betfair % book question

[wb]

Could someone explain in simple terms how the % over the back and lay side works on betfair. I know this is probrally an obvious one, but I can't seem to get my head around it. I read what they have to say on the website but cant see how it works.

For example, on the back side, if the book is below 100%, you could back every selection and still win. well, I saw the book go like this today, but one horse was even money. so how would you make money if you backed every horse :doh Would it only work with bot's?

Thanks,

Wayne

[presto]

the easiest i can explain it is:

the number % on the back side is how much you will need to bet to guarantee a £100 return.

on betfair the book is around 101% - so you would need £101 to win back £100.

.....................................................

as for guaranteeing a profit when the book dip's below 100% - i would say this is only possible with bot's, as you need to work out:
stake on each selection
odd's on each selection
ammount available on each selection

all this to just make a few pennies. - though the bot can calculate this instantly - and the book dosn't often dip below 100% for long.

[wb]

Ah, I see. Thanks presto.

small % changes are pretty much useless to the average punter using small stakes with no bot then. (me :( )

thanks

[Win2Win]

If it goes to say 99% on the win side, the bots will even it up again, taking the bonus off the top. This is very difficult to do now though with so many bots, and many of the prices you offer will not be settled, and at those margins it leaves you open to cockups.

[MarcusMel]

Just to confuse :D

Its the sum of the reciprocal betfair prices turned into a percentage by multiplying the sum by 100!

[MarcusMel]

Example

Sum of reciprocals in attached market is

1/1.03 + 1/13.5 = 0.97087 +0.07407=1.04494

To get as percentage
1.0449*100=104.5% rounded

[wb]

Thans mathare. Don't think I could work that out in running though :yikes: tee hee

[MarcusMel]

?mathare :doh

[wb]

?mathare :doh

typo