Derick E. Hingle-USA TODAY Sports. Pictured: Greg Zuerlein
- The Rams are 2.5-point underdogs in Super Bowl 53, which has surely tempted bettors into buying a half-point to the key number of 3.
- Looking at results of 2.5-point underdogs in the past, we can confirm whether or not that's a smart decision.
Considering you clicked on this post, you’re probably aware that the Patriots are 2.5-point favorites over the Rams in Super Bowl 53. While the line opened at a pick’em, oddsmakers were forced to favor the Pats thanks to their close to 80% backing.
The market activity on the Super Bowl is fascinating enough on its own — to me, at least — but the now 2.5-point spread raises perhaps a more interesting question, especially for those of you looking to bet the Rams.
I’m guessing many of you have been waiting for a move to +3 before placing your bet on LA, which is smart. Three points is the most common margin of victory in the NFL, which makes a team at +3 significantly more valuable than one at +2.5.
But unless you happened to be in Vegas last Tuesday between 2:57 and 3:15 p.m. ET, you probably haven’t had that opportunity yet.
Of course, there’s always the option to buy a half-point yourself and bet LA as a 3-point dog for a worse price.
The question (obviously) is, should you?
To answer that, I’ve looked back at every NFL game with a closing line of 2.5 points since 2003 to find out how many underdogs actually lost by three.
Here’s what I found.
Oddly enough, 2.5-point dogs have been shockingly profitable on their own. Since 2003, they’ve gone 144-119-0 (54.75%) against the spread (ATS). Assuming an standard average juice of -110, that’s good for 11.90 units won and a 4.52% return on investment.
In that 263-game sample, however, 18 games (6.8%) ended with an underdog loss of exactly three points. That means if you’d bought a half-point for every one of those games, your ATS record would become 144-101-18 — a significantly better 58.76% win rate.
The problem is, you’re no longer getting your bet at -110.
Most books charge 25 cents for a half-point that involves the key number of 3, which means each of your bets now comes at a premium price of -135. So while your win rate may have gone up, your unit total has actually fallen to 5.67 over the sample (a 2.15% ROI).
And for those wondering, buying a full point to +3.5 has turned out even worse. Here’s the full breakdown.
This probably shouldn’t come as a surprise, but yes, oddsmakers are well aware of the frequencies of given scoring margins. They aren’t looking to help you by offering the option to buy points.
So for those looking to bet LA tomorrow, don’t fall into the temptation of buying the half-point. While it’ll certainly help your chance of winning this one particular bet, it’ll also return you with about half as much money over the long term.
You’re far better off simply taking the 2.5 points, or continuing to look for a potential line move to +3 to come naturally.