Prices are regulated in many markets, ranging from healthcare to labor to telecommunications. This paper reinterprets the variables in the basic supply-demand model so that both product-definition and quantity are equilibrium outcomes. Specifically, compliance with price controls is achieved by...

Price theory says that the most important effects of policy and technological change are often found beyond their first point of contact. This appears opposed to econometric methods that rule out spillovers of one person's treatment on another's outcomes. This paper uses the industry model from...

This article addresses developments in the literature on The Rise of Market Power. First, it summarizes research about the result of De Loecker 2020 that the sales-weighted average markup has increased in the United States. Second, it summarizes and evaluates a set of industry studies that...

While the labor market implications of mergers have been historically ignored as "out of market" effects, recent actions by the Department of Justice (DOJ) place buyer market power (i.e., monopsony) at the forefront of antitrust policy. We develop a theory of multi-plant ownership and monopsony...

Online platforms often face challenges being both fair (i.e., non-discriminatory) and efficient (i.e., maximizing revenue). Using computer vision algorithms and observational data from a microlending marketplace, we find that choices made by borrowers creating online profiles impact both of...

We model financial innovations such as Exchange-Traded Funds, smart beta products, and many index-based vehicles as composite securities (CSs) that facilitate trading the common factors in assets' liquidation values. Through accessing a larger basket of assets in endogenously chosen proportions,...

Concentration is a single summary statistic driven by two opposing forces: the number of firms in a market and the evenness of their market shares. This paper introduces a generalized measure of concentration that allows researchers to vary the relative importance of each force. Using the...

We characterize the evolution of markups for consumer products in the United States from 2006 to 2019. Using detailed data on prices and quantities for products in more than 100 distinct product categories, we estimate flexible demand systems and recover markups under an assumption that firms...

Digital advertising, which uses consumer data to target ads to users, now accounts for most of global ad expenditures. Privacy concerns have prompted regulations that restrict the use of personal data. To inform these policy debates, we develop an equilibrium model of advertising and market...