The book’s primary contribution is the introduction of , a position-sizing method designed to maximize the long-term geometric growth rate of a trading account. Unlike traditional money management that often focuses on fixed dollar amounts, Optimal f determines the exact fraction of capital to risk on a single trade based on historical performance.
Some of the key formulas and techniques covered in the book include: The book’s primary contribution is the introduction of
Ralph Vince’s 1990 work, Portfolio Management Formulas , revolutionized quantitative trading by focusing on mathematical position sizing to maximize compounded growth rather than just entry signals. It introduced "Optimal f," a derivative of the Kelly Criterion designed to determine precise, risk-adjusted trading quantities based on historical maximum losses. For more details, visit QuantPedia It introduced "Optimal f," a derivative of the
Author: Ralph Vince Publication Date: November 1990 Vince, R
Raw Optimal ( f ) often tells a trader to risk 20%, 30%, or even 50% of their capital on a single trade. While mathematically optimal for logarithmic utility , this leads to massive drawdowns (sometimes 70% or more) before hitting the exponential growth curve.
Vince, R. (1990). Portfolio Management Formulas: Mathematical Trading Methods for the Futures, Options, and Stock Markets. John Wiley & Sons.
You have a system that wins 60% of the time ($P = 0.6$). Your average win is 2x your average loss ($B = 2$). $$f = \frac(2 \times 0.6) - 0.42 = \frac1.2 - 0.42 = \frac0.82 = 0.4$$