Introducing Broker - IB
A futures broker who has a direct relationship with a client, but delegates the work of the floor operation and trade execution to another futures merchant. The merchant firm is usually a close partner of the IB.
Investopedia Commentary
This is done to increase efficiency and lower the work load for futures brokers. It allows the IB to focus on the client while the futures merchant focuses on trading floor operations.
Related Links
Futures Fundamentals
Options Basics Tutorial
Also spelled: IB