The NFA will require that FDMs close trades on a first-in first-out basis beginning July 31, 2009. This effectively prevents them from facilitating the practice known as hedging, where a trader opens two canceling positions in the same account. Rule 2-43(b) is as follows:

Forex Dealer Members may not carry offsetting positions in a customer
account but must offset them on a first-in, first-out basis. At the
customer’s request, an FDM may offset same-size transactions even if
there are older transactions of a different size but must offset the
transaction against the oldest transaction of that size.