A spread order is a combination of individual orders (legs) that work together to create a single trading strategy. You can create combinations of option/option, option/stock stock/stock on the same or multiple underlyings, as well as futures spreads.

When your spread order is transmitted, IB SmartRouting will compare native spread prices when available (i.e. ISE) with implied spread prices from all available option and stock exchanges and route each leg independently to the best priced location(s). If your order is marketable, IB will route the spread order or each leg of the spread independently to the best possible venue(s). Non-marketable spread orders native to the ISE on a single underlying will be temporarily routed to the ISE book, while non-marketable orders that are not native to the ISE will remain at IB. From that moment on, IB SmartRouting will continuously evaluate changing market conditions and will dynamically route and re-route based on this evaluation to achieve optimal execution.