What is the SMART order routing destination?

A combination  order is a special type of order that is constructed of multiple separate positions, or ‘legs’, but executed as a single transaction. The legs of the combination may be comprised of the same position type (e.g. stock vs. stock, option vs. option) or different position types (e.g. stock vs. option). It i important to note that many combination order types, while submitted via our trading platform as a combination, are not native to (i.e., supported by) the exchanges and therefore may not be guaranteed by us. Accordingly, our policy is to guarantee only Smart-Routed U.S. stock vs. option and option vs. option combination orders…

IBKR clients can add liquidity and interact with our retail order flow by direct-routing their US equity and index options orders to the IBUSOPT destination. Orders routed to IBUSOPT will be held at this liquidity-providing destination, and will be eligible to participate in an exchange auction to potentially fill against other SMART-routed marketable orders from IBKR clients…

IBKR Lite clients will not be able to select SMART routing for orders in US stocks outside of the Overnight; such orders will be routed through Lite where possible.

For all other orders entered by an IBKR Lite client SMART will need to be selected when available since direct routing of an order is not supported…

Currently (as of 7/1/2021) the following order types can be used to route non-marketable US Stock orders to IBKR ATS:

• Limit
• Relative…