Feb 14, 2023

February 14, 2023

Your Top Questions About Market Operations, Answered

An image of a man sitting at a desk looking at a computer screen with a wall of screens showing the movements of stock market in the background

Head of Market Operations Thomas O'Brien breaks down the most popular questions our team of Market Ops Specialists receive from broker-dealer Members

Market Operations is one of those job functions that can be hard to explain to someone outside the trading industry. At the end the day (and bright and early at the beginning of the day!), we are here to ensure that the markets run smoothly both in terms of technology and processes.  

At IEX Exchange, my team of Market Ops Specialists are online well before the start of pre-market trading to ensure that we can answer any questions that our broker-dealer Members may have about their physical port connection to access IEX market data; technical specifications for new order types; and more.  

We answer hundreds of queries a week from Members and have gathered the ones we're asked most frequently, along with our responses, here.

1. How do I add or remove order entry sessions(s) on IEX Exchange?

To add or remove an order entry session(s) on IEX Exchange, one will need to submit a signed and completed Equities Port Request Form. On the form you can indicate an “Addition” or “Removal”. You can also specify the session(s) in the SenderCompId field to be removed. This form must be signed or approved by someone on the Authorized Personnel List that was submitted to IEX Exchange.

2. How do I modify my existing order entry session(s) settings on IEX Exchange?

To make changes to an existing session on IEX Exchange, we ask that you submit a completed Equities Port Request Form. On the form you can indicate “Change to Existing” and specify the session(s) in the SenderCompId field to be changed. You can also provide more details around the associated change(s) in the “Additional Comments or Request Notes” section on the succeeding page. This change form will also need to be signed or approved by an individual on the authorized Personnel list that was submitted to IEX Exchange.

3. How do I register a new MPID on IEX Exchange?

To register a brand new MPID on IEX Exchange with a new NSCC# we require a Clearing Letter of Guarantee that specifies the new clearing relationship. We also require the clearing firm to be a member of IEX Exchange as well. If you are registering a new MPID over an existing connection, you would just need to submit a completed and signed Equities Port Request Form detailing the new information in tandem with the above. Additionally, if the new MPID will have brand new physical connectivity associated with it, we require an IEX Connectivity Services Agreement and Forms (pages 3-7; page 8 to request a direct connection; page 9 if connecting through a Service Bureau).

4. What time can I connect to IEX Exchange each day?

IEX Exchange carries out a fresh system startup every day. This is done to minimize system issues and ensure the quality of the customer experience. Given the manual nature of this process, we do experience variance in startup times. 99% of startups are completed by 07:45:00 EST. Just to note, our Pre-Market Sessions commence at 8am EST Monday – Friday. If the system needs to be brought up after this time, we will reach out with a System Status alert.

5. What are IEX Exchange’s hours of operation?

Orders may be executed on IEX Exchange or routed away during the Pre-Market (8:00AM EST – 9:30AM EST), Regular Market (9:30AM EST – 4:00PM EST), and Post-Market Sessions (4:00PM EST – 5:00PM EST). The Market Ops team is around to field questions from clients at approximately 7:00AM EST until after the close.

6. How do I identify my routed executions through IEX Exchange?

The best way to identify routed executions through IEX Exchange is through FIX tag number 30. Tag 30 (LastMarket) displays the Market of Execution for last fill. The value of this FIX tag will display the venue in which the order was last executed on (IEXG, XNYS, ARCX etc.). For a list of all the possible LastMarket values passed back in Tag 30, please see Appendix D of the IEX FIX Specification.  

7. Where can I find the symbols eligible for trading on IEX Exchange each day?

You can always find the up-to-date list of eligible symbols for trading on IEX Exchange right here on our website. This list is updated daily at approximately 7:45 AM EST.

8. How can I test my port-level configurations functionality before deploying in production?

You can test your port-level configurations before deploying them in production in our IEX Testing Facility or the ITF (IEX Test Facility). The ITF is a simulated instance of our exchange that members can use to certify compatibility of their systems with ours or test new features of our system that may be released there first.

9. Who has permission to modify connectivity at my firm?

To make any connectivity changes to sessions on IEX Exchange, we will need authorization from someone on the Authorized Personnel list that was submitted to the Market Ops team.  

10. How long do connectivity modifications take to become effective in production?

Depending on the complexity and nature of the modifications, IEX Market Operations and our dedicated Software Reliability Engineers (SRE) work to provide the quickest turnaround time for production session changes. Market Operations will always communicate these timeframes to the best of our ability.

From order entries to routed executions to connectivity, Market Operations is available to give you the most relevant information we can, when you need it. Don't see a question above that you've been pondering? Email us at and we'll be in touch.