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...

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...

Because market definition is frequently outcome determinative, it is both a central and contested part of antitrust litigation. Recognition of business methods known as multisided platforms presents the challenge of whether and how to incorporate their characteristically interconnected groups...