Notable March Madness bets from U.S. sportsbooks

March Madness comes about you fast -- bet after bet, bracket after bracket. With the American Gaming Association estimating that over $8.5 billion will be bet on the tournament, plenty of money will be flying around at sportsbooks across the U.S.

We'll keep you updated on the action throughout the NCAA tournament with this updating file of the biggest bets and wildest wagers.

The notables

• MGM's sportsbook in January took a five-figure bet on the Virginia Cavaliers to win the national championship at 12-1.

• MGM took a $15,000 bet on Gonzaga to win the national championship at 6-1 on Monday, according to sportsbook supervisor Scott Shelton. Shelton also said the book took a $5,000 on Purdue at 30-1.

• FanDuel's sportsbook took a $25,000 bet on Virginia at +750, the largest futures wager the book had taken as of Monday morning.

• DraftKings sportsbook's largest futures bet is a $9,750 bet on Duke at +250 odds.

• The team with the most bets to win the national championship at sportsbook operator CG Technology is Gonzaga. The team with the most money bet is Duke.

• Derek J. Stevens, a Las Vegas casino owner and big sports bettor, placed a $100,000 wager at +105 earlier this season on either Duke, Gonzaga, Michigan or Kansas winning the national championship (against the field) at the South Point sportsbook.

• Caesars sportsbook took a $25,000 bet on Duke to win the national championship at 5-2 odds during the regular season.

• William Hills US took a $10,000 bet on North Carolina to win the title at 8-1 odds. UNC (6-1) winning the title would be the "worst-case scenario" for CG Technology, along with Florida State (28-1) and Texas Tech (22-1).

Most money wagered to win the national championship at the SuperBook at Westgate Las Vegas (as of Sunday night):

1. Duke
2. Gonzaga
3. North Carolina
4. Kentucky
5. Virginia

Most bets to win the NCAA tournament at the SuperBook at Westgate Las Vegas (as of Sunday night):

1. Gonzaga
2. Duke
3. Michigan
4. Kentucky
5. North Carolina

Longshot futures bets still alive at William Hill US sportsbooks:

$2,000 on Cincinnati at 200-1
$2,000 on Purdue at 150-1
$1,000 on Louisville at 250-1
$1,000 on Minnesota at 200-1
$100 on Temple at 2000-1
$200 on Buffalo at 1000-1
$2,000 on Florida State at 75-1
$1,000 on Ohio State at 150-1
$300 on UCF at 500-1
$50 on San Diego State at 3000-1

Three notable bets placed at Caesars Palace sportsbooks this week:

• $2,000 on New Mexico State at 100-1 to win the Midwest Region. Would pay $200,000.

• $5,000 on Purdue to win it all at 30-1. Would pay $150,000.

• $3,000 on Wisconsin to win South Region at 30-1. Would pay $90,000.

Underdogs and unders

• Since the field expanded to 64 teams in 1985, more underdogs than favorites have covered the spread in 20 of 33 tournaments, including in seven of the past eight years. Overall, underdogs are 1,070-1,044-45 (50.6 percent) ATS in the NCAA tournament since 1985.

• Underdogs are 529-519-24 ATS in Round of 64 since 1985.

• "Years ago, we basically needed the 'dog," MGM vice president of race and sports Jay Rood said of his 20-plus years booking the NCAA tournament. "Now, a lot higher percentage of the wagering public is taking the points."

• More games (1,832) stayed under the total in the regular season than in any other season dating back to 2004-05, according to sports betting database BetLabsSports.com. (Unders were 116-101-3 in conference tournaments this year).

• In 2018, 37 of 67 tournament games stayed under the total, the third-most unders in the past 14 years.

• The under is 28-17-1 in Kansas tournament games since 2005.

• Unders went 18-13-1 in the Round of 64 last season, the third-best mark for unders in the past 14 tournaments.

• There have been more unders than overs in the Round of 64 in nine of the past 14 tournaments.

• Seven of Michigan coach John Beilein's last eight Round of 64 games have stayed under the total.

Odds and ends

• Beilein is 23-12-1 ATS in the NCAA tournament.

• Louisville coach Chris Mack is 12-5-1 ATS in the NCAA tournament.

• Purdue coach Matt Painter is 11-2 ATS in the Round of 64.

• Ken Pomeroy on why his model has Virginia and Gonzaga rated ahead of Duke: "It basically comes down to scoring margin adjusted for schedule, so Virginia and Gonzaga have been superior to Duke over the full season."