why does the economy fall to pieces after a financial crisis the worst fi nancial crisis in the history of the united states and many other he worst fi nancial crisis in the history of the united states and many other countries started in 1929 the great depression followed the second worst countries started in 1929 the great depression followed the second worst struck in the fall of 2008 and the great recession followed commentators struck in the fall of 2008 and the great recession followed commentators have dwelt endlessly on the causes of these and other deep fi nancial collapses have dwelt endlessly on the causes of these and other deep fi nancial collapses less conspicuous has been the macroeconomists concern about why output and less conspicuous has been the macroeconomists concern about why output and employment collapse after a fi nancial crisis and remain at low levels for several or employment collapse after a fi nancial crisis and remain at low levels for several or many years after the crisis this article pursues modern answers to that question it many years after the crisis this article pursues modern answers to that question it focuses on events in the united states since 2008 focuses on events in the united states since 2008 existing macroeconomic models account successfully for the immediate effects existing macroeconomic models account successfully for the immediate effects of a fi nancial crisis on output and employment i will lay out a simple macro model of a fi nancial crisis on output and employment i will lay out a simple macro model that captures the most important features of modern models and show that realistic that captures the most important features of modern models and show that realistic increases in fi nancial frictions that occurred in the crisis of late 2008 will generate increases in fi nancial frictions that occurred in the crisis of late 2008 will generate declines in real gdp and employment of the magnitude that occurred but this declines in real gdp and employment of the magnitude that occurred but this model cannot explain why gdp and employment failed to recover once the fi nancial model cannot explain why gdp and employment failed to recover once the fi nancial crisis subsided the model implies a recovery as soon as fi nancial frictions return to crisis subsided the model implies a recovery as soon as fi nancial frictions return to normal at the end of the article i will mention the ideas that are in play to explain normal at the end of the article i will mention the ideas that are in play to explain the persistent adverse effects of temporary crises but these ideas have not made their the persistent adverse effects of temporary crises but these ideas have not made their way into the mainstream model way into the mainstream model this article cites only a few of the many important contributions to the mainthis article cites only a few of the many important contributions to the mainstream model my paper hall 2009 contains many citations and the forthcoming stream model my paper hall 2009 contains many citations and the forthcoming new volume of the new volume of the handbook of monetary economics discusses the literature fully discusses the literature fully

a direct mechanism characterization of sequential bargaining with one sided incomplete information we characterize the sequential equilibria of a class of infinite horizon bargaining games with one sided incomplete information when the seller the uninformed party makes all the offers we prove a folk theorem every incentive compatible individually rational direct bargaining mechanism is implementable by sequential equilibria introducing buyer counteroffers eliminates outcomes which are unfavorable to that party as the proportion of buyer offers increases the set of implementable mechanisms shrinks continuously when the proportion reaches one only the single outcome most favorable to the buyer remains thus depending on the offer structure sequentiality may or may not impose restrictions beyond static incentive compatibility

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

on the strategic role of outside options in bilateral bargaining this paper studies a model of the situation in which two players are bargaining face to face over the partition of a unit size cake and moreover one of the players can choose to temporarily leave the negotiating table to search for an outside option a main conclusion is that the equilibrium outcome does not depend on whether a bargainer is allowed within the game form to choose to return to the negotiating table to resume bargaining after having searched for some finite time moreover it is shown that our strategic bargaining search game approximately implements an appropriately defined nash bargaining solution

bargaining search and outside options abstract this paper studies a two sided incomplete information bargaining model between a seller and a buyer the buyer has an outside option which is modeled as a sequential search process during which he can choose to return to bargaining at any time two cases are considered in regime i both agents have symmetric information about the search parameters we find that in contrast to bargaining with complete information the option to return to bargaining is not redundant in equilibrium however the no delay result still holds in regime ii where agents have asymmetric information about the outside option delay is possible the solution characterizes the parameters for renegotiation and those for search with no return to the bargaining table

decentralized trading strategic behaviour and the walrasian outcome for a market with a finite number of agents pairwise matching and bargaining it is shown that even when the market is frictionless the equilibrium is not necessarily competitive it depends on the amount of information agents use if their behaviour is conditioned only on the sets of agents present and the time the competitive solution is the unique subgame perfect equilibrium if agents have full information and condition their behaviour on some of it there are also noncompetitive equilibria in which behaviour depends on specific information such as the identity of the trading partner and past events

signalling in a dynamic labour market this paper analyzes a multiperiod version of the spence job market signalling model in which workers cannot commit to an education choice and firms make wage offers at any point in time the dynamic competition combined with the incomplete information yield a multiplicity of sequential equilibria including ones that sustain implicit collusion even though the length of the game is finite emphasis is placed on equilibria that satisfy the independence of never weak best response criterion of kohlberg and mertens 1986 it is shown that in the limit as the time between offers tends to zero any such equilibrium results in expectation in the unique stable outcome of the static spence model

bargaining with two sided incomplete information an infinite horizon model with alternating offers this paper examines an infinite horizon bargaining model incorporating five features two sided incomplete information with potentially information revealing strategies an infinite horizon uncertainty concerning the potential gains from trade an illumination of interesting qualitative bargaining issues and plausible free from arbitrarily specified out of equilibrium conjectures equilibria these features motivated in the paper have powerful implications a nash equilibrium exists and is generically both unique and sequential comparative static implications of variations in the game s specifications are developed we find that natural indications of bargaining strength emerge from the model and establish the intuitive result that an increase in a player s relative bargaining strength makes that player more likely to capture the gains from bargaining

outside options and the failure of the coase conjecture a buyer wishes to purchase a good from a seller who chooses a sequence of prices over time each period the buyer can also exercise an outside option abandoning their search or moving on to another seller we show there is a unique equilibrium in which the seller charges a constant price in every period equal to the monopoly price contravening the coase conjecture we then embed the singleseller model into a search framework and show the result provides a foundation for the usual no haggling assumption jel c78 d42 d43 l12 l13 the coase conjecture is a cornerstone of modern microeconomic theory informing monopoly theory and providing a canonical example of the problem of commitment the idea is that for any given price high value buyers are more likely to purchase than low value buyers leading to negative selection in the demand pool accordingly the seller cuts its price over time causing high value buyers to delay their purchases the seller s inability to commit thus leads its later selves to exert a negative externality on its former selves reducing its overall profit gul sonnenschein and wilson 1986 this idea of negative selection is robust versions of it hold when costs are nonlinear kahn 1986 when goods depreciate over time bond and samuelson 1984 when there is entry of new buyers sobel 1991 and when the buyers face future competition fuchs and skrzypacz 2010 in this article we show that the coase conjecture fails in a natural environment where buyers have an outside option they can choose to exercise we consider a seller who faces a buyer or a continuum of buyers with unknown value for the good and unknown outside option each period the seller chooses price p t the buyer then chooses to buy wait or exercise his option and terminate the game the outside option may come from the possibility of buying another product for example when waiting for the price of the iphone to fall a customer could instead buy a comparable phone from a competitor similarly when bargaining over the price of a car a buyer may abandon negotiations and move on to the next dealer the outside option may also come from pursuing other objectives once the negotiation has terminated for example after he finishes bargaining at a bazaar a tourist could start seeing local attractions

okun s law theoretical foundations and revised estimates okun s law has been accepted as an empirical regularity that predicts a 3 percentage point increase in output for every 1 point reduction in the unemployment rate but only because other facts such as weekly hours induced labor supply and productivity tend to rise as well when output gaps are estimated for the u s economy with a production function approach using two different data sets for potential output and nairu it is found that the marginal contribution of a 1 point reduction in unemployment is only about two thirds percent increase in output changes in weekly hours and capacity utilization have independent effects on the output gap copyright 1993 by mit press

okun s law and productivity innovations a long tradition in macroeconomics dating back to arthur okun 1965 and walter oi 1962 regards cyclical productivity fluctuations as an artifact a residual generated from the incomplete and lagged response of employment and labor hours to demand driven fluctuations in real output in okun s version a one percent decline in output relative to trend is divided up into a reduction of 1 3 point in productivity and 2 3 point in aggregate hours the latter is further subdivided into a reduction of 1 3 point in the employment rate with the remaining adjustment taking the form of lower hours per employee and in the labor force participation rate hereafter lfpr yet this tradition of regarding cyclical productivity fluctuations as a byproduct of demand driven output cycles has been almost forgotten over the past three decades as a result of widespread adoption of the real business cycle rbc model in which productivity shocks are treated as exogenous as unexplained as unrelated to aggregate demand and as the sole driver of business cycles even in the more enlightened modern macro work on dynamic stochastic general equilibrium models aggregate demand and sticky prices have reappeared but most recent papers still include an autonomous technology shock as one of several causes of short term business cycle fluctuations revisiting and rethinking the business cycle

foundations of dynamic monopoly and the coase conjecture subgame perfect equilibria are characterized for a market in which the seller quotes a price each period assume zero costs positive interest rate continuum of buyers and some technical conditions if buyers valuations are positive then equilibrium is unique buyers strategies are stationary and the price sequence is determinant along the equilibrium path but possibly randomized elsewhere otherwise a continuum of stationary equilibria can exist but at most one with analytic strategies coase s conjecture is verified for stationary strategies reducing the period length drives all prices to zero or the least valuation connections to bargaining models are described journal qf economic literature classification

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

the role of external search in bilateral bargaining we consider the problem of bargaining between two individuals who can also search for possible alternatives to each other s offers we explicitly incorporate the search activity into the process of bargaining a disagreement in bargaining will lead each individual to search for an outside offer in the hope of improving his future bargaining position and attaining a more favorable outcome we model the interlaced phases of bargaining and search over time as an extensive noncooperative game we characterize the associated subgame perfect equilibrium outcome and strategies finally we show that superior search ability yields an individual a more favorable outcome and hence represents a greater bargaining strength

public vs private offers in the market for lemons we study the role of observability in bargaining with correlated values short run buyers sequentially submit offers to one seller when previous offers are observable bargaining is likely to end up in an impasse in contrast when offers are hidden agreement is always reached although with delay

ipo underpricing and international corporate governance it is well established that a link exists between a country s legal system and the size liquidity and value of its capital markets we study how differences in country level governance affect the underpricing of initial public offerings ipos examining 4462 ipos across 29 countries from 2000 to 2004 we find the surprising result that underpricing is higher in countries with corporate governance that strengthens the position of investors relative to insiders we conjecture that when countries give outsiders more influence ipo issuers underprice more to generate excess demand for the offer which in turn leads to greater ownership dispersion and reduces outsiders incentives to monitor the behavior of corporate insiders in other words underpricing is a cost that insiders pay to maintain control in countries with legal systems designed to empower outsiders consistent with this control motivation for underpricing we find that underpricing has a negative association with post ipo outside blockholdings and a positive association with private control benefits in addition firms whose insiders are entrenched either by majority ownership or by dual class structures do not underprice more in countries with better governance in these firms the ownership structure protects managers from outside influence eliminating the incentive to increase outside ownership dispersion through underpricing

bargaining and search with recall a two period model with complete information two standard results of previous bargaining models state that delay is generally not expected to occur under complete information and bargaining outcome depends crucially on the bargainers intrinsic characteristics that determine their reservation prices and in general bargainers with better reservation prices tend to get better outcomes this paper considers a bilateral bargaining problem with complete information in which one of the bargainers the buyer is allowed to search while bargaining more importantly we assume that the buyer is allowed to recall past outside offers we find that quite contrary to the standard results of previous complete information bargaining models complete information renders no guarantee for immediate resolution of bargaining and the effect of changing the buyer s search cost on each player s bargaining outcome is unpredictable the major driving force of these two results is the assumption that the buyer can recall past outside offers

rubinstein auctions on competition for bargaining partners abstract this paper analyzes the effect of competition for bargaining partners on the prices that prevail in thin markets as well as how the matches are simultaneously determined three trading processes or bargaining procedures are described in all the variants that we consider except for one case of public offers either there is no pure strategy subgame perfect equilibrium or such equilibria exhibit delay in reaching agreement journal of economic literature classification numbers c72 d43

bargaining and reputation in search markets in a two sided search market agents are paired to bargain over a unit surplus the matching market serves as an endogenous outside option for a bargaining agent behavioral agents are commitment types that demand a constant portion of the surplus the frequency of behavioral types is determined in equilibrium even if the frequency of behavioral types is negligible they aect the terms of trade and eciency in an unbalanced market where the entering

bilateral trading and incomplete information price convergence in a small market abstract we study a model of decentralised bilateral interactions in a small market where one of the sellers has private information about her value in addition to this seller with private information there are two identical buyers and another seller whose valuation is commonly known to be in between the two possible valuations of the seller with private information we consider an infinite horizon game with simultaneous one sided offers and simultaneous responses we construct one particular pbe of the game and show that as the discount factor goes to 1 prices in all transactions converge to the same value we then show that this is the case with any stationary equilibrium of the game that is the asymptotic outcome is unique across all stationary equilibria

asymptotic efficiency for discriminatory private value auctions we consider discriminatory auctions for multiple identical units of a good players have private values possibly for multiple units none of the usual assumptions about symmetry of players distributions over values or symmetry of equilibrium play are made because of this equilibria will typically involve inefficient allocations equilibria also become very difficult to solve for using an approach which does not depend on explicit equilibrium calculations we show that such auctions become arbitrarily close to efficient as the number of players and possibly the number of objects grows large and provide a simple characterization of limit equilibria

output unemployment and okun s law some evidence from the g7 an economy may move between high effort and low effort states our estimates of the threshold unemployment rate which separates these states are significantly positive for g7 countries only german data exhibit tendency to being persistently in the high effort state

is there a core of practical macroeconomics that we should all believe with emphasis on the adjective practical and the normative verb should my answer to the question of this session is a resounding yes indeed i spent a good deal of time between january 1993 and january 1996 acting on the belief that there is such a core macro model so i certainly hope it exists this believable core model falls well short of perfection leaves many questions unanswered and is subject to substantial stochastic errors nonetheless it is both useful and extensively used in policy analysis where contact with reality is a necessity and you cannot beat something with nothing it also closely resembles but does not quite match the way macroeconomics is taught to beginning and intermediate but not to graduate students in this short presentation i will describe briefly the main practical elements that i think we should agree on without worrying too much about their theoretical underpinnings then i will turn to two critical failings of the standard macro model which cry out for theoretical and empirical repair my organizing principle is the textbook exposition that has been standard though not universal in teaching intermediate macroeconomics for years the question is how does it differ from the core model used in policy analysis

bargaining and search with incomplete information about outside options abstract this paper considers a model of bargaining in which the seller makes offers and the buyer can search at a cost for an outside option the outside option cannot be credibly communicated and the seller s offer is recallable by the buyer for one period there are essentially two equilibrium regimes for sufficiently high search cost the game ends immediately otherwise the search occurs in equilibrium compared to the case where the buyer can communicate his outside option the seller is worse off and the game results in search for a smaller set of values of the search cost i e less equilibrium delay c72

on the role of outside options in bargaining with obstinate parties the presence of obstinate types in bargaining has been shown to alter dramatically the bargaining equilibrium strategies and outcomes this paper shows that outside options may cancel out the effect of obstinacy in bargaining when parties have access to stationary outside options we show that when opting out is preferable to accepting the inflexible demand of the other party there is a unique perfect bayesian equilibrium in which each party reveals himself as rational as soon as possible a similar conclusion holds when outside options may only be available at a later date or when only one party has access to an outside option

gdp dynamics and unemployment changes in developed and developing countries abstractwe design a new specification of okun s model that takes the following features into account estimation of the relation in first differences the possible lagged effect of gdp dynamics on

a multistage model of bargaining this paper presents a simple multistage model of bargaining wherein a seller makes an offer that can be either accepted or refused if rejected the process continues how the seller s ability to make commitments affects bargaining outcomes is analysed by comparing the commitment equilibria to those arising when commitment is impossible the effects of increasing uncertainty about preferences and varying the length of the bargaining horizon are analysed the ways in which the bargaining environment can be changed to improve outcomes are discussed

on delay in bargaining with one sided uncertainty recently attention has been given to a model of two person bargaining in which the parties alternate making offers and there is uncertainty about the valuation of one party the purpose of the analysis has been to identify delay to agreement with a screening process where agents with relatively lower valuations distinguish themselves by waiting longer to settle we point out a fundamental difficulty with this program by demonstrating that the assumptions used in the literature allow for delay only in so far as the time between offers is significant

uncertainty shocks and unemployment dynamics in u s recessions abstract what are the effects of uncertainty shocks on unemployment dynamics we answer this question by estimating non linear smooth transition vars with post wwii u s data the relevance of uncertainty shocks is found to be much larger than that predicted by standard linear vars in terms of i magnitude of the reaction of the unemployment rate to such shocks and ii contribution to the variance of the prediction errors of unemployment at business cycle frequencies the ability of different classes of dsge models to replicate our results is discussed