We quantify externalities on profitability and market shares of competing firms in oligopolistic markets through the transition from an n to an n - 1 player oligopoly after a merger. Competitors are identified via the European Commission's market investigations and our methodology allows us to...

Worldwide, the overwhelming majority of large horizontal mergers are cleared by antitrust authorities unconditionally. The presumption seems to be that efficiencies from these mergers are sizeable. We calculate the compensating efficiencies that would prevent a merger from harming consumers for...

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...