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Type Stock exchange
Location New York, New York (office),
Weehawken, New Jersey (matching engine), United States
Founded 2012
Owner IEX Group, Inc.
Key people Brad Katsuyama (CEO)
Ronan Ryan (President)
John Ramsey
Currency USD
Volume 160 million shares/day (May 2017)

IEX (also known as the Investors Exchange) is a stock exchange based in the United States. Started by Brad Katsuyama, it opened for trading on October 25, 2013. The company’s offices are located at 4 World Trade Center in New York City. The matching engine is located across the Hudson River in Weehawken, New Jersey, and the initial point of presence is located in a data center in Secaucus, New Jersey.[1] IEX's main innovation is a 38-mile coil of optical fiber placed in front of its trading engine. This 350 microsecond delay adds a round-trip delay of 0.0007 seconds and is designed to negate the certain speed advantages utilized by some high-frequency traders.[2] 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.[3][4][5]

Operating principles[edit]

IEX was created in response to questionable trading practices that had become widely used across traditional public Wall Street exchanges as well as dark pools and other alternative trading systems. The IEX exchange aims to attract investors by promising to "play fair" by operating in a transparent and straightforward manner, while also helping to level the playing field for traders. Strategies to achieve those goals include:[6]

  • Publishing the matching rules used in the exchange's computerized order matching engine.
  • Offering a limited number of simple and familiar order types.
  • Charging fixed fees on most orders (or a flat percentage rate on small orders).
  • Ensuring market pricing data arrives at external points of presence simultaneously.
  • Slightly delaying market pricing data to all customers (no colocation).
  • Refusing to pay for order flow.

These strategies are intended to ensure the trustworthiness of the exchange. A few dark pools are owned by trading companies that pay for certain types of orders to allow them to fill orders within the pool, rather than routing orders to public exchanges. IEX offers no rebates for orders,[7] and only charges a flat fee of $0.0009 per share on trades executed within the dark pool (or 0.30% with shares worth less than $1.00). Trades forwarded to other trading venues are charged a lower rate.[8]

IEX has five order types: market, limit, primary peg (pegged to national best bid/offer), midpoint peg and patent-pending discretionary peg.[9] IEX discretionary peg is a primary peg that may execute at up to midpoint price when the quote is stable.[10] A few optional parameters can be attached to the orders, leaving IEX with many fewer order types than most other exchanges.

IEX delays the flow of data from the exchange and ensures that it arrives simultaneously at two points of presence in New Jersey. Traders are not allowed to co-locate equipment adjacent to IEX's own servers, unlike many other trading platforms. IEX has its own low-latency links to other trading venues in the New York region, which it can use to execute trades for customers in under 320 microseconds. The point-of-presence links for traders to gain access to IEX have a built-in, round-trip delay of 700 microseconds from a 38-mile coil of fiber, so traders cannot beat IEX's own computers as orders propagate outward.[2] The data delay prevents many predatory behaviors.[11][12] It deters the practice of liquidity fading, where they peer into various trading venues and try to detect orders as they propagate from a broker's order router, and use this information to withdraw liquidity ahead of toxic order flow.[13]

Market share (in percent)[edit]


(Source: IEX)

Broker priority[edit]

Before becoming an exchange, IEX operated a dark pool which did not adhere entirely to priority by price then time, unlike other U.S. trading venues. Instead, the IEX prioritized orders by price, followed by broker, and lastly time. Katsuyama argues that this arrangement advantages regular investors contrarily to high frequency trading firms, by preventing, for instance, HFT firms from jumping to the top of the order queue and front-running normal investors.[14]

When IEX applied for exchange status, it dropped the broker-based priority mechanism, and as an exchange it gives priority to the best price first followed by the time of order submittal (as do other exchanges).[15][16]


Michael Lewis' book Flash Boys[17] focused on the new trading platform, arguing that it was better than other dark pools since it created an equal playing field for investors by slowing down trading. Critics of the book argue that liquidity-provider firms need speed and direct market connectivity to manage risk,[18] and a market that limits speed, such as IEX, would be illiquid and expensive for price discovery.[19]

See also[edit]


  1. ^ Foxman, Simone (2013-10-25). "How the "Navy SEALs" of trading are taking on Wall Street’s predatory robots". Quartz. 
  2. ^ a b Lewis, Michael (2014-03-31). "The Wolf Hunters of Wall Street". The New York Times. 
  3. ^ Matt, Levine (16 September 2015). "The 'Flash Boys' Exchange Is Growing Up". Bloomberg. Retrieved 16 September 2015. 
  4. ^ Popper, Nathaniel. "IEX Group, Critical of Wall St., Gains Approval for Stock Exchange". Retrieved 18 June 2016. 
  5. ^
  6. ^ Picardo, Elvis (2014-04-21). "How IEX is combating predatory types of high-frequency traders". Investopedia. Retrieved 2014-04-25. 
  7. ^ "About Us". IEX. Retrieved 20 July 2014. 
  8. ^ ""Flash Boys" Boosts IEX Trades 40%". Barron's. 9 April 2014. 
  9. ^ "IEX ATS Subscriber Manual v2.7" (PDF). IEX. 27 January 2016. Retrieved 11 May 2016. 
  10. ^ "Discretionary Peg™ Order". IEX. Retrieved 11 May 2016. 
  11. ^ "On A 'Rigged' Wall Street, Milliseconds Make All The Difference". Fresh Air. Transcript. Philadelphia. 2014-04-01. WHYY. 
  12. ^ Mamudi, Sam (2014-03-31). "IEX Welcomes High-Speed Traders, as Long as They Behave". Bloomberg L.P. 
  13. ^ Kroft, Steve (2014-03-30). "Is the U.S. stock market rigged?". CBS News. 
  14. ^ Katsuyama, Brad (2013-05-29). "IEX president Katsuyama addresses 'broker priority'". CNBC. 
  15. ^ "Letter from our CEO". 
  16. ^ "IEX Trading Alert #2016-023: Clarification to Prior Announcement IEX Trading Alert #2016-014: Important Technical Notice Regarding IEX Transition from ATS to Exchange". 
  17. ^ Lewis, Michael M. (2014). Flash boys : a Wall Street revolt (First ed.). New York: W.W. Norton & Company. ISBN 9780393244663. LCCN 2014003208. 
  18. ^ Larry, Tabb (2014-03-31). "No, Michael Lewis, the US Equities Market Is Not Rigged". Tabb Forum. Retrieved 2014-09-07. 
  19. ^ "Opinions published in response to Michael Lewis' Flash Boys and recent comments" (PDF). Futures Industry Association. Retrieved 2014-09-07. 

External links[edit]