query
for $10 i bet the horse at 10 and layed it at 9 offset bet with greening. i thought the profit should be $1.11 but it says only .89c THEN when i check the betfair account it says a profit completely different to anything
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then i back at 11 and lay at 10 for $10 to lose $3???? offset betting with greening. do i have to manually click the the green trade profit amount in the green column? i thought this was auto
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JollyGreen
- Posts: 2047
- Joined: Sat Mar 21, 2009 10:06 am
That is quite strange at first glance.
In the first one if you back at 10.0 with $10.00 you should be laying at 9.00 with $11.11
In the second one if you backed at 11.0 for $10 you should be laying at 10.0 for $11
Did you have any other bets with residual amounts?
In the first one if you back at 10.0 with $10.00 you should be laying at 9.00 with $11.11
In the second one if you backed at 11.0 for $10 you should be laying at 10.0 for $11
Did you have any other bets with residual amounts?
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marksmeets302
- Posts: 527
- Joined: Thu Dec 10, 2009 4:37 pm
Here's an explanation of the calculations:
If you have backed B at odds p, then the amount you need to lay (L) at odds q can be derived from this:
if the horse wins, your profit will be B * (p-1) - L.
if the horse loses, your profit will be L * (q-1) - B.
Therefore, to make sure you receive equal amounts no matter if the horse wins or loses you need:
B * (p-1) - L = L * (q-1) -B
or: Bp = Lq
In your first case this means L = 10*10/9 = 11.11
Second case: L = 11*10/10 = 11
If you have backed B at odds p, then the amount you need to lay (L) at odds q can be derived from this:
if the horse wins, your profit will be B * (p-1) - L.
if the horse loses, your profit will be L * (q-1) - B.
Therefore, to make sure you receive equal amounts no matter if the horse wins or loses you need:
B * (p-1) - L = L * (q-1) -B
or: Bp = Lq
In your first case this means L = 10*10/9 = 11.11
Second case: L = 11*10/10 = 11
We've handled this query via support, but for the benefit of others reading this thread. The reason for the unexpected values was due to the odds of the lay bets being modified manually after the bets were placed. Although the odds were manually modified, the stakes were not, which spoiled the offset bet's automatic green-up staking.