U.S. Options

As previously announced in the April 25, 2023 and June 7, 2023 Alerts, the MIAX Emerald Options Exchange will introduce new Top of Market (ToM) message types for single sided ToM Best Bid or Offer (BBO) messages on July 28, 2023.

• ToM Feed – Priority Customer Message Types – mandatory change
  • When a new Priority Customer Order is entered and improves the BBO, ToM will publish the following additional message types with the existing BBO information:
    • Simple Top of Market Best Bid or Offer Message – Compact Format
      • “h” = Simple Top of Market on Bid side with Priority Customer Order improves best bid
      • “i” = Simple Top of Market on Offer side with Priority Customer Order improves best offer
    • Simple Top of Market Best Bid or Offer Message – Wide Format
      • “j” = Simple Top of Market on Bid side with Priority Customer Order improves best bid
      • “k” = Simple Top of Market on Offer side with Priority Customer Order improves best offer

• The new message types will only be sent upon entry of a Priority Customer Order that improves the BBO and not for subsequent order or BBO updates.

NOTE: The ToM Feed will continue to publish the BBO messages with the existing message types for BBO updates that do not meet any of the above scenarios. The new message types only indicate that a BBO update is due to a Priority Customer Order establishing a new aggressive BBO.
 
The new message types are currently available in the MIAX Emerald Options Firm Test Bed (FTB2) environment.
 
Additional details on updated interface specifications can be found on the MIAX website at MIAX Emerald Options Exchange Specifications.

Please contact MIAX Trading Operations at TradingOperations@miaxglobal.com or (609) 897-7302 to discuss any specific issues and to arrange interface testing.