Swap contracts can include exchanging currencies, interest rates, or commodities. An interest rate swap can be used to transform a floating rate into a fixed rate, and vice versa. A currency swap can be used to transform a loan in foreign currency into one of another currency. It is a sophisticated operation and because of this it is the treasury departments of banks and investment fund managers who are the ones that most use the swap market. The idea is that two investors make investments that are “married” so that on the expiration date they will serve as protection of the money or even as speculation to increase capital.