money and capital abstract the effects of money anticipated inflation on capital formation is a classic issue in macroeconomics previous papers adopt reduced form approaches putting money in the utility function or imposing cash in advance but using otherwise frictionless models we follow instead a literature that tries to be explicit about the frictions making money essential this introduces new elements including a two sector structure with centralized and decentralized markets stochastic trading opportunities and bargaining these elements matter quantitatively and numerical results differ from findings in the reduced form literature the analysis also reduces a gap between microfounded monetary economics and mainstream macro

does one soros make a difference a theory of currency crises with large and small traders do large investors increase the vulnerability of a country to speculative attacks in the foreign exchange markets to address this issue we build a model of currency crises where a single large investor and a continuum of small investors independently decide whether to attack a currency based on their private information about fundamentals even abstracting from signaling the presence of the large investor does make all other traders more aggressive in their selling relative to the case in which there is no large investors small investors attach the currency when fundamentals are stronger yet the difference can be small or null depending on the relative precision of private information of the small and large investors adding signaling makes the influence of the large trader on small traders behaviour much stronger

choosy search and the mismatch of talents this article proposes a multi sector matching model where workers have symmetric sector specific skills and the search market is segmented by sector workers choose the range of markets they are willing to participate in i identify a composition externality workers do not take into account the impact of their choice on sector specific mean productivity among the pools of job seekers consequently workers prospect too many market segments and there is room for public policy even when the so called hosios condition holds

limit theorems for markets with sequential bargaining this paper models trade as a non coopertative strategic game played at an inlinite sequence of dates a single indivisible commodity is traded buyers and sellers have transferable utility and are characterized by their reservation utilities they meet at random and bargain over the price at which a single unit of the good will be exchanged under a variety of circumstances it is shown that as the costs of search and bargaining become negligible the outcome of the game converges to the competitve flow equilibrium even when there is complete information journal of economic literature classification numbers 022 19x7

information percolation with equilibrium search dynamics we solve for the equilibrium dynamics of information sharing in a large population each agent is endowed with signals regarding the likely outcome of a random variable of common concern individuals choose the effort with which they search for others from whom they can gather additional information when two agents meet they share their information the information gathered is further shared at subsequent meetings and so on equilibria exist in which agents search maximally until they acquire sufficient information precision and then search minimally a tax whose proceeds are used to subsidize the costs of search improves information sharing and can in some cases increase welfare on the other hand endowing agents with public signals reduces information sharing and can in some cases decrease welfare

valuing thinly traded assets we model illiquidity as a restriction on the stopping rules investors can follow in selling assets and apply this framework to the valuation of thinly traded investments we find that discounts for illiquidity can be surprisingly large approaching 30 50 in some cases immediacy plays a unique role and is valued much more than ongoing liquidity we show that investors in illiquid enterprises have strong incentives to increase dividends and other cash payouts thereby introducing potential agency conflicts we also find that illiquidity and volatility are fundamentally entangled in their effects on asset prices this aspect may help explain why some assets are viewed as inherently more liquid than others and why liquidity concerns are heightened during financial crises this paper was accepted by gustavo manso finance

the relative contributions of private information sharing and public information releases to information aggregation we calculate learning rates when agents are informed through public and private observation of other agents actions we characterize the evolution of the distribution of posterior beliefs if the private learning channel is present convergence of the distribution of beliefs to the perfect information limit is exponential at a rate equal to the sum of the mean arrival rate of public information and the mean rate at which individual agents are randomly matched with other agents if however there is no private information sharing then convergence is exponential at a rate strictly lower than the mean arrival rate of public information c 2009 elsevier inc all rights reserved

competitive search equilibrium in this paper i construct an equilibrium for markets with frictions which is competitive in the sense that all agents are price takers and maximize utility subject to a set of market parameters i show that the equilibrium allocation is socially optimal i also show how the competitive search equilibrium can be achieved if employers with vacancies can advertise publicly the wages they pay

education ranking and competition for jobs i study workers incentives to invest in general human capital education in the presence of search induced unemployment workers queue for jobs and firms prefer to hire the most productive applicants because of rent sharing as a result an unemployed worker s ranking relative to other job seekers will influence his job finding rate this creates a rat race where workers invest in education partly in order to achieve a better ranking in equilibrium identical workers may have incentives to diversify in terms of education and the investments in education may exceed the socially optimal level

money as the mechanism of exchange abstract the existence and use of money remained an embarrassing puzzle for monetary analysis we observe over man s history that social groups without generally accepted media of exchange exhibit poor survival characteristics most social groups do not use assets or commodities at random in the execution of exchanges one observes that a small subset of assets is dominantly used in transactions these transaction dominating assets are usually referred to as money the literature contains many suggestive attempts to explain the emergence and role of money the classic writers made passing references in somewhat pictorial language to the extension markets and increasing labor productivity induced by the use of a general medium of exchange this idea has never been systematically developed however karl brunner 1971

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

the value of diffusing information abstract how does the speed by which information diffuses affect its value to a stock market investor in a structural model solved in closed form this speed has two opposing effects on the empirically dominant term of the value of information faster diffusing information means quicker and less noisy profits but also increases competing informed trading impounding more information into prices and eroding profits structural empirical analysis of stock market reaction to drug approvals using media coverage as a proxy for the transmission rate of information finds that the value of information is hump shaped in its future transmission rate moreover the estimated amount of noise trading is small

the effect of bond rating changes on common stock prices abstract the evidence in this paper suggests that downgrades by both moody s and standard and poor s are associated with negative abnormal stock returns in the two day window beginning the day of the press release by the rating agency significant negative abnormal performance can still be detected after eliminating observations containing obvious concurrent potentially contaminating news releases there is little evidence of abnormal performance on announcement of an upgrade significant abnormal returns are associated with announcements of additions to the standard and poor s credit watch list if either a potential downgrade or a potential upgrade is indicated

a search theoretic approach to monetary economics the essential function of money is its role as a medium of exchange the authors formalize this idea using a search theoretic equilibrium model of the exchange process that captures the double coincidence of wants problem with pure barter one advantage of the framework described here is that it is very tractable the authors also show that the model can be used to addre ss some substantive issues in monetary economics including the potenti al welfare enhancing role of money the interaction between specializat ion and monetary exchange and the possibility of equilibria with multip le fiat currencies copyright 1993 by american economic association

learning from private and public observations of othersʼ actions we study how a continuum of agents learn about disseminated information by observing others actions every period each agent observes a public and private noisy signal centered around the aggregate action taken by the population the public signal represents an endogenous aggregate variable such as a price or a quantity the private signal represents the information gathered through private communication and local interactions we identify conditions such that the average learning curve is s shaped learning is slow initially intensifies rapidly and finally converges slowly to the truth we show that increasing public information always slows down learning in the long run and under some conditions reduces welfare lastly optimal diffusion of information requires that agents strive to be different agents need to be rewarded for choosing actions away from the population average

the distribution of money balances and the nonneutrality of money recent monetary models with explicit microfoundations are made tractable by assuming that agents have access to centralized markets after one round of decentralized trade given quasi linear preferences this makes the distribution of money degenerate which keeps the models simple but precludes the discussion of distributional effects of monetary policy we generalize these models by assuming two rounds of trade before agents can readjust their money holdings to study a range of new distributional effects analytically we show that unexpected symmetric lump sum money injections may increase short run output and welfare whereas asymmetric injections may increase long run output and welfare

unique equilibrium in a model of self fulfilling currency attacks even though self fulfilling currency attacks lead to multiple equilibria when fundamentals are common knowledge we demonstrate the uniqueness of equilibrium when speculators face a small amount of noise in their signals about the fundamentals this unique equilibrium depends not only on the fundamentals but also on financial variables such as the quantity of hot money in circulation and the costs of speculative trading in contrast to multiple equilibrium models our model allows analysis of policy proposals directed at curtailing currency attacks

credit rating inflation and firms investments we analyze credit rating effects on firm investments in a rational bond financing game that features a feedback loop the credit rating agency cra inflates the rating providing a biased but informative signal to creditors creditors response to the rating affects the firm s investment decision and thus its credit quality which is reflected in the rating the cra might reduce ex ante economic efficiency which results solely from its strategic effect the cra assigns more firms high ratings and allows them to gamble for resurrection we derive empirical predictions on the determinants of rating standards and inflation and discuss policy implications

search bargaining money and prices the goal of this paper is to extend existing search theoretic models of fiat money which until now have assumed that the price level is exogenous by explicitly incorporating bilateral bargaining this allows us to determine the price level endogenously and leads to additional insights concerning the role of money for example we find that monetary equilibria are generally inefficient in the sense that output and prices differ from the solution to a social planner s problem although the difference can become small as the discount rate or search friction vanishes we also find that there exist nonstationary inflationary equilibria

the loser s curse and information aggregation in common value auctions we consider an auction in which k identical objects of unknown value are auctioned off to n bidders the k highest bidders get an object and pay the k 1st bid bidders receive a signal that provides information about the value of the object we characterize the unique symmetric equilibrium of this auction we then consider a sequence of auctions a r with n r bidders and k r objects we show that price converges in probability to the true value of the object if and only if both k r and n r k r i e both the number of objects and the number of bidders who do not receive an object go to infinity

rating the raters are reputation concerns powerful enough to discipline rating agencies abstract credit rating agencies cras are accused of bearing a strong responsibility for contributing to the subprime crisis by having been deliberately too lax in the ratings of some structured products in response to this accusation cras argue that such an attitude would be too dangerous for them since their reputation is at stake the objective of this article is to examine the validity of this argument within a formal model are reputation concerns sufficient to discipline rating agencies we show that the reputation argument only works when a sufficiency large fraction of the cra income comes from other sources than rating complex products by contrast when rating complex products becomes a major source of income for the cra we show that it is always too lax with a positive probability and inflates ratings with probability one when its reputation is good enough we provide some empirical support for this prediction by showing that ceteris paribus the proportion of subprime residential mortgage backed securities rmbs that were rated aaa by the three main cras indeed increased over the last eight years we analyze the policy implications of our findings and advocate for a new business model of cras that we call the platform pays model

equilibrium in a market with sequential bargaining this paper considers a market where pairs of agents who are interested in carrying out a transaction are brought together by a stochastic process and upon meeting initiate a bargaining process over the terms of the transaction the basic bargaining problem is treated with the strategic approach the paper derives the steady state equilibrium agreements analyzes their dependence on market conditions such as the relative numbers of agents of different types and discusses their relations with the competitive equilibrium outcome and other results in the search equilibrium literature this paper considers a market that operates in the following way pairs of agents who have mutual interest in carrying out a transaction are brought together by a stochastic process when two agents meet they initiate a bargaining process over the terms of the transaction if two agents reach an agreement a transaction takes place and they leave the market of course the bargaining positions and hence the agreement reached in any particular meeting will be affected by the conditions prevailing in the market these will include the chances that each of the negotiating parties have of meeting other partners in the event that the agreement in the current negotiations is delayed also the expected length of time required to achieve an alternative transaction and the expected behavior of alternative partners the study of such a market mechanism is of interest for two reasons firstly it captures some realistic aspects of the trade in certain specific markets e g asset markets such as housing and some labor markets secondly it contributes to an understanding of the micro mechanisms of price formation and their role in shaping market outcomes in both cases the features studied are largely neglected in the traditional market equilibrium analyses the related literature includes the articles by diamond 4 5 diamond and maskin 6 mortensen 8 9 and zusman and bell 13 these articles consider markets of the type described above in which transactions are concluded at pairwise meetings of agents the major difference between our work and these articles is in the approach to the basic bargaining problem in the cited articles it is assumed that a meeting is concluded with an instantaneous agreement which divides the associated surplus in an arbitrary predetermined way when the surplus is assumed to be divided equally the division rule is in fact nash s axiomatic bargaining solution in contrast the present paper treats the basic bargaining problem with the strategic approach see rubinstein 19 which constitutes an attempt to look into the bargaining black box this approach explicitly models the time dimension of the bargaining process describes in detail the bargaining procedure and justifies the agreement as a perfect equilibrium in

generalized search theoretic models of monetary exchange abstract virtually all simple search models of money assume agents with money cannot produce and so everyone has either 0 or 1 units of money in steady state we alternatively assume agents can always produce and simply restrict money inventories to 0 or 1 this seems better for many issues for example in the standard model it is difficult to interpret increases in the money supply because increasing the fraction of agents holding money decreases the economy s productive capacity our model avoids these problems and thus delivers more natural and simpler implications in many contexts we compare results on existence multiplicity and welfare across models

toward a theory of international currency we use the framework of random matching games and develop a two country model of the world economy in which two national currencies compete and may be circulated as media of exchange there are multiple equilibria which differ in the areas of circulation of the two currencies in one equilibrium the two national currencies are circulated only locally in another one currency is circulated as an international currency there is also an equilibrium in which both currencies are accepted internationally we also find an equilibrium in which the two currencies are directly exchanged we first characterize the existence conditions of these equilibria in terms of the relative country size and the degree of economic integration and then use an evolutionary approach to equilibrium selection to explain the evolution of the international currency as the two economies become more integrated some welfare implications are also discussed for example a country can improve its national welfare by letting its own currency circulate internationally provided the domestic circulation is controlled for when the total supply is fixed however a resulting currency shortage may reduce the national welfare

equilibrium wage dispersion and interindustry wage differentials this paper develops a search theoretic explanation of interindustry wage differentials given coordination problems in the labor market the probability of filling a vacancy is an increasing function of the wage offered in equilibrium firms that find vacancies more costly will offer higher wages the model thus explains the persistence of interindustry wage differentials and their correlation with industry average capital labor ratio and profitability additionally the model predicts that high wage firms will receive more applications per job opening and that wages in the labor market will behave as strategic complements

reprint of information percolation in segmented markets we study equilibria of dynamic over the counter markets in which agents are distinguished by their preferences and information over time agents are privately informed by bids and offers investors differ with respect to information quality including initial information precision and also in terms of market connectivity the expected frequency of their bilateral trading opportunities we characterize endogenous information acquisition and show how learning externalities affect information gathering incentives more liquid markets lead to higher equilibrium information acquisition when the gains from trade and market duration are sufficiently large on the other hand for a small market duration the opposite may occur if agents vary sufficiently in terms of their market connectivity c 2014 published by elsevier inc

price discovery in a matching and bargaining market with aggregate uncertainty abstract we introduce aggregate uncertainty into a rubinstein and wolinsky 1985 type dynamic matching and bilateral bargaining model the market can be either in a high state where there are more buyers than sellers or in a low state where there are more sellers than buyers traders do not know the state they randomly meet each other and bargain by making take it or leave it offers the only information transmitted in a meeting is the time a trader spent on the market there are two kinds of search frictions time discounting and exogenous exit we find that as the search frictions vanish the market discovers the competitive price quickly the prices offered in equilibrium converge in expectation to the true state walrasian price at the rate linear in the total search friction this rate is the same as it would be if the state were commonly known

money as a medium of exchange in an economy with artificially intelligent agents abstract we study the exchange economies of kiyotaki and wright 1989 in which agents must use a commodity or fiat money as a medium of exchange if trade is to occur our agents are artificially intelligent and are modeled as using classifier systems to make decisions in the assignment of credit within the classifier systems we introduce some innovations designed to study sequential decision problems in a multi agent environment for most economies that we have simulated trading and consumption patterns converge to a stationary nash equilibrium even if agents start with random rules in economies with multiple equilibria the only equilibrium that emerges in our simulations is the one in which goods with low storage costs play the role of medium of exchange i e the fundamental equilibrium of kiyotaki and wright

toward a strategic foundation for rational expectations equilibrium a step toward a strategic foundation for rational expectations equilibrium is taken by considering a double auction with n buyers and m sellers with interdependent values and affiliated private information if there are sufficiently many buyers and sellers and their bids are restricted to a sufficiently fine discrete set of prices then generically there is an equilibrium in nondecreasing bidding functions that is arbitrarily close to the unique fully revealing rational expectations equilibrium of the limit market with unrestricted bids and a continuum of agents in particular the large double auction equilibrium is almost efficient and almost fully aggregates the agents information

screening peers softly inferring the quality of small borrowers this paper examines the performance of new online lending markets that rely on nonexpert individuals to screen their peers creditworthiness we find that these peer lenders predict an individual s likelihood of defaulting on a loan with 45 greater accuracy than the borrower s exact credit score unobserved by the lenders who only see a credit category moreover peer lenders achieve 87 of the predictive power of an econometrician who observes all standard financial information about borrowers screening through soft or nonstandard information is relatively more important when evaluating lower quality borrowers our results highlight how aggregating over the views of peers and leveraging nonstandard information can enhance lending efficiency this paper was accepted by amit seru finance

rational expectations information acquisition and competitive bidding most rational expectations market equilibrium models are not models of price formation and naive mechanisms leading to such equilibria can be severely manipulable in this paper a bidding model is developed which has the market like features that bidders act as price takers and that prices convey information higher equilibrium prices convey more favorable information about the quality of the objects being sold than do lower prices bidders can benefit from trading only if they have a transactions motive or if they have access to inside information apart from exceptional cases prices are not fully revealing a two stage model is developed in which bidders may acquire information at a cost before bidding and for which the equilibrium price is fully revealing resolving a well known paradox

mean field equilibrium in dynamic games with strategic complementarities we study a class of stochastic dynamic games that exhibit strategic complementarities between players formally in the games we consider the payoff of a player has increasing differences between her own state and the empirical distribution of the states of other players such games can be used to model a diverse set of applications including network security models recommender systems and dynamic search in markets stochastic games are generally difficult to analyze and these difficulties are only exacerbated when the number of players is large as might be the case in the preceding examples we consider an approximation methodology called mean field equilibrium to study these games in such an equilibrium each player reacts to only the long run average state of other players we find necessary conditions for the existence of a mean field equilibrium in such games furthermore as a simple consequence of this existence theorem we obtain several natural monotonicity properties we show that there exist a largest and a smallest equilibrium among all those where the equilibrium strategy used by a player is nondecreasing and we also show that players converge to each of these equilibria via natural myopic learning dynamics as we argue these dynamics are more reasonable than the standard best response dynamics we also provide sensitivity results where we quantify how the equilibria of such games move in response to changes in parameters of the game for example the introduction of incentives to players

on money as a medium of exchange we analyze economies in which individuals specialize in consumption and production and meet randomly over time in a way that implies that trade must be bilateral and quid pro quo nash equilibria in trading strategies are characterized certain goods emerge endogenously as media of exchange or commodity money depending both on their intrinsic properties and on extrinsic beliefs there are also equilibria with genuine fiat currency circulating as the general medium of exchange we find that equilibria are not generally pareto optimal and that introducing fiat currency into a commodity money economy may unambiguously improve welfare velocity acceptability and liquidity are discussed

facts and figures on intermediated trade over the past several years trade economists have begun exploring the role that intermediar ies play in facilitating trade papers by james e rauch and joel watson 2004 dimitra petropoulou 2007 and pol antras and arnaud costinot 2009 model intermediaries as agents that facilitate matching between sellers exporters and foreign buyers these papers examine how improved intermediation matching technolo gies affect trade volumes and the gains from trade bernardo s blum sebastian claro and ignatius horstmann 2009 embed a reduced form match ing model inspired by robert townsend 1983 into a heterogeneous firm trade model and exam ine how changes in the trading environment affect trade costs export import volumes and the extent of trade flowing through trade intermediaries a key modeling challenge for this literature is how to structure matching and intermediation technologies in trading environments blum claro and horstmann 2009 provide certain facts for chile colombia trade and use these facts to structure trading technologies in this paper we provide a broader set of facts on trade intermediaries using new datasets for chile and for chile argentina trade 1 we think that these facts will prove particularly useful for future modeling of trade intermediaries

liquidity premia in dynamic bargaining markets abstract this paper develops a search theoretic model of the cross sectional distribution of asset returns abstracting from risk premia and focusing exclusively on liquidity in contrast with much of the transaction cost literature it is not assumed that different assets carry different exogenously specified trading costs instead different expected returns due to liquidity are explained by the cross sectional variation in tradeable shares the qualitative predictions of the model are consistent with much of the empirical evidence

existence of steady states with positive consumption in the kiyotaki wright model we prove the general existence of steady states with positive consumption in an n goods and fiat money version of the kiyotaki wright model by admitting mixed strategies we also show that there always exists a steady state in which everyone accepts a least costly to store object in particular if fiat money is one such object then there always exists a monetary steady state we also establish some other properties of steady states and comment on the relationship between steady states and incentive feasible allocations

sorting versus screening search frictions and competing mechanisms in a market where sellers compete by posting trading mechanisms we allow for a general search technology and show that its features crucially affect the equilibrium mechanism price posting prevails when meetings are rival i e when a meeting by one buyer reduces another buyer s meeting probability under price posting buyers reveal their type by sorting ex ante only if the meeting technology is sufficiently non rival price posting is not an equilibrium multiple buyer types then visit the same sellers who screen ex post through auctions

a theory of a generally acceptable medium of exchange and barter abstract this paper develops a model that accounts both for the existence of money defined as a generally acceptable medium of exchange and for the survival of some barter exchange in economies in which money exists in contrast to jones 1976 seminal article in which individuals are restricted to fix trading strategies before entering the market the present model assumes that individuals have conditional trading strategies that allow them to effect exchange according to the types of trades they encounter in the market the analysis shows how decentralized market forces generate money and lead to a unique level of monetization

information percolation in segmented markets we study equilibria of dynamic over the counter markets in which agents are distinguished by their preferences and information over time agents are privately informed by bids and offers investors differ with respect to information quality including initial information precision and also in terms of market connectivity the expected frequency of their bilateral trading opportunities we characterize endogenous information acquisition and show how learning externalities affect information gathering incentives more liquid markets lead to higher equilibrium information acquisition when the gains from trade and market duration are sufficiently large on the other hand for a small market duration the opposite may occur if agents vary sufficiently in terms of their market connectivity c 2014 published by elsevier inc

public information private information and the multiplicity of equilibria in coordination games abstract i study coordination games with incomplete public and private information and relate equilibrium convergence to convergence of higher order beliefs as the players signals become more and more precise the equilibrium manifold converges to the correspondence of common knowledge equilibria whenever the variance of the public signal converges to 0 at a rate faster than one half the rate of convergence of the variance of private signals the same condition also determines the convergence of common p belief to common knowledge which leads to a simple intuition for its origin and an immediate generalization of the former results about equilibrium convergence journal of economic literature classification numbers c72 d82

signaling in a global game coordination and policy traps this paper introduces signaling in a global game so as to examine the informational role of policy in coordination environments such as currency crises and bank runs while exogenous asymmetric information has been shown to select a unique equilibrium we show that the endogenous information generated by policy interventions leads to multiple equilibria the policy maker is thus trapped into a position in which self fulfilling expectations dictate not only the coordination outcome but also the optimal policy this result does not rely on the freedom to choose out of equilibrium beliefs nor on the policy being a public signal it may obtain even if the policy is observed with idiosyncratic noise

search with adverse selection this paper analyzes a sequential search model with adverse selection we study information aggregation by the price how close the equilibrium prices are to the full information prices when search frictions are small we identify circumstances under which prices fail to aggregate information well even when search frictions are small we trace this to a strong form of the winner s curse that is present in the sequential search model the failure of information aggregation may result in inefficient allocations

holdups and efficiency with search frictions a natural holdup problem arises in a market with search frictions firms have to make a range of investments before finding their employees and larger investments translate into higher wages in particular when wages are determined by ex post bargaining the equilibrium is always inefficient recognizing that capital intensive production relations have to pay higher wages firms reduce their investments this can only be prevented by removing all the bargaining power from the workers but this in turn depresses wages below their social product and creates excessive entry of firms in contrast to this benchmark we show that efficiency is achieved when firms post wages and workers can direct their search toward more attractive offers this efficiency result generalizes to an environment with imperfect information where workers only observe a few of the equilibrium wage offers we show that the underlying reason for efficiency is not wage posting per se but the ability of workers to direct their search toward more capital intensive jobs

ex ante price offers in matching games non steady states a matching problem is considered in which sellers can publicly commit to a trading price that differs from the price at which buyers expect to trade elsewhere in the market when demand and supply are nearly equal the equilibrium ex ante price offer lies below the price associated with the nash bargaining split this relationship reverses when the level of excess demand is large sellers always have an incentive to make ex ante offers when prices elsewhere are determined by nash bargaining this can be interpreted to mean that nash bargaining is an unstable pricing institution copyright 1991 by the econometric society

ratings shopping and asset complexity a theory of ratings inflation abstract many identify inflated credit ratings as one contributor to the recent financial market turmoil we develop an equilibrium model of the market for ratings and use it to examine possible origins of and cures for ratings inflation in the model asset issuers can shop for ratings observe multiple ratings and disclose only the most favorable before auctioning their assets when assets are simple agencies ratings are similar and the incentive to ratings shop is low when assets are sufficiently complex ratings differ enough that an incentive to shop emerges thus an increase in the complexity of recently issued securities could create a systematic bias in disclosed ratings despite the fact that each ratings agency produces an unbiased estimate of the asset s true quality increasing competition among agencies would only worsen this problem switching to an investor initiated ratings system alleviates the bias but could collapse the market for information

the assignment of workers to jobs in an economy with coordination frictions this paper studies the assignment of heterogeneous workers to heterogeneous jobs owing to the anonymity of a large labor market workers use mixed strategies when applying for jobs this randomness generates coordination frictions two workers may apply for a particular job whereas an identical job gets no applications the model generates assortative matching with a positive but imperfect correlation between matched workers and firms types it predicts that a worker s wage is increasing in her job s productivity and a firm s profit is increasing in its employees productivity the model also yields a version of the welfare theorems

a contribution to the pure theory of money abstract this article analyzes a general equilibrium model with search frictions and differentiated commodities because of the many differentiated commodities barter is difficult in that it requires a double coincidence of wants and this provides a medium of exchange role for fiat currency we prove the existence of equilibrium with valued fiat money and show it is robust to certain changes in the environment rate of return dominance liquidity and the welfare implications of fiat money are discussed

a decentralized market with common values uncertainty non steady states we analyse a market where i trade proceeds by random and anonymous pairwise meetings with bargaining ii agents are asymmetrically informed about the value of the traded good and iii no new entrants are allowed once the market is open we show that information revelation and efficiency never obtain in equilibrium even as discounting is removed this holds whether the asymmetry is two sided or one sided in some cases there exist equilibria where a substantial amount goes untraded this contrasts with the earlier literature which was based on the steadystate equilibria of a model where agents enter the market every period

are credit ratings procyclical abstract this paper studies the influence of the state of the business cycle on credit ratings in particular we assess whether rating agencies are excessively procyclical in their assignment of ratings our analysis is based on a model of ratings determination that takes into account factors that measure the business and financial risks of firms in addition to indicators of macroeconomic conditions utilizing annual data on all us firms rated by standard poor s we find that ratings do not generally exhibit excess sensitivity to the business cycle in addition we document that previously reported findings of a secular tightening of ratings standards are not robust to a more complete accounting of systematic changes to measures of risk

a directed search model of intermediated trade abstract this paper complements antras and costinot s 2010 analysis of a two good two country ricardian economy in which farmers produce either goods but require intermediaries to exchange their production in the goods markets the intermediation market is frictional whereas the goods market is perfectly competitive unlike their random search and price bargaining setup intermediaries herein post intermediation prices and farmers direct their search contrary to their findings we show that opening the economy to international trade always leads to welfare gains this is the case because domestic farmers benefit from relatively efficient intermediation technologies in terms of higher matching probabilities but also lower intermediation prices

information revelation in a market with pairwise meetings the paper presents a simple pairwise meetings model of trade the new feature is that agents have asymmetric information about the true state of the world the focus is on the transmission of the information through the process of trade the qualitative question is to what extent is the information revealed to uninformed agents through the trading process when the market is in some sense frictionless in particular does the decentralized process give rise to full revelation results as derived by the literature on rational expectations for centralized and competitive environments in the context of the model of this paper it turns out that the information is not fully revealed to uninformed agents even when the market is in some sense approximately frictionless

an introduction to the theory of rational expectations under asymmetric information every good economics textbook contains the cliche that market prices provide signals which facilitate the allocation of resources to their best use in a world not subject to random shocks consumers and producers when faced with competitive prices need look no further than their own preferences or production technology to be able to make a decision they need give no thought to the tastes endowments or technology of other agents however in a world subject to random shocks this is no longer the case agents are faced with the problem of forecasting future states of nature and more importantly of forecasting the impact of these states on the actions of other agents rational expectations theories provide a model of how agents make those forecasts in a world subject to random shocks it will be the case that agents acquire or at least attempt to acquire information about the future realization of the shocks it will in general be the case that different agents have access to different information the fact that information is dispersed throughout the economy has the potential to cause a misallocation of resources relative to what would be the case if all agents knew everything an efficient allocation of resources will in general require the transfer of information from consumers who have some information about their future demands to producers who can take current actions to mitigate avoidable scarcities or surpluses though many classical and neo classical writers emphasize the informational role of prices the standard marshallian or walrasian model of competitive equilibrium does not involve prices transferring information across traders the purpose of this paper is to show that rational expectations models are radically different from walrasian models in an economy where traders have diverse information this is demonstrated by showing that unlike what occurs in a walrasian equilibrium of an economy with heterogeneous information if there is a complete set of insurance markets and utility is additively separable over time then there exists a rational expectations equilibrium which gives consumers the same allocation as if each consumer has access to all of the economy s information this implies that under the above assumptions a central planner with all the economy s information could not pareto dominate the competitive allocation achieved when traders have diverse information and rational expectations this paper makes no attempt to survey the literature on rational expectations the reader is referred to shiller 1978 barro 1981 for a survey of macroeconomics and rational expectations and radner 1980 for a survey of the microeconomics and mathematical theory of rational expectations this paper will however try to outline the evolution of the rational expectations concept from a notion of optimal forecasting to a virtually complete departure from the walrasian model of equilibrium the rest of this section is devoted to a discussion of pre rational expectations ideas

information percolation momentum and reversal abstract we propose a joint theory of time series momentum and reversal based on a rational expectations model we show that a necessary condition for momentum to arise in this framework is that information flows at an increasing rate we focus on word of mouth communication as a mechanism that enforces this condition and generates short term momentum and long term reversal investors with heterogeneous trading strategies contrarian and momentum traders coexist in the marketplace although a significant proportion of investors are momentum traders momentum is not completely eliminated word of mouth communication spreads rumors and generates price run ups and reversals our theoretical predictions are in line with empirical findings

information percolation in large markets we introduce a simple model of the percolation of information of common interest through a large market as agents encounter each other over time and reveal information to each other some of which they may have received earlier from other agents we are particularly interested in the evolution over time of the cross sectional distribution in the population of the posterior probability assignments of the various agents we provide a market example based on privately held auctions and obtain a relatively explicit solution for the cross sectional distribution of posterior beliefs at each time our results contribute to the literature on information transmission in markets hayek 1945 argues that markets allow information that is dispersed in a population to be revealed through prices grossman s 1981 notion of a rational expectations equilibrium formalizes this idea in a setting with price taking agents milgrom 1981 pesendorfer and swinkels 1997 and reny and perry 2006 provide strategic foundations for the rational expectations equilibrium concept in centralized markets a number of important markets however are decentralized these include over the counter markets and private auction markets wolinsky 1990 and blouin and serrano 2002 study information transmission in decentralized markets in contrast to these two papers equilibrium behavior in our market example leads to full revelation of information we happily acknowledge conversations with manuel amador frank kelly jeremy stein and pierre olivier weill and research assistance from sergey lobanov rubinstein and wolinsky 1985 and gale 1986a 1986b study decentralized markets without asymmetric information satterthwaite and shneyerov 2003 study decentralized market with private value asymmetric information amador and weill 2006 study a more abstract setting regarding transmission of common and private i nformation

decentralized trading with private information the paper studies how asset prices are determined in a decentralized market with asymmetric information about asset values we consider an economy in which a large number of agents trade two assets in bilateral meetings a fraction of the agents has private information about the asset values we show that over time uninformed agents can elicit information from their trading partners by making small offers this form of experimentation allows the uninformed agents to acquire information as long as there are potential gains from trade in the economy as a consequence the economy converges to a pareto efficient allocation

presidential address social transmission bias in economics and finance i discuss a new intellectual paradigm social economics and finance the study of the social processes that shape economic thinking and behavior this emerging field recognizes that people observe and talk to each other a key underexploited building block of social economics and finance is social transmission bias systematic directional shift in signals or ideas induced by social transactions i use five fables models to illustrate the novelty and scope of the transmission bias approach and offer several emergent themes for example social transmission bias compounds recursively which can help explain booms bubbles return anomalies and swings in economic sentiment

heterogeneous beliefs in over the counter markets the behavior and stability of over the counter markets is of central concern to regulators little is known however about how the structure of these markets determine their properties in this paper we consider an over the counter market populated by boundedly rational heterogeneous traders in which the structure is represented by a network stability is found to decrease as the market becomes less well connected however the configuration of connections has a significant effect the presence of hubs such as those found in scale free networks increases stability and decreases volatility whilst small world short cut links have the opposite effect volatility in the fundamental value increases market volatility however volatility in the riskless asset returns has an ambiguous effect

experiments on percolation of information in dark markets in dark markets order submissions are bilateral and transaction prices are known only to the trading counterparties here we study to what extent the information aggregation theory proposed by duffie and collaborators predicts outcomes in a laboratory version of such markets we find that prices aggregate the available information but not in the strict sense of the theory where prices converge exponentially fast to average private signals prices instead fluctuate within bands around this average the band widths reflect in the best case the precision of the average signal and otherwise the precision of a single private signal

catalytic finance when does it work in a model of debt crisis caused partly by creditor coordination failure we show that bailouts that reduce ex post inefficiency will sometimes enhance the incentives for governments to take costly adjustment effort this model helps us understand a debate about the role of the imf in catalyzing lending to developing countries

coordination risk and the price of debt abstract creditors of a distressed borrower face a coordination problem even if the fundamentals are sound fear of premature foreclosure by others may lead to pre emptive action undermining the project recognition of this problem lies behind corporate bankruptcy provisions across the world and it has been identified as a culprit in international financial crises but has received scant attention from the literature on debt pricing without common knowledge of fundamentals the incidence of failure is uniquely determined provided that private information is precise enough this affords a way to price the coordination failure comparative statics on the unique equilibrium provides several insights on the role of information and the incidence of inefficient liquidation

credit rating and debt crises we develop an equilibrium theory of credit rating in the presence of rollover risk by influencing rational creditors ratings affect sovereigns probability of default which in turn affects ratings our analysis reveals a pro cyclical impact of credit rating in equilibrium the presence of a rating agency increases default risk when it is high and decreases default risk when it is low

crises and prices information aggregation multiplicity and volatility crises are volatile times when endogenous sources of information are closely monitored we study the role of information in crises by introducing a financial market in a coordination game with imperfect information the asset price aggregates dispersed private information acting as a public noisy signal in contrast to the case with exogenous information our main result is that uniqueness may not obtain as a perturbation from perfect information multiplicity is ensured with small noise in addition we show that a multiplicity may emerge in the financial price itself b less noise may contribute toward nonfundamental volatility even when the equilibrium is unique and c similar results obtain for a model where individuals observe one another s actions highlighting the importance of endogenous information more generally