I’m Darrin Mish. Tampa tax attorney, 32 years in, more than $100 million in IRS debt resolved. What follows isn’t theory – it’s what I’ve actually watched work.
Nobody wants an IRS audit. But the fear of one is usually worse than the reality. Most audits are straightforward, and knowing what triggers them can help you avoid unnecessary risk.
After three decades of representing clients through IRS audits, here are the things that actually put a target on your return.
1. Income Mismatches
The IRS receives copies of every W-2, 1099, and K-1 issued to you. Their computers match those documents to your return. If you report $85,000 in income but your W-2s and 1099s add up to $110,000, that discrepancy will generate a notice, and it’s one of the most common audit triggers.
This isn’t sophisticated detective work. It’s automated matching. The fix is simple: report all your income. If you think a 1099 is wrong, dispute it with the issuer. Don’t just leave it off your return.
2. High Deductions Relative to Income
The IRS knows what’s typical. If everyone in your income bracket claims $8,000 in charitable deductions and you claim $40,000, that stands out. The IRS uses statistical norms to identify outliers, and being an outlier doesn’t mean you’re wrong, but it does mean you need documentation to back up your claims.
The lesson isn’t to avoid legitimate deductions. The lesson is to keep records that support them.
3. Large Cash Transactions
Cash-heavy businesses attract IRS scrutiny because cash is harder to track. If you run a restaurant, a construction company, a salon, or any business that deals significantly in cash, the IRS pays closer attention to your reported income relative to your business type and size.
Banks report cash deposits over $10,000 to FinCEN, and “structuring” deposits to stay under $10,000 is itself a federal crime. Operate your cash business transparently and keep meticulous records.
4. Home Office Deduction
The home office deduction has a reputation as an audit trigger. That reputation is somewhat earned. The IRS knows it’s commonly abused. To claim it legitimately, your home office must be used regularly and exclusively for business. That spare bedroom that doubles as a guest room doesn’t qualify.
If you do have a legitimate home office, take the deduction. Just make sure you meet the requirements and can prove it.
5. Schedule C Losses Year After Year
Reporting a business loss on Schedule C is perfectly legitimate when your business actually loses money. But reporting losses year after year triggers the IRS’s hobby loss rules. Under IRC Section 183, if your activity doesn’t turn a profit in three out of five years, the IRS may reclassify it as a hobby and disallow the losses.
If you’re running a legitimate business that’s in its startup phase, document your profit motive: business plans, marketing efforts, adjustments to your business model. Show that you’re trying to make money, even if you haven’t gotten there yet.
6. Claiming 100% Business Use of a Vehicle
Unless you have a dedicated work vehicle that never touches personal errands, claiming 100% business use is a red flag. The IRS knows that most people use their vehicles for both business and personal purposes. Claiming otherwise invites scrutiny.
Keep a mileage log. Record the date, destination, business purpose, and miles driven for every business trip. It’s tedious, but it’s the documentation the IRS expects.
7. Unusually Large Charitable Contributions
Charitable giving is encouraged by the tax code, but claiming donations that are disproportionate to your income raises flags. Donating 30% of your income to charity when the national average is around 3% to 5% isn’t illegal, but it will get noticed.
Noncash donations are especially scrutinized. Donating clothes and claiming they’re worth $10,000, or donating a car and claiming full blue book value, are areas where the IRS sees frequent abuse. Get appraisals for high-value noncash donations and keep detailed records.
8. Earned Income Tax Credit Claims
The Earned Income Tax Credit (EITC) is heavily audited because it has a high error rate. The IRS estimates that roughly 25% of EITC claims contain errors. If you claim the EITC, make sure your qualifying children meet all the requirements and your income is accurately reported.
9. Foreign Income and Accounts
The IRS has significantly increased enforcement around foreign income and foreign financial accounts. FBAR (Foreign Bank Account Report) requirements and FATCA (Foreign Account Tax Compliance Act) have given the IRS unprecedented visibility into overseas accounts.
If you have foreign income or foreign financial accounts, report them. The penalties for non-reporting are severe, often worse than the tax itself.
10. Math Errors and Inconsistencies
Simple math errors don’t usually trigger a full audit, but they do generate automated correspondence from the IRS. And once the IRS is looking at your return for one reason, they may notice other issues.
Double-check your return before filing. Make sure the numbers add up and that your entries are consistent across forms.
Knowledge Is Protection
Understanding what triggers an IRS audit isn’t about gaming the system. It’s about filing accurate returns, keeping good records, and not taking shortcuts that invite problems.
If you’ve been selected for an audit or you’ve received a notice, let’s talk about your options. Most audits are manageable with the right preparation and representation.