Regulators are responding to growing platform power with curbs on platforms' potentially biased exercise of power, creating urgent needs for both a workable definition of platform bias and ways to detect and measure it. We develop a simple equilibrium framework in which consumers choose among...

Regulators around the world are discussing, or taking action to limit, self-preferencing by large platforms. This paper explores Amazon's search rankings of its own products as the European Union's Digital Markets Act (DMA) was coming into effect. Using data on over 8 million Amazon search...

Nearly half of all transactions in the $5 trillion market for manufactured goods in the United States were intermediated by wholesalers in 2012, up from 32 percent in 1992. Seventy percent of this increase is due to the growth of "superstar" firms - the largest one percent of wholesalers....

We examine merging firms' additions and removals of products for a sample of 66 mergers across a wide variety of consumer packaged goods markets. We find that mergers lead to a net reduction in the number of products offered by merging firms. Merging firms tend to both drop and add products at...

Using rich data on hourly physical productivity and thousands of ownership changes from US power plants, we study the effects of acquisitions on efficiency and underlying mechanisms. We find a 2% average increase in efficiency for acquired plants, beginning five months after acquisitions....

Mobile app commissions paid by app developers to a monopolist device maker/app store operator are examined. Three results are demonstrated. First, unregulated app commissions are set at a level that maximises consumer surplus. Second, eliminating app commissions will lead to higher device...

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...

This paper surveys the relevant existing literature that can help researchers and policy makers understand the drivers of competition in markets that constitute the provision of artificial intelligence products. The focus is on three broad markets: training data, input data, and AI predictions....

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...

Market definition and market power are central features of competition law and practice but pose serious challenges. On one hand, market definition suffers decisive logical infirmities that render it infeasible, unnecessary, and counterproductive, and the practice of stating market power...