Kelly Criterion stake given outstanding exposure

NewApproach

How do you calculate optimal stake under Kelly criterion when you already have exposure at a different price? Assume the following, and lets say for arguments sake that we are discussing a horse's chance in a certain race.

Bankroll: €100.
Initial Price: 9/1 (i.e. 10%)
Our estimate of chance: 14%
Kelly Stake: €4.44

Let's say certain influences have changed and we now consider that this selection has a 30% chance of winning, and his price has adjusted to 4/1 (i.e. 20%).

How do we calculate what the optimal additional stake now is at the revised price, taking into account our outstanding exposure on the same selection? I presume the perceived edge which provided for the original bet needs to be accounted for.

Any suggestions would be great!

diomed

I estimate about 12% of your remaining bank at the new odds. Ignore the previous bet.
I never use the Kelly Criterion.

NewApproach

You can't ignore the previous bet

paulo6891

Do some monte carlo simulations to find out the optimal solution. (If you don't know how to do them you arguably shouldn't be using kelly's staking method.)