Deregulating antitrust policy

Starting in the 1980s, market concentration began to rise dramatically decreasing competition and increasing market power for the firms that remain. Such developments have important effects on a number of economic variables such as the efficiency of our economy and income inequality. Thus, it is important to ask: how has the administration of antitrust policy changed over the last half century? To shed more light on these important questions, we explore both change in policy outline by the Department of Justice in its Horizontal Merger Guidelines and change in administrative actions looking at both secondary requests for mergers and acquisitions of different sizes, and pre, post and change in Herfindahl-Hirschman Index in mergers and acquisitions contested by the Department of Justice through the courts.