a multiobjective approach to vendor selection abstract purchases from vendors involve significant costs for many firms decisions related to these purchases include the selection of vendors and the determination of order quantities to be placed with the selected vendors such decisions are frequently multiobjective in nature that is they are evaluated by more than one criterion at least 23 criteria for various vendor selection problems have been identified in this article we present a multiobjective approach to systematically analyze the inherent tradeoffs involved in multicriteria vendor selection problems the approach is motivated by and demonstrated with an actual purchasing problem facing a division of a fortune 500 company

inefficient credit booms this paper studies the welfare properties of competitive equilibria in an economy with financial frictions hit by aggregate shocks in particular it shows that competitive financial contracts can result in excessive borrowing ex ante and excessive volatility ex post even though from a first best perspective the equilibrium always displays under borrowing from a second best point of view excessive borrowing can arise the inefficiency is due to the combination of limited commitment in financial contracts and the fact that asset prices are determined in a spot market this generates a pecuniary externality that is not internalized in private contracts the model provides a framework to evaluate preventive policies which can be used during a credit boom to reduce the expected costs of a financial crisis copyright 2008 wiley blackwell

fuzzy multiobjective linear model for supplier selection in a supply chain abstract within new strategies for purchasing and manufacturing suppliers play a key role in achieving corporate competition hence selecting the right suppliers is a vital component of these strategies in practice vagueness and imprecision of the goals constraints and parameters in this problem make the decision making complicated in spite of the importance of the problem the literature on this subject is relatively scarce in this paper a fuzzy multiobjective linear model is developed to overcome the vagueness of the information for the first time in a fuzzy supplier selection problem an asymmetric fuzzy decision making technique is applied to enable the decision maker to assign different weights to various criteria the model is explained by an illustrative example

asset price fluctuations without aggregate shocks we analyze the pricing of a productive asset in a class of dynamic exchange economies with heterogeneous infinitely lived agents and self enforcing intertemporal trades individual incomes fluctuate and are correlated preferences dividends and aggregate income are fixed almost all economies in this class have a unique stationary markovian equilibrium with fluctuations in asset prices as the set of unrationed households changes over time and states excess demand functions shift asset returns fluctuate and some households are shut out of asset markets examples suggest that the amplitude of these movements is negatively correlated with the productivity of the asset and with the penalty for default

anonymous markets and monetary trading abstract we study infinite horizon monetary economies characterized by trading frictions that originate from random pairwise meetings and commitment and enforcement limitations we prove that introducing occasional trade in centralized markets opens the door to an informal enforcement scheme that sustains a non monetary efficient allocation all is required is that trading partners be patient and their actions be observable we then present a matching environment in which trade may occur in large markets and yet agents trading paths cross at most once this allows the construction of models in which infinitely lived agents trade in competitive markets where money plays an essential role

optimal bankruptcy code a fresh start for some abstract what is the optimal consumer bankruptcy law i answer this question using an incomplete markets life cycle model with a planner who can choose state contingent bankruptcy costs i develop two main theoretical characterizations first whenever debt discharge is allowed it should occur without cost second bankruptcy should always be allowed for highly indebted households quantitatively the optimal policy can generate a welfare gain as large as 11 6 however attractive informal default asymmetric information and moral hazard can reduce the welfare gain to as little as 0 7

investments holdup and the form of market contracts the authors analyze incomplete contracts to induce efficient investment with exogenous switching costs fixed price contracts are efficient generate some rigidity in prices are renegotiated intermittently by possibly small amounts and when inflation is positive generate asymmetric responses to shocks all consistent with evidence on prices and wages with two sided specific investments efficiency requires prices to have sufficient escalator clauses to avoid renegotiation as observed in many long term contracts a third case with one sided specific investments can generate take or pay contracts and explain why firms sometimes pay for specific investments that appear to benefit employees directly

banking a new monetarist approach we develop a model where i banks take deposits and make investments ii their liabilities facilitate third party transactions other models have i or ii not both although we argue they are intimately connected we show that they both emerge from limited commitment we describe an environment characterize desirable allocations and interpret the outcomes as banking arrangements banks are essential without them the set of feasible allocations is inferior as a technical contribution we characterize dynamically optimal credit allocations with frictions show they involve backloading and analyse how this interacts with banking we also confront the theory with economic history copyright 2013 oxford university press

stationary sunspot equilibria in a finance constrained economy abstract stationary sunspot equilibria are shown to exist in a production economy with infinite lived agents when it is not possible to borrow against future wage income equilibrium fluctuations exhibit persistence over time scales of the same order of magnitude as observed business cycles an active fiscal policy that stabilizes aggregate money expenditures can prevent such fluctuations

on the future of macroeconomics a new monetarist perspective this article argues that a pressing goal for macroeconomics is to incorporate financial considerations but we need models with solid microfoundations in particular the use of assets in facilitating exchange as well as different credit or other financial arrangements should be outcomes of not inputs to theories as a preview i suggest that mainstream macro does a good job explaining many phenomena and a financial crisis does not disprove such theory but understanding crises requires better incorporating factors related to money credit banking and liquidity the approach called new monetarist economics can help a lot in this regard

heterogeneous beliefs and trading inefficiencies abstract heterogeneous beliefs are introduced into the monetary economy of lagos and wright 2005 and the implications for monetary equilibria are considered an endogenous fraction of agents hold rational expectations and the remaining agents employ an adaptive learning rule similar to evans and honkapohja 2001 and brock and hommes 1997 three primary results follow from the finding that heterogeneous beliefs can destabilize a stationary monetary equilibrium and lead to non linear dynamics bounded around the monetary steady state first heterogeneous beliefs can lead to equilibria that are welfare reducing due in part to a lower acceptance rate in decentralized meetings second when buyers who are uncertain about their beliefs behave like bayesians by placing a prior on sellers beliefs uncertainty impacts dynamic stability and welfare third the model s unique predictions provide an explanation of new findings about the acceptance rate in monetary laboratory experiments

a note on simple strategic bargaining for models of money or credit many papers on liquidity have bilateral trade with buyers constrained by their money holdings or debt limits axiomatic bargaining typically nash determines the terms of trade however there are reasons to prefer strategic bargaining i analyze a bargaining game that is useful in models of liquidity advantages include i it has simple microfoundations both in and out of steady state ii it is more tractable than nash but the outcomes share interesting features iii the benchmark version is consistent with axiomatic approaches in the literature while another version is not but can still be used and iv it is arguably realistic

agency and optimal investment dynamics agency problems limit firms access to capital markets curbing investment firms and investors seek contractual ways to mitigate these problems what are the implications for investment we present a theory of a firm s investment dynamics in the presence of agency problems and optimal long term financial contracts we derive results relating firms investment decisions current and past cash flows firm size capital structure and dividends among the results optimal investment is increasing in current and past cash flow and optimal investment is positively serially correlated over time after controlling for investment opportunities these results hold for a range of agency problems jel g30 g31 g32 g35 d82 d86 d92 copyright 2007 oxford university press

bubbles and self enforcing debt we characterize equilibria with endogenous debt constraints for a general equilibrium economy with limited commitment in which the only consequence of default is losing the ability to borrow in future periods first we show that equilibrium debt limits must satisfy a simple condition that allows agents to exactly roll over existing debt period by period second we provide an equivalence result whereby the resulting set of equilibrium allocations with self enforcing private debt is equivalent to the allocations that are sustained with unbacked public debt or rational bubbles in contrast to the classic result by bulow and rogoff 1989a positive levels of debt are sustainable in our environment because the interest rate is sufficiently low to provide repayment incentives

financial intermediary capital we propose a dynamic theory of financial intermediaries that are better able to collateralize claims than households that is have a collateralization advantage intermediaries require capital as they have to finance the additional amount that they can lend out of their own net worth the net worth of financial intermediaries and the corporate sector are both state variables affecting the spread between intermediated and direct finance and the dynamics of real economic activity such as investment and financing the accumulation of net worth of intermediaries is slow relative to that of the corporate sector the model is consistent with key stylized facts about macroeconomic downturns associated with a credit crunch namely their severity their protractedness and the fact that the severity of the credit crunch itself affects the severity and persistence of downturns the model captures the tentative and halting nature of recoveries from crises

lending terms and aggregate productivity abstract several empirical studies suggest that lending terms are eased in expansions and tightened in recessions thereby influencing the mix of financed entrepreneurs we study a model of adverse selection in competitive financial markets and show that lending terms deteriorate with the aggregate state under two general conditions if exogenous increments to entrepreneurs productivity raise returns to investment and or tighten the credit line needed to screen out a given entrepreneur type competition results in contracts with less screening two endogenous effects on productivity emerge production scales grow closer to optimal but lower productivity entrepreneurs enter the mix of producers the positive negative effect dominates at low high aggregate states

optimal security design how should new securities be designed traditional theories have little to say on this the literature on capital structure and general equilibrium theories with incomplete markets take the securities firms issue as exogenous this paper explicitly incorporates the transaction costs of issuing securities and develops a model where the instruments that are traded are chosen optimally and the economy s market structure is endogenous among other things it is shown that the firm s income stream should be split so that in every state all payoffs are allocated to the security held by the group that values them most this abstract was borrowed from another version of this item

liquidity constrained markets versus debt constrained markets this paper compares two different models in a common environment the first model has liquidity constraints in that consumers save a single asset that they cannot sell short the second model has debt constraints in that consumers cannot borrow so much that they would want to default but is otherwise a standard complete markets model both models share the features that individuals are unable to completely insure against idiosyncratic shocks and that interest rates are lower than subjective discount rates in a stochastic environment the two models have quite different dynamic properties with the debt constrained model exhibiting simple stochastic steady states while the liquidity constrained model has greater persistence of shocks

money and credit redux do we need both money and credit in models with explicit roles for payment instruments we show the answer is no if credit is easy money is useless if credit is tight money can be essential but then credit is irrelevant and changes in debt limits are neutral real balances respond endogenously to leave total liquidity constant this is true for exogenous or endogenous policy and debt limits secured or unsecured credit and fairly general preferences and pricing mechanisms while we also show how to overturn some results the benchmark model suggests credit conditions matter less than some people think

equilibrium models displaying endogenous fluctuations and chaos abstract this paper surveys current developments in dynamic general equilibrium theory concerned with conditions under which endogenous fluctuations are possible existing contributions are divided into two classes the larger one consists of models with a unique perfect foresight equilibrium while the second includes models where equilibrium is indeterminate and the set of equilibria involving endogenous fluctuations includes sunspots equilibria while the two classes of models involve oscillations of different natures and with different policy implications we show that both are consistent with optimizing behavior and competitive equilibrium

the societal benefit of a financial transaction tax we provide a novel justification for a financial transaction tax for economies where agents face stochastic consumption opportunities a financial transaction tax makes it more costly for agents to readjust their portfolios of liquid and illiquid assets in response to liquidity shocks which increase both the demand for and the price of liquid assets the higher price improves liquidity insurance and welfare for other market participants we calibrate the model to u s data and find that the optimal financial transaction tax is 1 6 and that it reduces the volume of financial trading by 17

integrated fuzzy multi criteria decision making method and multi objective programming approach for supplier selection and order allocation in a green supply chain abstract an organization s environmental performance is affected by its suppliers environmental performance and selecting green suppliers is a strategic decision in order to be more competitive in today s global market the supplier selection problem involves several quantitative and qualitative criteria in the supplier selection process if suppliers have limited capacity or other constraints it is necessary to determine the best supplier and order quantity of each supplier in this paper we present an integrated approach of fuzzy multi attribute utility theory and multi objective programming for rating and selecting the best green suppliers according to economic and environmental criteria and then allocating the optimum order quantities among them at first the fuzzy analytic hierarchy process and fuzzy technique for order preference by similarity to ideal solution is applied in order to analyze the importance of multiple criteria by incorporating experts opinion and to determine the best green suppliers next multi objective linear programming is used to consider and to formulate various constraints such as quality control capacity and other objectives the objective of the mathematical model is simultaneously to maximize the total value of purchasing and to minimize the total cost of purchasing to handle the subjectivity of decision makers preferences fuzzy logic has been applied the efficiency and application of the proposed approach has been illustrated with a case study in an automobile manufacturing company the obtained results help firms establish a systematic approach for tackling green supplier selection and order allocation problems in a realistic situation finally managerial implications conclusions and directions for additional research are introduced

money in search equilibrium in competitive equilibrium and in competitive search equilibrium we compare three market structures for monetary economies bargaining search equilibrium price taking competitive equilibrium and price posting competitive search equilibrium we also extend work on the microfoundations of money by allowing a general matching technology and entry we study how equilibrium and the effects of policy depend on market structure under bargaining trade and entry are both inefficient and inflation implies first order welfare losses under price taking the friedman rule solves the first inefficiency but not the second and inflation may actually improve welfare under posting the friedman rule yields the first best and inflation implies second order welfare losses

dynamic security design convergence to continuous time and asset pricing implications an entrepreneur with limited liability needs to finance an infinite horizon investment project an agency problem arises because she can divert operating cash flows before reporting them to the financiers we first study the optimal contract in discrete time this contract can be implemented by cash reserves debt and equity the latter is split between the financiers and the entrepreneur and pays dividends when retained earnings reach a threshold to provide appropriate incentives to the entrepreneur the firm is downsized when it runs short of cash we then study the continuous time limit of the model we prove the convergence of the discrete time value functions and optimal contracts our analysis yields rich implications for the dynamics of security prices stock prices follow a diusion reflected at the dividend barrier and absorbed at zero their volatility as well as the leverage ratio of the firm increase after bad performance stock prices and book tomarket ratios are in a non monotonic relationship a more severe agency problem entails lower price earning ratios and firm liquidity and higher default risk

moral hazard credit cycles with risk averse agents abstract we consider a simple overlapping generations model with risk averse financial agents subject to moral hazard efficient contracts for such financial intermediaries involve back loaded late career rewards compared to the analogous model with risk neutral agents risk aversion tends to reduce the growth of agents responsibilities over their careers this moderation of career growth rates can reduce the amplitude of the widest credit cycles but it also can cause small deviations from steady state to amplify over time in rational expectations equilibria we find equilibria in which fluctuations increase until the economy enters a boom bust cycle where no financial agents are hired in booms

multi objective models for lot sizing with supplier selection abstract in this paper two multi objective mixed integer non linear models are developed for multi period lot sizing problems involving multiple products and multiple suppliers each model is constructed on the basis of three objective functions cost quality and service level and a set of constraints the total costs consist of purchasing ordering holding and backordering and transportation costs ordering cost is seen as an ordering frequency dependent function whereas total quality and service level are seen as time dependent functions the first model represents this problem in situations where shortage is not allowed while in the second model all the demand during the stock out period is backordered considering the complexity of these models on the one hand and the ability of genetic algorithms to obtain a set of pareto optimal solutions we apply a genetic algorithm in an innovative approach to solve the models comparison results indicate that in a backordering situation buyers are better able to optimize their objectives compared to situations where there is no shortage if we take ordering frequency into account the total costs are reduced significantly

liquidity and asset market dynamics this study analyzes economies with an essential role for liquid assets in the exchange process the model can generate multiple stationary equilibria across which asset prices market participation capitalization output and welfare are positively related it can also generate a variety of nonstationary equilibria even when fundamentals are deterministic and time invariant including periodic chaotic and stochastic sunspot equilibria with recurrent market crashes some equilibria have asset price trajectories that resemble bubbles growing and bursting endogenous private and public liquidity is also introduced sometimes it is efficient to provide enough liquid assets to satiate demand other times it is not

the effect of liquidity constraints on consumption a cross sectional analysis this paper examines the effect of liquidity constraints on consumption expenditures using a single year cross section data set a reduced form equation for consumption is estimated on high saving households by the tobit procedure to account for the selectivity bias since high saving households are not likely to be liquidity constrained the estimated equation is an appropriate description of how desired consumption that would be forthcoming without liquidity constraints is related to the variables available in the cross section data when the reduced form equation is used to predict desired consumption the gap between desired consumption and measured consumption is most evident for young households

impatience versus incentives this paper studies the dynamics of long term contracts in repeated principal agent relationships with an impatient agent despite the absence of exogenous uncertainty pareto optimal dynamic contracts generically oscillate between favoring the principal and favoring the agent

presidential politics budget deficits and monetary policy in the united states 1960 1976 this paper has focused on the extent to which the traditional tools of macroeconomic management in the united states monetary and fiscal policy have contributed to a political business cycle regardless of whether politicians can successfully influence real economic variables to their own ends the evidence presented here suggests that they tried and that they enjoyed some at least indirect aid from their independent monetary authorities in doing so several major conclusions emerge

business cycles and the political process the interrelationship between the political sector and the macroeconomy in democratic societies has been examined extensively in recent years research in this area has generally been concerned with two issues first following the lead of kramer 16 various authors have examined the impact of economic conditions on congressional 1 13 21 24 and presidential elections 4 5 the results at the congressional level have been mixed but it is reasonably safe to conclude that economic conditions do affect presidential elections the second issue and the one of primary concern in this study has dealt with the development of models of politico economic interaction the basic concept in these models is that an administration s popularity and therefore the probability of staying in power depends critically on economic conditions knowing this the administration seeks to manipulate the economy in order to maintain power the use of economic tools for political goals by governments is well established in the literature theoretical contributions by nordhaus 20 and macrae 18 have demonstrated the potential for a politically motivated business cycle in a world of politico economic interaction empirical support for the existence of such a cycle is provided by the work of frey and schneider 7 8 9 the main purpose of this paper is to develop a theoretical model of the political business cycle that generates empirically testable proposition the goal is to integrate the theoretical conclusions of a formal model similar to the nordhaus 20 and macrae 18 framework with the empirical support provided by frey and schneider 7 8 9 the possibility of a political business cycle is important for several reasons in macroeconometric models government policy that is endogenous to the system is usually treated as if it were exogenous this may cause serious misspecification errors further forecasts of the future course of economic events which depend heavily on government action will be inaccurate unless the political motivations of governments are considered

money and credit with limited commitment and theft we study the interplay among imperfect memory limited commitment and theft in an environment that can support monetary exchange and credit imperfect memory makes money useful but it also permits theft to go undetected and therefore provides lucrative opportunities for thieves limited commitment constrains credit arrangements and the constraints tend to tighten with imperfect memory as this mitigates punishment for bad behavior in the credit market theft matters for optimal monetary policy but at the optimum theft will not be observed in the model the friedman rule is in general not optimal with theft and the optimal money growth rate tends to rise as the cost of theft falls

international coordination of fiscal policy in limiting economies we examine the limiting behavior of cooperative and noncooperative fiscal policies as countries market power goes to zero we show that these policies converge if countries raise revenues through lump sum taxation however if there are unremovable domestic distortions such as distorting taxes there can be gains to coordination even when a single country s policy cannot affect world prices these results differ from the received wisdom in the optimal tariff literature the key distinction is that contrary to the tariff literature the spending decisions of governments are explicitly modeled

the political timing of errors in inflation forecasts errors in inflation forecasts do not display a regular electoral rhythm over the entire post war period these results are consistent with the work of mccallum 1978 who explored a sample of similar length and failed to find an electoral pattern in unemployment rates however if unanticipated inflation is regarded as a lagging indicator of policy effectiveness then the data do suggest that three of the four most recent administrations have enjoyed a certain success in manufacturing a pre election upturn

the total cost of logistics in supplier selection under conditions of multiple sourcing multiple criteria and capacity constraint abstract little attention is given in the literature to decisions on the appropriate selection of suppliers and on assigning order quantities to these suppliers in the case of multiple sourcing with multiple criteria and with suppliers capacity constraints only a few mathematical programming models to analyse such decisions have been published to date and these have tended to consider only net price as the cost of purchasing although the costs of transportation ordering and storage may be significantly important to the decision in this paper a mixed integer non linear programming model is presented to solve the multiple sourcing problem which takes into account the total cost of logistics including net price storage transportation and ordering costs buyer limitations on budget quality service etc can also be considered in the model an algorithm is proposed to solve the model and the model is illustrated using a numerical example

a model of moral hazard credit cycles this paper considers a simple model of credit cycles driven by moral hazard in financial intermediation financial agents or bankers must earn moral hazard rents but the cost of these rents can be efficiently spread over an agent s entire career by promising large late career rewards if the agent has a consistently successful record dynamic interactions among different generations of financial agents can create credit cycles with repeated booms and recessions in recessions a scarcity of trusted financial intermediaries limits investment and reduces employment under such conditions taxing workers to subsidize bankers may increase employment enough to make the workers better off

intermediation in markets for goods and markets for assets abstract we analyze agents decisions to act as producers or intermediaries using equilibrium search theory extending previous analyses in various ways we ask when intermediation emerges and study its efficiency in one version of the framework meant to resemble retail middlemen hold goods which entails storage costs that model always displays uniqueness and simple transition dynamics in another version middlemen hold assets which entails negative costs i e positive returns that model can have multiple equilibria and complicated belief based dynamics these results are consistent with the venerable view that intermediation in financial markets is more prone to instability than in goods markets

the role of intergenerational transfers in aggregate capital accumulation this paper uses historical u s data to directly estimate the contribution of intergenerational transfers to aggregate capital accumulation the evidence presented indicates that intergenerational transfers account for the vast majority of aggregate u s capital formation only a negligible fraction of actual capital accumulation can be traced to life cycle or hump savings a major difference between this study and previous investigations of this issue is the use of more accurate longitudinal age earnings and age consumption profiles these profiles are simply too flat to generate substantial life cycle savings this paper suggests the importance of and need for substantially greater research and data collection on intergenerational transfers life cycle models of savings that emphasize savings for retirement as the dominant form of capital accumulation should give way to models that illuminate the determinants of intergenerational transfers

credit markets limited commitment and government debt a dynamic model with credit under limited commitment is constructed in which limited memory can weaken the effects of punishment for default this creates an endogenous role for government debt in credit markets and the economy can be non ricardian default can occur in equilibrium and government debt essentially plays a role as collateral and thus improves borrowers incentives the provision of government debt acts to discourage default whether default occurs in equilibrium or not these are our own views and not necessarily those of the federal reserve banks of richmond and st louis or the board of governors of the federal reserve system we thank seminar and conference participants at the chicago federal reserve bank workshop on money banking and payments the 2012 sed meetings along with 3 anonymous referees and the editor dimitri vayanos for their helpful comments and suggestions

pareto optima and competitive equilibria with adverse selection and moral hazard this paper explores the extent to which standard general equilibrium analysis of pareto optima and of competitive equilibria can be applied to environments with moral hazard and adverse selection problems allowing for lotteries contracts with random components we first establish that an adverse selection insurance economy a moral hazard insurance economy a signaling economy and a private information labor market economy are all special cases of a simple general structure we then show that techniques for characterizing pareto optimal contracts as solutions to concave programming problems are useful and nice and appear to be broadly applicable allowing for lotteries we show how to characterize the optimal allocations for the adverse selection insurance and labor market economies we then show that standard existence and optimality theorems for competitive equilibria apply in the linear space containing lotteries if agents with characteristics which are distinct and privately observed at the time of initial trading enter the economy wide resource constraints in a homogeneous way other kinds of diversity are not critical for economies with moral hazard which satisfy the homogeneity condition competitive contract markets single out a subset of the optima and thus can be consistent with apparent unemployment and with a random allocation of labor supplied though all households are averse to risk the adverse selection insurance and signaling economies however do not satisfy the homogeneity condition and are difficult to decentralize efficiently with a price system

bargaining and the value of money abstract search models of monetary exchange have typically relied on nash 1950 the bargaining problem econometrica 18 155 162 bargaining or strategic games that yield an equivalent outcome to determine the terms of trade by considering alternative axiomatic bargaining solutions in a search model with divisible money we show that the properties of the bargaining solutions do matter both qualitatively and quantitatively for questions of first degree importance in monetary economics such as i the efficiency of monetary equilibrium ii the optimality of the friedman rule and iii the welfare cost of inflation

sunspot equilibria rational bubbles in a model of money in the utility function abstract sunspot equilibria are constructed in brock s 1975 model of money in the utility function serial correlations of real balances and the nominal interest rate in these equilibria can be either positive or negative the example here suggests that local sunspots are more likely to exist when the agent s discount rate is small and that serial correlations in local sunspots when they exist are inversely related to the rate of money growth it is also shown that stationary sunspots may exist even when equilibrium cycles do not

a unified framework for monetary theory and policy analysis search theoretic models of monetary exchange are based on explicit descriptions of the frictions that make money essential however tractable versions of these models typically make strong assumptions that render them ill suited for monetary policy analysis we propose a new framework based on explicit micro foundations within which macro policy can be studied the framework is analytically tractable and easily quantifiable we calibrate the model to standard observations and use it to measure the cost of inflation we find that going from 10 percent to 0 percent inflation is worth between 3 and 5 percent of consumption much higher than previous estimates

on efficient distribution with private information this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with many consumers each of whom is subject to private idiosyncratic taste shocks we propose a recursive method for finding feasible allocations that are incentivecompatible and that are pareto optimal within this set the method is applied to several parametric examples we find that in an efficient allocation the degree of inequality continually increases with a diminishing fraction of the population receiving an increasing fraction of the resources we discuss the extent to which these allocations can be decentralized via market arrangements this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with private information the economy we study has a constant endowment flow of a single non storable consumption good which is to be allocated each period among a large number of consumers each period these consumers experience unpredictable idiosyncratic privately observed taste shocks affecting their marginal utility of current consumption efficiency dictates that more resources be allocated to those consumers who in any given period have a high marginal utility of current consumption

endogenous credit cycles this paper studies models of credit with limited commitment and therefore endogenous debt limits there are multiple stationary equilibria plus nonstationary equilibria in which credit conditions change simply because of beliefs there can be equilibria in which debt limits display deterministic cyclic or chaotic dynamics as well as stochastic sunspot equilibria in which they fluctuate randomly even though fundamentals are deterministic and time invariant examples and applications are discussed we also consider different mechanisms for determining the terms of trade and compare the setup to other credit models in the literature

endogenous credit limits with small default costs we analyze an exchange economy of unsecured credit where borrowers have the option to declare bankruptcy in which case they are temporarily excluded from financial markets endogenous credit limits are imposed that are just tight enough to prevent default economies with temporary exclusion differ from their permanent exclusion counterparts in two important properties if households are extremely patient then the first best allocation is an equilibrium in the latter economies but not necessarily in the former in addition temporary exclusion permits multiple stationary equilibria with both complete and with incomplete consumption smoothing

optimal lending contracts and firm dynamics we develop a general model of lending in the presence of endogenous borrowing constraints borrowing constraints arise because borrowers face limited liability and debt repayment cannot be perfectly enforced in the model the dynamics of debt are closely linked with the dynamics of borrowing constraints in fact borrowing constraints must satisfy a dynamic consistency requirement the value of outstanding debt restricts current access to short term capital but is itself determined by future access to credit this dynamic consistency is not guaranteed in models of exogenous borrowing constraints where the ability to raise short term capital is limited by some prespecified function of debt we characterize the optimal default free contract which minimizes borrowing constraints at all histories and derive implications for firm growth survival leverage and debt maturity the model is qualitatively consistent with stylized facts on the growth and survival of firms comparative statics with respect to technology and default constraints are derived borrowing constraints are an important determinant of firm growth and survival 1 such constraints may arise in connection to the financing of investment opportunities faced by firms or temporary liquidity needs such as those required to survive a recession this paper develops a theory of endogenous borrowing constraints and studies its implications for firm dynamics in our model debt is constrained by the firm s limited liability and option to default a lending contract specifies an initial loan size future financing and a repayment schedule the choice of these variables in turn determines future growth the firm s future borrowing capacity and its ability and willingness to repay hence borrowing constraints and firm dynamics are jointly determined we study this dynamic design problem our model builds on thomas and worral s 1994 model of foreign direct investment at time zero a risk neutral borrower firm or entrepreneur has a project which requires a fixed initial set up cost every period the project yields revenues that increase with the amount of 1 there is considerable evidence suggesting that financing constraints are important determinants of firm dynamics gertler and gilchrist 1994 argue that liquidity constraints may explain why small manufacturing firms respond more to a tightening of monetary policy than do larger manufacturing firms perez quiros and timmermann 2000 show that in recessions smaller firms are more sensitive to the worsening of credit market conditions as measured by higher interest rates and default premia evans and jovanovic 1989 show that the liquidity constraints are essential in the decision to become an entrepreneur fazzari hubbard and petersen 1988 among others view financial constraints as an explanation for the dynamic behaviour of aggregate investment and cabral and mata 1996 are able to fit reasonably well the size distribution of portuguese manufacturing firms by estimating a simple model of financing constraints for surveys see hubbard 1998 and stein 2003

bargaining in a non stationary environment we study an alternating offers bargaining model in which the set of possible utility pairs evolves through time in a non stationary but smooth manner in general there exists a multiplicity of subgame perfect equilibria however we show that in the limit as the time interval between two consecutive offers becomes arbitrarily small there exists a unique subgame perfect equilibrium furthermore we derive a powerful characterization of the unique limiting subgame perfect equilibrium payoffs we then explore the circumstances under which nash s bargaining solution implements this bargaining equilibrium finally we extend our results to the case when the players have time varying inside options 2003 elsevier science usa all rights reserved

sticky prices and costly credit we develop a theory of money and credit as competing payment instruments then put it to work in applications agents use cash and credit because the former latter is subject to the inflation tax transaction costs frictions that make the choice of payment method interesting also imply equilibrium price dispersion we derive closed form solutions for money demand and show how to simultaneously account for the price change facts cash credit shares in micro data and money interest correlations in macro data the effects of inflation on welfare price dispersion and markups are discussed as are nonstationary equilibria with dynamics in the price distribution

intertemporal distortions in the second best we consider a very general class of public nance problems that encompasses ramsey models of optimal taxation as well as economies with limited commitment private information and political economy frictions we identify a su cient condition to rule out permanent intertemporal distortions at the optimum if there exists an admissible allocation that converges to the rst best steady state then all intertemporal distortions are temporary in the second best we analyze a series of applications to illustrate the signi cance of this result

private money and banking regulation we show that the regulation of lending practices is desirable for the optimal provision of private money in an environment in which bankers cannot commit to repay their creditors neither an unregulated banking system nor a form of narrow banking in which banks hold 100 in reserves can provide the socially efficient amount of money if bankers provided such an amount then they would prefer to default on their liabilities we show that a regulation that increases the value of the banking sector s assets e g by limiting competition in credit markets will mitigate the commitment problem if the return on the banking sector s assets is made sufficiently large then it is possible to implement an efficient allocation

indeterminacy in credit economies abstract we characterize the equilibrium set of a two good pure credit economy with limited commitment under both pairwise and centralized meetings we show that the set of equilibria derived under not too tight solvency constraints alvarez and jermann 2000 commonly used in the literature is of measure zero in the whole set of perfect bayesian equilibria there exist a continuum of stationary equilibria a continuum of endogenous credit cycles of any periodicity and a continuum of sunspot equilibria irrespective of the assumed trading mechanism equilibria featuring too tight solvency constraints can generate growing credit limits over time periodic credit shutdowns and heterogeneous debt limits across ex ante identical borrowers moreover we provide examples of credit cycles that dominate from a social welfare point of view all equilibria with not too tight solvency constraints

liquidity a new monetarist perspective this essay surveys the new monetarist approach to liquidity work in this literature strives for empirical and policy relevance plus rigorous foundations questions include what is liquidity is money essential in achieving desirable outcomes which objects can or should serve in this capacity when can asset prices differ from fundamentals what are the functions of commitment and collateral in credit markets how does money interact with credit and intermediation what can and should monetary policy do the research summarized emphasizes the micro structure of frictional transactions and studies how institutions like monetary exchange credit arrangements or intermediation facilitate the exchange process

debt constrained asset markets we develop a theory of general equilibrium with endogenous debt limits in the form of individual rationality constraints similar to those in the dynamic consistency literature if an agent defaults on a contract he can be excluded from future contingent claims markets trading and can have his assets seized he cannot be excluded from spot markets trading however and he has some private endowments that cannot be seized all information is publicly held and common knowledge and there is a complete set of contingent claims markets since there is complete information an agent cannot enter into a contract in which he would have an incentive to default in some state in general there is only partial insurance variations in consumption may be imperfectly correlated across agents interest rates may be lower than they would be without constraints and equilibria may be pareto ranked

a dynamic equilibrium model of search bargaining and money abstract this paper considers dynamic equilibria in a model with random matching strategic bargaining and money equilibrium in the bargaining game is characterized in terms of a simple differential equation when we embed this characterization into the monetary economy the model can generate outcomes such as limit cycles that never arise if one imposes a myopic nash bargaining solution as has been done in the past journal of economic literature classification numbers c78 d83 e31

a weighted max min model for fuzzy multi objective supplier selection in a supply chain abstract supplier selection is one of the most important activities of purchasing departments this importance is increased even more by new strategies in a supply chain supplier selection is a multi criteria decision making problem in which criteria have different relative importance in practice for supplier selection problems many input information are not known precisely the fuzzy set theories can be employed due to the presence of vagueness and imprecision of information a weighted max min fuzzy model is developed to handle effectively the vagueness of input data and different weights of criteria in this problem due to this model the achievement level of objective functions matches the relative importance of the objective functions in this paper an analytic hierarchy process ahp is used to determine the weights of criteria the proposed model can help the decision maker dm to find out the appropriate order to each supplier and allows the purchasing manager s to manage supply chain performance on cost quality and service the model is explained by an illustrative example

macroeconomic fluctuations and bargaining abstract i study the limit rule for bilateral bargaining when agents recognize that the aggregate economy and thus the match surplus follows a finite state poisson process the rule derived in this paper is of special importance for decentralized exchange economies with bargaining two simple applications are presented to illustrate this fact the first example is a model of wage bargaining and trade externalities i show that in such situations sophisticated bargaining tends to increase the volatility of the wage bill the second example is based on the kiyotaki wright model of money i explain how equilibrium prices depend in a fundamental way on the dynamic bargaining solution