It stands for automatic execution suspension; with respect to an exchange trading and its control parameters/ curbs, it refers an execution halt that is triggered by a breach in the tolerance levels during the continuous trading phase. This trading control is used in a dynamic price monitoring, so that if the price of a potential execution surpasses (in either direction) a defined percentage above or below the applicable reference price(s), then no executions will take place at that price. Instead, automatic execution will be temporarily halted and a trading session (auction) will be triggered to allow the security’s price to orderly re-adjust and return to its level as at regular trading.

An automatic execution suspension (AESP) is often referred to as a circuit breaker.