Integration of Complementary Multiproduct Firms

Two firms offer product series from which multiple complementary pairs are formed. The firms engage in a price- or quantity-choosing game in the market. It is found that the integration of the two firms may not necessarily lower the equilibrium prices because it precludes "indirect competition" in the market. Therefore, the integration, which may appear as a vertical integration, could be an antitrust concern even in the absence of exclusionary purpose.