Complex Order Basics

A complex order is an order for two or more different options series "legs" sent to the Exchange as a single order. The order, if filled, is guaranteed to execute within a net price and ratio, unlike sending two or more individual orders. Complex orders on C1 and EDGX may include an equity leg (see Complex Orders with Stock Legs). Complex orders must use the New Order Multileg message.

Cboe Titanium U.S. Options Complex Book Process - Complex Order Basics | Cboe