Three mutually uncorrelated economic disturbances that we measure empirically explain 85% of the quarterly variation in real stock market wealth since 1952. A model is employed to interpret these disturbances in terms of three latent primitive shocks. In the short run, shocks that affect the...

We investigate whether short sellers are subject to the disposition effect using a novel dataset that allows to identify the weekly closing of short positions. Consistent with the disposition effect, the closing of short sale positions is strongly related to a proxy of Shortsale Capital Gains...

We investigate whether providers of high frequency news analytics affect the stock market. As identification, we exploit a unique experiment based on differences in news event classifications between different product releases of a major provider of news analytics. We document a causal effect of...

In a market with short term agents and heterogeneous information, when liquidity trading displays persistence, prices reflect average expectations about fundamentals and liquidity trading. Informed investors exploit a private learning channel to infer the demand of liquidity traders from the...

We describe a new mechanism that explains the transmission of liquidity shocks from one security to another ("liquidity spillovers"). Dealers use prices of other securities as a source of information. As prices of less liquid securities convey less precise information, a drop in liquidity for...

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...

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 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...

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...

We show that the endogenous stochastic process of the liquidity ofsecurities is as important to investment and valuation as the exogenous stochastic process of their cash flows.We develop a general-equilibrium model with heterogeneous investors who have an every-day motive to trade and pay...