We provide a model to investigate vertical integration decisions. This model assumes that local downstream manufacturers require two inputs to make their final products. One input is produced by a supplier shared by both manufacturers; another is produced by an exclusive supplier for each manufacturer. We show that vertical integration of each downstream firm with its exclusive supplier enhances the input demand for the common supplier, leading to an increase in the common supplier's input price due to the elimination of the double marginalization. Moreover, downstream firms that require a smaller quantity of inputs from the common supplier, for instance, those with efficient production technology or smaller downstream demand, are more likely to vertically integrate because vertical integration yields a smaller increase in input price. Thus, the cause of firm-size heterogeneity is important to consider when investigating the relationship between firm size and the tendency to vertically integrate.
This paper investigates an asymmetric duopoly model with R&D competition and product positioning. We find that an inefficient (small) firm may engage in R&D more intensively than an efficient (large) firm in spite of economies of scale in R&D activities. Contrary to the findings of previous studies, competition is more likely to have a positive effect on the investments of the small firm than on those of the large firm. We also find that improving the efficiency of the inefficient firm can reduce both social and consumer surplus.
We investigate the incentive and welfare implications of a merger when heterogeneous oligopolists compete both in process R&D and on the product market. We examine how a merger affects the output, investment, and profits of firms. In addition, we examine whether firms have merger incentives, and, if so, whether such mergers are desirable from the viewpoint of social welfare. If R&D is not expensive and if large cost differences between efficient and inefficient firms exist, a merger between homogeneous firms tends to occur even though it harms welfare.