How to spot an overlay?

Or a crude way and if you are left brained.........

Seeing as the bookies are the professionals in setting prices (or you could use your favourite reference like Winning Form, Sporting Post, newspaper, etc):

1. Note the first, original or opening price for each runner, I think this is key (or result depending on the event you are backing);
2. Convert each price into a probability or percentage (as davetheflower above described);
3. Total the sum of each probability, this sum should be more than 100% and probably 135%;
4. Proportionally adjust each probability so that the total equals 100% (you may want the adjusted total to equal 94% to accommodate any taxes);
5. Convert each adjusted probability into an ajusted price (again as Dave described);
6. Compare your adjusted price to the advertised price eg starting price.

I hope it doesn't sound so complicated :S

Mac Wrote:

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> Or a crude way and if you are left
> brained.........
>
> Seeing as the bookies are the professionals in
> setting prices (or you could use your favourite
> reference like Winning Form, Sporting Post,
> newspaper, etc):
>
> 1. Note the first, original or opening price for
> each runner, I think this is key (or result
> depending on the event you are backing);
> 2. Convert each price into a probability or
> percentage (as davetheflower above described);
> 3. Total the sum of each probability, this sum
> should be more than 100% and probably 135%;
> 4. Proportionally adjust each probability so that
> the total equals 100% (you may want the adjusted
> total to equal 94% to accommodate any taxes);
> 5. Convert each adjusted probability into an
> ajusted price (again as Dave described);
> 6. Compare your adjusted price to the advertised
> price eg starting price
>
> I hope it doesn't sound so complicated :S

That's correct Mac,with the 135% or say the bookies are betting to 123%,you divide the 23% by your remaining 7 runners which leaves
about 3.5 %. Take that off our original 12.5% which leaves 9%,making it a 10/1 chance.
Off course some of the other runners may tick a couple of form choices,so you calculate your prices accordingly.

Lucky_Dude Wrote:

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> Do you guys have any gems on how to spot a genuine
> overlay in the betting markets?

Regarding some of the above comment, to work out what the total market percentage add 1 to each price and divide it into 100.

e.g in a 3 horse field the prices are 15/10 18/10 and 2/1

100/(1.5 + 1) = 40
100/(1.8 +1) = 35.7
100/(2 + 1) = 33.3

Total percentage = 109%

The above market would possibly be found in the UK but never in SA who I believe price up at around 145% and then come down to around 120% at starting time.

That's why it's probably madness to bet early in SA on the form horses.

However, in order to take advantage of an "overlay" or good price it normally has to be spotted early. If a horse is being offered at a ridiculous looking price at the off it usually means they know it can't win

Wow. Lekker thread.

I see a business oppurtunity.

I know some already gets a headache of the calculations.

wonder how much can i charge per month for doing it ?

Lol

zesto Wrote:

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> I see a business oppurtunity.
>

> Lol

Hahahaha, its still not the holy grail to punting. We all remain with a daytime job.

Zesty now is your chance,race 7 Scottsville.
If you start now collating the form you should be finished in time:D

About Time we spoke about something to do with racing instead of all the BS concerning admin problems and TT presenters(which i do agree with)

If you go for any of the horses I fail to mention, you would be on to an overlay <

Some possible flaws in just taking the ante post prices and converting the percentages could be....

Some times bookies seem to be cautious with well bred first timers and will price them up very short to protect themselves, even if the horse is not very good. Only insiders know if the horse is prepped to win or if the race is being used as a prep run or just to gain experience. In other words, a horse that looks good on paper may be used by a trainer as a preprun for a feature race and has little intent on winning it. Any other thoughts as to why bookies may be way out with their AP prices?

How I understand how bookies price up "good" first-timers is that the first-timer is removed from the basis ie they price all the other runners to say 135% excl the first-timer. Then an arbitrary price is given to the first-timer resulting in a total over-rounding much greater than 135% and then market forces prevail which consumes the excessive over-roundedness into normal margins.
Furthermore ante-post pricing is not the same as the opening price. The opening price is the price before the 1st bet is laid for the event which does not cnntain market forces (and all runners are carded). AP pricing, after the 1st bet, then contains market forces.
Theoretically, the opening prices are made by the bookie, and the closing prices by the punter.