2023 NCAA Tournament odds: Sweet 16 betting trends

Updated Mar. 21, 2023 10:24 p.m. ET

With the opening weekend of March Madness finished, the NCAA Men's Tournament officially has just 16 teams left. That's right — we've reached the Sweet 16.

This tournament has already been full of surprises, as we've seen the Fairleigh Dickinson Knights take down the No. 1 seed Purdue Boilermakers to become the second 16-seed ever to win in the Round of 64. Opening weekend also featured the Princeton Tigers becoming the fourth 15-seed all-time to make the Sweet 16.

This week's action features familiar faces and some surprising teams, so buckle up for another fantastic two days of basketball.

When it comes to betting, as always, FOX Sports Research has you covered. We did a deep dive into the numbers to give you a chance at making some profitable wagers. We also highlighted some school- and coach-specific trends that could further serve in picking some winners this week. Let's dive in!

Underdogs historically cover in the Sweet 16

No matter what time frame you look at, underdogs consistently cover against the spread (ATS) in the Sweet 16.

Since the tournament expanded to 64 teams in 1985, they've gone 147-139-6 ATS (51.4%) and 85-207 straight up (29.1%) (SU).

From a more recent view, underdogs have gone a whopping 49-36-1 ATS (57.6%) and 31-55 SU (36%) since 2011.

Below are the underdogs for this year's Round of 16, with odds provided by FOX Bet:

Kansas State Wildcats (+3) vs. Michigan State Spartans

Arkansas Razorbacks (+3.5) vs. UConn Huskies

Florida Atlantic Owls (+5.5) vs. Tennessee Volunteers

Gonzaga Bulldogs (+2) vs. UCLA Bruins

Miami Hurricanes (+7) vs. Houston Cougars

Xavier Musketeers (+4) vs. Texas Longhorns

Princeton (+10) vs. Creighton Blue Jays

San Diego State Aztecs (+7.5) vs. Alabama Crimson Tide

One matchup to note is the ninth-seeded Owls taking on the fourth-seeded Volunteers. Surprisingly, 9-seeds are 5-2 ATS (71.4%) and 4-3 SU (57.1%) in the Sweet 16 since 1985. The Owls are currently 5.5-point underdogs at FOX Bet.

Since 1990, underdogs of four to six points are 38-29-1 ATS (56.7%) and 25-43 SU (36.8%). So it might be worth betting on Florida Atlantic and Creighton to cover if you like this trend.

Teams with 28-plus wins usually cover

This trend shouldn't surprise many, but teams that dominate in the regular season usually make a run in the tournament, specifically, teams that won 28 or more games before the NCAA Tournament. Those teams have gone 57-54-6 ATS (51.4%) and 84-34 SU (71.2%). However, the cover rate increases even more when going back to 2014. In that span, teams that enter the tournament with 28-plus wins are 22-15-1 ATS (59.5%) and 26-12 SU (68.4%).

There are currently five teams in the Sweet 16 who entered the tournament with 28-plus wins:

Florida Atlantic: entered tournament 31-3

Houston: entered tournament 31-3

Alabama: entered tournament 29-5

UCLA: entered tournament 29-5

Gonzaga: entered tournament 28-5

No. 1 seeds dominate in the Sweet 16

There are only two 1-seeds left in the Sweet 16: Alabama and Houston. While we saw Purdue and Kansas go down in the first two rounds of play, the Crimson Tide and Cougars have looked formidable, with both teams winning each of their first two games by double-digits. In fact, both of Alabama's wins came by 20-plus points. History says the two teams should cover, let alone win, as 1-seeds are 67-53-6 ATS (55.8%) and 101-25 SU (80.2%) in the Sweet 16 since 1985. Since 2014, they No. 1 seeds cover even more — going 16-8-1 ATS (66.7%) and 21-4 SU (84%) in that span.

In this year's Sweet 16, Alabama will take on San Diego State as a 7.5-point favorite, while Houston is currently a 7-point favorite at FOX Bet.

Since 1999, seven- to eight-point favorites have gone 9-7 ATS (56.3%) and 13-3 SU (81.3%) — more data that points towards betting on the Crimson Tide and Cougars this week.

Take the Under in the Sweet 16

Unders have dominated the tournament, having hit in 34 of 52 games (65.4%). That's the highest Under percentage through the tournament's first two rounds in the last 30 seasons.

Below are some other notable nuggets that point toward taking the Under in the Sweet 16:

Kelvin Sampson has coached in 16 games as Houston's head coach in the NCAA Tournament, with the Under hitting in 11 of those games (68.8%).
In the 15 games that Eric Musselman has coached in the NCAA Tournament, the Under has hit in 10 of those games with one push (71.4%).
Tennessee has hit the Under in 21 of 35 games (one push)(61.8%) this season, the highest Under rate of any team remaining in the tournament.
The Under has hit in 187 of 328 games with six pushes at Madison Square Garden since 2007 (58.1%), including 14 out of 19 games this season (73.7%) — Michigan State vs. Kansas State and Tennessee vs. Florida Atlantic will be played at the Garden.

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15-seeds are perfect against the spread

As mentioned earlier, the lone 15-seed to make the Sweet 16 is Princeton. This will be a quick trend, as the data is simple and sweet. It's a small sample set, but since the tournament expanded to 64 teams in 1985, 15-seeds are a shocking 3-0 ATS and 1-2 (33.3%) SU. The lone team to win was the Saint Peter’s Peacocks last year, defeating Purdue in the round. The other two who got there but could not win were the Oral Roberts Golden Eagles in 2021 and the Florida Gulf Coast Eagles in 2014. But if you are a bettor, 15-seeds cover.

Tom Izzo in familiar territory

The great Tom Izzo will appear in his 15th Sweet 16. This is his 25th NCAA Tournament appearance, the most of any coach all time. The 15 Sweet 16 appearances are tied for the fifth most of all-time with John Calipari (including his vacated appearances).

Izzo and the Spartans are currently two-point favorites at FOX Bet — a spot he's historically thrived in. Izzo is 8-6 ATS (57.1%) and 10-4 SU (71.4%) in the Sweet 16, and when a favorite in the round, he's an astonishing 6-3 ATS (66.7%) and 8-1 SU (88.9%).

So what are you waiting for? Head over to FOX Bet now and make some wagers on the Sweet 16 of the NCAA Men's Basketball Tournament!

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