I have argued again and again that we aren't concerned enough about the concentration of economic power:
Did Robert Bork Understate the Competitive Impact of Mergers? Evidence from Consummated Mergers, by Orley C. Ashenfelter, Daniel Hosken, and Matthew C. Weinberg, NBER: In The Antitrust Paradox, Robert Bork viewed most mergers as either competitively neutral or efficiency enhancing. In his view, only mergers creating a dominant firm or monopoly were likely to harm consumers. Bork was especially skeptical of oligopoly concerns resulting from mergers. In this paper, we provide a critique of Bork’s views on merger policy from The Antitrust Paradox. Many of Bork’s recommendations have been implemented over time and have improved merger analysis. Bork’s proposed horizontal merger policy, however, was too permissive. In particular, the empirical record shows that mergers in oligopolistic markets can raise consumer prices.