IEX may refer to:
- Irish Enterprise Exchange, see List of European stock exchanges
- IEX, an alternate stock exchange founded by Brad Katsuyama
IEX is an exchange based in the United States. Started by Brad Katsuyama, it opened for its first day of trading on October 25, 2013. The company's offices are located at 4 World Trade Center in New York City. However, the computer equipment that handles the actual dark pool is located across the Hudson River in Weehawken, New Jersey, and the initial point of presence for the dark pool is located in a data center in Secaucus, New Jersey. IEX's main innovation is a 38-mile coil of optical fiber placed in front of its trading engine, which adds a round-trip delay of 0.0007 seconds and is believed to limit traders' ability to respond on the dark pool ahead of IEX's own pricing algorithms. The exchange's market session runs from 9:30 am to 4:00 pm Eastern Time.
The SEC approved the IEX to be an official exchange on June 17, 2016.