We propose a new theory of suboptimal risk-taking based on contractual externalities. We examine an industry with a continuum of firms. Each firm's manager exerts costly hidden effort The productivity of effort is subject to systematic shocks. Firms' stock prices reflect their performance...

We study ffort and risk-taking behaviour in an economy with a continuum of principal-agent pairs where each agent exerts costly hidden effort. When the industry productivity is uncertain, agents have motivations to match the industry average effort, which results in contractual externalities....

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...

We study a model where the aggregate trading of currency speculators reveals new information to the central bank and affects its policy decision. We show that the learning process gives rise to coordination motives among speculators leading to large currency attacks and introducing...

The paper offers a new theoretical framework to examine the role of intermediaries between creators and users of new inventions. We find that uncertainty about the profitability of investing in new inventions generates a basis for intermediation. An intermediary may provide an opportunity to...

We study two-sided markets with heterogeneous, privately informed agents who gain from being matched with better partners from the other side. Agents are matched through an intermediary. Our main results quantify the relative attractiveness of a coarse matching scheme consisting of two classes...