In the pantheon of trading literature, few books strike as much fear into the hearts of casual investors as Portfolio Management Formulas: Mathematical Trading Methods for the Futures, Options, and Stock Markets by Ralph Vince. Published in November 1990, this is not a beach read. It is not filled with pretty charts of head-and-shoulders patterns or promises of turning $1,000 into $1 million overnight.
where f is the optimal fraction, bp is the probability of winning, and r is the ratio of the average win to average loss. In the pantheon of trading literature, few books
The formula is terrifyingly sensitive: [ f = \frac(\textAverage Trade Profit)(\textWorst Loss) \times \textProbability Adjustments ] where f is the optimal fraction, bp is
Reading Portfolio Management Formulas can be dangerous. Vince is clear: It maximizes growth, but it also maximizes drawdowns in the short term. A trader following Optimal f might see a 70% drawdown before the exponential growth kicks in. A trader following Optimal f might see a
For most aggressive futures or stock systems, Optimal ( f ) often lands between 0.15 and 0.30 (15% to 30% of your account on a single trade). To a traditional trader, this looks like suicide. To Vince, risking less than ( f ) is leaving money on the table; risking more than ( f ) is mathematical suicide.
This is remarkably prescient. Thirty years before "Machine Learning" trading, Vince was describing non-parametric distribution fitting.
