An optimum-currency-area odyssey

The theory of optimum-currency-areas was conceived and developed in three highly influential papers, written by Mundell (1961), McKinnon (1963) and Kenen (1969). Those authors identified characteristics that potential members of a monetary union should ideally possess in order to make it feasible to surrender a nationally-tailored monetary policy and the adjustment of an exchange rate of a national currency. We trace the development of optimum-currency-area theory, which, after a flurry of research into the subject in the 1960s, was relegated to intellectual purgatory for about 20 years. We then discuss factors that led to a renewed interest into the subject, beginning in the early 1990s. Milton Friedman plays a pivotal role in our narrative; Friedman's work on monetary integration in the early 1950s presaged subsequent optimum-currency-area contributions; Mundell's classic formulation of an optimal currency area was aimed, in part, at refuting Friedman's “strong” case for floating exchange rates; and Friedman's work on the role of monetary policy had the effect of helping to revive interest in optimum-currency-area analysis. The paper concludes with a discussion of recent analytical work, using New Keynesian models, which has the promise of fulfilling the unfinished agenda set-out by the original contributors to the optimum-currency-area literature, that is, providing a consistent framework in which a country's characteristics can be used to determine its optimal exchange-rate regime.