Grid Trading and the Risks of Martingale Position Sizing

Summary

The document describes a grid strategy that shifts a baseline when price moves by a chosen amount, enters in the direction of that shift, and places a profit target and stop one grid step away. It pairs this structure with either martingale sizing, which increases size after losses, or anti-martingale sizing, which increases size after wins. The author uses the setup to explain why progressive sizing can look appealing in theory while exposing an account to growing position sizes and steep losses during streaks.

The discussion highlights trading frictions such as spread and slippage, as well as gaps that can pass stop levels. It argues that these effects undermine the assumed recovery arithmetic, and suggests gentler sizing progressions as alternatives while noting their limitations. The document gives illustrative calculations and probability assumptions, but no independently validated performance study. Its central caveat is that backtests can obscure capital requirements, execution costs, and the potentially severe risk of long losing streaks.

Key ideas

• The grid enters in the direction of baseline changes and places exits one grid step away.
• Martingale sizing raises exposure after losses, while anti-martingale sizing raises it after wins.
• Exponential position growth can create large capital demands and severe drawdowns during streaks.
• Spread, slippage, and price gaps can prevent the theoretical recovery logic from working.
• The author discusses gentler sizing progressions but does not provide validated performance evidence.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.