America's gambling industry predicts $10 billion will be bet on the March Madness college basketball tournament - nearly all of it illegally or off-the-books.
That's one of the reasons the American Gaming Association favors the full legalization and regulation of sports betting in the United States.
The group found 54 million people - or about a quarter of the U.S. adult population - participated in a sports betting pool last year.
The U.S. Supreme Court is weeks away from ruling on New Jersey's challenge to a law limiting legal sports betting to just four states: Delaware, Montana, Nevada and Oregon.
AGA President Geoff Freeman says only 3 percent of the $10 billion the group predicts will be wagered on the games will be done through legal Nevada sports books.