when is a bank engaging in a currency exchange
Currency intervention Currency intervention, also known as foreign exchange market intervention or currency manipulation is a monetary policy operation. It occurs when a government or central bank buys or sells foreign currency in exchange for their own domestic currency, generally with the intention of influencing the exchange rate and trade policy.
Foreign exchange swap Once a foreign exchange transaction settles, the holder is left with a positive (or "long") position in one currency and a negative (or "short") position in another. In order to collect or pay any overnight interest due on these foreign balances, at the end of every day institutions will close out any foreign balances and re-institute them for the following day. To do this they typically use "tom-next" swaps, buying (or selling) a foreign amount settling tomorrow, and then doing the opposite, selling (or buying) it back settling the day after.