If your weekend plans include dropping a bet on the Super Bowl, don't forget that Uncle Sam wants a piece of anything you win. Americans are expected to wager about $6.8 billion on Sunday night's matchup between the Kansas City Chiefs and San Francisco 49ers in Miami. And no matter where you place your bet — whether at a casino, online, through a pool or fantasy league, or at your neighbor's annual bash — the IRS expects you come to clean at tax time. "Most people don't realize they have to report any kind of winnings from gambling activities," said Oscar Vives Ortiz, a CPA who serves on the American Institute of CPAs' personal financial specialist committee.

Fans celebrate after making bets through FanDuel Sportsbook during Super Bowl LIII in East Rutherford, New Jersey, on Feb. 3, 2019. Eduardo Munoz | Reuters

"Whether you win $10 or … a large amount, everything should be reported to the IRS," he said. Roughly 26 million people are expected to bet on the Super Bowl, according to the American Gaming Association. Of those bettors, 4 million will wager in person at a sportsbook and 5 million will do it — legally or illegally — through an online or mobile platform. The remainder — roughly 16 million — will bet with a bookie, in a pool or squares contest, or casually with family or friends. Since the Supreme Court overturned a federal law in May 2018 that had banned sports betting in most places, more than $17 billion has been wagered legally, according to the gaming group. There are 14 states that now offer regulated sports betting, with six more and the District of Columbia expected to soon.

While you might be less likely to tell the IRS about money you win outside of regulated channels, just be aware that it is considered taxable income. "The risk of not reporting it is that if you get audited, and they find it, you'd owe back taxes and penalties," Vives Ortiz said. For casual gamblers placing wagers through regulated sports betting in states that allow it, the IRS makes it a bit easier for you by placing reporting requirements on the payor (i.e., the casino), as well. Generally speaking, if you win more than $600 for a sports wager and the amount is 300 times the original bet, the payor is required to withhold 24% of your winnings for federal taxes, Vives Ortiz said.