Latest Updates | CATNMSPLAN

09/24/2026
Newsletter
Monthly CAT Update Newsletter: September 2026
09/23/2026
Technical Specifications
CAT Industry Member Technical Specifications (2d) v4.2.0 r2 (Clean)
09/23/2026
FAQ| D. Order Receipt
D13. An Industry Member receives an order with instructions to execute the order on a net basis. No specific instruction is given with respect to which trading session the order is eligible to be executed. The Industry Member accumulates shares during regular market hours but does not execute the customer order until after the close at a net price which is reported to the tape. What should be populated in the tradingSession field on the New Order or Order Accepted Event?
09/23/2026
FAQ| E. Order Routing and Execution
E28. Exchange origin code may be reported on CAT order route and route modified events when routing orders to an options exchange. However, the value is not required by all options exchange protocols for certain market maker orders. In these cases, with what should Industry Members populate the exchOriginCode field on applicable events?
09/23/2026
CAT Alert
CAT Alert 2026-02 - 23x5 Trading: CAT Reporting Requirements
09/23/2026
Technical Specifications
CAT Industry Member Technical Specifications (2d) v4.2.0 r2 (Redlined)
09/17/2026
Reference Material
SEC Approved CAT NMS Plan as of 9/3/2026
09/17/2026
Technical Specifications
CAT Reporting Technical Specifications for Plan Participants v4.4.0
09/16/2026
Reference Material
FINRA CAT Connectivity Supplement for Industry Members v1.20
09/02/2026
Reference Material
SEC Notice of Request for Exemption Related to Period 4 of the Financial Accountability Milestones
09/02/2026
Reference Material
Notice of Filing of Exemptive Request Letter Related to Period 4 of the Financial Accountability Milestones
08/27/2026
Technical Specifications
2026 Industry Member Releases (Transaction) - Scope and Schedule
08/26/2026
FAQ| C. Definitions
C5. When must the value ‘O’ (Market Making) be used for accountHolderType?
08/26/2026
FAQ| B. Reporting Requirements
B68. If an Industry Member uses the same account for both market making and non-market making proprietary activity, what accountHolderType must be used when reporting to CAT?
08/21/2026
Technical Specifications
CAT Technical Specifications for Billing Trade Details v1.3 r2 (Clean)

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A. General
B. Reporting Requirements
C. Definitions
D. Order Receipt
E. Order Routing and Execution
F. Representative Orders
G. Manual Orders
H. ATS
I. Foreign Securities
J. OTC Equity Securities
K. Options
L. Equity Floor Brokers
M. Firm Designated ID
N. Third Party Reporting
O. Technical Requirements
P. Feedback and Error Correction
Q. Customer and Account Information
R. Clock Synchronization
S. Security
T. Production Readiness Testing
U. Allocations
V. CAT Billing
W. Fee Dispute Resolution
X. Reference Database
All Topics

A. General
B. Reporting Requirements
C. Definitions
D. Order Receipt
E. Order Routing and Execution
F. Representative Orders
G. Manual Orders
H. ATS
I. Foreign Securities
J. OTC Equity Securities
K. Options
L. Equity Floor Brokers
M. Firm Designated ID
N. Third Party Reporting
O. Technical Requirements
P. Feedback and Error Correction
Q. Customer and Account Information
R. Clock Synchronization
S. Security
T. Production Readiness Testing
U. Allocations
V. CAT Billing
W. Fee Dispute Resolution
X. Reference Database
All Topics