According to reports by CNBC, between $60 Billion to $70 Billion is illegally wagered on college football in the United States each year.
Between $30 Billion to $40 Billion is illegally gambled on baseball in the United States each year. The amount of money gambled on baseball is lower than football due to the lack of point spreads.
Betting on the March Madness basketball tournament is believed to be around $2.5 Billion a year, according to the FBI.
The popularity of betting on college sports is due to gamblers having faith in the integrity of the games. According to research conducted by an academic professor, 1 percent of NCAA Basketball games in a 16 year period was fixed.
Source: Gillian Spear, “Think sports gambling isn’t big money? Wanna bet?,” NBC News, July 15, 2013.