U.S. Options

As previously announced in the August 17, 2023, September 8, 2023 and September 21, 2023 Alerts, the MIAX Options Exchange Interface specifications have been updated for the following changes:

1. ToM Feed v2.5 – Priority Customer Message Types – mandatory change 
   1. The MIAX Options Exchange will introduce new Top of Market (ToM) message types for single sided ToM Best Bid or Offer (BBO) messages
   2. 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:
      1. Simple Top of Market Best Bid or Offer Message – Compact Format
         1. “h” = Simple Top of Market on Bid side with Priority Customer Order improves best bid
         2. “i” = Simple Top of Market on Offer side with Priority Customer Order improves best offer
      2. Simple Top of Market Best Bid or Offer Message – Wide Format
         1. “j” = Simple Top of Market on Bid side with Priority Customer Order improves best bid
         2. “k” = Simple Top of Market on Offer side with Priority Customer Order improves best offer
   3. 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.
   4. This change will be effective for trading on October 18, 2023. 
      1. The ToM Feed will continue to publish 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. 

These changes are available in the MIAX Options Exchanges Firm Test Bed (FTB2) environment.

Additional details on updated interface specifications can be found on the miaxglobal.com website at MIAX Options Interface Specifications.

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