The new era-defining central bank ‘trilemma’ - Financial Times

The classic central bank "trilemma" once described the impossibility of simultaneously maintaining free capital flows, a fixed exchange rate, and an independent monetary policy. The new version framed in this analysis reflects a different set of constraints. Modern monetary authorities must now weigh price stability, financial stability, and government debt sustainability — three objectives that are increasingly difficult to reconcile in an era of elevated deficits and persistent inflation shocks.

This shift matters for markets because the policy response to an economic downturn may no longer be a straightforward playbook of rate cuts. Central banks may have to tolerate slower growth to protect credibility, or rely on tools that blur the line between monetary and fiscal policy. The consequences for bond markets, currency valuations, and yield curves are significant.

What observers should watch is central bank communication — specifically how officials justify trade-offs and which objective they prioritize when forced to choose. The era-defining nature of this trilemma suggests the policy path ahead will be less predictable, defined more by judgment than by a fixed rule.