An increasing body of empirical evidence is documenting trends toward rising concentration, profits, and markups in many industries around the world since the 1980s. Two major criticisms of these studies is that concentration and market shares are poorly measured at the national industry level...

This paper questions whether markets need contain products that are direct substitutes for consumers. It shows that there are many instances where markets consist of products that are not direct substitutes, and those which consumers cannot directly use or are at different functional levels in...

We describe a simple initial indicator of whether a proposed merger between rivals in a differentiated product industry is likely to raise prices through unilateral effects. Our diagnostic calibrates upward pricing pressure (UPP) resulting from the merger, based on the price/cost margins of the...

Amazon acts as both a platform operator and seller on its platform, designing rich fee policies and offering some products direct to consumers. This flexibility may improve welfare by increasing fee discrimination and reducing double marginalization, but may decrease welfare due to incentives to...

This paper develops a model of competition among multiproduct retailers that is consistent with observed pricing regularities, e.g., virtually all products have large mass points in their price distributions and most deviations fall below the mass point. The basis of the model is that, because...

This paper assesses a common view that has surfaced recently in a growing number of Government, industry and academic studies, that first claims streaming media services are likely to have adversely affected competition in media markets (both screen and music), and second recommends additional...

This paper addresses the analysis of market definition when the parties involved in an antitrust or merger analysis include one or more two-sided platforms. We discuss how standard market definition measures such as SSNIP tests, diversion ratios, and conditional logit demand analyses have to be...