In the fall of 2008, the United States was plunged into a financial crisis more severe than any since the Great Depression. As banks collapsed and the state scrambled to organize one of the largest transfers of wealth in history, manyincluding economists and financial expertswere shocked by the...

We study a model where a capital provider learns from the price of a firm’s security in deciding how much capital to provide for new investment. This feedback effect from the financial market to the investment decision gives rise to trading frenzies, where speculators all wish to trade like...

Over the past 10 years, financial firms have increased the size of their positions in the oil futures market. At the same time, oil prices have increased dramatically. The conjunction of these developments has led some observers to argue that financial speculation caused the run-up in oil...

What is the role of financial speculation in determining the real oil price? We find that while macroeconomic shocks have been the major upward driver of the real oil price since the mid 1980s, also financial shocks have sizably contributed since the early 2000s, and at a much larger extent...

We propose a new welfare criterion that allows us to rank alternative financial market structures in the presence of belief heterogeneity. We analyze economies with complete and incomplete financial markets and/or restricted trading possibilities in the form of borrowing limits or transaction...