As stated in FAQ M1, given the purpose of the Firm Designated ID (“FDID”) under the CAT NMS Plan, a change/replacement in the Firm Designated ID (FDID) value associated with a particular trading account would only be permissible in certain limited circumstances, such as system migration, change of vendors, change in clearing firm and change in masking methodology.
If an Industry Member has reported an FDID on a Transaction Order event (e.g., MENO, MEOF, MEOT) and subsequently changed the FDID associated with that particular trading account prior to the implementation of full Customer and Account Reporting, the Industry Member has additional obligations as outlined below. The same obligations would apply to an FDID value representing a Relationship Identifier (“Relationship ID”) and Entity Identifier (“Entity ID”).
All Industry Members:
- Must maintain as part of books and records the circumstances necessitating the FDID change/replacement, and make these records available to Regulators upon request.
In addition:
Industry Members who have already reported the FDID to CAT CAIS:
- Must report the change of FDID to CAIS. If reporting in schema version 1.0.0 (LTID Account Phase), see Scenario 3.4 (Ending FDID with Replacing Record) of the CAT CAIS Industry Member Reporting Scenarios – LTID Phase. If reporting in schema version 2.0.0, see the scenario titled “FDID Replaced by Another FDID Within the Same Firm” in the CAT CAIS Industry Member Reporting Scenarios – Full CAIS Phase.
Industry Members who have NOT reported the FDID to CAT CAIS:
- May report both the prior FDID and replacing FDID to CAIS. If reporting in schema version 1.0.0 (LTID Account Phase), see Scenario 3.4 (Ending FDID with Replacing Record) of the CAT CAIS Industry Member Reporting Scenarios– LTID Phase. If reporting in schema version 2.0.0, see the scenario titled “FDID Replaced by Another FDID Within the Same Firm” in the CAT CAIS Industry Member Reporting Scenarios – Full CAIS Phase. While Industry Members are not required to report all FDIDs to CAT CAIS until the implementation of full Customer and Account Reporting, Industry Members may voluntarily do so. Per FAQ Q8, if an Industry Member voluntarily provides such account reporting, the Industry Member is still subject to timely, accurate and complete reporting requirements. See CAT Alerts 2022-01 and 2023-01 for the Full CAIS Implementation Schedule.
- OR must notify FINRA CAT of FDID changes via the Customer and Account Reporting Disclosure Form. This Form, as well as the standards for submitting it, are outlined in CAT Alert 2021-02 (Standards for Completing the Customer and Account Reporting Disclosure Form). Industry Members choosing this option must also maintain mapping information that links the prior FDID to the replacing FDID and the associated trading account, Relationship ID, or Entity ID. Industry Members must not provide the FDID mapping information to FINRA CAT on the Customer and Account Reporting Disclosure Form, but must maintain such documentation, and make it available to Regulators upon request.
Note that after implementation of full Customer and Account Reporting, all Industry Members must maintain as part of books and records the circumstances necessitating the FDID change/replacement, and make these records available to Regulators upon request. In addition, all Industry Members must report a change/replacement of FDID value as described in the CAT Reporting Customer and Account Technical Specifications for Industry Members.
This FAQ was retired on May 5, 2026.