Maximum concurrent lots
The largest total position size open on an account at any one moment.
This is the peak exposure a strategy has ever carried, added up across every open position at its busiest moment. It is the number that decides how close the account came to a margin call, and it is what a subscriber inherits at the same leverage.
A strategy with a small average position size can still carry a large maximum if it adds to positions under a grid or martingale rule, which is why the peak matters more than the average here.