Listings Specifications, Testing Opportunities, and Timelines

IEX Trading Alert #2017 - 015


Pending SEC approval, IEX plans to become a primary listing exchange and support its first IEX-listed company in October 2017. As part of this initiative, the following new functionality will be deployed to the IEX trading platform, market data feeds, and public website:

  • Auctions (opening, closing, reopening)
  • Support for On-Open and On-Close order types
  • Support for Security Directory and Auction Information Messages on IEX market data feeds
  • Launch of dedicated IEX-listed test symbols
  • Quoting and printing for IEX-listed securities on Network B (i.e. Tape B) data feeds
  • Generation and distribution of daily list files

IEX will provide users with multiple opportunities to test the new functionality in the IEX Testing Facility ("ITF"), Production, and Disaster Recovery ("DR") environments beginning in July 2017. More information is provided below.

Auction Process & New Order Types

The IEX Auction Process provides electronic price discovery mechanisms that efficiently match orders in IEX-listed securities at a single price using a double auction. These auctions enable IEX participants to execute against On-Open and On-Close interest at IEX. They also allow for participation in IEX corporate initial public offerings ("IPOs"), new issues, auctions resulting from security halts, and auctions resulting from LULD trading pauses. During the auction process, IEX will calculate and disseminate current price, size, imbalance information, auction collar information, and other relevant information about upcoming auctions. For further information, please review the IEX Auction Process Specification.

IEX will also introduce four new order types for use in auctions exclusively: two for the Opening Auction (Market-On-Open, Limit-On-Open) and two for the Closing Auction (Market-On-Close, Limit-On-Close). Please review the IEX Auction Process Specification or IEX FIX Specification for more information.

Introduction of TOPS v1.6 and Imbalance Information

TOPS v1.6 will be introduced with the addition of administrative and auction messages to communicate system events, security directory (IEX-listed only), trading status, operational trading halts, short sale price test status, and auction information (IEX-listed only). TOPS v1.6 will be available in the ITF on July 10, 2017 and will be deployed to Production on August 14, 2017. Connectivity details for muticast transmission and gap fill servers may be found in the IEX TOPS Specification. TOPS v1.6 will continue to be a FREE market data offering of the Exchange.

TOPS v1.5 will be retired in Q4 2017.

As a reminder, IEX launched DEEP on May 15, 2017. Beyond real-time aggregated quotation information at all price levels, DEEP also provides Security Directory and Auction Information Messages for IEX-listed securities. For more information, please review IEX Trading Alert #2017 - 011 and the IEX DEEP Specification.

Participants who wish to consume IEX market data must complete, execute, and submit the necessary IEX Data Agreements and Forms, and may need to consult the IEX Connectivity Manual if establishing new connectivity to IEX. For additional information about IEX market data visit the IEX website.

Tape B and Test IEX-listed Securities

IEX-listed securities will be Network B eligible securities which will be quoted and printed to CTA's CQS and CTS data feeds, respectively. To allow for future production testing of updates to the CQS and CTS data feeds, IEX has reserved the following test symbols as IEX-listed securities:


Note that market participants should be prepared to accept messages for these test symbols on Network B production feeds as early as Monday, August 28, 2017. SIAC will provide two Saturday testing opportunities on July 22 and August 12.

Listings Timeline

Pending SEC approval, IEX intends to launch its listings program in October 2017. As such, IEX will provide support for the defined auction process during the timeframes specified below.

  • Auctions Availability in the IEX Testing Facility ("ITF")
    • TOPS v1.6 Deployed in the ITF
    • DEEP v1.0 and TOPS v1.6 Begin Publishing Auction Information and Security Directory Messages in the ITF for Test IEX-Listed Securities
  • 1st Member Testing Opportunity (Production Environment)
  • TOPS v1.6 Launched in the Production Environment
  • Auctions Available in Production for Test IEX-Listed Securities
    • Test IEX-Listed Securities (ZIEXT, ZEXIT, ZXIET)
    • DEEP v1.0 and TOPS v1.6 Begin Publishing Auction Information and Security Directory Messages in the Production Environment for Test IEX-Listed Securities
  • 2nd Member Testing Opportunity (Disaster Recovery Environment)
  • 3rd Member Testing Opportunity (Production Environment)
  • 4th Member Testing Opportunity (Production Environment)
  • Pending SEC Approval, IEX Launches as a Primary Listing Exchange, Phase-in Period Begins

IEX Testing Opportunities

To support User testing, comprehensive listings functionality will be deployed to the ITF environment by July 10, 2017. At this time, Security Directory and Auction Information Messages will also become available via the ITF instance of DEEP.

Testing of the auction process in the ITF using the test IEX-listed securities will begin on July 10, 2017. The ITF is available Monday through Friday from 7:00 a.m. to 9:00 p.m. ET.

The auction process and listings functionality for test IEX-listed securities will commence Monday, August 28, 2017 in the Production environment. The Production environment is available Monday through Friday from 8:00 a.m. to 5:00 p.m. ET.

Finally, IEX plans to offer the following Saturday testing opportunities of the defined auction process in advance of launching its listings program:

  • IEX Listings Industry Test #1: August 12, 2017
  • IEX Listings Industry Test #2 (in DR environment): September 9, 2017
  • IEX Listings Industry Test #3: September 23, 2017
  • IEX Listings Industry Test #4: October 7, 2017

As a reminder, in accordance with Regulation SCI, IEX will conduct testing of its Business Continuity and Disaster Recovery Plans during the planned SIFMA industry-wide test on Saturday October 14, 2017, during which time IEX will offer testing opportunities of the auction process from the DR environment. For more information, please review IEX Trading Alert #2017 - 002.

Corporate Actions and Daily Lists

For IEX-listed securities, the following data files will be posted to the IEX website each day for view or download:

  1. IEX-Listed Symbol Directory Daily List: Provides a list of all IEX-listed securities and their corresponding data fields
  2. IEX Corporate Actions Daily List: Lists new issues, symbol and name changes, and deleted issues, as well as new firms, name changes, and deleted firms for IEX-listed securities
  3. IEX Dividends Daily List: Details: Details upcoming dividend information and other corporate actions, such as stock splits, for IEX-listed securities
  4. IEX Next Day X-Dates Daily List: Provides advance notification of dividend declarations impacting IEX-listed securities

The IEX-Listed Symbol Directory Daily List will be posted at 8:30 p.m. ET for the following trading day and then once per hour from 9 p.m. until 6 p.m. ET the following day. All other reports will be posted once per hour from 8 a.m. to 6 p.m. ET each trading day.

Each report is available with and without CUSIP information, subject to IEX review of a user's licensing information. Please review the IEX Daily List File Specification for more details on each file.

More Information

Please contact IEX Market Operations, Sales, or Network Operations with any questions:

About IEX

IEX is on a mission to build fairer markets. Founded in 2012 and headquartered in New York City, IEX introduced its first trading venue in 2013 and launched as a U.S. stock exchange in 2016. IEX is the stock exchange that believes that every investor has the right to trade on equal and fair terms, on every trade. Learn more at: