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...

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...

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...

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...

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...

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...

Over the past four decades, the U.S. economy has seen a decline in the share of young firms alongside a rise in the profit share of GDP. This paper explores how population aging contributes to these twin trends through a demand-side channel. The core hypothesis is that younger households exhibit...