Modelling and predicting the competitive effects of vertical mergers: The bargaining leverage over rivals effect

A new competitive effect of vertical mergers, based on the Nash bargaining model, has begun to play an important role in antitrust authorities’ evaluations of vertical mergers in the United States, Canada and abroad. The key idea is that a vertical merger will increase the bargaining leverage of the merged firm over its downstream rivals. Its bargaining leverage increases because it now takes into account the additional profit that its own downstream division will earn if it withholds inputs from downstream rivals, which changes its threat point in the bargaining game with downstream rivals. Consequently, the merged firm can increase the price that it charges rival downstream firms for inputs. One strong appeal of this theory is that it provides a simple and very intuitive formula to measure the upward pricing pressure caused by a vertical merger due to changes in bargaining leverage, based on variables whose values can generally be estimated using available data. This article describes this new competitive effect, which will be called the bargaining leverage over rivals (BLR) effect, and derives the upward pricing pressure formula. It also explains why this new competitive effect is distinct from the older raising rivals’ costs (RRC) effect that has been widely discussed in the economics literature, and discusses the relationship between the two different effects.