March Madness Upsets: The Best 5 vs 12 Matchups to Target

The 12-5 upset is one of the most popular picks in March Madness odds with No. 12 seeds seemingly pulling off upset wins against No. 5 seeds at a far higher rate than they should. 

Is it a trend that holds weight or a narrative that has public attention because of memorable upsets during the NCAA Tournament? I break down this college basketball betting trend and look to see how you should bet on 5 vs. 12 matchups as you build your March Madness brackets before today's tip-off.

The trend

There is a prevailing narrative that No. 5 seeds are jinxed and that they get upset far more than they should at this time of year. Historically, No. 12 seeds have been almost as likely to pull off March Madness upsets in the first round as No. 11 seeds. 

Dating back to when March Madness expanded to 64 teams in 1985, No. 11 seeds have gone 58-94 for a 38.2 winning percentage. That's only slightly higher than No. 12 seeds who have gone 53-99 (34.9%).

After that, there is a big drop-off with No. 13 seeds winning just 32 times for a 21% upset rate. Not only have No. 12 seeds been pulling off upsets more often than expected but they've also been money for college hoops bettors, covering at a higher rate.

Despite a down year for the trend in 2023 with No. 12 seeds going 0-4 straight up and against the spread, the lower-ranked seed has still gone 24-36 SU and 34-26 ATS in these matchups over the last 15 tournaments.

March Madness myth?

At first glance, this might seem like a bit of a coincidence or simply March Madness bettors looking for patterns in a month of chaos. However, the numbers over a significant period of time indicate that there is substance to this narrative.

FiveThirtyEight published an in-depth article in 2015 where Benjamin Morris looked at the previous 20 years of data and came to the conclusion that there was a significant deviation between how No. 5 seeds actually performed and how they should be expected to perform given the other seeding matchups.

There are a few reasons why No. 5 seeds might be more susceptible to getting upset.

Because of how seeding is done, there is typically a fairly steep drop off from the No. 12 seed to the No. 13 seed. For example, three of the No. 12 seeds this year rank in the Top 60 of the KenPom ratings, while the No. 13 seeds all sit between between 80th and 104th in their rankings. As such, the 12-5 matchups represent the boundary at which the first round matchups tend to be more competitive.

Historically there was also a tendency for No. 5 seeds to get claimed by above-average schools from Power-Six conferences, while No. 12 seeds went to very good teams that were underestimated because they came from smaller conferences. However, that has become less of a thing in recent years with more parity across college hoops.

No. 12 seeds that have covered over the last 10 Tournaments

Is this trend worth betting?

As mentioned above, this March Madness trend fell flat on its face last year with No. 12 seeds going 0-4 SU and ATS. Going back to 2015, No. 12. seeds are just 9-23 SU (28.1% win rate). They've also gone 16-16 ATS which suggests that oddsmakers are doing a better job of setting accurate lines for these matchups. 

Over that same period of time, No. 11 seeds have gone 17-15 SU (53.1%) in the Round of 64 making them surprisingly more likely to win than their higher-seeded counterparts.

It is worth mentioning that the No. 5 seed jinx is now mentioned non-stop during March Madness (sorry for contributing to that chorus of voices). That means the No. 5 seeds are probably more locked in and less likely to underestimate their opponents during the opening round. In addition, as college basketball fans become more aware of this trend, the public is more likely to bet on No. 12 seeds which can shorten lines.

It's no surprise that last year saw some of the shortest lines for 5-12 matchups in history with every spread between 2.5 and 5.5. This year, two of the spreads are sitting at 5.5 (after opening at 4.5) and the largest spread of +7 for UAB isn't surprising when you consider that the Blazers sit outside the Top 100 in the NET and KenPom ratings.

While the long-term numbers certainly give weight to this narrative, the last few years suggest that it's important to tread lightly with this trend. Here are the four 5-12 matchups this year and which No. 12 seed I think is most likely to win in the first round.

5 vs 12 seed matchups in 2024 NCAA Tournament

I'm immediately dismissing UAB as an upset candidate against San Diego State. The Blazers are rated significantly lower than the other No. 12 seeds according to the NET rankings, KenPom, and BarTorvik. While the other No. 12 seeds are all in the Top 60 of those ratings, the Blazers are just outside the Top 100.

They finished in fourth place in the AAC during the regular season but claimed this seed due to winning the conference tournament in a shocking finals matchup that saw them face a terrible Temple squad. They won't knock off the highly-experienced Aztecs, who have the coaching, experience, and elite defense to take care of business in the opening round.

Looking at the other three matchups, I've narrowed it down to McNeese State as the No. 12 seed most likely to pull off the upset at +220 on the moneyline against Gonzaga. The Cowboys dominated the Southland Conference and they have the combination of tenacious defense and three-point shooting that has often led to Cinderella runs. The Zags are having a bit of a down year and their vulnerable defense could get them in trouble, especially if McNeese catches fire from deep.

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