Rationing rule, imperfect information and equilibrium

Summary. The impact of imperfect information on the price setting behaviour of firms is analysed. Specifically, consumers support an information cost to become informed about prices. Firms are endowed with U-shaped average cost curves. If a firm does not supply more than its competitive supply as determined by its marginal cost schedule, then we show that the existence of a pure strategy equilibrium is conditional on the rationing rule employed. If uninformed consumers are served first then the monopoly price is the sole equilibrium whenever consumers' information costs are high enough. Otherwise, a pure strategy equilibrium fails to exist contrary to the results of Salop and Stiglitz (1977) or Braverman (1980) who implicitly suppose that firms supply all the demand at a given price. Received: May 17, 1999; revised version: September 15, 2000     

Can a decline in search cost increase prices?

This paper provides a new explanation of why a decline in consumers’ price search cost may not lead to lower prices. In a duopoly with price competition, I show that when some consumers are captive to one firm, there may be a non‐monotonic relationship between search cost and market power; firms may charge high prices with higher probability and the average price charged may be higher when consumers’ price search cost falls below a critical level. Furthermore, when firms have asymmetric captive segments, expected prices charged by each firm may move in opposite directions as search cost declines.     

Costly Search, Capacity Constraints, and Bertrand Equilibrium Price Dispersion

This article analyzes the impact of transaction (search) costs and capacity constraints in an almost competitive market with homogeneous firms that compete on price. We characterize conditions under which Nash equilibria with price dispersion exist; in equilibrium, firms play pure strategies in prices and consumers adopt a symmetric mixed search strategy. Price dispersion is possible even though consumers all have the same search cost and valuation for the item and prices charged by all firms are common knowledge.     

Salience and horizontal differentiation

I study a horizontal differentiation model in which one of two attributes of a product, product fit and price, is more salient for a consumer than the other and different consumers can find a different attribute salient. The attribute that is more salient is determined by relative differences between the two products and is determined endogenously as a result of firms' pricing strategies. High (low) marginal costs soften (toughen) price competition between firms. Pass-through rates are greater than 1 for some parameter values. Both industry- and firm-level cost increases may be beneficial for firms.     

Influence of market-level and inter-firm differences in costs on product positioning and pricing

The objective of this article is to study the impact of differentiation and firm positioning on firm’s pricing decisions in a horizontally differentiated competitive market. We build a parsimonious game-theoretic model and analyse simultaneous entry of firms. The effect of differentiation is modelled as an additional cost incurred by both firms based on the degree of differentiation between the firms. The cost of positioning is modelled as a market level cost affecting both firms whereby firms incur a cost if they want to position themselves away from the centre of distribution of consumers. Our analysis provides some surprising results, explains some conflicting empirical observations documented in previous research and may also be useful for further empirical research in this area by providing sharper predictions about the impact of various types of costs on market outcomes. For example, we find that if the cost of positioning is sufficiently high, then a firm with lower cost of differentiation charges a higher price in equilibrium, even when no differences in exogenous costs exist. We also find that under some circumstances the cost disadvantaged firm can enjoy higher price-cost margins compared to the cost leader thereby suggesting that higher costs could be a blessing in disguise.     

Credence Goods,Misleading Labels,and Quality Differentiation

Due to differences in information disclosure mechanisms, consumer misinformation about the quality of many credence goods is more endemic at intermediate levels of the quality spectrum rather than at the extremes. Using an oligopoly model of vertical product differentiation, we examine how consumers’ overestimation of the quality of intermediate-quality products affects firms’ incentives to improve product quality. The firms non-cooperatively choose the quality of their product before choosing its price or quantity. Irrespective of the nature of second stage competition, Bertrand or Cournot, we find that quality overestimation by consumers increases profit of the intermediate-quality firm, and motivates it to raise its product’s quality. In response, the high-quality firm improves its product quality even further but ends up with lower profit. Overall, average quality of the vertically differentiated product improves, which raises consumer surplus. Social welfare increases when the firms compete in prices but falls when they compete in quantities.     

A laboratory study of advertising and price competition

We use a laboratory experiment to study advertising and pricing behavior in a market where consumers differ in price sensitivity. Equilibrium in this market entails variation in the number of firms advertising and price dispersion in advertised prices. We vary the cost to advertise as well as varying the number of competing firms. Theory predicts that advertising costs act as a facilitating device: higher costs increase firm profits at the expense of consumers. We find that higher advertising costs decrease demand for advertising and raise advertised prices, as predicted. Further, this comes at the expense of consumers. However, advertising strategies are more aggressive than theory predicts with the result that firm profits do not increase.     

Market share dynamics in a duopoly model with word-of-mouth communication

We analyze dynamic price competition in a homogeneous goods duopoly, where consumers exchange information via word-of-mouth communication. A fraction of consumers, who do not learn any new information, remain locked-in at their previous supplier in each period. We analyze Markov perfect equilibria in which firms use mixed pricing strategies. Market share dynamics are driven by the endogenous price dispersion. Depending on the parameters, we obtain different ‘classes’ of dynamics. When firms are impatient, there is a tendency towards equal market shares. When firms are patient, there are extended intervals of market dominance, interrupted by sudden changes in the leadership position.     

Horizontal mergers and product quality

We study the effects of a horizontal merger when firms compete on price and quality. In a Salop framework with three symmetric firms, several striking results appear. First, the merging firms reduce quality but possibly also price, whereas the outside firm increases both price and quality. As a result, the average price in the market increases, but also the average quality. Second, the outside firm benefits more than the merging firms from the merger, and the merger can be unprofitable for the merger partners, i.e., the “merger paradox” may appear. Third, the merger always reduces total consumer utility (though some consumers may benefit), but total welfare can increase due to endogenous quality cost savings. In a generalized framework with n firms, we identify two key factors for the merger effects: (i) the magnitude of marginal variable quality costs, which determines the nature of strategic interaction and (ii) the cross‐quality and cross‐price demand effects, which determines the intensity of price relative to quality competition. These findings have implications for antitrust policy in industries where quality is a key strategic variable for the firms.     

Costly horizontal differentiation

We study the effect of quadratic differentiation costs in the Hotelling model of endogenous product differentiation. The equilibrium location choices are found to depend on the magnitude of the differentiation costs (relatively to the transportation costs supported by consumers). When the differentiation costs are low, there is maximum differentiation. When they are high, there is partial differentiation, with a degree of differentiation that decreases with the differentiation costs. In any case, the socially optimal degree of differentiation is always lower than the equilibrium level. We also study the case of collusion between firms. If firms can combine locations but not prices, they locate asymmetrically when differentiation costs are high and choose maximum differentiation when they are low. When collusion extends to price setting, there is partial differentiation.     

ENTRY AND QUALITY SIGNALLING WHEN ONLY SOME CONSUMERS ARE INFORMED OF THE ENTRANT'S QUALITY

This paper focuses on competition between an incumbent and an entrant when only the entrant's quality is unknown to (some) consumers. The incumbent may or may not know the entrant's quality. The model reveals a separating equilibrium where the entrant's high price signals its high quality when the proportion of informed consumers is at some intermediate value. The case in which the incumbent knows the entrant's quality generates two additional equilibria. When the proportion of informed consumers is large enough, firms choose their prices as in the complete information case. The entrant's high price in combination with the incumbent's low price signals the entrant's high quality. When the proportion of informed consumers is at some intermediate value, the incumbent's high price signals the entrant's low quality, while its low price signals the entrant's high quality. Interestingly, we find that entry may be facilitated with informational product differentiation.     

Informative advertising by heterogeneous firms

This paper introduces a model to analyze the role of the cost of information dissemination in large markets where firms have varying degrees of intrinsic efficiency reflected in their marginal costs. Firms enter a market and discover how efficient they are. Those firms with high enough efficiency stay, others exit. Remaining firms then compete to attract consumers by disseminating information about their existence and their prices using a common advertising technology. The properties of the model’s equilibrium are analyzed. The model is then used to study the effect of the cost of information dissemination on the competitiveness of the market and key industry aggregates, such as price distribution and the distribution of firm value.     

ASYMMETRIC INFORMATION AND EXCHANGE OF INFORMATION ABOUT PRODUCT DIFFERENTIATION

We introduce asymmetric information about consumers’ transportation costs (i.e., the degree of product differentiation) in the model of Hotelling. When transportation costs are high, both firms have lower profits with asymmetric information than with perfect information. Contrarily, if transportation costs are low, both firms may prefer the asymmetric information scenario (the informed firm always prefers the informational advantage, while the uninformed firm may or may not prefer to remain uninformed). Information exchange is ex‐ante advantageous for both firms, but ex‐post damaging if transportation costs turn out to be low. If the information is unverifiable, the informed firm does not represent a reliable source of information, since it always prefers to announce that transportation costs are high and there is no contract that induces truthful revelation.     

QUANTITY VERSUS PRICE IN A HOMOGENEOUS PRODUCT DUOPOLY*

In a simple homogeneous product setting, the paper looks at the debate on whether firms should choose quantity or price as their strategic variable. It examines a two-stage game between firms with symmetric costs in which the firms choose the strategic mode of operation in the first period and then, in the second period, price or output are chosen simultaneously according to the mode chosen in the first stage. In this game it is possible to have two Nash equilibria where either both play in quantities or both play in prices. One firm choosing price and the other quantity can never be a Nash equilibrium in the two-stage game. Both choosing quantity is always a Nash equilibrium. Both choosing prices may be a Nash equilibrium only in some situations: the structure of the cost functions decides this issue.     

Consumer flexibility,data quality and location choice

We analyze firms’ location choices in a Hotelling model with two-dimensional consumer heterogeneity, along addresses and transport cost parameters (flexibility). Firms can price discriminate based on perfect data on consumer addresses and (possibly) imperfect data on consumer flexibility. We show that firms’ location choices depend on how strongly consumers differ in flexibility. Precisely, when consumers are relatively homogeneous, equilibrium locations are socially optimal regardless of the quality of customer flexibility data. However, when consumers are relatively differentiated, firms make socially optimal location choices only when customer flexibility data becomes perfect. These results are driven by the optimal strategy of a firm on its turf, monopolization or market-sharing, which in turn depends on consumer heterogeneity in flexibility. Our analysis is motivated by the availability of customer data, which allows firms to practice third-degree price discrimination based on both consumer characteristics relevant in spatial competition, addresses and transport cost parameters.     

Stakeholders’ relationships and product market competition

In this article, we study the relationships between main stakeholders (shareholders, consumers and employees) when firms are consumer oriented (CO) in the sense of caring about consumers’ interests in the objective function. We let these firms first bargain with labour union over their employees’ wages and then compete either in the quantity space (Cournot competition) or in the price space (Bertrand competition). Our model shows that taking care of the consumers’ interests when determining product market strategies may reverse the traditional ranking between Cournot and Bertrand equilibria. This implies that if shareholders in a CO firm can choose either a quantity or a price strategy, they will surprisingly choose the latter. Moreover, we show that the conflicting interests between main stakeholders are attenuated under Bertrand competition compared to Cournot competition.     

Information Provision by Interest Groups

We investigate interest groups’ incentives to inform consumers about the damaging practices of firms and the impact such an IG has on firms’ technology choices. The IG aims to reduce the production of some bad, say pollution. It can at a cost investigate firms’ production practices and inform consumers about its findings. Since consumers care about the environment, revealing differences in pollution levels between firms leads to vertical product differentiation. The information, by shifting sales from ‘dirty’ towards ‘clean’ firms, reduces pollution. We show that the IG is most inclined to investigate firms in relatively competitive industries and that the threat of being unmasked as a polluter prompts dirty firms to adopt a clean technology.     

Geographical separation of oligopolists can be very competitive

A given number of single, differentiated product oligopolists locate in one of two separate market-places, which consumers access at a cost. Firms set prices and the CES consumers choose purchases at one or both market-places. Firm agglomeration in one market-place produces positive profits because of product differentiation. But if consumer access costs are homogeneous and products are sufficiently good substitutes, geographical separation of firms produces prices analogous to homogeneous product Bertrand, and is “very competitive”, the reverse of textbook Hotelling. Hence a novel explanation emerges for the geographical agglomeration of firms producing very similar products.     

Markups,quality, and transport costs

This paper provides new evidence on trade prices based on firm-level data from France. It shows that firms charge higher free-on-board (net of transportation costs, hereafter noted as fob) unit values on exports to more distant countries. This finding holds within firms and products, and across destinations. The price premium paid by distant consumers is due to firms charging higher fob prices, and to higher transportation costs. A simple decomposition of the elasticity of import prices to distance shows that, after a fall in transport costs, almost 80% of the decline in import prices enjoyed by consumers is due to firms charging lower fob prices. This suggests a new channel through which changes in transport costs may affect welfare.     

SERVICE QUALITY IN REGULATED NETWORK INDUSTRIES

ABSTRACT ** : Economic regulators provide incentives for good quality of service as well as constraints on the prices or revenue which can be charged by firms with monopoly power. Economic theory suggests that regulators should choose standards according to consumers' valuation and the marginal cost of quality improvements, and that firms respond by equalizing the marginal costs from not making improvements (i.e. the regulatory penalty plus any loss in revenue) with the marginal costs of improvement. This paper explores the evidence for such economically rational behaviour by both regulators and regulatees. We use a specially constructed data set on service quality targets and achievements across the main UK utility sectors; documentary evidence from regulators; and interviews with managers in companies subject to those regulators. We conclude that regulators are motivated by political as well as economic factors. And that companies may not respond primarily to the regulator's financial rewards or penalties for their quality targets, with a consequent danger that regulated consumers pay for marketing in unregulated markets; the resulting level of service quality may be ‘too high’ in the economic sense.