A trader starts with $100,000. They take three aggressive trades, each risking 20% of total capital. Two lose. The account sits at $64,000. They feel close to breakeven. They are not. Getting back to $100,000 from $64,000 requires a 56.25% gain — from a starting point that is already weakened. Most traders never do that maths before they size the position.

This is the compounding loss problem, and it is purely arithmetic. Losses and gains are not symmetric. A 10% loss requires an 11.1% gain to recover. A 25% loss requires 33.3%. A 50% loss requires exactly 100%. The deeper the drawdown, the steeper the climb — and the longer the account stays impaired, the more psychological pressure distorts future decisions.

CONCEPTAsymmetric loss maths means every percent of drawdown costs more than one percent of recovery.
WARNINGA 50% drawdown requires a 100% gain just to break even — most traders never model this before sizing up.
KEY IDEAPosition sizing is not about limiting upside — it is about preserving the capital base that makes recovery mathematically possible.

The table below makes the relationship concrete. Notice how the required recovery gain accelerates sharply once drawdown crosses 30%. This is not bad luck — it is geometry. Each loss is calculated on a smaller base, so each subsequent gain must work proportionally harder. The curve does not lie.

Drawdown vs Recovery Gain Required0%50%100%150%200%0%10%20%30%50%67%Drawdown %

The practical response is a hard per-trade risk ceiling. Many systematic traders cap single-trade exposure at 1% to 2% of total equity — not of available margin, of total equity. At 1R risk per trade, a ten-trade losing streak produces a 9.6% drawdown, requiring a 10.6% recovery. Painful, but survivable. At 10R risk per trade, the same streak is terminal. The mechanics behind this are well documented under drawdown analysis, and the mathematical foundation sits in risk of ruin theory. Position sizing models such as the Kelly Criterion, covered thoroughly at Investopedia's Kelly Criterion page, formalise exactly how much capital to allocate given a known edge and variance.

Protect the base. Everything else is optional.

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