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...

Using a sample of 167 mergers during the period 1990-2002 involving 544 firms either as merging firms or competitors, we contrast a measure of the merger's profitability based on event studies with one based on accounting data. We find positive and significant correlations between them when...