Risk management · Intermediate

Risk of Ruin and Why It Matters

A 1-minute lesson from the MarketPro academy, one of 22 in risk management.

Last reviewed 15 September 2026 by the MarketPro research desk · Editorial policy

Short answer

Risk of ruin is a statistical concept describing the probability that a trading approach eventually depletes an account to the point where continuing to trade meaningfully is no longer possible. Risk of ruin depends heavily on how much capital is risked per trade and the pattern of wins and losses over time.

Risk of ruin is a statistical concept describing the probability that a trading approach eventually depletes an account to the point where continuing to trade meaningfully is no longer possible.

What Drives It

Risk of ruin depends heavily on how much capital is risked per trade and the pattern of wins and losses over time. Even a strategy with a reasonable long-run edge can face a meaningful risk of ruin if position sizes are too large relative to account size, because a string of losses — which can happen even under normal statistical variance — compounds quickly.

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A Hypothetical Illustration

Suppose one trader risks 1% of their account per trade while another risks 10%. A run of several consecutive losing trades reduces the first account only modestly, while the same losing streak can severely damage the second, and mathematically requires a much larger percentage gain just to recover to the starting point.

Smaller, consistent risk per trade generally lowers risk of ruin
Risk of ruin rises sharply, not just proportionally, as per-trade risk increases
No position sizing approach reduces risk of ruin to zero

Thinking in these terms shifts the focus from any single trade's outcome to the long-run survivability of an entire approach.

Step 6 of 10 on Risk Management Mastery

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The arithmetic in this category has a free calculator on this site, no sign-up and nothing leaves your browser: Position size calculator, Risk of ruin calculator, Drawdown calculator, Profit & loss calculator.

Written and reviewed by the MarketPro research desk

MarketPro is a trading-signal and trading-education app operated by Harajuku Holdings LTD (Cyprus). Our signal desk publishes and tracks every trade idea in-app, and every page here is checked against the app's live behaviour before publishing. Last reviewed 15 September 2026. How we produce signals and content · About MarketPro

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