Scholars and antitrust enforcers have raised concerns about anticompetitive effects that may arise when institutional investors hold substantial stakes in competing firms. Their concern rests on empirical evidence that such common concentrated ownership is associated with higher prices and lower...

We present a simple model of common ownership in which an investor chooses its stake in competing firms in light of the effects on firm behavior and firm profits. Two firms compete in Cournot duopoly, and ownership affects a firm’s objective function in the manner posited by Bresnahan & Salop...