A ´Loop Order´ is a perpetual or repeating order placed in anticipation of a cyclical movement in the market. It is a pair of matching orders where the first leg is active and the second dormant. When the desired price is reached for the active order, it is executed, the dormant order becomes active, and a new order (a copy of the one just executed) is created in a dormant state. This process repeats until the order is explicitly cancelled.
Normally both legs of a Loop Order are Limit orders and they always are for the same amount.
For example, if a trader expects the rate of an instrument to fluctuate between two levels (range trading), a Loop Order placed just inside the limits of the fluctuations will produce repeated good results.