Corporate barter focuses on larger transactions, which is different from a traditional, retail oriented barter exchange. Corporate barter exchanges typically use media and advertising as leverage for their larger transactions. It entails the use of a currency unit called a "trade-credit". The trade-credit must be known and guaranteed (contract to eliminate ambiguity and risk). Bartering is a medium in which goods or services are directly exchanged for other goods and/or services, without the use of money.^[1] It can be bilateral or multilateral, and usually exists parallel to monetary systems in most developed countries, though to a very limited extent. Barter usually replaces money as the method of exchange in times of monetary crisis, when the currency is unstable and devalued by hyperinflation.