We show how the timing of financial innovation might have contributed to the mortgage boom and then to the bust of 2007-2009. We study the effect of leverage, tranching, securitization and CDS on asset prices in a general equilibrium model with collateral. We show why tranching and leverage tend...

We show that cross-border financial flows arise when countries differ in their abilities to use assets as collateral. Financial integration is a way of sharing scarce collateral. The ability of one country to leverage and tranche assets provides attractive financial contracts to investors in the...

The steady application of Quantitative Easing (QE) has been followed by big and non-monotonic effects on international asset prices and international capital flows. These are difficult to explain in conventional models, but arise naturally in a model with collateral. This paper develops a...

Cross-border financial flows arise when (otherwise identical) countries differ in their abilities to use assets as collateral to back financial contracts. Financially integrated countries have access to the same set of financial instruments, and yet there is no price convergence of assets...

The literature on leverage until now shows how an increase in volatility reduces leverage. However, in order to explain pro-cyclical leverage it assumes that bad news increases volatility. This paper suggests a reason why bad news is more often than not associated with higher future volatility....

We discuss how leverage can be monitored for institutions, individuals, and assets. While traditionally the interest rate has been regarded as the important feature of a loan, we argue that leverage is sometimes even more important. Monitoring leverage provides information about how risk builds...

This is the graduation speech I gave on receiving an honorary doctorate at the University of Athens Economics and Business School. I talk about my Greek family, about how I got interested in economics, and then how in the 1990s I came to think about default, collateral, and leverage as 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 afterwards. This may seem puzzling, since it implies that creating a derivative...

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 study endogenous leverage in a general equilibrium model with incomplete markets. We prove that in any binary tree leverage emerges in equilibrium at the maximum level such that VaR=0, so there is no default in equilibrium, provided that agents get no utility from holding the collateral. When...