A foreign exchange swap (FXS) is an OTC derivative contract in which two parties exchange principal amounts in different currencies at the start of the trade (at one exchange rate), with the reverse exchange occurring at the close of the trade (at a different exchange rate).
FXS are part of a family of financial products known as currency derivatives.
FXS are also known as ‘plain vanilla foreign exchange swaps’, ‘spot/forward fx swaps’, and ‘forex swaps’.
Note: in a foreign exchange swap, because the principal amounts are paid in full, the term ‘notional’ (meaning ‘theoretical’) is not applicable, consequently the terms ‘principal’ and ‘principal amount’ are used instead.
FXS are used to mitigate foreign exchange risk.
Imagine that a firm needs to borrow a particular amount of a particular currency immediately, where the firm currently holds a different currency that the firm does not need immediately. An FXS trade is a temporary (therefore two-legged) exchange of the two currencies: