An estimated $2.72 billion could be wagered on the NCAA men’s and women’s basketball tournaments with American sportsbooks, according to an analysis released Thursday by the American Gaming Association.

The $2.72 billion estimate is nearly twice as much as is believed to have been wagered on this year’s Super Bowl ($1.4 billion), according to Dave Forman, head of research for the American Gaming Association (AGA), the Washington, D.C.-based lobbying group that represents the casino industry.

Forman said the AGA’s analysis was based on the monthly sports betting revenue reports released by states, and only bets placed on the NCAA tournaments — not conference tournaments — with U.S. sportsbooks were included in the estimate.

The American Gaming Association conducted online surveys in previous years to produce estimates on how much was bet on the tournament, including bracket pools. Last year’s survey indicated that $15.5 billion could be on the NCAA tournament, an estimate that included bracket pools and wagers with unlicensed sportsbooks and bookmakers.

“March Madness is the biggest and most mainstream betting event of the year, especially with the brackets,” Forman told ESPN. “But with legal sports betting having been around now for five years and available in almost 40 states, we wanted to turn our focus to the legal market.”

Forman said no state breaks out the amount wagered on the men’s and women’s games separately, but sportsbooks DraftKings, FanDuel and Tipico each reported significant year-over-year growth in their betting handles for the women’s regular season.

Las Vegas casino owner Derek Stevens said the betting action on just the first week of the men’s NCAA tournament “blows away the Super Bowl.” Stevens said his sportsbook at Circa in Downtown Las Vegas is sold out for the opening days of the men’s tournament.

“It’s definitively the biggest week of the year, and Super Bowl is definitively the second biggest,” Stevens said.

A report from research firm Eilers and Krejcik Gaming released this week estimates that 35-40% of the amount bet on the men’s NCAA tournament will come from in-game wagers, and 5% of the handle will be generated from same-game parlays. Eilers and Krejcik also estimated recent bans on prop bets involving NCAA players in Ohio and Maryland could cut sportsbook revenues by 5-10% in those states.

Defending champion UConn is the betting favorite to win the men’s tournament with +450 odds at ESPN BET, and South Carolina (-130) is the betting favorite to win the women’s tournament.

Sopurce: ESPN‘s Doug Greenberg contributed to this report.