Quote from ericmoles:
It is reasonable if your win loss ratio and win size to loss size allows it. It isn't reasonable if your system could potentially have 30 losses in a row. How much of a draw down are you willing to accept?
The amount you risk and your probability of ruin is all mathematical assuming good data and allowance for outliers.
Systems with low standard deviations may do ok with a 3.3% risk. If your system is highly variable, it may not work.
How did you choose 3.3% anyway?
Quote from ericmoles:
It is reasonable if your win loss ratio and win size to loss size allows it. It isn't reasonable if your system could potentially have 30 losses in a row. How much of a draw down are you willing to accept?
The amount you risk and your probability of ruin is all mathematical assuming good data and allowance for outliers.
Systems with low standard deviations may do ok with a 3.3% risk. If your system is highly variable, it may not work.
How did you choose 3.3% anyway?
Quote from mg_mg:
From Kelly formula (http://en.wikipedia.org/wiki/Kelly_criterion), the best bet is f* = (bp-q)/b, where: f* is the fraction of the current bankroll to wager; b is the net odds received on the wager; p is the probability of winning. If you receive 1-to-1 odds on a winning trade, i.e. b=1, then for obtaining 3.3% bet rate, we have 3.3% = p-q=2p-1 which gives p=51.65%, it mean that if you want to bet 3.3%, then the winning rate should be no less than 51.65%. If your winning rate is just 51%, then the best bet rate is (bp-q)/b = p-q = 2p-1 = 2*51% -1 =2%.
Quote from mg_mg:
From Kelly formula (http://en.wikipedia.org/wiki/Kelly_criterion), the best bet is f* = (bp-q)/b, where: f* is the fraction of the current bankroll to wager; b is the net odds received on the wager; p is the probability of winning. If you receive 1-to-1 odds on a winning trade, i.e. b=1, then for obtaining 3.3% bet rate, we have 3.3% = p-q=2p-1 which gives p=51.65%, it mean that if you want to bet 3.3%, then the winning rate should be no less than 51.65%. If your winning rate is just 51%, then the best bet rate is (bp-q)/b = p-q = 2p-1 = 2*51% -1 =2%.
Quote from mg_mg:
Kelly formula originated in gambling in which how much you bet is how much you lose in a losing bet, so what the formula gives can be understood as the optimal amount you can lose in a trade.
Quote from spindr0:
If I don't like how the trade is behaving, I cut it loose regardless of the profit or loss. Fixed arbitrary numbers don't work for me.