This paper is no longer available on-line from the NBER. A revised version of the paper has been published as "Diversification Across Time" in the Journal of Portfolio Management 39 (Winter 2013), pp.73-86.

We develop a new framework to study the implementation of monetary policy through the banking system. Banks finance illiquid loans by issuing deposits. Deposit transfers across banks must be settled using central bank reserves. Transfers are random and therefore create liquidity risk, which in...

The dangers of shouting "fire" in a crowded theater are well understood, but the dangers of rushing to the exit in the financial markets are more complex. Yet, the two events share several features, and I analyze why people crowd into theaters and trades, why they run, what determines the risk,...

We propose an equilibrium occupational choice model, where agents can choose to work in the real sector (become entrepreneurs) or to become informed dealers in financial markets. Agents incur costs to become informed dealers and develop skills for valuing assets up for trade. The financial...

We investigate the leverage of hedge funds in the time series and cross section. Hedge fund leverage is counter-cyclical to the leverage of listed financial intermediaries and decreases prior to the start of the financial crisis in mid-2007. Hedge fund leverage is lowest in early 2009 when the...

Heightened counterparty risk during the recent financial crisis has raised questions about the role clearinghouses play in global financial stability. Empirical identification of the effect of centralized clearing on counterparty risk is challenging because of the co-incidence of macro-economic...

A key result of the Capital Asset Pricing Model (CAPM) is that the market portfolio---the portfolio of all assets in which each asset's weight is proportional to its total market capitalization---lies on the mean-variance efficient frontier, the set of portfolios having mean-variance...

We conjecture that a mutual fund manager with superior stock selection ability is more likely to benefit from trading in stocks affected by information-events. Taking the probability of informed trading (PIN, Easley, Kiefer, O'Hara, and Paperman, 1996) to measure the amount of informed trading...

Commodity futures risk premiums vary across commodities and over time depending on the level of physical inventories, as predicted by the Theory of Storage. Using a comprehensive dataset on 31 commodity futures and physical inventories between 1969 and 2006, we show that the convenience yield is...

Evidence of stock return predictability by financial ratios is still controversial, as documented by inconsistent results for in-sample and out-of-sample regressions and by substantial parameter instability. This paper shows that these seemingly incompatible results can be reconciled if the...