Quick answer: Most IRS audits in 2026 are triggered by the same red flags: large unreported income (especially from a 1099-K), excessive Schedule C deductions, home office claims that look round-numbered, foreign account omissions, large charitable deductions on a modest income, and crypto activity that doesn’t reconcile with what the IRS already has. Filing late or amending late raises the score.
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.
Getting a letter from the IRS is nobody’s idea of a good day. Even taxpayers who file carefully and pay everything they owe can feel a jolt of anxiety at that official envelope – because the truth is, most people have no idea what actually draws IRS attention in the first place.
The IRS doesn’t audit returns randomly. There’s a system, and understanding how it works can make a real difference in how you file. According to TheStreet’s March 2026 report, the IRS audited more than 500,000 returns in fiscal year 2024. While your overall odds of being selected remain under 0.5% at most income levels, certain behaviors and filing patterns raise that risk dramatically.
Here’s what’s actually putting returns on the IRS’s radar right now.
How the IRS picks returns for audit
Before getting into specific triggers, it helps to know the mechanism behind audit selection. Every filed return passes through the IRS’s Discriminant Function System (DIF), a computer scoring program that compares your return against statistical norms for taxpayers with similar incomes, occupations, and filing situations. The higher your DIF score, the more your return deviates from what the IRS considers “normal” – and the more likely it gets flagged for a closer look.
A high DIF score doesn’t automatically trigger an audit. IRS agents review the highest-scoring returns manually. But it puts your return in the pool. The IRS also uses a separate Unreported Income DIF (UIDIF) score specifically designed to identify omitted income.
On top of that, the agency now uses AI-powered data matching. Income reported by employers, banks, brokerages, and payment processors gets cross-referenced against your return. Any gap is a potential flag.
9 common triggers that draw IRS scrutiny
1. Income that doesn’t match IRS records
This is the single most reliable audit trigger. The IRS receives copies of every W-2, 1099-NEC, 1099-INT, 1099-B, and 1099-K sent to you. If your return doesn’t reflect what those forms show, the mismatch gets caught automatically – often before a human being even looks at your file.
Common sources of mismatch: freelance payments you forgot to include, side income from platforms like Venmo or PayPal that now report above the $600 threshold, interest income from bank accounts, and investment proceeds. Missing even one 1099 can trigger a notice.
2. High income
The IRS is explicit about this: audit rates increase significantly as income rises. According to IRS fiscal year 2024 data reported by TheStreet, taxpayers earning between $5 million and $10 million face a 3.1% audit rate. Those earning above $10 million face rates projected to reach 16.5% by 2026, up from 11% in 2019. Even at $1 million to $5 million, you’re looking at roughly 11 audits per 1,000 returns.
More income means more complex returns, more deductions, and more opportunities for discrepancies – all of which the IRS knows and expects.
3. Disproportionately large deductions
The DIF system compares your deductions to what’s typical for your income bracket. If you’re claiming charitable contributions, business meals, home office expenses, or travel costs that are unusually high relative to your earnings, you’ll score higher than peers.
This doesn’t mean you shouldn’t claim legitimate deductions. It means you should be able to document every single one. A receipt you can’t produce in an audit is a deduction you can’t defend.
4. Schedule C losses – especially repeated ones
Self-employed filers filing Schedule C attract IRS attention for a couple of reasons. Cash-based businesses have historically been a vehicle for underreporting income. And businesses that consistently report losses raise a specific question: is this actually a business, or a hobby being used to generate deductions?
The IRS applies a “hobby loss” rule. If your business doesn’t show a profit in at least three of five consecutive years, the IRS may classify it as a hobby and disallow the losses. Repeated Schedule C losses year after year – especially paired with significant W-2 income – sit high on the DIF radar.
5. Claiming 100% business use of a vehicle
Very few people use a vehicle exclusively for business. The IRS knows this, and a 100% business-use claim on a vehicle almost always draws scrutiny. You’ll need a detailed mileage log documenting every business trip, date, destination, and purpose. Without it, the deduction won’t survive examination. A mileage log created after the fact won’t hold up either.
6. Cryptocurrency and digital asset transactions
Crypto enforcement is accelerating fast. Starting with tax year 2025, centralized exchanges are required to issue Form 1099-DA reporting gross proceeds. By 2026, cost basis reporting becomes mandatory as well. As a Forbes report from April 2026 noted, many taxpayers still aren’t complying with crypto reporting requirements despite these new disclosure rules.
Every crypto-to-crypto trade, every sale for fiat, every staking reward, and every airdrop is a taxable event. Leaving the digital asset question on Form 1040 blank – or answering “no” when you’ve had transactions – creates an automatic mismatch that can trigger scrutiny. The IRS has partnered with blockchain analytics firms to trace transactions across exchanges, making “the blockchain is anonymous” an increasingly unreliable defense.
If you’ve had crypto activity and aren’t sure how to handle the reporting, working with a tax attorney who understands the crypto tax landscape is worth doing before filing rather than after.
7. Foreign bank accounts and offshore assets
Failing to disclose foreign financial accounts is a serious compliance issue. U.S. taxpayers with foreign accounts holding over $10,000 at any point during the year must file an FBAR (Foreign Bank Account Report). Additionally, FATCA requires foreign financial institutions to report U.S. account holders to the IRS directly.
When those reports come in but your tax return doesn’t reflect the income, that discrepancy gets noticed. The penalties for willful failure to report foreign accounts can reach $100,000 or 50% of the account balance per violation.
8. Earned Income Tax Credit (EITC) claims
It might seem counterintuitive that lower-income filers face audit risk, but EITC claims draw significant IRS attention due to historically high rates of improper claims. According to Nolo’s audit data, taxpayers earning under $25,000 face audit rates of approximately 0.3% to 0.4% – driven largely by EITC checks. The IRS scrutinizes claimed dependents, filing status, and income figures carefully on these returns.
9. Math errors and data entry mistakes
The least glamorous audit trigger is also one of the most common: simple mistakes. Transposed Social Security numbers, miscalculated figures, mismatched names, or numbers that don’t add up will flag your return before anyone even looks at the substance. While math errors often result in a notice rather than a full audit, they can also pull your return into a broader review.
Filing electronically reduces math errors significantly, but data entry mistakes in address fields, dependent information, or income figures still slip through.
What happens if your return gets flagged
Being selected for audit doesn’t mean the IRS thinks you’re a criminal. Most audits are correspondence audits – the IRS sends a letter asking you to verify or explain a specific item on your return. You respond with documentation and the matter closes.
More complex cases involve office audits (you meet with an IRS agent at a local office) or field audits (the IRS comes to your home or business). Field audits are rare for individual filers but more common for businesses.
An audit can cover one specific issue or your entire return. The IRS generally has three years from the filing date to audit a return – but that window extends to six years if you’ve underreported income by more than 25%. There’s no statute of limitations at all if fraud is involved.
If you receive an audit notice, the single most important thing you can do is not respond alone. What you say – and what documents you voluntarily provide – can expand the scope of the examination. An experienced tax attorney can represent you before the IRS, handle all communications, and make sure your rights are protected throughout the process.
The documentation rule that covers most situations
Most audit triggers share a common vulnerability: poor documentation. If you can prove every deduction, every income figure, and every credit with contemporaneous records, an audit becomes far less threatening. Receipts, bank statements, mileage logs, contracts, and correspondence should be kept for at least three to seven years after filing.
The IRS’s position is simple: if you can’t document it, you don’t get it. That’s not unreasonable. The challenge is that most people don’t build documentation habits until after they’ve already faced a problem.
When an audit turns into something bigger
Some audits stay narrow and resolve quickly. Others expand – especially when the initial examination reveals issues the IRS didn’t originally notice, such as unfiled tax returns from prior years or patterns suggesting systematic underreporting.
If an audit uncovers significant additional tax owed, the IRS will also assess penalties and interest. Accuracy-related penalties run 20% of the underpayment. Fraud penalties reach 75%. Interest compounds daily from the original due date of the return.
At that stage, you’re dealing with more than an audit – you’re dealing with tax debt, possible tax liens or levies, and a much more adversarial collection process. Getting professional representation early in an audit is almost always cheaper and less stressful than dealing with the fallout after an audit goes badly.
The Law Offices of Darrin T. Mish, P.A. has spent over 25 years helping Tampa-area clients and taxpayers across the country navigate exactly these situations – from the moment the first IRS letter arrives through resolution. If your return has any of the red flags discussed above, or if you’ve already received an audit notice, a free consultation costs you nothing and could save you a great deal.
Filing smart starts with knowing what the IRS is looking for. But if the IRS is already looking at you, knowing your rights – and having someone in your corner who understands the system – matters even more.
Frequently Asked Questions
How long does an IRS audit take?
Most audits resolve within 3 to 18 months. Correspondence audits (handled by mail) are the fastest. Office audits and field audits with multiple issues take longer. The complexity of the case affects the timeline.
What triggers an IRS audit?
Common triggers include unusually high deductions relative to income, missing 1099 income (which can trigger a CP2000 first), large business losses claimed multiple years in a row, cash-intensive businesses, and statistical outliers based on the IRS DIF score.
Should I represent myself in an IRS audit?
Most taxpayers should not. The IRS examiner is trained and experienced. Anything you say can be used against you. Having a tax attorney file a Form 2848 means the IRS communicates with the representative instead of you.
Can I appeal an IRS audit decision?
Yes. If the audit results in a proposed assessment you disagree with, you can request a manager conference, then go to the IRS Office of Appeals, then file a Tax Court petition within 90 days of receiving a Notice of Deficiency.
What is the IRS audit statute of limitations?
Generally three years from the date you filed your return, six years if you understated income by more than 25 percent, and unlimited if there was fraud or you never filed.
What is the difference between an audit and a CP2000?
A CP2000 is a computer-generated proposed adjustment based on third-party data mismatches. An audit is a formal IRS examination with broader scope. CP2000s are usually fixable with a simple response. Audits are more involved and can open additional issues.