Skip to main content
Track Optimal f sizing
8 / 12
Library

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.
Entries in this reading3 entries

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.

Educational research material, not investment advice. Historical source context does not establish present-day performance.
8 of 12 in the Optimal f sizing track
20011-5 pp.Next on Optimal f sizingBounded crash risk with capital units and optimal fIndependent-event strings multiply single-trade chances: a four-event even-odds string is 0.0625, and an all-in 0.60-win and 0.40-loss process reaches 0.496 ruin in three or fewer trades and 0.542 once distinct paths through five trades are added.
All readings on this track · 12 readings
  1. 1990Constructing optimal f when trade sizes differ
  2. 1993Portfolio heat, optimal f, and drawdown limits
  3. 1994Construct historical-optimum-leverage from one equity-path
  4. 1995Optimal f as a leverage bound for commodity account growth
  5. 1998Secure f keeps Optimal f sizing inside a Drawdown limit
  6. 1998Optimal f contract counts versus equity fractions
  7. 1999Match futures starting capital to system risk
  8. 1999Search system inputs together with Optimal f sizing
  9. 2001Bounded crash risk with capital units and optimal f
  10. 2002Optimal f sizing and risk of ruin as exposure filters
  11. 2003Cap ruin and drawdown before optimal-f
  12. 2006Ruin odds, the Kelly fraction and optimal f as size filters
All 12 readings tagged Optimal f sizing
Also on Optimal f sizing5 readings