Bet Against The Second Half NBA Comeback

On January 8th, the Miami Heat went into Phoenix as 9.5-point pregame underdogs against the Suns. The Heat entered the game as heavy underdogs because Miami was without the services of Jimmy Butler, Bam Adebayo, Dewayne Dedmon, and Gabe Vincent. By contrast, the Suns had no significant injuries and were welcoming the return of DeAndre Ayton and Javale McGee from quarantine. The Heat were also playing the fifth game of an extended West Coast road trip. Shockingly, Miami jumped all over Phoenix in the first half and took a 71-50 lead into halftime.

I caught this game at a sportsbook and I noticed several bettors rush to the window to bet on the Suns to cover the second half spread once they saw the Suns listed as 11-point second half favorites. These bettors explained to me that the second half spread for the Suns represented “value” because their second half bets would win as long as the Suns finished the game with anything but a double-digit defeat. They reasoned that they were effectively getting the Suns at +10 for the full game, which was 19.5 points better than the pregame number of the Suns at -9.5. Their logic was that the Heat built the 21-point halftime lead by going 15-of-30 from the three-point line and could not sustain their scorching shooting in the second half.

The second half of the Heat-Suns game proceeded much like the first half. The Heat did not cool off as they shot 50% from the three-point line after halftime and the Suns failed to make a credible comeback. The Heat ended up beating the Suns 123-100, which meant that the bettors who hurriedly placed their second half bets on the Suns could tear up their tickets as the Heat easily covered the second half as well.

What took place in the first half of the Heat-Suns game on January 8th has been a regular occurrence this NBA season.

The pregame underdog has outperformed the full-game spread by at least 10 points at halftime an incredible 156 times this season. Pregame favorites have only ended up covering the full-game spread 22 out of the 156 times that they have finished the first half with a margin at least ten points worse than the original spread by which they were favored before the game.

However, while full game bets on such pregame favorites are likely dead, this situational spot has consistently presented bettors with an opportunity to make money with second half wagers.

Editor’s note: data presented in this article is as of January 16, 2022, and therefore subject to change moving forward.

Fade The Pregame Favorite In The Second Half

The notion that there is a value in betting on a pregame favorite that underperforms significantly in the first half to cover the second half spread comes in part from the belief that the pregame underdog that exceeded pregame expectations in the first half will inevitably regress in the second half. Many bettors have a tendency to expect the pregame favorite that has underwhelmed in the first half to naturally play closer to pregame expectations in the second half. 

However, BetQL’s analysis of the 156 times this season that a pregame underdog has gone into halftime with a margin at least ten points better than the full game spread shows bettors should bet against the prospect of a second half comeback by the pregame favorite.

A bettor who placed a halftime wager on the pregame underdog to cover the second half spread when the pregame underdog has outperformed the full game spread by at least ten points in the first half is 92-59 with five pushes in the 156 times that this situation has been available this season. 

The pregame underdog has covered the second half spread 58.9% while the pregame favorite has only covered the second half spread 37.8% of the time when the pregame underdog’s margin at halftime is ten points better than the pregame spread. A bettor would be up an astonishing 27.1 units if he or she just wagered one unit on the pregame underdog to cover the second half in the 156 times that this exact situation has arisen this season.

The trend of pregame underdogs covering the second half after significantly exceeding pregame expectations in the first half logically makes sense. Pregame favorites that have underperformed pregame expectations so significantly in the first half will typically need to win the second half by a considerable margin to cover the second half spread. 

A pregame underdog in this situation still covers most of the time even when the pregame favorite is able to mount somewhat of a comeback. A perfect illustration of the challenge with betting on the pregame favorite in the second half in this situation is the Spurs-Warriors game from December 4th. The Warriors were favored by nine points pregame but the Spurs took a nine point lead into halftime. The Warriors were ten-point favorites in the second half. Golden State made a spirited comeback but ultimately lost to San Antonio by five points. Even though the Warriors outscored the Spurs by four points in the second half, the Warriors still failed to cover the second half.

Placing a bet pursuant to this second half trend provides bettors who have placed a wager on a pregame favorite that enters halftime ten points worse than the full game spread with an opportunity to recoup some of their seemingly lost money on the original bet. It also provides bettors who apparently correctly placed a wager on the pregame underdog with a chance to potentially add to their winnings from the same game. Furthermore, this second half trend also allows bettors without any pregame action on a game to jump in with a situational second half bet that has worked almost 60% of the time over a large sample size.

Bet on Winning Underdogs To Cover the Second Half

I understand the concern of risk averse bettors with wagering on the second half even with the data cited in this article. Some skeptics will point to the failure of the Thunder to cover the second half against the Cavaliers on January 14th or the failure of the Hawks to cover the second half against the Heat on January 13th despite outperforming their pregame spreads in the first half by 15 and 11 points, respectively, as red flags. However, what the Hawks and Thunder have in common is that both teams are losing teams. The second half betting situation described in this article has worked even better with winning pregame underdogs that have exceeded expectations in the first half.

As of the conclusion of all NBA games on January 16, there are currently 16 teams with winning records (Warriors, Suns, Mavericks, Nuggets, Jazz, Grizzlies, Bulls, Nets, Bucks, Cavaliers, Knicks, Wizards, Hornets, 76ers, Raptors, Heat). These 16 teams have outperformed the pregame spread by at least 10 points in the first half as pregame underdogs 70 times this season. In those 70 games, these pregame underdogs with winning records are 46-23 with one push on the second half spread. Winning pregame underdogs in this situation have covered 65.7% of the second half spreads. 

A bettor would be up 20.7 units if he or she wagered one unit on these 16 teams to cover the second half when they were pregame underdogs in the 70 times that they have gone into halftime with a margin at least ten points better than the pregame spread.

So if betting on a bad team that got really hot against the pregame favorite in the first half to cover the second half is not your cup of tea, my recommendation is to focus on situational second half bets involving winning pregame underdogs that significantly outperform the pregame spread.

Conclusion

I am not advocating that you should always bet on a pregame underdog to cover the second half whenever the underdog outperforms the pregame spread by at least ten points at halftime. Betting on a trend does not work all the time and there is no substitute for actually watching and analyzing the first half of a professional basketball game before deciding whether to place a second half wager. 

However, data-driven bettors should not ignore what has clearly been a profitable situational second half bet over a prolonged stretch of time. Smart bettors should continue looking for exploitable wagering spots and the value bet in the second halves of NBA games this season has clearly been on pregame underdogs that have significantly beaten pregame expectations entering halftime. If anything, this second half trend has gotten stronger as the season has progressed. Since the start of 2022, pregame underdogs in this situation are 19-11 with two pushes.

While recreational bettors remember the times this season in which the pregame favorite made an incredible comeback after halftime, sharper bettors know that these great second-half comebacks rarely occur.