During economic downturns, when there is a keenly felt shortage of jobs and cash, people have historically adopted barter systems. The world’s most established bartering-style system is Switzerland’s wir: the German word for “we” as well as the abbreviation of Wirtschaftsring, which translates loosely to “economic circle.” In 1934, the economy in Switzerland had tanked—as it had in much of the world. Two businessmen who were facing bankruptcy, Paul Enz and Werner Zimmermann, gathered 15 of their associates in Zurich and hashed out a solution: a mutual credit system.

Debts in the wir currency, assigned the same value as the Swiss franc, could be paid with sales to any member of the bartering circle: if a baker needed to “purchase” eggs and flour from a farmer, the baker could pay off the debt by “selling” baked goods to another wir member. The farmer, in turn, could use his newly acquired credit to “buy” his own needed items or services. Despite a bank-led campaign to discredit the system, wir stuck. Today, it has more than 60,000 business participants and does the equivalent of about $4.4 billion in annual trade.
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 not only be known and guaranteed, but also be valued in an amount the media and advertising could have been purchased for had the "client" bought it themselves (contract to eliminate ambiguity and risk).[citation needed]
When barter has appeared, it wasn’t as part of a purely barter economy, and money didn’t emerge from it—rather, it emerged from money. After Rome fell, for instance, Europeans used barter as a substitute for the Roman currency people had gotten used to. “In most of the cases we know about, [barter] takes place between people who are familiar with the use of money, but for one reason or another, don’t have a lot of it around,” explains David Graeber, an anthropology professor at the London School of Economics.
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