1. Too-high deductions
Certain deductions you take can’t be fudged without raising some eyebrows at the IRS. For instance, the IRS receives information on the mortgage interest you paid, so you can’t inflate that figure. Others – such as charitable contributions – are easier to overstate, since the IRS doesn’t get documentation from charities on your donations.
2. Missing income
If you’re tempted to "forget" to include income from a side gig or contract work, don’t. The IRS receives copies of your W-2 and 1099 forms from companies you worked for. It will match the information it has against your tax return. If that data doesn’t line up, your return will be flagged for review.
3. You have foreign accounts
If you have a foreign financial account – such as a bank account, brokerage or mutual fund – you may need to report it to the IRS when you file your taxes.
4. Earning a lot of money
“Once you cross that $1 million income threshold, your tax return is more complex,” Allec says. “There are more places for the IRS to poke holes in.”
5. Inflated business expenses
This is what the IRS looks for:
Claiming more deductions than profits
Reporting round numbers for income and expense values
Reporting a business loss for too many consecutive years
Writing off 100 percent of an item as a business expense that is often used personally, such as a car or cell phone
6. Wrongly claiming a child
While this is usually an honest mistake, it could still trigger an IRS review or letter if the same dependent is claimed twice.
7. Rental losses
There are special rules that allow you to deduct rental real estate losses against your regular income. First, you can deduct up to $25,000 in losses if you actively participate in the renting of your property. That phases out if your income exceeds $100,000 and vanishes when it reaches $150,000.