Tax Preparers Warn: This Side Income Mistake Triggers Extra Scrutiny

January 8, 2026

Like most people these days, I have a side gig. The so-called gig economy is booming, from weekend Instacart runs to late-night Etsy sales. However, tax preparers are warning that there are some mistakes that may trigger an audit from the IRS. If you’re like my wife, being audited is one of your biggest nightmares. And you’re not alone, about 6 in 10 Americans say they have anxiety at tax time about potentially being audited. For gig workers, the anxiety is even higher. You may assume that because you didn’t get a 1099, you’re in the clear. It’s important to know that the IRS doesn’t need a form to know that you got paid. So, do yourself a favor and don’t make any of these seven mistakes. They could lead to an unpleasant encounter with the IRS.

1. Assuming You Don’t Need to Report Small Payments

A lot of side hustlers think if they earned under $600 from a client, they don’t have to report it. That’s a myth. All income is taxable, regardless of whether you receive a 1099-NEC or 1099-K. According to CNBC, underreporting income is one of the top audit triggers. Even if you’re paid in cash or through apps like Venmo or Zelle, the IRS may still see those deposits.

2. Waiting for a 1099 to File

In 2026, the IRS is cracking down on gig economy income, especially from platforms like Uber, DoorDash, and eBay. But not all platforms issue 1099s, especially if your earnings fall below the reporting threshold. That doesn’t mean you’re off the hook. If you wait for a form that never comes and skip reporting the income, you’re setting yourself up for penalties. Tax pros say to keep your own records and report all income, form or not.

3. Mixing Personal and Business Transactions

Using the same bank account for your side hustle and personal expenses might seem convenient, but it’s risky. When the IRS reviews your return, they may question large or frequent deposits that don’t match your reported income. This is especially true if you’re claiming deductions or business losses. A separate account makes it easier to track income, justify expenses, and avoid confusion. Clean records are your best defense against scrutiny.

4. Misclassifying Hobby Income

If you sell baked goods, flip furniture, or do photography gigs, you might think of it as a hobby. But if you’re making money and doing it regularly, the IRS may classify it as a business. That means you’re expected to report income and may be eligible for deductions, but only if you’re treating it like a business. Misclassifying hobby income can lead to denied deductions and increased audit risk. When in doubt, err on the side of transparency.

5. Overstating Deductions

Trying to offset side income with inflated deductions is a red flag. Claiming a home office, vehicle expenses, or equipment costs without proper documentation can backfire. The IRS uses algorithms to compare your deductions to industry norms. If your write-offs seem too high for your income level, expect questions. Only claim what you can prove and keep receipts.

6. Ignoring State Tax Obligations

Side income isn’t just a federal issue. Your state wants its cut too. Many gig workers forget to file state taxes or underreport income, especially if they work across state lines. This can lead to penalties, interest, and even double taxation. Some states are now cross-referencing IRS data to catch underreporting. Don’t assume your tax software will catch everything, and make sure you check your state’s rules.

7. Skipping Estimated Tax Payments

If you earn more than a few thousand dollars from side work, you may need to make quarterly estimated tax payments. Waiting until April to pay it all can result in underpayment penalties. Many men overlook this step, especially if their main job withholds taxes. But side income doesn’t come with automatic withholding. Use IRS Form 1040-ES to calculate and pay on time.

The IRS Is Watching (Even If You Think They Aren’t)

The biggest mistake isn’t just underreporting. With new enforcement tools and tighter reporting rules, side income is under the microscope in 2026. Tax preparers say the best defense is full transparency: track your income, report it accurately, and don’t wait for a form to do the right thing. A little diligence now can save you from a big headache later. When it comes to side gigs, honesty really is the best policy.

Have you ever made a side income mistake on your taxes, or caught one just in time? What helped you stay compliant? Share your experience in the comments.