The internet has facilitated the creation of new markets characterized by large scale, increased customization, rapid innovation and the collection and use of detailed consumer and market data. I describe these changes and some of the economic theory that has been useful for thinking about...

The pricing of medical products and services in the U.S. is notoriously complex. In health care, supply prices (those received by the manufacturer) are distinct from demand prices (those paid by the patient) due to health insurance. The insurer, in designing the benefit, decides what prices...

This paper provides a new and simple model of endogenous horizontal product differentiation based on a standard demand structure derived from quadratic utility. One objective of the paper is to explain the “empirical Bertrand paradox” – the failure to observe homogeneous product Bertrand...

We study bilateral exchange, both direct trade and indirect trade that happens through chains of intermediaries or middlemen. We develop a model of this activity and present applications. This illustrates how, and how many, intermediaries get involved, and how the terms of trade are determined....

We document cross-individual variation in U.S. credit card borrowing costs (APRs) that is large enough to explain substantial differences in household saving rates. Borrower default risk and card characteristics explain roughly 40% of APRs. The remaining dispersion exists because a borrower can...

We extend Kyle's (1985) model of insider trading to the case where liquidity provided by noise traders follows a general stochastic process. Even though the level of noise trading volatility is observable, in equilibrium, measured price impact is stochastic. If noise trading volatility is...

As it becomes cheaper to copy and share digital content, vendors are turning to technical protections such as encryption. We argue that if protection is nevertheless imperfect, this transition will generally lower the prices of content relative to perfect legal enforcement. However, the effect...

Search frictions can explain why the "law of one price" fails in retail markets and why even firms selling commodity products have pricing power. In online commerce, physical search costs are low, yet price dispersion is common. We use browsing data from eBay to estimate a model of consumer...

This paper develops search-theoretic models in which it is individually rational for firms to engage in obfuscation. It considers oligopoly competition between firms selling a homogeneous good to a population of rational consumers who incur search costs to learn each firm's price. Search costs...

This paper examines the influence of Irving Fisher's writings on Milton Friedman's work in monetary economics. We focus first on Fisher's influences in monetary theory (the quantity theory of money, the Fisher effect, Gibson's Paradox, the monetary theory of business cycles, and the Phillips...