Aside from the equilibrium that Hotelling (1931) displayed, his model of non-renewable resources also contains a continuum of bubble equilibria. In all the equilibria the price of the resource rises at the rate of interest. In a bubble equilibrium, however, the consumption of the resource peters...

Stock-market crashes tend to follow run-ups in prices. These episodes look like bubbles that gradually inflate and then suddenly burst. We show that such bubbles can form in a Zeira-Rob type of model in which demand size is uncertain. Two conditions are sufficient for this to happen: A declining...

We propose a model of money, credit and bubbles, and use it to study the role of monetary policy in managing asset bubbles. In this model, bubbles pop up and burst, generating fluctuations in credit, investment and output. Two key insights emerge from the analysis. First, the growth rate of...

The "equilibrium" bubble size depends on investor sentiment, however, and it typically does not coincide with the "optimal" bubble size. This provides a new rationale for macroprudential policy. A lender of last resort can replicate the "optimal" bubble by taxing credit when the "equilibrium"...