On the feasibility of monetary union: Does it make sense to look for shocks symmetry across countries when none of the countries constitutes an optimum currency area?

► This paper is a study of monetary union feasibility without symmetry of actual shocks. ► We argue that monetary policy can be destabilizing when shocks are symmetric. ► This may happen when investment sensitivity to interest rate differs across countries. ► Our approach focuses instead on common responses to monetary policy shocks. ► For NAFTA; we find that only Canada and the US are suitable for monetary union.