U.S. Options

As previously announced in the March 30, 2026 Alert, the MIAX Options Exchange will implement the below functionality enhancements.

1. Functionality Enhancements:
   1. Support for IEX and MX2 Options Exchange
      1. Updates to the following Interface Specifications are as follows:
         1. FOI Interface Specification v2.7a: SecurityExchange (tag = 207) field of ExecutionReport message (MsgType = 8) to include IEX and MX2 Options Exchange MIC code
         2. FXD Interface Specification v2.6c: SecurityExchange (tag = 207) field of ExecutionReport message (MsgType = 8) to include IEX and MX2 Options Exchange MIC code
         3. CTD Interface Specification v2.6d: Execution Exchange field of Trade message (Message Type = T) to include IEX and MX2 Options Exchange Code
   2. Previously announced Local Market Maker on PRIME/cPRIME Contra Functionality
      1. The functionality, previously published in the March 30, 2026 Alert, has been reverted back to its prior state.
      2. Updates to the FOI Interface Specification v2.7a are as follows:
         1. New Order Cross message to exclude Market Maker (MM) as a valid “CustomerOrFirm” value for PRIME.
         2. New Order Cross – Multileg message to exclude Market Maker (MM) as a valid “CustomerOrFirm” value for cPRIME.
2. Schedule for All Enhancements:
   1. MEI v2.11 Changes
      1. Friday, September 4, 2026
         1. Quote Width Relief Notification Functionality
         2. Mass Cancel Trigger Reason on Line Disconnect
      2. Friday, September 11, 2026
         1. Selective Liquidity Auto Purge (SLAP) Functionality
         2. Aggregate Risk Manager (ARM) Origin Multiplier Functionality
      3. All MEI v2.11 features require a certification.
   2. AIS v2.6a Changes
      1. Updates:
         1. New “Origin” field in both Simple and Complex Liquidity Seeking Event Notifications
         2. PRIME and cPRIME Auction Start Price will no longer be disseminated (i.e. will always be 0) via the AIS Feed
      2. Roll out schedule will be cloud by cloud:
         1. Day 1 - Tuesday, September 1, 2026: Cloud 21  
         2. Day 2 - Wednesday, September 2, 2026: Clouds 18 – 20
         3. Day 3 - Thursday, September 3, 2026: Clouds 1 – 8
         4. Day 4 - Friday, September 4, 2026:  Clouds 9 – 17 and 22 – 24
3. Additional Details:
   1. These changes are available in the MIAX Options Exchange's Firm Test Bed (FTB2) environment.
   2. Visit MIAX Options Interface Specifications for additional details.

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