Cobb-Douglas Preferences and Pollution in a Bilateral Oligopoly Market

In this paper, we investigate how pollution changes with preferences, focusing on a finite bilateral oligopoly model where agents have asymmetric Cobb-Douglas preferences. Producers are also consumers and the choice of heterogeneous preferences is related to the psychological foundations and identity aspects of group membership. We compare two strategic equilibria: the Stackelberg-Cournot equilibrium with pollution (SCEP) and the Cournot equilibrium with pollution (CEP). We show that considering the asymmetric preferences helps the public decision-maker to identify precisely the category of agents (consumer–producers or pure-consumers) for which a change in environmental preference parameters will most effectively reduce pollution. Furthermore, we find that firms’ emissions’ elasticity decreases with market power (when the market power increases) if their marginal cost is lower than their competitor. Finally, we show that when producers are also consumers, an action on pure-consumers’ preference parameters reduces more emissions than a similar action on consumer–producers, and this regardless of the timing of interaction.

Market Entry, Fighting Brands, and Tacit Collusion: Evidence from the French Mobile Telecommunications Market

We study a major new entry in the French mobile telecommunications market, followed by the introduction of fighting brands by the three incumbents. Using an empirical oligopoly model, we find that the incumbents’ fighting brand strategies are difficult to rationalize as unilateral best responses. Instead, their strategies are consistent with a breakdown of tacit semi-collusion: before entry, the incumbents could successfully coordinate on restricting product variety to avoid cannibalization; after entry, this outcome became harder to sustain because of increased business stealing incentives. Consumers gained considerably from the added variety and, to a lesser extent, from the incumbents’ price responses. (JEL L13, L21, L96, M31)

Estimating the degree of market power in the vegetable market in Japan

To adequately capture the market structure of vegetables in Japan, it is necessary to develop an oligopolistic model due to the potential market power of producers vs. retailers. We first estimate the market power between producers and retailers by extending the bilateral oligopoly model. Next, we evaluate the role of the wholesale market and its effect on economic welfare. Our results indicate that the wholesale market benefits both producers and consumers through a reduction in retail margins. This study contributes to the industrial organization literature by developing a bilateral oligopoly model and empirically measuring the wholesale market system in Japan.

Strategic Complements or Substitutes? The Case of Adopting Health Information Technology by U.S. Hospitals

This paper explores the adoption choice of electronic medical records by U.S. hospitals, which could exhibit strategic complements or substitutes. I find complementarities in adoption through a reducedform analysis with instruments for unobserved market characteristics. I further develop a dynamic oligopoly model to allow for strategic timing incentives that are missing in the static model. Adopting a dominant local vendor could increase perperiod profits from adoption by 9.2% over choosing a marginal vendor. A counterfactual analysis suggests an incentive program rewarding coordination, not just adoption, is more effective in achieving interoperability, especially before the widespread adoption of the technology.

Drivers learn city-scale dynamic equilibrium

Understanding driver behavior in on-demand mobility services is crucial for designing efficient and sustainable transport models. Drivers' delivery strategy is well understood, but their search strategy and learning process still lack an empirically validated model. Here we provide a game-theoretic model of driver search strategy and learning dynamics, interpret the collective outcome in a thermodynamic framework, and verify its various implications empirically. We capture driver search strategies in a multi-market oligopoly model, which has a unique Nash equilibrium and is globally asymptotically stable. The equilibrium can therefore be obtained via heuristic learning rules where drivers pursue the incentive gradient or simply imitate others. To help understand city-scale phenomena, we offer a macroscopic view with the laws of thermodynamics. With 870 million trips of over 50k drivers in New York City, we show that the equilibrium well explains the spatiotemporal patterns of driver search behavior, and estimate an empirical constitutive relation. We find that new drivers learn the equilibrium within a year, and those who stay longer learn better. The collective response to new competition is also as predicted. Among empirical studies of driver strategy in on-demand services, our work examines the longest period, the most trips, and is the largest for taxi industry.

Consistent Conjectural Variations Equilibrium in the Semi-Mixed Oligopoly

We study a variant of the mixed oligopoly model with conjectural variations equilibrium, in which one of the producers maximizes not his net profit but the convex combination of the latter with the domestic social surplus. The coefficient of this convex combination is named socialization level. The producers’ conjectures concern the price variations depending upon their production output variations. In this work, we extend the models studied before, considering the case of the producers’ cost functions being convex but not necessarily quadratic. The notion of exterior and interior equilibrium is introduced (similarly to previous works), developing a consistency criterion for the conjectures. Existence and uniqueness theorems are formulated and proven. Results concerning the comparison between conjectural variations, perfect competition, and Cournot equilibriums are provided. Based on these results, we formulate an optimality criterion for the election of the socialization level. The existence of the optimal socialization level is proven under the condition that the public company cannot be too weak as compared to the private firms.

Foreign Direct Investment and the Choice of Environmental Policy

We use a simple two-country oligopoly model of intra-industry trade to examine the implications of foreign direct investment for the pollution haven hypothesis and environmental policy. Countries which lower environmental standards to be more competitive in world markets generate pollution havens if environmental policy is exogenous. However, if FDI is a viable option as a mode of entry, profit-shifting considerations weaken in favour of environmental considerations and FDI recipients tighten environmental policy, reducing incentives to relocate production. Interestingly, when countries are sufficiently similar in their environmental awareness, "grey" countries can become greener than originally "green" countries but firms in the latter still engage in FDI in the former, in spite of the stricter standard they face, in order to level the playing field. We derive conditions under which FDI-receiving countries have incentives to manipulate their environmental standards to prevent or attract FDI, potentially eliminating or creating pollution havens.

Foreign Direct Investment and the Choice of Environmental Policy

We use a simple two-country oligopoly model of intra-industry trade to examine the implications of foreign direct investment for the pollution haven hypothesis and environmental policy. Countries which lower environmental standards to be more competitive in world markets generate pollution havens if environmental policy is exogenous. However, if FDI is a viable option as a mode of entry, profit-shifting considerations weaken in favour of environmental considerations and FDI recipients tighten environmental policy, reducing incentives to relocate production. Interestingly, when countries are sufficiently similar in their environmental awareness, "grey" countries can become greener than originally "green" countries but firms in the latter still engage in FDI in the former, in spite of the stricter standard they face, in order to level the playing field. We derive conditions under which FDI-receiving countries have incentives to manipulate their environmental standards to prevent or attract FDI, potentially eliminating or creating pollution havens.

Optimal destabilization of cartels

This paper introduces an oligopoly model that includes three actors: a cartel (comprising two or more firms that operate like one merged company), a group of competing fringe firms, and a welfare maximizing antitrust authority. The cartel is the Stackelberg quantity leader and the fringe firms are in Cournot competition with respect to the residual demand. The cartel is internally stable if none of its member firms finds it profitable to become a fringe firm. The antitrust authority can destabilize the cartel in the sense of making the cartel internally instable. To this end, the antitrust authority has three policy instruments at its disposal: its own effort, a fine for detected cartels, and a leniency program for cartel members that cooperate with the authority. Taking into account that the use of these instruments is not costless for society, a unique optimal antitrust policy is derived. The analysis reveals that both, the optimal force and mix of the antitrust authority’s policy depend on market characteristics such as the efficiency of the authority’s operations, the public respect for the rule of law, the ethical standards of the firms’ managers, the market volume, and the number of firms operating on the market.