One Size Must Fit All National Divergences in a Monetary Union *

What policy objective should a common central bank in a heterogeneous monetary union pursue? Should it base its decisions on the EU-wid average of inflation and growth or should it instead focus on (appropriately weighted) national welfare losses based on national rates of inflation and growth? We find that a central bank that minimises the sum of national welfare losses reacts less to common shocks and that this can lead to higher average union-wide expected welfare, if the variability of common shocks is large relative to the inflation bias. But for countries with a transmission mechanism close to the average, welfare can actually be lower in this case. The inflationary bias depends on the interaction between the transmission mechanism and distortions in labour markets