Dear TXSE Member,
In response to requests emanating from participants in our UAT and production environments, TXSE is introducing new functionality across all protocols. Technical Specifications are attached and will be added to the TXSE website on June 15.
Notable changes are detailed below.
1. OPENING AND CLOSING AUCTIONS NOW AVAILABLE IN SPECIFICATIONS:
Auction-related message values have been added to the specification, including new TimeInForce, CancelReason, RejectReason, RestatementReason, and LiquidityIndicator values. These changes introduce protocol support for upcoming auction functionality; however, auction functionality will not be enabled as part of this release. The Exchange is making these message definitions available in advance to allow firms to prepare their systems. Deployment timing for auction functionality will be communicated in a future notice.
2. NOTABLE PROTOCOL ENHANCEMENTS:
TXSE will be releasing a series of protocol enhancements in advance of the June 18 Production Test. The changes outlined below will be deployed to the UAT environment on June 15, 2026,and will be available in the Production environment during the June 18, 2026 Production Test.
FIX: ClientID (Tag 109) Added to Additional Execution Reports
The firm identifier (ClientID / Tag 109, MPID) has been added to the remaining Execution Report message types that previously did not include it.
Firms may now expect Tag 109 consistently across all Execution Report variants.
FIX: Symbol (Tag 55) is now optional on rejected execution reports when the submitted symbol is unknown or cannot be resolved by the Exchange. Firms should not assume Symbol (55) will always be present on rejection messages.
New Cancel Reasons in SEED & FIX Order Entry
The following cancel reasons have been added and may now be received in order cancellation notifications:
PEG_REFERENCE_PRICE_BREACHES_LIMIT_PRICE
Indicates a pegged order was canceled because the calculated reference price moved beyond the order’s limit price and the limit price collar prevented further repricing.
ODD_LOT_NOT_EXECUTABLE
Indicates an odd-lot order was canceled because it could not execute against available contra-side liquidity on the TXSE book.
3. DOCUMENTATION UPDATES:
BALE Specification Documentation
Updated BALE specification documents have been published to reflect the latest protocol revisions and message definitions.
Trade-before-Top-of-Book Ordering Clarification
Documentation has been updated to correct and clarify event sequencing related to trade reporting and Top-of-Book updates.
If you have questions or require assistance, please contact marketops@txse.com.
We look forward to working with you.
Sincerely, TXSE Market Operations