Trailing drawdown is the rule responsible for more blown evaluations than almost any other. It looks simple on a rules page, but in practice it surprises traders who are used to thinking in terms of starting balance.
How trailing drawdown works
A trailing drawdown defines a maximum loss that moves with your account's high-water mark. If your account grows, the floor under your account grows with it. If you give back profits, you can hit the drawdown limit even while still showing a net positive trade history.
Why traders fail it
- They size up after a winning streak, then a normal pullback breaks the new tighter limit.
- They don't realize unrealized profits often count toward the high-water mark.
- They confuse trailing drawdown with daily loss limits, which reset.
- They treat the starting balance as the loss floor — it isn't, once the account grows.
How to avoid breaking it
Treat the trailing drawdown as your true stop-out. Track the distance between current equity and the trailing value, not the distance to your starting balance. Reduce size after a strong winning session — that is exactly when the limit tightens the most.