Collusion Under Imperfect Monitoring with Asymmetric Firms

We explore the effects of asymmetries in capacity constraints on collusion where market demand is uncertain and where firms’ sales and prices are private information. We show that all firms can infer when at least one firm's sales are below some firm‐specific ‘trigger level.’ When firms use this public information to monitor the collusive agreement, price wars may occur on the equilibrium path. Symmetry facilitates collusion but, if price wars are sufficiently long, then the optimal collusive prices of symmetric capacity distributions are lower on average than the competitive prices of asymmetric capacity distributions. We draw conclusions for merger policy.     

Collusion and leadership

The paper explores the role of price or quantity leadership in facilitating collusion. It extends the standard analysis of tacit collusion by allowing firms to make their strategic choices either simultaneously or sequentially. It is shown that price leadership indeed facilitates collusion by making it easier to punish deviations by the leader. In case of pure Bertrand competition, price leadership restores the scope for (perfect) collusion in markets where collusion would not be sustainable otherwise. When firms face asymmetric costs or offer differentiated products, price leadership can also enhance the profitability of collusion—in case of asymmetric costs, the less efficient firm must act as the leader. Finally, such leadership is less effective in case of Cournot competition since, following an aggressive deviation by the leader, the follower would rather limit its own output, making it more difficult to punish the deviation. Still, quantity leadership may enhance collusion when it is already somewhat effective in a simultaneous move setting.     

Evidence of directional price discrimination in the U.S. airline industry

This paper explores possible determinants that may affect an airline’s decision to charge passengers different roundtrip fares depending on trip origin, a case of directional price discrimination. Such fare differences cannot be the result of differences in cost, as the cost of flying a roundtrip passenger does not significantly differ depending on direction. It is argued that directional fare differences result from airlines recognizing that passenger price elasticities differ between route endpoints. A price discriminating airline will then charge a higher roundtrip fare at the endpoint where the passenger price elasticity of demand is comparatively lower. Evidence is found suggesting that airlines do use differences in income to price discriminate when setting roundtrip fares. Fares are found to be $0.18-$0.43 higher on average for each $1000 difference in average per capita income between origin and destination metro areas. This finding is sensible assuming that higher incomes reduce the price elasticity of demand for air travel, with richer passengers being less sensitive to the cost of travel.     

Sustaining Collusion Via a Fuzzy Trigger

Probability theory is the standard economic representation of uncertainty, although it is not always an accurate one. Fuzzy logic is an alternative representation that does not require individual beliefs regarding the explicit functional form of uncertainty. This paper applies fuzzy logic to an oligopoly trigger pricing game. The fuzzy trigger pricing game reverses the standard cyclical price war prediction; collusion-sustaining price wars are most likely to occur during times of high demand. The fuzzy model also predicts that markets with relatively volatile prices are more likely to undergo collusion-sustaining price wars. The predictions are consistent with available empirical evidence.     

Price Wars and the Stability of Collusion: A Study of the Pre-World War I Bromine Industry

Between 1885 and 1914 US bromine producers colluded to raise prices and profits. This collusion was disrupted by price wars. Bromine price wars are compared with Green/Porter and Abreu/Pearce/Stacchetti models. Some price wars resulted from the imperfect monitoring problems which motivate these models. Several empirical implications of the APS model are borne out, but the bromine industry's price wars were generally milder than contemplated by APS. More severe price wars were part of a bargaining process, in which firms tried to force renegotiation to a new collusive equilibrium with a different distribution of rents.     

国有企业主导与行政性垄断下的价格合谋——“京沪空中快线”引发的若干思考

本文基于民航产业的价格同盟进行的模型分析和经验研究，在一定程度上解释了行政垄断和企业间合谋的关系。研究发现，在规制缺失或默许的条件下．包含惩罚方式的价格合谋是一个可行和可实施的机制安排，而寡头垄断和行政垄断的结合是诱发规制者干预价格竞争，最终形成所谓“价格同盟”的结构和制度条件。规制者和垄断国有企业关系的交织和错位下的反竞争行为，是未来《反垄断法》实施的主要障碍。     

Low-cost airlines and online price dispersion

This paper presents a new form of online pricing tactic where airlines post, at the same time and for the same flight, fares in different currencies that violate the Law of One Price. Unexpectedly for an online market, price dispersion may be accompanied by a hidden discount that tends to persist in the period preceding a flight's departure. The econometric analysis reveals that airlines post dispersive fares in less competitive routes with more heterogeneous demand. Furthermore, temporal persistence of intra-firm fare dispersion suggests that it is an equilibrium phenomenon engendered by the airlines' need to manage stochastic demand conditions for a specific flight.     

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.     

Multi-market collusion with territorial allocation

We develop a supergame model of collusion between price-setting oligopolists located in different markets separated by trade costs. The firms produce a homogeneous good and sustain collusion based on territorial allocation of markets. We first show, in a much more general framework than some earlier literature, that a reduction in trade costs can paradoxically increase the sustainability of collusion. Then we prove a new paradox in which the scope for collusion may be enhanced by an increase in the number of firms. The paper thus highlights several hitherto unknown theoretical implications of collusion under price competition.     

Publication of Information and Market Response: The Case of Airline on Time Performance Reports

This paper investigates market response to publication of on time performance information. Theory suggests that reduction in search costs generates more honest airlines and better quality service, a distribution of price-quality bundles, increased demand, exit by inefficient airlines and reduction of price rigidity. An ARIMA study of U.S. domestic airline operations finds that after publication of performance information the market generated better performance, increased quality distribution, enhanced demand, exit by four of fourteen airlines and reduced price-quality rigidity. Publication of information may improve performance in markets characterized by asymmetric information and high search costs.     

Competition Among Middlemen When Buyers and Sellers Can Trade Directly

This paper examines competition among middlemen when sellers and buyers can trade directly. Direct trade alters the supply and demand facing the middlemen, making them interdependent, and reduces the market power of intermediaries. However, it does not alter the Stahl [1988] result that middlemen may have an incentive to “corner” the market if demand is inelastic. The model is applied to market making in financial markets, vertical integration in goods markets and to the question of bypass in utilities. This discussion suggests that cornering is most likely in markets for essential inputs and that it may enable seller collusion.     

The Effect of Explicit Communication on pricing: Evidence from the Collapse of a Gasoline Cartel

We study the collapse of collusion in Québec's retail gasoline market following a Competition Bureau investigation, and show that it involved two empirical regularities: high margins, and asymmetric price adjustments. Using weekly, station‐level prices we test whether collusion was successful, and whether asymmetric adjustments were part of the cartel's strategy. We do so in the markets targeted by the investigation, and in markets throughout the province with similar pre‐collapse pricing (cyclical markets). Our results suggest that stations in both target and cyclical markets adjusted pricing following the announcement: margins fell (by 30%/15% in target/cyclical markets), and adjustments became more symmetric.     

The economics of international codesharing: an analysis of airline alliances

International airline alliances allow airlines to coordinate their operations in providing international service. This paper analyzes the effect of such alliances on traffic levels, fares, and welfare. In the model, the benefits of alliances arise because cooperative pricing of trips by the partners puts downward pressure on fares in the interline city-pair markets (these are markets where travel on both carriers is necessary). The loss of competition in the interhub market, which connects the hub cites of the partners, generates a countervailing effect, tending to raise the fare in that market. While the presence of economies of traffic density complicates these impacts by generating cost links across markets, simulation analysis shows that the above tendencies typically prevail. Welfare analysis shows that both consumer and total surplus typically rise following formation of an alliance despite the harm to interhub passengers, suggesting that the positive effects of alliances may outweigh any negative impacts.     

What difference does dynamics make? The case of digital cameras

When the well-known BLP model is applied to products with rapid technological changes and declining prices it tends to yield implausible results. A sequence of increasingly sophisticated dynamic demand models, most recently Gowrisankaran and Rysman (2009, hereafter GR), have been developed to overcome these problems. We apply both models to new data on the US digital camera market. In addition, we demonstrate that the GR model can be specified as a BLP model plus an additional set of terms. This suggests that a dynamic model can be estimated as a BLP model plus a non-parametric function which is less computationally demanding. As a first step to implementing this semi-parametric approach we estimate a BLP model augmented with age as a proxy for the non-parametric component. We find that demand for digital cameras is more elastic when demand dynamics is accounted for in both the dynamic model and the BLP model with the age proxy. This suggests that the market is more competitive though the results are consistent with firms engaging in intertemporal price discrimination. Merger simulations predict the lowest price and quantity changes using the GR model.     

Cartel sustainability in retail markets: Evidence from a health service sector

This paper studies the role of cost asymmetries and product differentiation on cartel sustainability by drawing data from a failed retail cartel. Unlike the extensive theoretical literature, little empirical evidence exists on these relationships. First, we analyze cartel compliance and find that players are more likely to comply when cost is symmetric and own cost is high. Next, based on a structural model and counterfactual experiments, we show that a cartel price that satisfies all cartel members does not exist. This result indicates an inherent difficulty of sustaining collusion in retail markets with heterogeneous players. We also show that firm heterogeneities, especially product differentiation rather than cost asymmetries, hinder collusion more. Finally, we derive the level of patience (or the discount factor) required for cartel sustainability when firms split profits based on the Shapley value.     

Tacit collusion, firm asymmetries and numbers: Evidence from EC merger cases

This paper estimates the implicit model, especially the roles of size asymmetries and firm numbers, used by the European Commission to identify mergers with coordinated effects. This subset of cases offers an opportunity to shed empirical light on the conditions where a Competition Authority believes tacit collusion is most likely to arise. We find that, for the Commission, tacit collusion is a rare phenomenon, largely confined to markets of two, more or less symmetric, players. This is consistent with recent experimental literature, but contrasts with the facts on ‘hard-core’ collusion in which firm numbers and asymmetries are often much larger.     

COLLUSION AND FIGHTS IN AN EXPERIMENT WITH PRICE‐SETTING FIRMS AND ADVANCE PRODUCTION*

We present results from 50‐round duopoly and triopoly experiments. Firms decide repeatedly both on price and quantity of a perishable good. Each firm has capacity to serve the whole market. The stage game does not have an equilibrium in pure strategies. Most markets evolve either to monopolies as a consequence of bankruptcies or to collusion at the monopolistic price. Evolution is faster in markets with two than in those with three firms. Therefore, over time average price is lower with three than with two. Consumer surplus is higher with three firms, but efficiency is lower in markets with three firms.     

INPUT PRICE DISCRIMINATION WHEN BUYERS OPERATE IN MULTIPLE MARKETS*

This paper revisits third‐degree price discrimination when input buyers serve multiple product markets. Such circumstances are prevalent since buyers often use the same input to produce different outputs, and even homogenous outputs are routinely sold through different locations. The typical view is that price discrimination stifles efficiency (and welfare) by resulting in price concessions to less efficient firms. When buyers serve multiple markets, price discrimination leads to price breaks for firms in markets with lower demand. When lower demand markets also have less competition, price discrimination can provide welfare gains by shifting output to less competitive markets.     

The component procurement problem for the loss-averse manufacturer with spot purchase

This paper studies the purchasing behaviour of a loss-averse engineer-to-order manufacturer, who purchases a key component for his final product from a supplier under a single-wholesale-price contract with spot purchase opportunities, where both the product demand and the component spot price are uncertain. Through newsvendor type of models, we analyze several key issues, including the effects of the manufacturer's loss aversion, and the effects of demand and spot price uncertainties on the manufacturer's decision behaviour. We find that the purchasing behaviour of the loss-averse manufacturer differs from those of the risk-neutral and risk-averse ones. Specifically, we identify some sufficient conditions under which the loss-averse manufacturer may purchase a larger order quantity in advance when demand becomes more uncertain or when the price becomes more uncertain. We also discuss the two-wholesale-price contract and show that fixing the emergency supply price may lead to a smaller order quantity.     

ALTERNATING MONOPOLY AND TACIT COLLUSION*

This paper considers the use of the alternating monopoly strategy (AMS) as a (tacit) collusion device. We show that firms may choose this strategy in particular environments, when other collusive strategies are also feasible. In particular, we stress how the presence of an observable move (entry), distinct from the competitive stage (price setting), can serve as a coordination device, reducing monitoring costs in incomplete information environments. The paper thus shows that AMS may be preferable to the classic market sharing strategy (MSS) and in some cases it is the only collusive equilibrium.