Collusion in a price-quantity oligopoly

In the context of an infinitely repeated oligopoly game, we study collusion among firms that simultaneously choose prices and quantities. We compare a price cartel with a price-quota cartel and analyze when and why firms prefer the latter to the former. Output quota may be required to solve coordination and incentive problems when market demand is sufficiently elastic. If market demand is sufficiently inelastic, then the cartel faces a trade-off between increasing prices and the amount of costly overproduction. We find that a price cartel prices consistently below the monopoly price to mitigate excessive production. In this case, a quota arrangement allows firms to avoid overproduction and to sustain the monopoly price. From a policy perspective, our findings suggest that an overall price increase in conjunction with more stable prices and market shares is indicative of collusion in industries where production precedes sales and outputs are imperfectly observable.     

Durable goods oligopoly

This paper models a durable-goods oligopoly as a differential game. Two cases are treated: sales, where firms cannot lease but must sell the good in question, and leasing, where firms do not sell but only rent. In the sales case, firms face increasing marginal cost of production and the good in question depreciates. For this case, a rational expectations feedback Nash equilibrium is constructed for which monopoly or oligopoly output is less than the efficient level. This gap between oligopoly and competitive output diminishes as the number of firms increases. When firms can only lease the good, the good is assumed not to depreciate and the monopoly level of steady state output is compared with the level of steady state output for a feedback equilibrium duopoly. For this case, the duopoly equilibrium has steady-state output that is less than the corresponding efficient level, but greater than the monopoly level. The leasing model is shown to be isomorphic to the adjustment-cost duopoly model of Driskill and McCafferty (Journal of Economic Theory, 49 (1989) 324–338).     

The incentives for takeover in oligopoly

We present a model of takeover where the target optimally sets its reserve price. Under relatively standard symmetry restrictions, we obtain a unique equilibrium. The probability of takeover is only a function of the number of firms and of the insiders' share of total industry gains due to the increase in concentration. Our main application is to the linear Cournot and Bertrand models. A takeover is more likely under Bertrand competition if goods are substitutes, and more likely under Cournot competition if goods are complements.     

Multiproduct activity in an experimental differentiated oligopoly

In a symmetric differentiated experimental oligopoly with multiproduct firms we test the predictive power of the corresponding Bertrand-Nash equilibria. Subjects are not informed on the specification of the underlying demand model. In the presence of intense multiproduct activity, and provided that a parallel pricing rule is imposed to multiproduct firms, strategies tend to confirm the non-cooperative multiproduct solution.     

Rational conjectures in the theory of oligopoly

The paper employs the notion of rational conjectural equilibrium to remove the arbitrary nature of conjectures about rivals' reactions which characterises the traditional non-cooperative theory of oligopoly. A general definition of these equilibria is given, and the concept is then applied to a simple duopoly model. The standard models of perfect competition, monopoly, limit-price dominant firms are shown to emerge as special cases of rational conjectural equilibria.     

The emerging oligopoly of pay-TV in the USA

The pay-television industry in the USA has been developing very rapidly in the past five years and is providing network quality alternatives to the mass taste programming of commercial television. However, the industry has been developing along lines very similar to the early history of radio in the USA with the emergence of strong distributor networks, restrictive affiliation contracts, and wide-spread vertical integration across all stages of production. History and economic efficiencies suggest that the result will be a strong oligopoly market structure. The proper public policy, then, is to insure that the unavoidable degree of concentration is not greater than that needed for efficiency reasons.     

Apparent collusion and conjectural variations in differentiated oligopoly

The conjectural variations model has become the standard exposition of oligopoly theory, although rivals' assumed behaviour is not profit-maximising. One response has been models with consistent conjectures, developed from rational expectations concepts. This paper adopts another approach, based on Stigler's famous (1964) paper. Collusion is enforced by the threat of retaliating to price cuts, but is imperfect because of their imperfect knowledge, which limits the probability of retaliation, or retaliation lags. Three models of imperfect collusion incorporating these features, separately and in combination, demonstrate the formal equivalence between the results of imperfectly policed collusion and proportional conjectural variations.     

Rationalizability and efficiency in an asymmetric Cournot oligopoly

This paper studies rationalizability in a linear asymmetric Cournot oligopoly with a unique Nash equilibrium. It shows that mergers favor uniqueness of the rationalizable outcome. When one requires uniqueness of the rationalizable outcome maximization of consumers' surplus may involve a symmetric oligopoly with few firms. We interpret uniqueness of the rationalizable outcome as favoring a dampening of strategic ‘coordination’ uncertainty. An illustration to the merger between Delta Air Lines and Northwest shows that a reallocation of 1% of market share from a small carrier to a larger one has implied a lower production volatility over time, yielding a 1.5% decrease in the coefficient of variation of number of passengers.     

Employment,technological diffusion and oligopoly

This paper takes a simple model of the diffusion process and analyses the employment implications. Two factors tending to make employment fall to a low point at some intermediate position along the diffusion path are identified. It is argued that the path of industry employment during diffusion will in general not be monotomic.     

An oligopoly model of ocean liner shipping

In this paper I develop a simultaneous equations oligopoly model of the regulated international ocean liner shipping industry. The firms act as a cartel to determine price jointly and then set their own quality levels to maximize individual profits. The cartel does not attain monopoly profits, because each conference member myopically determines quality without regard for overall cartel profits. The results indicate that an increase in the number of firms in the cartel will increase both cartel price and quality level. An increase in price will also lead to an increase in quality level.I would like to thank Professors Alamarin Phillips, Robert Summers, and Bruce Allen for their helpful comments on earlier research for my dissertation in the Economics Department of the University of Pennsylvania on which this work is based. I am especially grateful to Professor Lawrence J. White for his encouragement and valuable suggestions at various stages of my work.     

Distributional assumptions in the theory of oligopoly information exchange

We analyze the profitability of information sharing among Cournot oligopolists receiving private information about random demand. In this setting, previous authors showed information exchange to be unprofitable when firms' marginal costs are constant and outputs are perfect substitutes. We introduce a measure of the increase in the accuracy of firms' demand forecasts when information is shared. We provide two examples showing when this measure is large, information exchange is profitable, even though firms' marginal costs are constant and outputs are perfect substitutes. Moreover, we show that in the linear-conditional-expectations framework, which has been standard in the literature, this measure reveals these accuracy gains to be severely limited.     

Third-degree price discrimination in oligopoly with endogenous input costs

This paper examines the output effect of third-degree price discrimination in symmetrically differentiated oligopoly. We find that when the sellers’ input costs are chosen endogenously by an upstream supplier with market power, as opposed to being fixed exogenously, long-standing qualitative conclusions about the effect of price discrimination on aggregate output can be reversed. In contrast to previous findings (e.g., by Holmes, 1989), more intense competition in the strong market than in the weak market can make it less likely that price discrimination raises aggregate output. For linear demand functions, we establish necessary and sufficient conditions under which the output effect changes sign when input costs are endogenized.     

The measurement of conjectural variations in an oligopoly industry

Using independently derived estimates for the market demand elasticity and firm marginal cost, this paper measures the conjectural variations (cv's) of the eight largest U.S. steel firms for the years 1920 to 1972. Comparisons are then made between the measured cv's and those predicted by certain industry conduct hypotheses. Specifically the hypotheses are those for competitive behavior, Cournot behavior, imperfect collusion, and industry profit maximization (perfect collusion). One of the two extreme theories of firm behavior, industry profit maximization, is rejected, but the acceptance or rejection of the other theories depends on the assumptions made about the cost structure of the sample firms.     

Divisionalization and strategic managerial incentives in oligopoly under uncertainty

This paper argues that divisionalization and incentive contracting are complementary rent shifting tools in the presence of demand uncertainty. The role for divisionalization arises if managers know the state of demand prior to making output decisions and if incentive contracts are linear and non-state contingent. In this context incentive contracts achieve expected Stackelberg outcomes but have no impact on the firm's responsiveness to demand shocks. Divisionalization, on the other hand has the strategically beneficial effect of making the firm more responsive to demand shocks.     

Stackelberg versus Cournot oligopoly with private information

We compare an $n$-firm Cournot model with a Stackelberg model, where $n$-firms choose outputs sequentially, in a stochastic demand environment with private information. The expected total output, consumer surplus, and total surplus are lower, while expected price and total profits are higher in the Stackelberg perfect revealing equilibrium than in the Cournot equilibrium. These rankings are the opposite of the rankings of prices, total output, surplus, and profits under perfect information. We also show that the first $n-1$ firms’ expected profits form a decreasing sequence from the first to the $(n-1){}^{st}$ in the Stackelberg game. The last mover earns more expected profit than the first mover if $n\le 4,$ or the ratio of the signals’ informativeness to the prior certainty is sufficiently low. Lastly, there is a discontinuity between the Stackelberg equilibrium of the perfect information game and the limit of Stackelberg perfect revealing equilibria, as the noise of the demand information of firms vanishes to zero at the same rate. We provide various robustness checks for the results when the precision of signals are asymmetric, there is public information or cost/quality uncertainty, or the products are differentiated.     

Group purchasing, nonlinear tariffs, and oligopoly

Loyalty discounts are nonlinear tariffs that condition rebates or marginal prices on meeting aggregate purchase or market share targets. These discounts are widespread, and are often the impetus for consumers to form buying groups, or group purchase organizations (GPOs). This paper models the competitive effects of the introduction of a GPO into a market within which the preferences of the GPO's members are horizontally differentiated. While nonlinear tariffs are an effective way for a monopolist to extract consumer surplus, when two suppliers compete using such schedules, the results are far more competitive in comparison to simple Bertrand–Nash competition with linear tariffs. This result holds when the product of each of the suppliers is attractive to a substantial portion of consumers. In our model, the nonlinear schedule puts all customers “in play” to a degree that contrasts sharply with the competition at the margin characteristic of constant per unit prices. Moreover, competing in nonlinear tariffs removes allocative inefficiency that can result from single price competition.     

The competition effects of industry-wide vertical price fixing in bilateral oligopoly

This paper examines the competition and welfare effects of vertical price fixing through industry-wide resale price maintenance (RPM) arrangements, such as those benefiting from exemption from a general prohibition against RPM. A bilateral oligopoly framework is employed incorporating differentiation between manufacturer products and between retailer services. Transactions between the stages involve prices being determined through bargaining. We do not find RPM to be universally undesirable. However where retailer power is strong, the social effects of RPM are likely to be adverse, since the practice can assist in coordinating final price levels and prevent socially desirable countervailing power arising.     

Dynamic oligopoly pricing: Evidence from the airline industry

We explore how pricing dynamics in the European airline industry vary with the competitive environment and with customer heterogeneity. We document three main findings. First, the rate at which prices increase towards the scheduled departure date is significantly reduced in more competitive markets. Second, the sensitivity of the intertemporal slope to competition increases in the heterogeneity of the customer base. Third, ex-ante predictable advance purchase discounts account for 83 percent of within-flight dispersion in prices and for 17 percent of cross-market variation in pricing dynamics.     

The welfare effects of cooperative R&D in oligopoly with spillovers

This paper provides a more complete characterization of the welfare effects of cooperative cost-reducing R&D investments in Cournot oligopoly with spillovers. I show that R&D cooperation reduces both R&D spending and social surplus when the spillover rate in R&D is neither sufficiently high nor sufficiently low. As the elasticity of the slope of the inverse demand function increases, however, the set of spillover rates over which cooperative R&D reduces social welfare shrinks, and in the limit, cooperative R&D is socially beneficial for all spillover rates.     

A characterization for the negative welfare effects of cost reduction in Cournot oligopoly

This paper characterizes the welfare effects of cost reductions in a Cournot model with linear costs. Under linear demand, a small reduction in a firm’s marginal cost reduces welfare if and only if its market share is less than 1/(2n+2), or equivalently, its marginal cost exceeds a critical level determined by the market. A large cost reduction by the firm increases welfare if and only if its magnitude is at least twice the difference between the current marginal cost and its critical value. The paper also extends the results to non-linear demand, but the characterizations become less tractable.