Bookies compile lists of all the competitors in an event. They will offer odds for each competitor representing that Bookies opinion of the likely winner. Backers use these odds to calculate likely returns should they win. This list, together with the Bookies quoted odds, is known as a ‘book’.
In most events, every participating competitor will have different abilities, strengths and weaknesses. As such, the chance of any one competitor winning will be different to the chances of the other competitors. Each competitors chances of winning is assessed by the Bookies team of ‘experts’ so that appropriate odds can be offered (see below).
Bookies are out to make money by taking as much as possible in bets and paying out as little as possible in winnings. Obviously the amount they pay out is determined by the odds of the winner. So, in an attempt to ensure a profit the Bookie must have a very good idea of the winning chances of competitors, and knock a bit off when setting their odds. In other words, the odds a Bookie sets do not reflect the true odds (or chance) of winning.
Whereas a punter usually only bets on one competitor per event, the Bookie has to be prepared to take bets on any of the competitors and therefore has to calculate a price for them all.
Example 1
After using his expert knowledge and inside information to weigh up each competitors chance, the Bookie decides he has the following amount of confidence in each competitor:
Competitor | True Odds | |
A | 20% | 4/1 |
B | 10% | 9/1 |
C | 30% | 9/4 |
D | 25% | 3/1 |
E | 15% | 11/2 |
Total | 100% |
The Bookie now has what he thinks are the fair odds – the true odds for each runner. Being profit orientated, he now knocks a bit off each.
Competitor | True Odds | Bookies Odds | |
A | 20% | 4/1 | Maybe shortened to 7/2 |
B | 10% | 9/1 | Maybe shortened to 8/1 |
C | 30% | 9/4 | Maybe shortened to 2/1 |
D | 25% | 3/1 | Maybe shortened to 5/2 |
E | 15% | 11/2 | Maybe shortened to 5/1 |
Total | 100% |
These odds are now put on display and offered to the general betting public.
If you convert the Bookies odds into percentages (see how earlier), and add them up, the result should be greater than 100%. This represents the Bookies profit. Bookies aim for a percentage profit on every event.
Competitor | True Odds | Bookies Odds | ||
A | 20% | 4/1 | Maybe shortened to 7/2 | 22.22% |
B | 10% | 9/1 | Maybe shortened to 8/1 | 11.11% |
C | 30% | 9/4 | Maybe shortened to 2/1 | 33.33% |
D | 25% | 3/1 | Maybe shortened to 5/2 | 28.57% |
E | 15% | 11/2 | Maybe shortened to 5/1 | 16.67% |
Total | 100% | 111.90% |
A book with a total percentage greater than 100% is called ‘over round’. However, if the total percentage is less than 100, then a loss will occur. In this instance the book is called ‘over broke’.
The following table is an example of a book from a typical Horse Racing event:
Horse |
Fractional Odds | Decimal Odds | Percentage |
French Executive | 3/1 | 4.00 | 25 |
Possible Pardon | 5/1 | 6.00 | 16.67 |
Nordic Prince | 11/2 | 6.50 | 15.38 |
Tom’s Prize | 7/1 | 8.00 | 12.5 |
Lord Rapier | 8/1 | 9.00 | 11.11 |
Mistletoe | 10/1 | 11.00 | 9.09 |
Prince Sorinieres | 10/1 | 11.00 | 9.09 |
Helvetius | 10/1 | 11.00 | 9.09 |
Somemanforoneman | 14/1 | 15.00 | 6.67 |
Total percentage |
114.60 |
This book has a percentage total of 114% so is ‘over round’.
The following table shows the same Horse Racing event, but I’ve changed the odds. This time the book is ‘over broke’.
Horse |
Traditional Odds | Decimal Odds | Percentage
Of Book |
French Executive | 3/1 | 4.00 | 25 |
Possible Pardon | 7/1 | 8.00 | 12.50 |
Nordic Prince | 17/2 | 9.50 | 10.53 |
Tom’s Prize | 11/1 | 12.00 | 8.33 |
Lord Rapier | 14/1 | 15.00 | 6.67 |
Mistletoe | 20/1 | 21.00 | 4.76 |
Prince Sorinieres | 22/1 | 23.00 | 4.35 |
Helvetius | 25/1 | 26.00 | 3.85 |
Somemanforoneman | 25/1 | 26.00 | 3.85 |
Total percentage |
79.84 |