We study a dynamic economy where credit is limited by insufficient collateral and, as a result, investment and output are too low. In this environment, changes in investor sentiment or market expectations can give rise to credit bubbles, that is, expansions in credit that are backed not by...

This review provides a guide to macroeconomic applications of the theory of rational bubbles. It shows that rational bubbles can be easily incorporated into standard macroeconomic models and illustrates how they can be used to account for important macroeconomic phenomena. It also discusses the...

What are the effects of a housing bubble on the rest of the economy? We show that if firms and banks face collateral constraints, a housing bubble initially raises credit demand by housing firms while leaving credit supply unaffected. It therefore crowds out credit to non-housing firms. If time...

What is the role of monetary policy in a bubbly world? To address this question, we study an economy in which financial frictions limit the supply of assets. The ensuing scarcity generates a demand for ``unbacked" assets, i.e., assets that are backed only by the expectation of their future...

How do housing bubbles affect other economic sectors? We show that in the presence of collateral constraints, a bubble initially raises housing credit demand and crowds out credit to non-housing firms. If the bubble lasts, however, housing credit repayments raise banks' net worth and expand...

We explore a view of the crisis as a shock to investor sentiment that led to the collapse of a bubble or pyramid scheme in financial markets. We embed this view in a standard model of the financial accelerator and explore its empirical and policy implications. In particular, we show how the...

We explore a view of the crisis as a shock to investor sentiment that led to the collapse of a bubble or pyramid scheme in financial markets. We embed this view in a standard model of the financial accelerator and explore its empirical and policy implications. In particular, we show how the...

We develop a stylized model of economic growth with bubbles. In this model, financial frictions lead to equilibrium dispersion in the rates of return to investment. During bubbly episodes, unproductive investors demand bubbles while productive investors supply them. Because of this, bubbly...

We study a dynamic economy where credit is limited by insufficient collateral and, as a result, investment and output are too low. In this environment, changes in investor sentiment or market expectations can give rise to credit bubbles, that is, expansions in credit that are backed not by...