Price and Quantity Competition in a Differentiated Duopoly With Network Compatibility Effects

We consider the efficiency of price and quantity competition in a network products market, where we observe product compatibility with network externalities (hereafter, network compatibility effects). In particular, if network compatibility effects between firms are sufficiently asymmetric, the Cournot equilibrium is more efficient than the Bertrand equilibrium in terms of larger consumer, producer and total surpluses. Then, we consider an endogenous choice of the strategic variables, price and quantity. If the degree of network compatibility effects of the rival firm is larger (smaller) than the degree of product substitutability, then choosing prices (quantities) is a dominant strategy for the firm. Thus, if the network compatibility effects of both firms are larger (smaller), the Bertrand (Cournot) equilibrium arises. Furthermore, if the network compatibility effects between the firms are sufficiently asymmetric, the firm with a larger (smaller) network compatibility effect than a certain level of product substitutability chooses quantities (prices). In this case, the Cournot–Bertrand equilibrium arises, which is less (more) efficient than the Cournot equilibrium in terms of consumer (producer) surplus.     

Tariffs,Quality Choice,and Cost Functions: a Foreign Monopoly Case*

It has been shown that trade restrictions such as tariffs, import quotas, and voluntary export restrictions, lead to quality upgrading of imports. In this paper, however, we reconsider this proposition by focusing on the nature of cost functions. Based on a standard vertical differentiation model, we analyze the effects of tariffs on quality and quantity of imports. We show that if a fixed cost is an increasing function of quality, tariffs lead to quality downgrading of imports. Moreover, we discuss minimum quality requirements (MQR) for such a trade policy. We show that MQR increases the amount of imports and an importing country's welfare in the presence of the fixed cost function. These issues will be addressed in the context of a foreign monopoly.     

Optimal Timing of Advertising with Demand Spillovers

We construct a model of a horizontally differentiated duopoly with demand spillovers in which advertising influences the willingness-to-pay of consumers for products and thereby affects not only market share, but also the level of market demand. Furthermore, firms decide the timing as well as the level of advertising. We first derive a subgame perfect Nash equilibrium and Stackelberg equilibria in the advertising competition. Then, using the framework of an endogenous timing decision game with an observable delay (i.e., Hamilton and Slutsky, Games Econ Behavior 2: 29–46, 1990), we consider the optimal timing of advertising. We demonstrate that the optimal timing depends on the degree of demand spillovers and the product substitutability. In particular, if there are sufficient asymmetric demand spillovers between firms, there is a unique Stackelberg equilibrium in the advertising competition, in which the firm providing the product with small (large) demand spillovers chooses to invest in advertising early (late), regardless of the mode of competition.     

On the “merger paradox” in price competition with asymmetric product differentiation

By assuming asymmetric product differentiation, we consider the “merger paradox” in price competition (or the incentive to collude in prices). We investigate whether the emergence of the merger paradox depends on the degree of product differentiation between firms. In particular, unlike Deneckere and Davidson (1985), we demonstrate that if the degree of product differentiation between the insider and outsider is sufficiently small, then they are strategic substitutes, and thus, the merger paradox arises in price competition.