For those who made money from real estate, you'll need to submit a 1099-S form. Also, if you came up on some big wins from gambling, you'll need to report that to the IRS as well via a W-2G form.

If you received a Form 1099-B, which reports proceeds from broker and barter exchange transactions, filing might be necessary. If adding the amount in box 1d to your other gross income pushes you ...