I am trying to trade one NQ contract in each of four accounts in my Friends and Family Advisor account, and every time I attempt to execute or preview margin, I get the message 'Could not retrieve margin information: trade may be invalid.' When I try to trade one contract in each account individually, it goes through without a problem. I don't know if I'm doing something wrong with my allocations, but it seems like setting it for equal quantity default allocation and the default order size to 4 should work. IB technical support wasn't much help. Any help I could get on this forum would be greatly appreciated.