Should-Read: James Kwoka: U.S. antitrust and competition policy amid the new merger wave: "This dramatic and well-documented increase in concentration raises the question about its causes...
...Could it simply be the unfortunate side effect of the rise of information technology and network industries that typically do not support numerous firms? It’s certainly the case that those sectors of the economy have grown in visibility and importance, yet consolidation has affected lots of other, more traditional industries as well. Perhaps, then, the decline in competitiveness is due to the increased prevalence of barriers to entry used by incumbent firms to forestall competition by others. There is certainly evidence of this as well—some cited by CEA—but again, this appears to be localized in specific sectors. A third possible explanation is the role of antitrust policy, specifically the ways in which it has changed and permitted the emergence of ever-larger firms...."