The simple answer is yes, a contract is a contract. Some clients believe that if they book a currency trade and the market turns against them, they can simply walk away. Clients may buy USD at a set rate and on the day of settlement the USD is cheaper, some clients think they are able to get the lower rate or even cancel the trade. This is not the case currency exchange providers would go out of business very quickly if this were to happen. When you buy stocks or bonds, your broker expects you pay the settlement amount on time, no matter the current price of the assets. You would not expect your currency provider to reprice your USD purchase higher if the USD got stronger. Markets are volatile and this is part of doing business.