This chapter first reviews the economic theory underlying the unilateral competitive effects of mergers, focusing on the Cournot model, commonly applied to homogeneous products; the Bertrand model, commonly applied to differentiated consumer products; and models of auctions and bargaining,...

Contrary to the suggestion of Williamson (1968), a merger enhancing total social welfare through the creation of substantial efficiencies nevertheless may violate current antitrust law in the United States, which considers only the effects of mergers on consumers. To avoid violating antitrust...