Middles and negative middles have been used by pro-punters for a while now, that's why many call it the "holy grail of sports arbitrage". See why here.
My name is Gavin Wood and I have been a professional sports gambler for over 13 years now.
I hope you find the following article useful. For more advice articles as well as free value tips please take a look at my blog betcraft.co.
The life of somebody working full-time in sports arbitrage is one of large, regular bets and small profits which hopefully total enough to pay the bills.
That is unless they hit a middle, the holy grail of sports arbitrage where 2 bets can make more in a few minutes than the accumulated total of all other bets placed that month.
Middles & Negative Middles: Explained With Examples
A middle arises in either a handicap or totals (under/over) market where 2 bets are simultaneously placed at different sites, such that should the score land on a number, or one several numbers, both bets will win.
Best illustrated numerically:
- Team A-5.5 odds 2.0
- Team B +6.5 odds 2.0
Should Team A win by exactly 6 points, both bets are winners.
- Over 199.5 points odds 2.0
- Under 200.5 points odds 2.0
Should there be exactly 200 points in the game, both bets are winners.
The other part to this is a push/side or I guess more logically described as a ‘half middle’.
This is where, following the initial paragraph, should your number ‘hit’ you will win one bet, whilst the other would be refunded:
- Team A-6 odds 2.0
- Team B +6.5 odds 2.0
Should Team A win by exactly 6 points, your first bet would be refunded, the second graded as a winner.
- Over 200 points odds 2.0
- Under 200.5 points odds 2.0
Should there be exactly 200 points in the game, your first bet would be refunded, the second graded as a winner.
You are most likely to come across middle opportunities in high scoring sports, so basketball, rugby, American football…but do lookout for unexpected possibilities in sports like tennis, where the game handicap can be left behind.
I had my largest ever win in sports betting on a middle (in fact almost all of my large wins have come from them), which I have described elsewhere on the site.
The most useful tool for those who do hunt out middles is Pinnacle.com (currently not available in the UK although when I last spoke to them they were expecting to be licensed by July 2017!) and their moveable spread/totals.
A rumour may well drop a NBA points total offering from 200 to say 198 in a flash, leaving other books stuck at 200. By being able to move the line at pinnacle you will be looking at perhaps a 2.1 over 199.5 against a 1.91 for under 200 – giving you your chance.
Your chance is, however, a small one, you are unlikely to become a rich man by relying on middle – after all how many times are exactly 200 points scored in an NBA match?
Not many, but it does happen, after all bookmakers have set the ‘200 points total’ because, out of all possible points totals, that one in the most likely.
Let’s consider an extension to middles, we will call them ‘negative middles’ and briefly explained are a middle that gives a negative return should your number not hit.
Your middle either hits and you win big, or it doesn’t and you win small, you will see that it is effectively a value bet where the long term expected return is positive.
A negative middle can be found in handicap and total markets, and will be available in just about every game where books are offering differing lines.
The trick is knowing which ones to take, which is all about calculating the percentage chance of the middle hitting weighed against the percentage loss should the middle not hit.
Let’s consider handicaps, although the same theory can be used for totals.
In order to calculate the % probability of team A winning by an exact number of points over team B I have made an assumption, that being that the derivation of Pinnacle’s alternative lines is correct.
Pinnacle are the sharpest book in the game, their odds generally guide the market and react accordingly to volume and size of bets being placed as well as to news which will affect those odds.
They are the gold standard in bookmaking and as far as I am concerned, their odds are as correct as they can be.
For those that don’t know, pinnacle provide a range of handicaps in their ‘pull-down’ format.
I am not going to question the method of arriving at the odds for each handicap, but no doubt tens of thousands of game data has been inputted to arrive at them.
A sample of handicap odds taken from an NBA game is shown below:
The first step is to convert these odds to an implied percentage probability of each of these bets winning, something not complicated.
For the favourite take the absolute value (ie the positive value) of the odds and divide that by the absolute value plus 100, so a/(a+100), for the underdog take 100 and divide that by the odds plus 100 so 100/(a+100). The first line of the above table gives the following percentage:
- 127/(127+100) = 55.95%
- 100/(114+100) = 46.73%
You will notice that the above two percentages do not add up to 100%, as these numbers contain the juice (vigorish) taken by the book, to remove that we simply scale down the percentages as follows:
- 55.95%/(55.95%+46.73%) = 54.59%
- 46.73%/(55.95%+46.73%) = 45.41%
I have filled out the above table with appropriate implied probability percentages:
If the implied probability percentage of Team A covering the 5.5 spread is 54.49% and the 6.5 spread is 50.00%, the implied probability percentage of them winning by 6 points is 4.49%.
So that is really all you need, should your negative middle of say Team A -5.5 odds of 1.91 and Team B +6.5 odds of 2.00 be less than 4.49%, it is going to be worth taking because there is value, over the long run you will be in profit (in this case it is 2.30%).
If Pinnacle are offering a range of spreads then you will have the option of taking an arbitrage opportunity, or the negative middle.
I always go for the middle because that shot at glory is worth far more than the dribble of small profits when you have been doing this for as long as I have, but if they are not, then keeping a record of the approximate chances of each point hitting will give a great source of value.
I hope that has given some food for thought, even if you just have a play around with the numbers then you will be several steps ahead of most punters!