Consolidated Audit Trail (CAT)

SEC Rule 613 requires FINRA and the national securities exchanges to jointly submit a National Market System (NMS) plan detailing how they would develop, implement and maintain a consolidated audit trail that collects and accurately identifies every order, cancellation, modification and trade execution for all exchange-listed equities and options across all U.S. markets. FINRA is working with the exchanges to develop an NMS plan that meets the requirements of Rule 613.

For more information, see the CAT NMS Plan website.

Industry Education

CAT Reporting Technical Specifications and Webinars

On October 30, 2018, the participants of the CAT NMS Plan (“Participants”) published the final version of the CAT Reporting Technical Specifications for Industry Members (“Technical Specifications”). This version incorporates industry feedback submitted to the Participants since publication of the Version 0.6 draft published on September 5, 2018. No further material changes to the Technical Specifications are planned for publication before the November 15, 2019 CAT implementation date.

Industry Members should note that the Participants have created a separate companion document to be used in conjunction with the Technical Specifications, the CAT Reporting Scenarios for Industry Members (“Reporting Scenarios”). The Reporting Scenarios document contains detailed reporting guidance on how to report various equity and options order handling and execution scenarios. This document will be updated periodically as new scenarios are presented to the Participants. The Reporting Scenarios document is subject to the same Operating Committee approval process as the Technical Specifications. The reporting scenarios section of the Technical Specifications has been removed in lieu of this new companion document.

The participants have also published two new CAT Alerts related to these Technical Specifications which may be found at the following links:

Finally, the Participants will hold three upcoming educational webinars related to these documents as follows:

  • General Overview and Key Implementation Dates - Wednesday, November 7, 2018 at 4:15 pm, ET
  • Equity Deep Dive - Wednesday November 14, 2018 at 4:15 pm, ET
  • Options Deep Dive - Thursday, November 15, 2018 at 4:15 pm, ET

Additional information regarding these webinars, including registration information will be announced.

CAT Reporting Technical Specifications for Industry Members

On September 5, 2018, CAT NMS, LLC published version 0.6 of the CAT Reporting Technical Specifications for Industry Members (“IM Technical Specifications”) for Industry Member reporting to the CAT. The IM Technical Specifications are available on the CAT NMS Plan website. This version of the IM Technical Specifications represents the last draft version that will be published for industry comment before the release of the final IM Technical Specifications, targeted for October 30, 2018. This version covers both Phase 2A and Phase 2B reporting under the following phased approach to the implementation of Industry Member reporting:

Phase Phase
2A – Equities Part 1 11/15/2019
2B – Options Part 1 5/31/2020
2C – Equities Part 2 9/1/2020
2D – Options Part 2 5/15/2021

The national securities exchanges and Financial Industry Regulatory Authority that are the participants (“Participants”) in the National Market System Plan Governing the Consolidated Audit Trail ("CAT NMS Plan") seek input on any missing or unclear elements that will prevent Industry Members from implementing the IM Technical Specifications for Phase 2A and Phase 2B. Please note that the Participants have received industry feedback on a number of issues, incorporating changes to the IM Technical Specifications to address these where possible and as further described in the IM Technical Specifications. View CAT Alert 2018-001 for additional details.

This final draft can be used for planning and design purposes for Phase 2A and Phase 2B but is subject to change based on industry feedback. The SROs encourage feedback specifically focused on areas where further explanation is required in order to begin development work.

The Participants plan to file a proposed modification to the CAT NMS Plan with the Securities and Exchange Commission (“Commission or SEC”) to reflect the phased approach for Industry Member reporting described in the newest version of the IM Technical Specifications. The proposal will be subject to the Commission’s approval.

Feedback and questions can be directed to the Thesys CAT Help Desk:

  • Email Address:
  • Hours of Operation: 9AM-5PM Eastern Time (Weekdays only; except US Equity Market Observed Holidays)


Rule 613 of the Securities Exchange Act of 1934 requires national securities exchanges and national securities associations to submit a national market system plan to the Commission to create, implement, and maintain the CAT that would allow regulators to more efficiently and accurately track all activity in U.S. equity and options markets. Pursuant to Rule 613, the Participants filed with the Commission the CAT NMS Plan, which was approved by the Commission on November 15, 2016.

Under Rule 613(g)(2), each member of a national securities exchange or national securities association is required to comply with all the provisions of the CAT NMS Plan. Relatedly, as mandated under Rule 613, the CAT NMS Plan requires each Participant to adopt rules requiring its members to comply with Rule 613 and the CAT NMS Plan, and to agree to enforce compliance by its members in that regard. Accordingly, each Participant has adopted rules requiring its members to comply with Rule 613 and the CAT NMS Plan. See, e.g., FINRA Rule 6800 Series.

The Participants jointly own CAT NMS, LLC, which was formed by the Participants to arrange for and oversee the creation, implementation, and maintenance of the CAT as required under Rule 613. Thus, the CAT is a facility of each SRO Participant. CAT NMS, LLC selected Thesys CAT LLC as the Plan Processor to create, implement, and maintain the CAT System; however, CAT NMS, LLC is the exclusive owner of the CAT System. Thus, when Industry Member reporting commences, Industry Members will submit data to an SRO facility, rather than a system that is owned by a non-SRO entity.


FINRA's Office of General Counsel (OGC) staff provides broker-dealers, attorneys, registered representatives, investors and other interested parties with interpretative guidance relating to FINRA’s rules. Please see FINRA OGC Interpretative Guidance for more information.

OGC staff contacts:
Alex Ellenberg and Julia Bogolin
1735 K Street, NW
Washington, DC 20006
(202) 728-8000