1999issue C081-5
Search system inputs together with Optimal f sizing
Two five-trade sequences reversed rank after Optimal f sizing. From the same 10000 starting equity, the sequence with 3100 of unlevered net profit became 4087 of profit, while the sequence with 2800 became 4255, because the second series had a smaller holding-period-return standard deviation and a higher Sharpe ratio.
- A five-trade sequence with 3100 unlevered net profit produced a 43.3 percent Optimal f sizing fraction and a 40.87 percent compounded return.
- A rival sequence with 2800 unlevered net profit produced a 46.3 percent fraction and a 42.55 percent compounded return, finishing ahead from the same 10000 starting equity.
- Return-based sizing such as Optimal f sizing sets the next stake from the historical profit-and-loss series rather than from the unlevered net-profit ranking alone.
- System inputs and money-management inputs should be searched together. Changing a Stop-loss order can help after a return-based fraction even when it reduced unlevered system profit.
A larger unlevered profit can finish smaller
A five-trade sequence with 3100 unlevered net profit produced an optimal fraction of 43.3 percent. After that fraction was applied, the sequence showed a 40.87 percent compounded return.
A different five-trade sequence with 2800 unlevered net profit produced an optimal fraction of 46.3 percent and a 42.55 percent compounded return after that fraction was applied.
From the same 10000 starting equity, applying those optimal fractions turned the 3100-profit sequence into 4087 of profit and the 2800-profit sequence into 4255 of profit.
The sequence that earned about 10.71 percent more before any sizing rule produced about 1.7 percent less after Optimal f sizing, because the rival sequence had a smaller holding-period-return standard deviation and a higher Sharpe ratio.
The next stake comes from the trade series
Return-based sizing such as Optimal f sizing, martingale, and antimartingale sets the next stake from the historical profit-and-loss series. The fraction and the resulting account path depend on that series rather than on the unlevered net-profit ranking alone.
Optimal f sizing is the equity fraction that maximizes terminal wealth relative, the product of holding-period returns, when each trade is scaled by that fraction relative to the worst loss.
Search system inputs and money management together
A mechanical system with tunable inputs, illustrated as a two-input moving-average crossover, should have those inputs searched together with the money-management inputs rather than in a two-step sequence of system first and size second.
Changing a Stop-loss order level can raise profitability after a return-based sizing rule even when the same stop reduced unlevered system profit, because the stop reshapes the trade-return series that the fraction consumes.
All readings on this track · 12 readings
- 1990Constructing optimal f when trade sizes differ
- 1993Portfolio heat, optimal f, and drawdown limits
- 1994Construct historical-optimum-leverage from one equity-path
- 1995Optimal f as a leverage bound for commodity account growth
- 1998Secure f keeps Optimal f sizing inside a Drawdown limit
- 1998Optimal f contract counts versus equity fractions
- 1999Match futures starting capital to system risk
- 1999Search system inputs together with Optimal f sizing
- 2001Bounded crash risk with capital units and optimal f
- 2002Optimal f sizing and risk of ruin as exposure filters
- 2003Cap ruin and drawdown before optimal-f
- 2006Ruin odds, the Kelly fraction and optimal f as size filters