This may be a silly question on futures trading, but I haven't found a clear answer on the CME website.
I trade this contract via a broker, for example Interactive Brokers (IB) or etrade or any broker offering futures, and also suppose I have a USD base account.
How do a brokers in the US (such as IB or etrade, etc.) take the margin paid my account? Do they convert some of the USD into JPY and then retain it as margin?
Subsequently, if I had a profit, will they give me back JPY or will they convert it into USD?