. Thresholds: $50,000 single / $100,000 joint at year-end, or $75,000 / $150,000 at any point during the year.

These are separate requirements. FBAR goes to FinCEN. Form 8938 goes to IRS. Different thresholds. Different deadlines. Different penalties. Many taxpayers file one but not the other.

I have a client who inherited $80,000 in a Canadian bank account. She filed Form 8938 but not FBAR. Penalty: $10,000. "I did not know about FBAR," she said. The IRS does not accept ignorance as an excuse. Both forms are required if thresholds are met.

The Trust Fund Recovery Penalty

If you are a business owner with employees, you withhold payroll taxes (income tax, Social Security, Medicare) from employee paychecks. You hold these funds "in trust" for the government. If you do not remit them on time, the IRS can assess the Trust Fund Recovery Penalty (TFRP) against "responsible persons"—owners, officers, check-signers.

The TFRP is 100% of the unpaid trust fund taxes. Personal liability. Not dischargeable in bankruptcy. The IRS actively pursues this. I have seen business owners lose homes, cars, savings over unpaid payroll taxes.

A restaurant owner client fell behind on payroll taxes during COVID. Owed $47,000. IRS assessed TFRP against him personally. He sold his house to pay it. "I thought I could catch up," he said. The IRS does not wait for catch-up.

If you have employees, payroll taxes are sacred. Pay them first. Before rent. Before suppliers. Before yourself. The IRS will destroy you for playing games with payroll taxes.

The Innocent Spouse Relief

If your spouse (or ex-spouse) underreported income, overstated deductions, or committed fraud on a joint return, you may qualify for innocent spouse relief. You must prove: you did not know about the error, you had no reason to know, and it would be unfair to hold you liable.

This is hard to prove. The IRS assumes spouses know what is on joint returns. "I just signed it," is not enough. You need evidence: separate bank accounts, no involvement in finances, domestic abuse, fraud concealment.

I have filed 12 innocent spouse relief requests in my career. Four were granted. Four were denied. Four are pending. The odds are not great. The best protection: file separately if you suspect your spouse is cheating on taxes. Yes, you lose some benefits. But you protect yourself from joint liability.

A client discovered her husband had hidden $200,000 in gambling income on their joint returns for three years. IRS assessed: $89,000 tax, $22,000 penalties, $8,000 interest. She filed for innocent spouse relief. Denied. "You had access to bank statements," the IRS said. She did. She just never looked. Now she owes $119,000. They are divorced. She is paying it off over 10 years.

The Statute of Limitations: Know Your Deadlines

The IRS generally has three years to audit your return from the filing date (or due date, whichever is later). Six years if you underreported income by 25% or more. Indefinitely if fraud is involved. Indefinitely if you did not file.

Keep records for at least six years. I recommend seven. If fraud is alleged, you need records forever. Scan everything. Cloud storage. Back it up. Paper fades. Ink bleeds. Digital is forever.

I audited a taxpayer in 2016 for his 2012 return. Four years after filing. He had thrown away all records. "It was four years ago," he said. The IRS does not care. We reconstructed his income from bank deposits. Deductions denied. All of them. He owed $34,000 plus penalties. Records matter.

My Final Advice

Be boring. Be documented. Be reasonable. Do not round numbers. Do not claim extreme percentages. Do not get creative. The best tax return is the one that never gets audited.

And if you do get audited? Cooperate. Be polite. Provide documentation. Do not argue. The auditor has discretion. Angry taxpayers get worse outcomes. Polite, prepared taxpayers get better ones.

I spent twelve years on the audit side. I saw taxpayers yell, cry, threaten, lie. None of it worked. The ones who got the best outcomes were organized, respectful, and factual. They brought folders. They answered questions directly. They did not volunteer extra information.

Now I prepare clients for audits before they happen. Documentation systems. Record-keeping protocols. "Audit-ready" file structures. If the IRS comes knocking, we open the folder and hand it over. No panic. No scrambling. Just facts.

That is the peace of mind that comes from doing it right. And it is why Cooper gets so many walks these days—I am not driving to audit sites three days a week anymore. I am in my office, helping people stay out of trouble. Much better use of my time.

About the author: Michael spent 12 years at the IRS before opening his CPA practice in Austin. He has two kids who think taxes are "boring" and a dog who does not care.