contracts as a barrier to entry it is shown that an incumbent seller who faces a threat of entry into his or her market will sign long term contracts that prevent the entry of some lower cost producers even though they do not preclude entry completely moreover when a seller possesses superior information about the likelihood of entry it is shown that the length of the contract may act as a signal of the true probability of entry

effects of information revelation policies under market structure uncertainty geographically dispersed sellers in electronic reverse marketplaces such as those hosted by market makers like ariba are uncertain about the number of competitors they face in any given market session we refer to this uncertainty about the number of competitors as market structure uncertainty over the course of several market sessions sellers learn about the competitive nature of the marketplace how they learn to reduce the market structure uncertainty depends on the market transparency scheme or the revelation policy adopted a revelation policy determines the extent to which information the number of sellers in a session their bidding patterns etc is revealed to sellers because these policies control what sellers learn and how they bid in future sessions they determine buyer surplus possibly because market structure uncertainty is more prevalent in information technology enabled marketplaces than traditional ones prior work has not addressed the impact of revelation policies on this type of uncertainty currently there is little guidance available to buyers in choosing the appropriate revelation policy to address this information technology enabled problem we use game theory to compare the buyer surplus generated under a set of revelation policies commonly used in electronic reverse marketplaces we demonstrate that the policy that generates the least amount of market structure uncertainty for the sellers always maximizes buyer surplus we further investigate to provide intuition regarding how bidders reactions to overcome uncertainty differs with the nature of uncertainty and how those reactions impact buyer surplus

bundling equilibrium in combinatorial auctions this paper analyzes ex post equilibria in the vcg combinatorial auctions if is a family of bundles of goods the organizer may restrict the bundles on which the participants submit bids and the bundles allocated to them to be in t he vcg combinatorial auctions obtained in this way are known to be truth telling mechanisms in contrast this paper deals with non restricted vcg auctions in which the buyers choose strategies that involve bidding only on bundles in and these strategies form an equilibrium we fully characterize those that induce an equilibrium in every vcg auction and we refer to the associated equilibrium as a bundling equilibrium the main motivation for studying all these equilibria and not just the domination equilibrium is that they afford a reduction of the communication complexity we analyze the tradeoff between communication complexity and economic efficiency of bundling equilibrium

mean field equilibria of dynamic auctions with learning we study learning in a dynamic setting where identical copies of a good are sold over time through a sequence of second price auctions each agent in the market has an unknown independent private valuation that determines the distribution of the reward she obtains from the good for example in sponsored search settings advertisers may initially be unsure of the value of a click though the induced dynamic game is complex we simplify analysis of the market using an approximation methodology known as mean field equilibrium mfe the methodology assumes that agents optimize only with respect to long run average estimates of the distribution of other players bids we show a remarkable fact in a mean field equilibrium the agent has an optimal strategy where she bids truthfully according to a conjoint valuation the conjoint valuation is the sum of her current expected valuation together with an overbid amount that is exactly the expected marginal benefit of one additional observation about her true pri

common marketing agency as a device for facilitating collusion in a variety of markets firms voluntarily and independently delegate control over certain aspects of marketing to common agents in this article we present an explicit model of agency delegation where firms noncooperatively select agents name output prices and choose compensation schemes we exhibit an equilibrium in which all strategic variables not merely the marketing choices delegated to agents but prices as well are selected perfectly cooperatively this cooperative equilibrium is very simple and attractive each firm sets the collusive output price and employs a commission scheme to compensate the agent although each

the declining price anomaly abstract data from wine auctions indicate that identical products sold sequentially typically follow a decreasing pattern of prices known as the declining price anomaly this is explained for both first and second price auctions by appealing to risk averse bidders earlier bids are then equal to expected later prices plus a risk premium associated with the risky future price we show that this logic rests on the assumption of nondecreasing absolute risk aversion which is necessary for pure strategy equilibrium bidding functions to exist thus decreasing absolute risk aversion implies ex post inefficiency with positive probability data from wine auctions are used to confirm the existence of the declining price anomaly journal of economic literature classification numbers d43 d44 d81 d82 l81

auctions an introduction abstract this is a detailed introduction to auction theory it begins with a simple analysis of standard auctions and then uses a strikingly simple general solution of symmetric private values auctions to prove the payoff equivalence of many auction rules the basic framework is then modified to admit risk aversion multi unit and repeated auctions as well as collusion then follows an introduction to optimal auctions with and without stochastic entry and to common value auctions and the winner s curse problem the survey closes with a sample of applications from the regulation of natural monopolies to price competition in oligopoly and the government securities market

intergenerational mobility a comparative study between turkey and the united states abstract i examine the degree of intergenerational mobility in turkey through the effect of parental education on economic welfare parental education is important for the quantity of education received but has no further impact on economic well being turkish intergenerational mobility is less than in the united states particularly for women

a learning approach to auctions we analyze a repeated first price auction in which the types of the players are determined before the first round it is proved that if every player is using either a belief based learning scheme with bounded recall or a generalized fictitious play learning scheme then for sufficiently large time the players bids are in equilibrium in the one shot auction in which the types are commonly known

fictitious play property for games with identical interests abstract ann person game has identical interests if it is best response equivalent in mixed strategies to a game with identical payoff functions it is proved that every such game has the fictitious play property journal of economic literatureclassification numbers c72 c73

how auctions work for wine and art interview auctioneers and even to buy a little wine in the meantime i have also had the opportunity with john abowd 1988 to observe and collect data on the auction sale of impressionist and contemporary paintings this paper reports on some of the empirical regularities that i and others have observed in the actual operation of the auction markets for these items in view of the rich and diverse array of theoretical literature on auctions it seems high time economists began to spell out precisely what facts it is meant to explain 2

rebates as incentives to exclusivity we show how rebates or fidelity discounts that take the form of lump sum payments made to retailers can be used by an incumbent manufacturer to achieve exclusivity and to deter the entry of a more efficient rival the results which hold whatever the degree of differentiation between retailers and whatever the cost advantage of the entrant are found despite minimizing asymmetries that may favour the incumbent as such there is no need to introduce buyers disorganization discriminatory offers economies of scale non coincident markets or liquidated damages to find that exclusivity can lead to anti competitive effects

naked exclusion efficient breach and downstream competition previous papers by eric b rasmusen j mark ramseyer and john s wiley jr 1991 and ilya r segal and michael d whinston 2000 argue that exclusive contracts can inefficiently deter entry in the presence of scale economies and multiple buyers we first show that these results no longer hold when buyers are final consumers who can breach these contracts and pay expectation damages we then show however that exclusive contracts can inefficiently deter entry if buyers are downstream competitors even in the absence of scale economies and even if breach is possible

observable contracts strategic delegation and cooperation the role of commitments in noncooperative games is well acknowledged and documented one way to achieve commitments is by letting delegates represent the players of a game in this paper the authors study a delegation game in which the players can use agents strategically to play on their behalf and the contracts they sign with them are common knowledge they show that in such cases every pareto optimal outcome of the game can become the unique subgame perfect nash equilibrium of the delegation game the authors demonstrate this result by discussing the cournot type duopolistic game copyright 1991 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

exclusive dealing and entry when buyers compete rasmusen et al 1991 and segal and whinston 2000 show that an incumbent monopolist might prevent entry of a more efficient competitor by exploiting externalities among buyers we show that their results hold only when downstream competition among buyers is weak under fierce downstream competition if entry took place a free buyer would become more competitive and increase its output and profits at the expense of buyers that sign an exclusive deal with the incumbent anticipating that orders from a single buyer would trigger entry no buyer will sign the exclusive deal and entry will occur this result is robust across different specifications of the game jel k21 l12 l42

do slotting allowances harm retail competition slotting allowances are fees paid by manufacturers to get access to retailers shelf space both in the usa and europe the use of slotting allowances has attracted attention in the general press as well as among policy makers and economists one school of thought claims that slotting allowances are efficiency enhancing while another school of thought maintains that slotting allowances are used in an anti competitive manner in this paper we argue that this controversy is partially caused by inadequate assumptions of how the retail market is structured and organized using a formal model we show that there are good reasons to expect anti competitive effects of slotting allowances we further point out that competi tion authorities tend to use an unsatisfactory basis for comparison when analyzing welfare consequences of slotting allowances

mechanism design by competing sellers a dynamic model with many sellers and buyers is constructed agents failing to trade may trade in the next period an equilibrium is found where sellers hold identical auctions and buyers randomize over the sellers they visit the distribution of buyer valuations is endogenous an auction with efficient reserve is an optimal mechanism from each seller s point of view in spite of the ability of any seller to alter the distribution of buyer types participating in the seller s mechanism by altering the mechanism copyright 1993 by the econometric society

learning in games with strategic complementarities revisited fictitious play is a classical learning process for games and games with strategic complementarities are an important class including many economic applications knowledge about convergence properties of fictitious play in this class of games is scarce however beyond games with a unique equilibrium global convergence has only been claimed for games with diminishing returns v krishna learning in games with strategic complementarities hbs working paper 92 073 harvard university 1992 this result remained unpublished and it relies on a specific tie breaking rule here we prove an extension of it by showing that the ordinal version of strategic complementarities suffices the proof does not rely on tie breaking rules and provides some intuition for the result

intergenerational education mobility and the level of development abstract the main goal of this paper is to analyze the empirical relationship between economic development and intergenerational education mobility by exploiting large regional variation in the level of economic development across turkey we find that educational outcomes of daughters who grow up in more developed regions depend less on their parents educational outcomes we do not find evidence for a similar relationship between development and mobility for males moreover the development level of place of residence during childhood has a stronger positive association with intergenerational education mobility compared to the development level of place of residence during adolesence we find that regions that feature higher school availability greater level of social capital more favorable cultural attitudes toward women higher level of home resources and lower degree of educational inequalities also tend to feature higher degree of intergenerational mobility

iterative computation of cournot equilibrium abstract in a homogeneous coumot model with quasi concave profit functions the problem of determining an equilibrium can be posed as one of solving an equation in one real variable total sales if the response functions are monotone or firms are identical then a certain iterative process based on averaging converges to an equilibrium such iterations have the interpretation that every firm responds to the average of sales by other firms in brevious periods

exclusion via non exclusive contracts we establish that non linear vertical contracts can allow an incumbent to exclude an upstream rival in a setting that does not rely on the exclusivity of the incumbent s contracts with downstream firms or any limits on distribution channels available to the incumbent or rival the optimal contract we describe is a three part quantity discounting contract that involves the payment of an allowance to a downstream distributor and a marginal wholesale price below the incumbent s marginal cost for sufficiently large quantities the optimal contract is robust to allowing parties to renegotiate contracts in case of entry l exclusion par le biais des contrats non exclusifs nous etablissons que des contrats verticaux non lineaires peuvent permettre a un titulaire d exclure un rival en amont dans un cadre qui ne de pend pas de l exclusivite des contrats du titulaire avec les entreprises en aval ou des limites sur les canaux de distribution disponibles pour le titulaire ou un rival le contrat optimal que nous decrivons est un contrat de rabais en trois parties base sur la quantite pre voyant le versement d une indemnite a un distributeur en aval et un prix de gros marginal inferieur au cout marginal de l operateur historique pour des quantites suffisamment importantes le contrat optimal est robuste si on permet aux parties de renegocier les contrats en cas d entree

reputation in repeated second price auctions abstract a model in which two bidders take part in a series of second price comon value auctions is examined the question of an optimal auction from an auctioneer s standpoint in a repeated auction setting is partially addressed it is shown that the results from single auction models do not carry over to repeated auctions when one of the bidders is endowed with a reputation for bidding aggressively second price auctions with two bidders are highly susceptible to manipulative behaviour by an aggressive bidder and yield much lower revenues to the auctioneer

on the convergence of genetic learning in a double auction market abstract we study the learning behavior of a population of buyers and a population of sellers whose members are repeatedly randomly matched to engage in a sealed bid double auction the agents are assumed to be boundedly rational and choose their strategies by imitating successful behavior and adding innovations triggered by random errors or communication with other agents this process is modelled by a two population genetic algorithm a general characterization of the equilibria in mixed population distributions is given and it is shown analytically that only one price equilibria are attractive for the ga dynamics simulation results confirm these findings and imply that in cases with random initialization with high probability the gain of trade is equally split between buyers and sellers

endogenous market structures and contract theory delegation principal agent contracts screening franchising and tying abstract i study the role of unilateral strategic contracts for firms active in markets with price competition and endogenous entry traditional results change substantially when the market structure is endogenous rather than exogenous they concern 1 contracts of managerial delegation to non profit maximizers 2 incentive principal agent contracts in the presence of moral hazard on cost reducing activities 3 screening contracts in case of asymmetric information on the productivity of the managers 4 vertical contracts of franchising in case of hold up problems and 5 tying contracts by monopolists competing also in secondary markets firms use always these contracts to strengthen price competition and manage to obtain positive profits in spite of free entry

on the anti competitive effects of quantity discounts abstract we analyze the competitive effects of quantity discounts in an asymmetric duopoly we find that for a sizeable set of parameter values quantity discounts harm the smaller firm and reduce consumers surplus they can even decrease social welfare i e the sum of producers and consumers surpluses however the circumstances in which quantity discounts may decrease social welfare are limited and difficult to identify in practice

naked exclusion comment the ability of an incumbent firm to deter entry by writing exclusionary contracts with customers has been a subject of contention in the antitrust literature the courts concern with such exclusionary contracts has been challenged by those who argue that an incumbent faced with buyers whose interest is to promote entry and competition would have to pay buyers more for the inclusion of exclusionary provisions than it could possibly gain from exclusion in a provocative article eric b rasmusen et al 1991 henceforth rrw have argued that an incumbent may in fact be able to exclude rivals profitably using such contractual provisions because it can exploit buyers lack of coordination in essence if buyers expect other buyers to sign such provisions then they may see little reason not to do so themselves the rrw argument is potentially an important one because most alleged instances of entry deterrence through exclusionary contracts with customers occur in situations with multiple buyers unfortunately however rrw s two main results contain errors in this note we reconsider the rrw model providing correct characterizations of the likelihood and cost of exclusion for an incumbent firm our results indicate that while the intuition suggested by rrw is valid the equilibrium likelihood and cost of exclusion differ from what rrw derive moreover our analysis illuminates some further aspects of exclusionary contracting with multiple buyers among these issues we focus on how an incumbent can use discriminatory offers to exploit the externalities that exist among buyers in the provision of competition in section i we review the basic assumptions of the rrw model in sections ii and iii we then consider in turn the cases of simultaneous and sequential offers studied by rrw for the simultaneous model we distinguish between settings in which the incumbent can and cannot discriminate in its offers to different buyers this distinction is the source of the problem in rrw s analysis their simultaneous offer model assumes no discrimination but the proof of their proposition 2 assumes at times that discrimination is feasible we show that absent the ability to discriminate the incumbent can exclude profitably only when buyers fail to coordinate on their most preferred continuation equilibrium in contrast we show that when discrimination is possible the incumbent need not rely on a lack of buyer coordination to segal department of economics landau building stanford university stanford ca 94305 e mail ilya segal stanford edu whinston department of economics northwestern university 2003 sheridan road evanston il 60208 e mail mwhinston nwu edu we thank eric rasmusen john wiley and participants in the berkeley stanford iofest the university of copenhagen vertical restraints conference and a seminar at the antitrust division of the u s department of justice for helpful comments we thank federico echenique for excellent research assistance 1 for example a recent department of justice investigation concerned the use of exclusive contracts by the leading provider of computerized ticketing services ticketmaster most major cities have several large concert sports venues in many cities ticketmaster has exclusive contracts with a very large share of these venues 2 the other leading response to the argument that contracts with buyers cannot be a profitable method of exclusion is given in philippe aghion and patrick bolton 1987 section i one factor limiting the applicability of the aghion and bolton theory however is that it involves partial exclusion the contracts signed are not fully exclusionary they involve finite stipulated damages and the profitability of the strategy arises from extracting rents from an entrant when entry occurs indeed in the aghion and bolton model contracts that fully exclude offer no benefits over writing no contract at all in section iii of their paper aghion and bolton also discuss a two buyer version of their model in which externalities arise across buyers in contrast to the analysis here and in rrw they allow the incumbent to make an offer to a buyer i that is conditional on the acceptance decision of the other buyer 3 r innes and r j sexton 1994 also discuss the use of discriminatory offers in the context of a model in which buyers can form coalitions with the entrant

competition with exclusive contracts and market share discounts we analyze firms that compete by means of exclusive contracts and market share discounts conditional on the seller s share of customers total purchases with incomplete information about demand firms have a unilateral incentive to use these contractual arrangements to better extract buyers informational rents however exclusive contracts intensify competition thus reducing prices and profits and in all pareto undominated equilibria increasing welfare market share discounts by contrast produce a double marginalization effect that leads to higher prices and harms buyers we discuss the implications of these results for competition policy jel d43 d83 d86 k21 l14 l42 in this paper we study firms that compete by means of exclusive contracts or mar ket share discounts i e discounts that depend on the seller s share of a customer s total purchases these are common yet seldom studied forms of competition the literature has mainly focused on incumbents use of exclusive contracts or marketshare discounts to deter new entrants whilst paying less attention to competitors deploying similar pricing strategies we show that exclusive contracts intensify competition reducing equilibrium prices whereas market share discounts have a double marginalization effect and hence result in higher prices these findings have a bearing on the current lively policy debate 1 fueled by the fact that antitrust authorities view competition by means of exclusive contracts or marketshare discounts with some suspicion to say the least the authorities main concern appears to be that a dominant firm can use exclusivity or market share discounts to eliminate not only potential competitors but also existing ones a prime instance of this is the case of intel intel whose main competitor amd has been operating for years in the microchip sector offered electronics manufacturers discounts that depended on their buying a minimum share of their total purchases of microchips from intel some customers to qualify for the discount had to opt for an exclusive supply contract that

sequential common value auctions with asymmetrically informed bidders we study an in nitely repeated rst price auction with common values we focus on one sidedincomplete information in which one bidder learns the objects value which itself does not change overtime learning by the uninformed bidder occurs only through observation of the bids the proprietaryinformation is eventually revealed and the seller extracts essentially the entire rent for large discountfactors both players pay offs tend to 0 as the discount factor tends to 1 however the uninformed bidderdoes relatively better than the informed bidder we discuss the case of two sided incomplete informationand argue that under a markovian re nement the outcome is pooling as information is revealed onlyinsofar as it does not affect prices

consistency and cautious fictitious play we study a variation of fictitious play in which the probability of each action is an exponential function of that action s utility against the historical frequency of opponents play regardless of the opponents strategies the utility received by an agent using this rule is nearly the best that could be achieved against the historical frequency such rules are approximately optimal in i i d environments and guarantee nearly the minmax regardless of opponents behavior fictitious play shares these properties provided it switches infrequently between actions we also study the long run outcomes when all players use consistent and cautious rules

upfront payments and exclusion in downstream markets although upfront payments are often observed in contracts between manufacturers and retailers little is known about their competitive effects or the role retailers play in securing them in this article we consider a model in which two competing retailers make take it or leave it offers to a common manufacturer we find that upfront payments are a feature of equilibrium contracts and in all equilibria only one retailer buys from the manufacturer these findings support the claims of small manufacturers who argue that they are often unable to obtain widespread distribution for their products because of upfront payments copyright 2007 rand

on the existence of pure and mixed strategy nash equilibria in discontinuous games a game is better reply secure if for every nonequilibrium strategy x and every payoff vector limit u resulting from strategies approaching x some player i has a strategy yielding a payoff strictly above u i even if the others deviate slightly from x if strategy spaces are compact and convex payoffs are quasiconcave in the owner s strategy and the game is better reply secure then a pure strategy nash equilibrium exists better reply security holds in many economic games it also permits new results on the existence of symmetric and mixed strategy nash equilibria

strategic effects of three part tariffs under oligopoly the distinct element of a three part tariff 3pt compared with linear pricing lp or a two part tariff is its quantity target within which the marginal price is zero this quantity target instrument enriches the firm s strategy set in dictating the competition to a specific level even in the absence of a usual price discrimination motive with general differentiated linear demands the competitive effect of a 3pt in contrast to lp depends on the degree of substitutability between products competition is intensified when two products are more differentiated yet softened when two products are more substitutable

rationalizability learning and equilibrium in games with strategic complementarities we study a rich class of noncooperative games that includes models of oligopoly competition macroeconomic coordination failures arms races bank runs technology adoption and diffusion r d competition pretrial bargaining coordination in teams and many others for all these games the sets of pure strategy nash equilibria correlated equilibria and rationalizable strategies have identical bounds also for a class of models of dynamic adaptive choice behavior that encompasses both best response dynamics and bayesian learning the players choices lie eventually within the same bounds these bounds are shown to vary monotonically with certain exogenous parameters we study the class of noncooperative supermodular games introduced by topkis 1979 and further analyzed by vives 1985 1989 who also pointed out the importance of these games in industrial economics supermodular games are games in which each player s strategy set is partially ordered the marginal returns to increasing one s strategy rise with increases in the competitors strategies so that the game exhibits strategic complementarity 2 and if a player s strategies are multidimensional marginal returns to any one com ponent of the player s strategy rise with increases in the other components this class turns out to encompass many of the most important economic applications of noncooperative game theory in macroeconomics diamond s 1982 search model and bryant s 1983 1984 rational expectations models can be represented as supermodular games in each of these models more activity by some members of the economy raises the returns to increased levels of activity by others in oligopoly theory some models of bertrand oligopoly with differentiated products qualify as supermodu lar games in these games when a firm s competitors raise their prices the marginal profitability of the firm s own price increase rises a similar structure is present in games of new technology adoption such as those of dybvig and spatt 1983 farrell and saloner 1986 and katz and shapiro 1986 when more users hook into a communication system or more manufacturers adopt an interface standard the marginal return to others of doing the same often rises similarly in some specifications of the bank runs model introduced by diamond and dybvig 1983 when more depositors withdraw their funds from a bank it is more worthwhile for other depositors to do the same in the warrant exercise

intergenerational mobility and the process of development this paper offers an explanation for some evidence that intergenerational earnings mobility is higher in more developed economies and that mobility is positively correlated with wage equality in the model mobility promotes economic growth via its effect on the accumulation and allocation of human capital growth influences mobility via its effect on incentives to acquire education and its effect on liquidity constraints upon such acquisition in the process of development mobility increases and the distribution of education becomes better correlated with ability redistributive policy has a negative effect on growth in developed economies and a positive effect in developing economies

does retailer power lead to exclusion this article examines whether retailer bargaining power and upfront slotting allowances prevent small manufacturers who have no bargaining power from obtaining adequate distribution in contrast to the findings of marx and shaffer 2007 who show that all equilibria involve limited distribution i e exclusion of a retailer we show that there is always an equilibrium in which full distribution is obtained provided that full distribution is the industry profit maximizing outcome the key feature leading to this differing result is that we do not restrict each retailer to offering the manufacturer a single tariff

learning mixed equilibria we study learning processes for finite strategic form games in which players use the history of past play to forecast play in the current period in a generalization of fictitious play we assume only that players asymptotically choose best responses to the historical frequencies of opponents past play this implies that if the stage game strategies converge the limit is a nash equilibrium in the basic model plays seems unlikely to converge to a mixed strategy equilibrium but such convergence is natural when the stage game is perturbed in the manner of harsanyi s purification theorem journal of economic literature classification number c72

divisionalization and entry deterrence this paper assumes that incumbent firms can create new independent divisions more cheaply than potential entrants who must incur the additional overhead costs of new entry the main theoretical result is that such divisionalization ability leads perfectly informed incumbents to preempt all rational entry into their industries in contrast existing models of entry deterrence imply that informed incumbents even those with steadily decreasing average costs will often allow rational entry our result may explain why successful large scale entry by firms with no informational advantage is extremely rare the use of divisions to preempt entry may also explain why large firms in high profit oligopolies often divisionalize allowing their divisions to compete freely despite the negative pecuniary externality that each division imposes on others