The recent Eurozone debt crisis has witnessed sharp decouplings in cross-country bond yields without commensurate shifts in relative fundamentals. We rationalize this phenomenon in a model wherein countries with different fundamentals are on different equilibrium paths all along, but which...

A recent literature shows how an increase in volatility reduces leverage. However, in order to explain pro-cyclical leverage it assumes that bad news increases volatility, that is, it assumes an inverse relationship between first and second moments of asset returns. This paper suggests a reason...

We review the theory of leverage developed in collateral equilibrium models with incomplete markets. We explain how leverage tends to boost asset prices and create bubbles. We show how leverage can be endogenously determined in equilibrium and how it depends on volatility. We describe the...

We show how the timing of financial innovation might have contributed to the mortgage bubble and then to the crash of 2007-2009. We show why tranching and leverage first raised asset prices and why CDS lowered them afterward. This may seem puzzling, since it implies that creating a derivative...

We provide a pricing theory for emerging asset classes, like emerging markets, that are not yet mature enough to be attractive to the general public. We show how leverage cycles can cause contagion, flight to collateral, and issuance rationing in a frequently recurring phase we call the anxious...

We show how vicious circles in countries' credit histories arise in a model where output persistence is coupled with asymmetric information about output shocks. In such an environment, default signals the borrower's vulnerability to adverse shocks and creates a pessimistic growth outlook. This...