If your Series 3 is held with FCM X, can you also have a separate account with FCM-Y (outside of the FCMs offered if holding series 3 w/ a IIB rather than a GIB)? I'm sure its possible, just was curious if it was ever done, or if its too much of a compliance / reg issue for the holding FCM. Always wondered whether some of these brokers kept/trade money outside their own IB / FCM. not implying anything nefarious, I have just always been curious.
Dual and Multiple registrations are allowed by the NFA/CFTC however, each entity that registers the associated person is also responsible for their actions. Because of that, I don't see any FCM allowing that. Most Broker dealers do not allow this either. If you question is,"if I'm register with an FCM, may I open a trading account with that or any other FCM?" Well, that would be based on the policies of that firm and can differ around the street. No body wants a conflict of interest or their employees trading during work hours.