Galí (2014) showed that a monetary policy rule that raises interest rates in response to bubbles can paradoxically lead to larger bubbles. This comment shows that a central bank that wants to dampen bubbles can always do so by raising interest rates aggressively enough. This result is different...

We study the optimal monetary policy problem in a New Keynesian economy with a zero lower bound (ZLB) on the nominal interest rate, when the steady state natural rate (r*) becomes permanently negative. We show that the optimal policy aims to approach gradually a new steady state with positive...