Herd Behaviour in Asset Market Booms and Crashes: The Role of Monetary Policy

Abstract

One important conclusion of Robert Shiller's influential 2015 book, Irrational Exuberance, is that bubbles are random exogenous phenomena that cannot be foreseen and do not depend on macroeconomic policies. This CEPR Policy Insight throws light on the root causes of speculative fevers in asset markets and related financial booms and busts. It shows empirical evidence indicating that Shiller may have overlooked the role that lax monetary policy played in triggering financial bubbles in the 2000s by offering investors a perverse promise of ever-increasing asset prices.

Keywords: financial instability, bubbles and manias, investors' expectations, monetary policy

JEL Classification: G01