Failing to Report All Taxable Income

The IRS gets copies of all 1099s and W-2s you receive. This includes the 1099-R (reporting payouts from retirement plans, such as pensions, 401(k)s and IRAs) and 1099-SSA (reporting Social Security benefits). Make sure you report all required income on your return. IRS computers are pretty good at matching the numbers on the forms with the income shown on your return. A mismatch sends up a red flag and causes the IRS computers to spit out a bill. If you receive a tax form showing income that isn't yours or listing incorrect income, get the issuer to file a correct form with the IRS.