Trailing drawdown is a type of risk rule used by prop firms where your maximum allowed loss is calculated from the highest equity point your account reaches, not from your original starting balance.
In simple terms:
As your balance goes up, your allowable drawdown “trails” behind it — making the challenge harder the more you grow your profits.
For example, on a $100,000 challenge with a 5% trailing drawdown:
That’s why many traders are confused when they lose their challenge while still being in profit.