Route to Best Destination
IB SmartRouting software is designed to maximize execution price and speed. If the order is natively supported on ISE, the system compares the ISE price with an implied price (calculated using the best price for each leg). If the implied price is better, the order is routed leg by leg to the best destinations. Note the following:

• You cannot modify an order while any of the legs are working.

• If you cancel an order and the last unexecuted leg is working, the system will wait 5 seconds to allow the leg to execute before cancelling the order. If an order is cancelled, any executed legs are sent to the IB error account.

• Due to market latency issues, if Amex is alone at the NBBO for a limit spread leg, the spread is held in the IB system until a competing price is available.