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...

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...

Although fake online customer reviews have become prevalent on platforms such as Amazon, Google, and Facebook, little is known about how these reviews influence consumer behavior. This paper provides the first experimental estimates of the effects of fake reviews on individual demand and...

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...

Information flows, and thus information technology (IT) are central to the structure of firms and markets. Using data from the U.S. Census Bureau, we provide firm-level evidence that increases in IT intensity are associated with increases in firm size and concentration in both employment and...