If the financial returns on an asset exceed the opportunity cost of the funds or alternately, if the financial costs of a liability are less than the opportunity cost, they are considered as outputs; otherwise, they are considered as inputs. The value-added approach identifies major categories of produced deposits and loans as outputs because they form a significant proportion of value added.
We have learned from Benjamin Cohen and Paul Krugman – who studied the cases of the pound sterling and the US dollar, respectively – that an international currency fulfils the standard Aristotelian functions of money (medium of exchange, store of value and unit of account) for private and official transactions between residents and nonresidents.