Tomomichi Mizuno

Vertical Separation as a Defense against Strong Suppliers

We provide a simple model to investigate decisions about vertical separation. The key feature of this model is that more than one input is required for the final product of the downstream monopolist. We show that as the bargaining powers of independent complementary input suppliers grow larger, the downstream monopolist tends to separate from its input units. The results are related to a visible difference between the vertical structures of Japanese and US auto assemblers.

Equilibrium Vertical Integration with Complementary Input Markets

Abstract 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 suppliers 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.

Direct Marketing in Oligopoly

We consider a game in which symmetric manufacturers decide whether to set up sites (e.g., web sites) where consumers can buy their products directly. Following this decision, the manufacturers choose quantities to sell to the retailers, and then the manufacturers with direct‐sales sites and retailers choose quantities to sell to the consumers. We show that since an increase in the number of retailers may drive the direct‐selling manufacturers from the retail market, it may raise the retailers’ profit and reduce social welfare. Finally, we discuss two cases: an oligopolistic wholesale market and a market with price competition and differentiated products.

Input Specificity and Product Differentiation

Using a simple product differentiation model with elastic demands, we investigate the relationship between differentiation strategies and vertical relations. Depending on the competitive structure in the upstream market, three differentiation patterns (maximum, minimum and partial differentiation) can appear in equilibrium even though each downstream firm freely determines the degree of product differentiation. When downstream firms must incur positive investment costs to differentiate their products, they tend to do so if the upstream market is competitive.

Why Do Large Firms Tend to Integrate Vertically

We provide a theoretical framework to discuss the relation between firm size and vertical structures. The framework is based on a Hotelling model with three downstream and three upstream firms. We show that vertical integration enhances the degree of product differentiation and show the strategic complementarity of product positioning. We also show that the downstream firm that has the largest market share is more likely to integrate vertically. Enhancing the degree of product differentiation is more beneficial for the large firm than for the rest of the downstream firms because the large firm supplies a large amount of product.

Market Definition of Long Distance Transportation Market in Japan: An Event Study Approach

After the September 11th attacks, passengers avoided air travel. Hence, companies competing with air carriers may have benefited from the terrorist attacks. Using the market model with a dummy variable and generalized autoregressive conditional heteroskedasticity (GARCH) for an event study, we examine the impact of the attacks on Japanese airline and high-speed railway industries. We show that terrorist attacks negatively impacted the stock prices of the airline industry but increased those of the high-speed railway industry. Thus, because of the competition between air carriers and railway companies, terrorist attacks benefited the high-speed railway industry. We conclude that the Japanese transportation market can be defined as a market containing both air carriers and railway companies.

Rules of origin and uncertain compliance cost

Abstract This study considers the role of the cost uncertainty associated with meeting the rules of origin (ROO) in a free trade area/agreement (FTA). While the literature tends to overlook the cost uncertainties of ROO compliers, we show that the uncertain production costs resulting from meeting the ROO yield the coexistence of compliers and non-compliers in symmetric oligopoly firms. We also show that the regime in which compliers and non-compliers coexist is not the best one for an FTA importer, while it may be the best one for world welfare. We also discuss the case that uncertain production costs are firm-specific.

Divisionalization and Horizontal Mergers in a Vertical Relationship

In this paper we evaluate the effects of horizontal mergers in a vertical relationship. Each downstream firm can create autonomous divisions. We show that an infinitesimal merger of downstream firms may exhibit a positive welfare effect if the upstream and downstream sectors are sufficiently unconcentrated. However, any merger of upstream firms reduces social welfare. Moreover, a decrease in the concentration in the upstream stage (respectively downstream stage or non-merging stage) makes the welfare effects of the merger in the upstream stage (respectively downstream stage or non-merging stage) less negative (respectively ambiguous or ambiguous).