immigration and employer transitions for stem workers immigrants play a significant role in many aspects of the us economy but their impact in occupations related to science technology engineering and mathematics stem is especially pronounced immigrants account for about a quarter of all stem workers with college degrees or higher in the 2000 census and about half of those with doctorates much of the recent growth in us employment in stem occupations is linked to immigrants given the importance of innovation for economic growth the economic consequences of immigrants in stem occupations have been closely examined in recent research of particular importance has been the impact of stem immigrants on the employment opportunities and wages of native workers how immigrants impact the aggregate innovation rate of the us economy and similar research questions studies in this literature have often employed quite different techniques datasets and time periods perhaps as a consequence the literature has also found mixed results on several dimensions 1 most notably the extent to which immigrants displace natives from stem occupations remains hotly debated

optimal collusion with internal contracting abstract in this paper two firms play an infinitely repeated bertrand game and each firm has an agent who produces the firm s output and holds private information about production costs the colluding firms fix prices and allocate market shares based on their agents information we develop a model of collusion in which firms use the presence of agents as a strategic opportunity to restrict their incentives to distort private information we show that such firm behavior may expand the scope of optimal collusion whether market allocation schemes are asymmetric or symmetric

communication in repeated games with private monitoring abstract the paper considers repeated games where each player can be observed by only a subset of the other players and where players can make public announcements about the behavior of the players they observed we address the following question what is the minimal level of observability that is required to obtain efficient outcomes the main result is that the limit set of sequential equilibrium payoffs when the discount factor tends to one contains the set of individual rational payoffs whenever each player is observed by at leasttwoother players journal of economic literatureclassification number c73

resale price maintenance and collusion the article revisits the conventional wisdom according to which vertical restrictions on retail prices help upstream firms to collude we analyze the scope for collusion with and without resale price maintenance rpm when retailers observe local shocks on demand or retail costs in the absence of rpm retail prices react to retailers information and deviations from collusive behavior are thus difficult to detect by eliminating retail price flexibility rpm facilitates the detection of deviations but reduces profits and thus increases the short run gains from a deviation overall rpm can facilitate collusion and reduce total welfare when firms adopt it

menu costs and dynamic duopoly examining a state dependent pricing model in the presence of menu costs and dynamic duopolistic interactions this paper claims that the assumption regarding market structure is crucial for identifying the menu costs for price changes prices in a dynamic duopolistic market can be more rigid than those in more competitive markets such as a monopolistic competition market therefore the estimates of menu costs under monopolistic competition are potentially biased upward due to the price rigidity from strategic interactions between dynamic duopolistic firms by developing and estimating a dynamic discrete choice model with duopoly to correct for this potential bias this paper provides empirical evidence that dynamic strategic interactions as well as menu costs play an important role in explaining the observed degree of price rigidity in weekly retail prices

competition and price variation when consumers are loss averse we modify the salop 1979 model of price competition with differentiated products by assuming that consumers are loss averse relative to a reference point given by their recent expectations about the purchase consumers sensitivity to losses in money increases the price responsiveness of demand and hence the intensity of competition at higher relative to lower market prices reducing or eliminating price variation both within and between products when firms face common stochastic costs in any symmetric equilibrium the markup is strictly decreasing in cost even when firms face different cost distributions we identify conditions under which a focal price equilibrium where firms always charge the same focal price exists and conditions under which any equilibrium is focal

skilled immigration and the employment structures of u s firms we study the impact of skilled immigrants on the employment structures of us firms using matched employer employee data unlike most previous work we use the firm as the lens of analysis to account for greater heterogeneity and the fact that many skilled immigrant admissions are driven by firms themselves e g the h 1b visa ols and iv specifications show rising overall employment of skilled workers with increased skilled immigrant employment by the firm employment expansion is greater for young natives than for their older counterparts the departure rates for older workers relative to younger workers appear highest for those in stem occupations

collusive equilibrium in cournot oligopolies with unknown costs the article studies collusive equilibria in an infinitely repeated cournot oligopoly with unknown costs i look at collusive pooled perfect bayesian equilibria and separating equilibria either with signaling or with communication in the separating equilibria with signaling the firms play the strictly separating bayesian nash equilibrium in period 1 and produce the optimal incentive compatible collusive quantity vector from period 2 onwards in the separating equilibrium with communication the optimal incentive compatible quantity vector is produced from period 1 onwards among these the optimal separating equilibrium with communication gives the highest expected discounted joint profits

impossibility of collusion under imperfect monitoring with flexible production we show that it is impossible to achieve collusion in a duopoly when 1 goods are homogenous and firms compete in quantities 2 new imperfect information arrives continuously without sudden events and 3 firms are able to respond to this new information quickly the result holds even if we allow for asymmetric equilibria or monetary transfers the intuition is that the flexibility to respond to new information quickly unravels any collusive scheme and that signals about the aggregate behavior only cannot be used effectively to provide individual incentives via transfers our result applies both to a simple stationary model and a more complicated one with prices following a mean reverting markov process

collusion and price rigidity we consider an in nitely repeated bertrand game in which prices are publicly observed and each rm receives a privately observed i i d cost shock in each period we focus on symmetric perfect public equilibria sppe wherein any punishments are borne equally by all rms we identify a tradeoff that is associated with collusive pricing schemes in which the price to be charged by each rm is strictly increasing in its cost level such fully sorting schemes offer efficiency bene ts as they ensure that the lowest cost rm makes the current sale but they also imply an informational cost distorted pricing and or equilibrium path price wars since a higher cost rm must be deterred from mimicking a lower cost rm by charging a lower price a rigid pricing scheme where a rm s collusive price is independent of its current cost position sacri ces efficiency bene ts but also diminishes the informational cost for a wide range of settings the optimal symmetric collusive scheme requires i the absence of equilibrium path price wars and ii a rigid price if rms are sufficiently impatient however the rigid pricing scheme cannot be enforced and the collusive price of lower cost rms may be distorted downward in order to diminish the incentive to cheat when the model is modi ed to include i i d public demand shocks the downward pricing distortion that accompanies a rm s lower cost realization may occur only when current demand is high

collusion with almost no information we analyze noncooperative collusion in an infinitely repeated bertrand game where each of the n firms receives a privately observed i i d cost shock in each period and firms only and privately observe whether they have won the unit mass of consumers no other information is available and no communication is allowed we prove that there exist equilibria in private strategies approximating first best profits when firms are sufficiently patient in particular productive efficiency obtains in the limit

optimal cartel pricing in the presence of an antitrust authority the dynamic behavior of a price fixing cartel is explored when it is concerned about creating suspicions that a cartel has formed consistent with preceding static theories the cartel s steady state price is decreasing in the damage multiple and the probability of detection however contrary to those theories it is independent of the level of fixed fines it is also shown that the cartel prices higher when a more competitive benchmark price is used in calculating damages

the initiation and withdrawal of odd eighth quotes among nasdaq stocks an empirical analysis christie and schultz 1994 journal of finance 49 1813 1840 nd that market makers in many active nasdaq stocks avoid odd eighth quotes this paper studies 67 58 nasdaq stocks whose market makers initiate withdraw odd eighth quotes these regime shifts are often completed within the span of a day and coincide with dramatic changes in dollar percentage and e ective spreads in most cases we are unable to identify comparable changes in the costs of making markets we do identify long run changes in average prices that may provide a partial explanation however we also nd

optimal cartel trigger price strategies abstract a dynamical model of industry equilibrium is described in which a cartel deters deviations from collusive output levels by threatening to produce at cournot quantities for a period of fixed duration whenever the market price falls below some trigger price in this model firms can observe only their own production level and a common market price the market demand curve is assumed to have a stochastic component so that an unexpectedly low price may signal either deviations from collusive output levels or a downward demand shock

business cycles and monetary regimes in emerging economies a role for a monopolistic banking sector abstract this study shows that the presence of imperfect competition in the banking system propagates external shocks and amplifies the business cycle strategic limit pricing aimed at protecting retail niches from potential competitors generates countercyclical bank markups markup increments during recessions directly increase borrowing costs for firms and indirectly damage the financial position of firms balance sheets increasing the risk perception of lenders i use bayesian techniques and data from argentina to show that the inclusion of monopolistic banking improves the fit of the new keynesian small open economy model

testing the purchasing power parity through i 2 cointegration techniques this paper contributes to the empirical literature on the purchasing power parity ppp over the post bretton woods period by providing a time series based interpretation of the controversial evidence characterizing the dynamics of real exchange rates it is shown that the persistence of deviations from the ppp between a set of european countries and the united states may be empirically attributed to the presence of i 2 stochastic trends in prices using consumer price indices interestingly the slow adjustment towards the equilibrium can be modelled through integral proportional equilibrium correction models and this evidence can be partly reconciled with theories where the inflation rate reduces the markup of profit maximizing firms acting on imperfectly competitive markets copyright 2005 john wiley sons ltd

the folk theorem with imperfect public information the authors study repeated games in which players observe a public outcome that imperfectly signals the actions played they provide conditions guaranteeing that any feasible individually rational payoff vector of the stage game can arise as a perfect equilibrium of the repeated game with sufficiently little discounting the central condition requires that there exist action profiles with the property that for any two players no two deviations one by either player give rise to the same probability distribution over public outcomes the results apply to principal agent partnership oligopoly and mechanism design models and to one shot games with transferable utilities copyright 1994 by the econometric society

a theory of dynamic oligopoly ii price competition kinked demand curves and edgeworth cycles we provide game theoretic foundations for the classic kinked demand curve equilibrium and edgeworth cycle we analyze a model in which firms take turns choosing prices the model is intended to capture the idea of reactions based on short run commitment in a markov perfect equilibrium mpe a firm s move in any period depends only on the other firm s current price there are multiple mpe s consisting of both kinked demand curve equilibria and edgeworth cycles in any mpe profit is bounded away from the bertrand equilibrium level we show that a kinked demand curve at the monopoly price is the unique symmetric renegotiation proof equilibrium when there is little discounting we then endogenize the timing by allowing firms to move at any time subject to short run commitments we find that firms end up alternating thus vindicating the ad hoc timing assumption of our simpler model we also discuss how the model can be enriched to provide explanations for excess capacity and market sharing keiiwords tacit collusion markov perfect equilibrium kinked demand curve edgeworth cycle excess capacity market sharing endogenous timing

long run power storage requirements for high shares of renewables review and a new model abstract the purpose of this article is twofold first we review model based analyses that explore the role of power storage in energy systems with high shares of variable renewables second we introduce a new model that is specifically designed for exploring long term storage requirements the literature survey focuses on recent contributions in the peer reviewed energy economics and engineering literature we compare key characteristics of the different models provide an overview of model applications and summarize key findings on power storage requirements we also evaluate which system values of storage are covered by respective model analyses based on the literature survey we identify common findings and key model features required for a sound assessment of future storage requirements in order to raise complementary insights we introduce dieter a new dispatch and investment model the model contributes to the literature by capturing multiple system values of power storage related to arbitrage capacity and reserve provision further the model is designed as an open source tool that can be freely used and modified results of a first application of the new model are presented in a companion paper

communication in repeated games with imperfect private monitoring this paper examines repeated games in which each player observes a private and imperfect signal on the actions played and in which players are allowed to communicate using public messages providing incentives for players to reveal their observations generates revelation constraints that combined with signal imperfections may be a source of inefficiencies however by delaying the revelation of their observations players may economize on the cost of deterring deviations and thereby avoid these inefficiencies because a player would not want to trigger a sanction that would penalize him too revelation constraints also tend to make sanctions difficult to enforce however with at least three players detecting deviations may not require that all the players reveal their observations in that case we obtain a nash threat version of the folk theorem with two players we do not obtain a similar result nevertheless we show that an efficient outcome can almost always be approximated

private monitoring in auctions abstract we study infinitely repeated first price auctions in which a bidder only learns whether or not he won the object while repetition of the stage game equilibrium is the unique nash equilibrium in public strategies with patient bidders there are simple nash equilibria in private strategies that improve on bid rotation sequential rationality is appropriately captured by essentially perfect bayesian equilibrium epbe which ignores behavior after irrelevant histories our main result is the construction of epbea that improve upon bid rotation assuming symmetry the exclusionary schemes of skrzypacz and hopenhayn tacit collusion in repeated auctions j econ theory 114 2004 153 169 including asymptotically efficient ones are supported as epbea

building routines learning cooperation and the dynamics of incomplete relational contracts this paper studies how agents with conflicting interests learn to cooperate when the details of cooperation are not common knowledge it considers a repeated game in which one player has incomplete information about when and how her partner can provide benefits initially monitoring is imperfect and cooperation requires inefficient punishment as the players common his tory grows the uninformed player can learn to monitor her partner s actions which allows players to establish more efficient cooperative routines because revealing information is costly it may be optimal not to reveal all the existing information and efficient equilibria can be path dependent jel c73 d82 d83 d86 this paper studies how agents with conflicting interests go about developing a successful cooperative relationship when the details of cooperation are not common knowledge in cir cumstances where formal contracts are unavailable or inconvenient agents frequently rely on informal cooperative agreements or relational contracts to resolve incentive conflicts in fact whenever the interested parties have better information than do outside courts relational con tracts can outperform formal contracts by allowing agents to adapt their joint behavior to contin gencies that cannot be assessed by third parties 1 the starting point of this paper is to recognize that even when agents have better information than outside courts this does not mean that the details of how and when cooperation should occur are common knowledge between the parties for instance a new plant manager may not have a complete understanding of what her produc tion teams can and cannot do a firm s ceo may have only partial understanding of how research teams should operate and so on the question is then how do players go about building a com mon agreement or formulated in a slightly different way how do they go about specifying the contingencies of their relational contract the model developed in the paper considers two players engaged in an infinitely repeated game with asymmetric information in each period player 1 decides to stay and interact with player 2 or exit and skip interaction for one period staying is costly for player 1 and yields a benefit for player 2 if player 1 stays player 2 can reciprocate by taking some action from a set of available actions which is randomly drawn in each period from a countable superset player 2 can take actions of two types unproductive actions that are costless to player 2 but yield zero benefit to

optimal cartel equilibria with imperfect monitoring abstract there exist optimal symmetric equilibria in the green porter model 4 8 having an elementary intertemporal structure such an equilibrium is described entirely by two subsets of price space and two quantities the only production levels used by firms in any contingency the central technique employed in the analysis is the reduction of the repeated game to a family of static games

traders vs relationship managers reputational conflicts in full service investment banks we present a model that explains why investment bankers struggle to manage conflicts of interest banks can build a type reputation for technical competence by performing complex deals that may not serve their clients interest on the other hand banks can sustain a behavioral reputation by refraining from doing so a behavioral reputation is a luxury reserved for banks that have proven their abilities the model sheds light on conflicts between the trading and advisory divisions of investment banks as well as the consequences of technological change for time variation in the relative strength of behavioral and type reputation concerns

cartel enforcement with uncertainty about costs what cartel agreements are possible when firms have private information about production costs in order for a cartel agreement to work it must take into account the incentives for firms to misrepresent their cost information and it must provide sufficient reward so that no firm wishes to defect for private cost uncertainty we characterize the set of cartel agreements with side payments that can be supported as bayesian nash equilibria we show that if defection results in either cournot or bertrand competition the incentive problems in large cartels are severe enough to prevent the cartel from achieving the monopoly outcome in contrast with common cost uncertainty the incentive problems become less severe in large cartels allowing perfect collusion

a theory of hub and spoke collusion abstract we develop a model of hub and spoke collusion between a manufacturer and two retailers demand is stochastic and collusion between retailers is difficult the best collusive equilibrium is inefficient rotemberg and saloner 1986 in the hub and spoke collusive agreement retailers transmit their information about the state of demand to the supplier the supplier uses this information to adjust the wholesale price by organizing the collusion the supplier increases profits of the vertical chain we show that surprisingly this type of collusive agreement can under some conditions improve consumer welfare

the impact of collusion on price behavior empirical results from two recent cases abstract we use extended arch and garch models to examine the differences in the behavior of the first two moments of the price distribution during collusive and competitive phases of two recently discovered conspiracies citric acid and lysine according to our results the conspirators managed to raise prices by 9 and 25 cents per pound in the short run relative to non collusive periods also the variance of prices during the lysine conspiracy was lower and the variance of prices during the citric acid conspiracy was higher than during more competitive periods the proposed methodology may be used for antitrust screening and prosecution purposes

competitive procurement with corruption we study competitive procurement administered by a corrupt agent who is willing to manipulate his evaluation of contract proposals in exchange for bribes with complete information and no corruption the efficient firm will win the contract for sure if the agent is corrupt and has large manipulation power however bribery makes it costly for the efficient firm to secure a sure win so in equilibrium the efficient firm loses the contract with positive probability the optimal scoring rule for the buyer deemphasizes quality relative to price and does not fully handicap and may even favor the efficient firm

tacit collusion with imperfect monitoring in the canadian manufacturing industry an empirical study this article undertakes a cross sectoral analysis of a salient empirical implication of the model of tacit collusion advanced by abreu pearce and stachetti 1986 specifically we assess the prevalence of a first order markovian process for alternating between price wars and collusive periods through nonparametric tests the analysis focuses on 30 different industries in canada the evidence provides weak support for optimal collusion in one industry which is consistent with the idea that such kind of collusive arrangements is unusual or if collusion is all too common that price wars as deviations from collusion are rare

the rigidity of prices this paper uses evidence on individual transaction prices to analyze price behavior the evidence shows that for many transactions pricesremain rigid for periods exceeding one year the rigidity of price ispositively correlated with industry concentration for several productsthe correlation of price changes across buyers is low the paper alsoinvestigates the relationship between price rigidity price change andthe length of time a buyer and seller have been doing business together the author interprets the evidence as emphasizing the importance of nonprice rationing and the inadequacy of models in whichprice movements alone clear markets copyright 1986 by american economic association

collusion with persistent cost shocks we consider a dynamic bertrand game in which prices are publicly observed and each firm receives a privately observed cost shock in each period although cost shocks are independent across firms within a firm costs follow a first order markov process we analyze the set of collusive equilibria available to firms emphasizing the best collusive scheme for the firms at the start of the game in general there is a trade off between productive efficiency whereby the low cost firm serves the market in a given period and high prices we show that when costs are perfectly correlated over time within a firm if the distribution of costs is log concave and firms are sufficiently patient then the optimal collusive scheme entails price rigidity firms set the same price and share the market equally regardless of their respective costs when serial correlation of costs is imperfect partial productive efficiency is optimal for the case of two cost types first best collusion is possible if the firms are patient relative to the persistence of cost shocks but not otherwise we present numerical examples of first best collusive schemes

what happens to the careers of european workers when immigrants take their jobs following a representative longitudinal sample of native european residents over the period 1995 2001 we identify the effect of the inflows of immigrants on natives career employment and wages we control for individual country year occupation group year and occupation group country heterogeneity and shocks and construct an imputed inflow of the foreign born population that is exogenous to local demand shocks we find that native european workers are more likely to move to occupations associated with higher skills and status when a larger number of immigrants enters their labor market we find no evidence of an increase in their probability of becoming unemployed

an anatomy of cartel contracts we study cartel contracts using data on 18 contract clauses of 109 legal finnish manufacturing cartels one third of the clauses relate to raising profits the others deal with instability through incentive compatibility cartel organization or external threats cartels use three main approaches to raise profits price market allocation and specialization these appear to be substitutes choosing one has implications on how cartels deal with instability simplifying we find that large cartels agree on prices cartels in homogenous goods industries allocate markets and small cartels avoid competition through specialization

auctions and corruption an analysis of bid rigging by a corrupt auctioneer in many auctions the auctioneer is an agent of the seller this invites corruption we analyze a model in which the auctioneer orchestrates bid rigging by inviting a bidder to either lower or raise his bid whichever is more profitable the interplay between these two types of corruption gives rise to a complex bidding problem that we tackle with numerical methods our results indicate that corruption does not only redistribute surplus away from the seller but also distorts efficiency we furthermore explain why both the auctioneer and bidders have a vested interest in maintaining corruption

collusive price rigidity under price matching punishments by analysing an infinitely repeated game where unit costs alternate stochastically between low and high states and where firms follow a price matching punishment strategy we demonstrate that the best collusive prices are rigid over time when the two cost levels are sufficiently close this provides game theoretic support for the results of the kinked demand curve in contrast to the kinked demand curve it also generates predictions regarding the level and the determinants of the best collusive price which in turn has implications for the corresponding collusive profits the relationships between such price rigidity and the expected duration of a high cost phase the degree of product differentiation and the number of firms in the market are also investigated

endogenous price commitment sticky and leadership pricing evidence from the italian petrol market this article studies dynamic pricing strategies in the italian gasoline market before and after the market leader unilaterally announced its commitment to adopt a sticky pricing policy using daily italian firm level prices and weekly average eu prices we show that the effect of the new policy was twofold first it facilitated price alignment and coordination on price changes after the policy change the observed pricing pattern shifted from cost based to sticky leadership pricing second using a dif in dif estimation and a synthetic control group we show that the causal effect of the new policy was to significantly increase prices through sticky leadership pricing our paper highlights the importance of price commitment by a large firm in order to sustain tacit collusion

collusion over the business cycle we present a theory of collusive pricing for markets in which demand alternates stochastically between fast growth boom and slow growth recession phases we show that 1 the most collusive prices are weakly procyclical countercyclical when demand growth rates are positively negatively correlated through time and 2 the amplitude of the collusive pricing cycle is larger when the expected duration of boom phases decreases and when the expected duration of recession phases increases we also offer a generalization of rotemberg and saloner s 1986 model interpreting their findings in terms of transitory demand shocks that occur within broader business cycle phases

repeated insurance contracts and moral hazard abstract an attempt is made to account for the frequently observed phenomenon of insurance companies offering discounts to clients who possess a favorable record of past claims we argue that such discounts provide a mechanism which enables both insurer and insured to counteract the inefficiency which arises from moral hazard

bertrand competition when rivals costs are unknown the conclusions of the bertrand model of competition are substantially altered by the presence of asymmetric information about rivals costs asymmetric information eliminates the discontinuity in the bertrand model and significantly alters the properties of the market equilibrium in the bertrand nash equilibrium when rivals costs are unknown firms price above marginal cost and have positive expected profit the analysis is extended to franchise competition the market equilibrium is sensitive to market structure and yields incentives for entry copyright 1995 by blackwell publishing ltd

price cutting and business stealing in imperfect cartels although economists have made substantial progress toward formulating theories of collusion in industrial cartels that account for a variety of fact patterns important puzzles remain standard models of repeated interaction formalize the observation that cartels keep participants in line through the threat of punishment but they fail to explain two important factual observations first apparently deliberate cheating actually occurs second it frequently goes unpunished even when it is detected we propose a theory of equilibrium price cutting and business stealing in cartels to bridge this gap between theory and observation

the impact of cyclical demand movements on collusive behavior recent work by rotemberg and saloner 1986 investigates the effect of the business cycle on optimal collusive pricing by specifying that demand is subject to i i d shocks an implication of the i i d assumption is that firms expectations on future demand are unrelated to the current level of demand we put forth a model that allows for both the level of current demand and firms expectations on future demand to change over time thus it captures two important properties of the business cycle our analysis reveals that while the gain to deviating from a collusive agreement is greatest during booms firms find it most difficult to collude during recessions as the forgone profits from inducing a price war are relatively low an implication of this effect for pricing behavior is that at the same level of demand price is lower when demand is declining than when demand is rising consistent with previous theoretical work we find that firms price countercyclically for a range of values for the discount factor however numerical simulations reveal a greater tendency for firms to price countercyclically during recessions than during booms

the political economy of indirect control this paper characterizes the efficient sequential equilibrium when a government uses indirect control to exert its authority we develop a dynamic principal agent model in which a principal a government delegates the prevention of a disturbance such as riots protests terrorism crime or tax evasion to an agent who has an advantage in accomplishing this task our setting is a standard dynamic principal agent model with two additional features first the principal is allowed to exert direct control by intervening with an endogenously determined intensity of force which is costly to both players second the principal suffers from limited commitment using recursive methods we derive a fully analytical characterization of the likelihood intensity and duration of intervention the first main insight from our model is that repeated and costly interventions are a feature of the efficient equilibrium this is because they serve as a punishment to induce the agent into desired behavior the second main insight is a detailed analysis of a fundamental tradeoff between the intensity and duration of intervention which is driven by the principal s inability to commit finally we derive sharp predictions regarding the impact of various factors on likelihood intensity and duration of intervention we discuss these results in the context of some historical episodes