Bertrand versus Cournot revisited

Summary. Bertrand criticized Cournot's analysis of the competitive process, arguing that firms should be seen as playing a strategy of setting price below competitors' prices (henceforth, the Bertrand strategy) instead of a strategy of accepting the price needed to sell an optimal quantity (the Cournot strategy). We characterize Nash equilibria in a generalized model in which firms choose among Cournot and Bertrand strategies. Best responses always exist in this model. For the duopoly case, we show that iterated best responses converge under mild assumptions on initial states either to Cournot equilibrium or to an equilibrium in which only one firm plays the Bertrand strategy with price equal to marginal cost and that firm has zero sales. Received: December 11, 1995; revised version October 2, 1996     

Price versus quantity in a mixed duopoly with foreign penetration

We characterize the endogenous competition structure (in prices or quantities) in a differentiated duopoly between a public firm that maximizes domestic welfare and a private firm that can be owned by domestic or foreign investors. The market for which they compete can be domestic or integrated: in the first case Bertrand competition emerges endogenously and in the second case Cournot competition can emerge if the fraction of domestic consumers in the integrated market is low enough. We also determine the optimal degree of foreign penetration showing the optimality of a partial foreign ownership. Finally, we extend the model to increasing marginal cost confirming the robustness of the results.     

Efficiency and surplus bounds in Cournot competition

We derive bounds on the ratios of deadweight loss and consumer surplus to producer surplus under Cournot competition. To do so, we introduce a parameterization of the degree of curvature of market demand using the parallel concepts of ρ-concavity and ρ-convexity. The “more concave” is demand, the larger the share of producer surplus in overall surplus, the smaller is consumer surplus relative to producer surplus, and the lower the ratio of deadweight loss to producer surplus. Deadweight loss over total potential surplus is at first increasing with demand concavity, then eventually decreasing.     

Bertrand competition when firms hold passive ownership stakes in one another

We show that the Bertrand oligopoly model with cost asymmetries may admit multiple Nash equilibria when firms hold passive ownership stakes in each other. The equilibrium price may be as high as the monopoly price of the most efficient firm.     

Effect of credible quality investment with Bertrand and Cournot competition

We show how credible revelation and ability to commit to quality choice effect equilibrium qualities and welfare when product market is either Bertrand or Cournot competition. We show that results depend on the type of competition but not generally on the cost of quality function. We show that with Bertrand competition, the equilibrium qualities are lower with credible commitment. Competition is moderated and producer surplus is higher and consumer surplus lower. With Cournot competition, higher quality will be better but lower quality will be worse with credible commitment. Consumer surplus is always greater with credible commitment and if cost does not increase too quickly with quality, producer surplus will also increase. Thus credible commitment is a collusive device with Bertrand competition but it can improve social welfare with Cournot competition. Received: February 8, 2000; revised version: February 14, 2002 RID="*" ID="*" The idea of this paper originated in the weekly workshops of Mordecai Kurz at Stanford. I am forever in debted to Mordecai and fellow students – Luis Cabral, Peter DeMarzo, John Hillas, Michihiro Kandori, Steve Langois, Patrick McAllister, Steve Sharpe, Peter Streufert, Steve Turnbull and Gyu-Ho Wang – for their criticism and encouragement. I also benefited from comments from Yi-Heng Chen, Jin-Li Hu, Kala Krishna, Jinji Naoto, Thomas J. Prusa, and Shyh-Fang Ueng at various later stages of this work. Last but not least, I am grateful for the detailed comments of the referee.     

Location choice with delegation: Bertrand vs. Cournot competition

The conventional wisdom indicates that firms' optimal locations are sensitive to the modes of product-market competition, leading to a difficulty for firms to make concrete location decisions. This difficulty is especially crucial for the high entry-cost firms. The paper develops an uncovered-market model à la Economides (1984) to explore this sensitivity by taking into account a delegation game. It shows that firms' location configurations remain unchanged regardless of the modes of product-market competition as the owners offer the managers a contract with a relative-performance incentive scheme. Moreover, the paper shows that, by introducing a delegation game, the competition between managers under Bertrand competition is mitigated such that the managers have no incentive to choose price undercutting as they locate themselves far enough away from each other.     

Mixed pricing in oligopoly with limited monopoly

We analyze price competition between two brands. Buyers consist of switchers and two segments of customers with limited brand loyalty. We identify a unique symmetric mixed-strategy price equilibrium and find that competition is most relaxed when there exists some switchers.     

Optimal pollution control in a mixed oligopoly with research spillovers

We study optimal pollution abatement under a mixed oligopoly when firms engage in emissions‐reducing research and development (R&D) with imperfect appropriation. The regulator uses a tax to curb emissions. Results show that in a mixed oligopoly, the public firm has positive emissions reduction in equilibrium; however, emissions reductions of the private firm could be positive or zero. Under certain conditions, the optimal pollution tax is positive; otherwise, the tax reverts to a subsidy. Comparing mixed and private duopolies, privatisation leads to reductions in R&D and output, but to an increase in overall emissions, so privatisation tends to make the environment worse.     

Imported inputs and privatization in downstream mixed oligopoly with foreign ownership

This paper examines welfare implications of privatization in a mixed oligopoly with vertically related markets, where an upstream foreign monopolist sells an essential input to public and private firms located downstream in the domestic country. The impact on domestic welfare of privatizing the downstream public firm is shown to contain three effects. The first is an output distortion effect, which negatively affects welfare since privatization decreases the production of final good for consumption. The second is an input price lowering effect resulting from a decrease in derived demand for the input. When the level of privatization increases, a decrease in final good production lowers input demand, causing input price to decline and domestic welfare to increase. The third is a rent‐leaking effect associated with foreign ownership in the downstream private firm. The rival domestic firm strategically increases its final good production, causing profits accrued to foreign investors to increase and domestic welfare to decline. Without foreign ownership in the downstream private firm, the optimal policy toward the public firm is complete privatization as the output distortion effect is dominated by the input price lowering effect. With foreign ownership, however, complete privatization can never be socially optimal due to the additional negative impact on domestic welfare of the rent‐leaking effect. We further discuss implications for domestic welfare under different privatization schemes (e.g., selling the privatization shares to the upstream foreign monopolist or to the rival domestic firm).     

Spatial Cournot Competition in a Linear City with Directional Delivery Constraints

This study investigates a sequential game of location and transportation mode choices, as well as the subsequent quantity choice. The results show that spatial Cournot competition with directional delivery constraints yields a richer set of spatial configurations, involving midpoint agglomeration, maximum differentiation and asymmetric dispersion, and a richer set of transportation mode selections, involving delivery in different directions, asymmetric delivery between duopoly firms, and delivery in two directions by each firm, depending on the fixed cost of a transportation instrument. This paper concludes with an investigation of welfare analysis on optimal locations and transportation modes.     

Endogenous timing game in a mixed duopoly with partial foreign ownership and asymmetric increasing marginal costs

This study examines a timing game in a mixed duopoly wherein public and private firms compete by taking account of the increasing marginal cost of both firms, as well as partial foreign ownership of the private firm. This study finds that if the private firm has a strong cost advantage over the public firm, public leadership is a risk dominant equilibrium irrespective of foreign ownership ratio. This result means that the cost difference between the public and private firms matters in selecting the risk-dominant equilibrium of the timing game. Additionally, if the private firm has only a weak cost advantage over the public firm, then private leadership (public leadership) is the risk dominant equilibrium if the foreign ownership ratio is (not) small.     

The codetermined firm in a Cournot duopoly: A stability analysis

This paper aims to study the stability issue in a Cournot duopoly with codetermined firms. We show that when both firms codetermine employment together with decentralised employees' representatives, a rise in wages acts as an economic (de)stabiliser when the wage is fairly (high) low, while under profit maximisation a rise in wages always acts as a stabilising device because the parametric stability region monotonically increases with the wage in such a case. Moreover, a rise in the union's bargaining power has a de-stabilising effect, except when the wage is low and the firm power is already high. Therefore, under codetermination a change either in the wage or firm power in the Nash bargaining plays an ambiguous role on stability. We also show with numerical simulations that complex dynamics can also occur.     

Comparative dynamics in a productive asset oligopoly

We build a subgame perfect Nash equilibrium of a common property productive asset oligopoly and analyze separately the impact of a change in the implicit growth rate of the asset and a change in the number of firms exploiting the asset. We show that the steady state level of asset can be a decreasing function of the asset's implicit growth rate. This phenomenon arises when the initial stock of asset is below a certain threshold. In the short-run we show that firms’ exploitation rate can be a decreasing function of the implicit growth rate. We study the impact of a change in the number of firms that share access to the asset. Reducing the number of firms can result, in the long-run, in higher industry production. In the short-run, it can result in an increase of the industry's exploitation and a decrease of the level of the asset's stock.     

Coalition-proof supply function equilibria in oligopoly

In an industry where firms compete via supply functions, the set of equilibrium outcomes is large. If decreasing supply functions are ruled out, this set is reduced significantly, but remains large. Specifically, the set of prices that can be sustained by supply function equilibria is the interval between the competitive price and the Cournot price. In sharp contrast, when the number of firms is above a threshold we identify (e.g., three if demand is linear), only the Cournot outcome can be sustained by a coalition-proof supply function equilibrium.     

HORIZONTAL MERGERS IN A DIFFERENTIATED COURNOT OLIGOPOLY

Using a standard differentiated goods quantity competition setting, we show three facts about horizontal two‐firm mergers that are not true for a homogeneous goods Cournot market. First, merger of two firms is profitable for the merging firms provided that goods are sufficiently distant substitutes. Second, merging of two firms can lead to more two‐firm mergers. Third, an initially non‐profitable two‐firm merger can occur in anticipation of subsequent mergers. These facts imply that mergers are more likely to occur in differentiated goods markets than in homogeneous goods markets.     

The dynamics of a differentiated duopoly with quantity competition

We analyse the dynamics of a Cournot duopoly with heterogeneous players to investigate the effects of micro-founded differentiated products demand on stability. The present study, which indeed modifies and extends Zhang et al. (2007) (Zhang, J., Da, Q., Wang, Y., 2007. Analysis of nonlinear duopoly game with heterogeneous players. Economic Modelling 24, 138–148) and Tramontana, F., (2010) (Tramontana, F., 2010. Heterogeneous duopoly with isoelastic demand function. Economic Modelling 27, 350–357), reveals that a higher degree of product differentiation may destabilise the market equilibrium. Moreover, we show that a cascade of flip bifurcations may lead to periodic cycles and ultimately chaotic behaviours. Since a higher degree of product differentiation implies weaker competition, then a theoretical implication of our findings, that also constitute a policy warning, is that a fiercer (weaker) competition tends to stabilise (destabilise) the unique positive Cournot–Nash equilibrium.     

Low-quality leadership in a vertically differentiated duopoly with Cournot competition

We model a vertically differentiated duopoly with quantity-setting firms as an extended game in which firms noncooperatively choose the timing of moves at the quality stage, to show that at the subgame, perfect equilibrium sequential play obtains, with the low-quality firm taking the leader’s role.     

BERTRAND Vs. COURNOT COMPETITION WITH UPSTREAM FIRM INVESTMENT

This paper compares Bertrand and Cournot competition in a vertical structure in which the upstream firm sets the input price and makes R&D investments. We show that from the downstream firms’ point of view, Cournot competition has the advantage of a more monopolistic effect, leading to the setting of a higher price, but has the disadvantage of inducing a lower incentive for the upstream firm to invest. On the other hand, Bertrand competition has the advantage of providing a greater incentive for the upstream firm to invest but has the disadvantage of a more competitive effect, leading to the setting of a lower price. Our main findings are as follows. First, R&D investment level is greater under Bertrand competition than under Cournot competition. Second, from the standpoint of the upstream firm and industry, Bertrand competition is more efficient than Cournot competition. Third, from the standpoint of the downstream firms, Bertrand competition is more efficient than Cournot when investment is sufficiently efficient and products are sufficiently differentiated.     

Unemployment and product market competition in a Cournot model with efficiency wages

This paper analyzes the impact of product market competition on unemployment, wage and welfare in a model where unemployment is caused by the efficiency wage consideration and oligopolistic firms compete in quantity. It is shown that while more intense competition in the product market increases output and reduces price, it does not necessarily lead to a lower unemployment rate or a higher wage for workers. Depending on the technologies, the relationship between the intensity of competition and the level of employment (respectively, wage, welfare) is not always monotonic, and, in some instances, has an inverted U‐shape.