Mathamatically how do i distribute free bet across other runners

[Guest]

ok lads lets say I place a back bet and lay bet on a runner which is expected to lose.

Normally I would place the following:
Back $10 @ 51
Lay $30 @ 16

If lucky to get matched this greens the bet and would yield

Runner wins = $500 profit - $450 liability = $50
Runner loses = $30 - $10 = $20



However what if my back bet gets taken BUT only $10 of my lay bet is taken. Then due to low liquidly or the runner market has moved I can't lay the other $20. This leaves me with a free bet on a runner which will most likely lose, ie

Runner wins = $500 profit - $150 liability = $350
Runner loses = $10 - $10 = $0


My question is how can I distribute that $350 either backing or laying the remaining runners in that race to turn the free bet into a green bet?

[eventcatering4rum]

Hi TROYEDWARDS
WHY DONT YOU GREEN OUT IN ONE GO IF YOUR TRADE GETS MATCHED AT THOSE ODDS
My original stake = 40
odds my stake was matched at = 51
Current odds =
Payout if the original bet wins, is 2040

To win, whatever the result, lay 127.5 at odds of 16

Commission to pay would be 4.38

Profit after commission will be 83.12

GOOD LUCK, LET ME KNOW ANY ODDS AND YOU CAN SEND ME COMMISSION HA HA X

[Lopiner]

Hi troyedwards8

The reasoning is simple, you would have to back every other selection. An example, imagine that you were left with this market, where you have an upside of 350€ on selection X but unfortunately no one is trying to back that horse:



As the market sits, laying selection X is like backing every other selection. The implicit odd of laying X is given by:

1/(1-(1/9)+(1/2.7)+(1/6.5)+(1/5)+(1/14)+(1/14)+(1/200)) = 59.47
This means you can green up to a profit of 350/59.47 = 5.89

But what stake do you have to bet in each selection?
It's easy:

Back selection Y for UpSide * 1 / Odd = 350 * (1/9) = 38.89
Back selection Z for 350 * (1/2.7) = 129.63
...

In the end it would look like this:

[Guest]

Thanks and one more calc

Thanks Lopiner, exactly what I was looking for. And fantastic example given although would have been easier to have 3 or runners in the example

Given your example this works well with the market book % at 101.65% being very close to fair. A market book at 105% might not work, but I guess if u need to green up only seconds before a race jumps to lock in some profit but more importantly take no loss I guess the MB% should be close to 100% anyway so little loss.


Although I would probably just take a green exit (equal profit on any runner winning), I assume there a way I could distribute the green up to return green on the first 3 favourites and just $0 for the others, thereby increasing a win on the chances one of the favourites win.

Lopiner I know I am asking for a lot here but is there a formular to place more weight on the favourites. I guess the formular would start with which runners am I happy to take $0 profit if they win, and then we re-distribute the rest.

Thamks