Boom-Busts in Asset Prices, Economic Instability, and Monetary Policy

The link between monetary policy and asset price movements has been of perennial interest to policy makers. In this paper we consider the potential case for pre-emptive monetary restrictions when asset price reversals can have serious effects on real output. First, we provide some historical background on two famous asset price reversals: the U.S. stock market crash of 1929 and the bursting of the Japanese bubble in 1989. We then present some stylized facts on boom-bust dynamics in stock and property prices in developed economies. We then discuss the case for a pre-emptive monetary policy in the context of a stylized 'Dynamic New Keynesian' framework with collateral constraints in the productive sector. We find that whether such a policy is warranted depends on the economic conditions in a complex, non-linear way. The optimal policy cannot be summarized by a simple policy rule of the type considered in the inflation-targeting literature.