WHY JOIN A CURRENCY UNION? A NOTE ON THE IMPACT OF BELIEFS ON THE CHOICE OF MONETARY POLICY

We argue that a fixed exchange rate can be an optimal choice even if a policy maker could commit to the first-best monetary policy whenever the private sector's beliefs reflect incomplete information about the policy maker's dependability. This model implies that joining a currency area may be optimal for its impact not on the behavior of the policy maker, but on the beliefs of the private sector. Monetary policies are evaluated using a new Keynesian model of a small open economy solved under imperfect policy credibility. We quantify the minimum distance between announced policy and the private sector's beliefs that is necessary for a peg to perform better than an independent monetary policy when the policy maker can commit to the first-best policy.