No, the firmDesignatedID submitted to CAIS must be the same firmDesignatedID populated on the related Transaction Order event for a specific trading account, Relationship ID or Entity ID. 

Per FAQ M1, given the purpose of the FDID under the CAT NMS Plan, it is important that this identifier be unique, persistent and consistent within the firm and across all vendors and systems the Industry Member may use to report Transaction Order events requiring an FDID to CAT and associated Customer and Account information for the FDID to CAT CAIS, and unique across time.

This FAQ was retired on May 5, 2026.