If you had to guess the sports in which betting underdogs outright in the postseason blindly is more profitable, it would probably be something like:
- NCAA Tournament: Chaos! Sleepers! Cinderellas!
- NHL: It's hockey, anything can happen!
- NCAAF bowl season: No one cares, the good teams all quit!
Actually, it's quite the opposite. Blindly betting underdogs in the NCAA Tournament has been the worst postseason bet in sports over the last 20 years, according to our data at Bet Labs. It's been a little better over the last five years, but swings wildly year to year — 2022-2024 was good, and 2025 was a complete disaster, the second worst on record. So that put to rest any idea that the market was wildly misjudging the impact of NIL, the transfer portal, and a new era of college basketball.
Let's take a look at four different measurements of postseason underdogs by sport.
Postseason Moneyline Results by Sport since 2005
Over the last ~20 years, college basketball moneyline underdogs rank last in both total units won/lost and ROI, by a pretty significant margin. It was especially bad in the mid-2000s, which feels like centuries ago with how much the betting market has changed, but we'll look at more recent results below.
Postseason ML Results Last 5 Years
Over the last five years, college basketball has done a little better.
But in all these sports, and CBB is probably the poster child for this, the results are so heavily skewed by one team. Saint Peter's during its run to the Elite Eight as a No. 15 seed was +19.5 units in four games, including +11 against Kentucky in the opening round, and +650 vs. Purdue in the Sweet 16. Same for UMBC, which beat Virginia as a No. 16 seed at +2000.
Small ML Dog Postseason Results since 2005
OK, but what if you look at just smaller underdogs — +100 to +200 for college basketball? Does ruling out the 16 seeds who (rarely) win help our case?
The results are much better for college basketball over the last 20 years when looking only at small underdogs, going from an -8.9% ROI for all underdogs to about break-even at 0.5% for underdogs +100 to +200.
Small ML Dog Postseason Results Last 5 Years
And finally, small underdogs from the last five years. College basketball has been about breakeven, fourth on the list.
The results seem better over the last 5 years — has anything changed about college basketball?
Both college basketball and college football have seen seismic shifts in roster construction and continuity due to the transfer portal. Every mid-major team is losing its best players to Power 4 schools, and lack the upperclassmen who always delivered in March — or at least that's the common narrative. But if anything, that's an argument for why underdogs would perform worse in the NCAA Tournament, not better.
Underdogs had a bit of a resurgence in the last five years, but last year was a complete disaster. It was a chalky tournament, and the moneyline results reflect it.
