Risk of ruin, in plain numbers

Two traders can run the same system with the same win rate and end up in completely different places. The difference is almost always position size.

The arithmetic of survival

• Risk 1% per trade, lose 10 in a row: −9.6%. You carry on.
• Risk 5% per trade, lose 10 in a row: −40%. You now need +67% to get back.
• Risk 10% per trade, lose 10 in a row: −65%. You need +186%.

Long losing streaks are normal, not exceptional. At a 40% win rate, ten losers in a row will happen if you trade long enough.

The uncomfortable part

Risk per trade is the one dial that converts "unavoidable" into "survivable". Which is why sizing deserves more of your attention than entry timing.

Practical floor

Many professionals work in the 0.25–1% band per idea, with a hard cap on correlated exposure. Try it in the risk manager and see what your current size does to a ten-loss streak.