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 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...

As a result of debt enforcement problems, many high-productivity firms in emerging economies are unable to pledge enough future profits to their creditors and this constrains the financing they can raise. Many have argued that, by relaxing these credit constraints, reforms that strengthen...

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...

In 2007, countries in the euro periphery were enjoying stable growth, low deficits, and low spreads. Then the financial crisis erupted and pushed them into deep recessions, raising their deficits and debt levels. By 2010, they were facing severe debt problems. Spreads increased and,...

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...

In 2007, countries in the euro periphery were enjoying stable growth, low deficits and low spreads. Then the financial crisis erupted and pushed them into deep recession, raising their deficits and debt levels. By 2010, they were facing severe debt problems. Spreads increased and, surprisingly,...