The account or entity identifier used to place the order must be reported. In scenarios where a master/top account or entity identifier is used to place an order, the Firm Designated ID (FDID) representing the master/top account or entity identifier should be reported to CAT for Transaction Order events requiring an FDID (e.g. New Order and Trade events). In such scenarios, the FDID represents the master/top account or entity that is authorized to place orders for one or more legal entities or customers. The Industry Member performing the allocation will also be required to report an allocation to the master/top account via a Post Trade Allocation (MEPA)/Options Post-Trade Allocation (MOPA), as well as subaccount allocations to the underlying subaccounts using the FDIDs associated with such subaccounts. For more information on allocation reporting and subaccounts, see FAQ U2.