Optimal currency area
In economics, an optimum currency area (or region) (OCA, or OCR) is a geographical region in which it would maximize economic efficiency to have the entire region share a single currency. There are two models, both proposed by Robert A. Mundell: the stationary expectations model and the international risk sharing model. Mundell himself advocates the international risk sharing model and thus concludes in favour of the euro.
Transaction costs and risks
The most obvious benefit of adopting a single currency is to remove the cost of exchanging currency, theoretically allowing businesses and individuals to consummate previously unprofitable trades. For consumers, banks in the Eurozone must charge the same for intra-member cross-border transactions as purely domestic transactions for electronic payments (e.g. credit cards, debit cards and cash machine withdrawals).
The absence of distinct currencies also removes exchange rate risks. The risk of unanticipated exchange rate movement has always added an additional risk or uncertainty for companies or individuals that invest or trade outside their own currency zones. Companies that hedge against this risk will no longer need to shoulder this additional cost. This is particularly important for countries whose currencies have traditionally fluctuated a great deal, particularly the Mediterranean nations.
Financial markets on the continent are expected to be far more liquid and flexible than they were in the past. The reduction in cross-border transaction costs will allow larger banking firms to provide a wider array of banking services that can compete across and beyond the Eurozone.
Price parity
Another effect of the common European currency is that differences in prices—in particular in price levels—should decrease because of the 'law of one price'. Differences in prices can trigger arbitrage, i.e. speculative trade in a commodity across borders purely to exploit the price differential. Therefore, prices on commonly traded goods are likely to converge, causing inflation in some regions and deflation in others during the transition. Some evidence of this has been observed in specific markets.
Macroeconomic stability
Low levels of inflation are the hallmark of stable and modern economies. Because a high level of inflation acts as a tax (seigniorage) and theoretically discourages investment, it is generally viewed as undesirable. In spite of the downside, many countries have been unable or unwilling to deal with serious inflationary pressures. Some countries have successfully contained them by establishing largely independent central banks. One such bank was the Bundesbank in
Many national and corporate bonds denominated in euro are significantly more liquid and have lower interest rates than was historically the case when denominated in legacy currencies. While increased liquidity may lower the nominal interest rate on the bond, denominating the bond in a currency with low levels of inflation arguably plays a much larger role. A credible commitment to low levels of inflation and a stable debt reduces the risk that the value of the debt will be eroded by higher levels of inflation or default in the future, allowing debt to be issued at a lower nominal interest rate.
