Risk of Ruin: How Many Losses Your Account Survives

Divide the room you have by the size of one full loss. On a $100,000 account with an 8% maximum drawdown you have $8,000 of room. Risking 1% ($1,000) per trade gives eight consecutive losses before the account is gone.

Eight is not a comfortable number. Strategies that win half their trades produce five-loss streaks routinely and eight-loss streaks over a long enough sample. Risking 0.5% instead doubles the count to sixteen, which is the difference between surviving a bad fortnight and not.

With a 50% win rate, the chance of five losses in a row inside a hundred trades is very high — it is close to certain rather than exotic. At a 40% win rate, which many trend strategies run, seven-loss streaks are ordinary.

This is why traders who blame the streak have usually misdiagnosed the problem. The streak was always coming; the sizing decided what it cost.

A daily loss limit is a second, tighter version of the same calculation. On a 3% daily rule, risking 1% per trade leaves you three losses before the day locks — and three losses inside one session is an ordinary morning.

Size so that a normal bad day cannot reach the daily floor. If three losses is your realistic worst session, risk no more than a third of the daily allowance on any single trade, and stop after two.

Cutting risk per trade is the direct lever, but it is not the only one. Reducing correlated exposure matters just as much: three long positions on EUR/USD, GBP/USD and gold during a dollar move are one trade wearing three costumes.

Raising the average win relative to the average loss also helps, because it shortens the recovery needed after each streak. A profit factor above 1.5 with 0.5% risk is a durable combination; a profit factor of 1.1 with 2% risk is not.