crossing network versus dealer market unique equilibrium in the allocation of order flow the allocation of order flow to alternative trading systems can be understood as a game with strategic substitutes between buyers on the same side of the market as well as one of positive network externalities we consider the allocation of order flow between a crossing network and a dealer market we show that small differences in traders preferences generate a unique switching equilibrium in which patient traders use the crossing network while impatient traders submit orders directly to the dealer market our model explains why assets with large turnovers and low price volatility are likely to be traded on crossing networks while less liquid assets are traded on dealer markets

optimal taxation with endogenously incomplete debt markets abstract empirical analyses of labor tax and public debt processes provide prima facie evidence for imperfect government insurance this paper considers a model in which the government s inability to commit to future policies or to report truthfully its spending needs renders government debt markets endogenously incomplete a method for solving for optimal fiscal policy under these constraints is developed such policy is found to be intermediate between that implied by the complete insurance ramsey model and a model with exogenously incomplete debt markets in contrast to optimal ramsey policy optimal policy in this model is consistent with a variety of stylized fiscal policy facts such as the high persistence of labor tax rates and debt levels and the positive covariance between government spending and the value of government debt sales

measuring climatic impacts on energy consumption a review of the empirical literature abstract this paper reviews the literature on the relationship between climate and the energy sector in particular we primarily discuss empirical papers published in peer reviewed economics journals focusing on how climate affects energy expenditures and consumption climate will affect energy consumption by changing how consumers respond to short run weather shocks the intensive margin as well as how people will adapt in the long run the extensive margin along the intensive margin further research that uses household and firm level panel data of energy consumption may help identify how energy consumers around the world respond to weather shocks research on technology adoption e g air conditioners will further our understanding of the extensive margin adjustments and their costs we also note that most of the literature focuses on the residential sector similar studies are urgently needed for the industrial and commercial sectors

taxing capital not a bad idea after all we quantitatively characterize the optimal capital and labor income tax in an overlapping generations model with idiosyncratic uninsurable income shocks and permanent productivity difierences of households the optimal capital income tax rate is signiflcantly positive at 36 percent the optimal progressive labor income tax is roughly a at tax of 23 percent with a deduction of 7 200 relative to average household income of 42 000 the high optimal capital income tax is mainly driven by the life cycle structure of the model whereas the optimal progressivity of the labor income tax is attributable to the insurance and redistribution role of the tax system jel e62 h21 h24

the non linear link between electricity consumption and temperature in europe a threshold panel approach this paper investigates the relationship between electricity demand and temperature in the european union we address this issue by means of a panel threshold regression model on 15 european countries over the last two decades our results confirm the non linearity of the link between electricity consumption and temperature found in more limited geographical areas in previous studies by distinguishing between north and south countries we also find that this non linear pattern is more pronounced in the warm countries finally rolling regressions show that the sensitivity of electricity consumption to temperature in summer has increased in the recent period

optimal capital income taxation with incomplete markets borrowing constraints and constant discounting for a wide class of infinitely lived agent models chamley has shown that the optimal capital income tax rate is zero in the long run lucas has argued that for the u s economy there is a significant welfare gain from switching to this policy this paper shows that for the bewley class of models with incomplete insurance markets and borrowing constraints the optimal tax rate on capital income is positive even in the long run therefore cutting the capital income tax to zero may well lead to welfare losses

trading volume and asset liquidity since the depth and liquidity of a market depend on the entry decisions of all potential participants each trader assesses them according to conjectures about entry by others if trade is equally costly across markets this externality leads to the concentration of trade on one market if not it can produce multiple conjectural equilibria some where trade concentrates on one market and others where large traders resort to a separate market or to search for a trading partner while fragmentation is welfare reducing in the two market case no such ranking is possible if it involves off exchange search

designing optimal disability insurance a case for asset testing we analyze an implementation of an optimal disability insurance system as a competitive equilibrium with taxes an optimum is implemented by an asset tested disability system in which a disability transfer is paid only if an agent has assets below a specified maximum the logic behind this result is that an agent who plans to falsely claim disability a finds doing so unattractive if he does not adjust his savings and b cannot collect disability insurance if he does adjust his savings in the desired direction upward for a calibrated economy we find that welfare gains from asset testing are significant

ruling out multiplicity and indeterminacy the role of heterogeneity it is well known that economies of scale that are external to the individual decision makers can lead to self fulfilling prophecies and the multiplicity or even indeterminacy of equilibrium we argue that the importance of this source of multiplicity and indeterminacy is overstated in representative agent models as they ignore the potential stabilizing effect of heterogeneity we illustrate this in a version of matsuyama s 1991 two sector model with increasing returns to scale two main results are shown first sufficient homogeneity with respect to individual productivity leads to the instability and non uniqueness of a given stationary state and the indeterminacy of the corresponding stationary state equilibrium second sufficient heterogeneity leads to the global saddle path stability and the uniqueness of a given stationary state and the global uniqueness of equilibrium

redistributive taxation in a simple perfect foresight model abstract we investigate the redistributive potential of capital taxation in an intertemporal maximizing model of capital formation first even unanticipated redistributive capital taxation is severely limited in its effectiveness since it depresses wages second under any convergent redistributive tax policy which maximizes a paretian social objective the capital income tax will converge to zero independent of the factor supply elasticities these results are independent of workers holdings of capital

optimal taxation without state contingent debt in an economy studied by lucas and stokey tax rates inherit the serial correlation structure of government expenditures belying barro s earlier result that taxes should be a random walk for any stochastic process of government expenditures to recover a version of barro s random walk tax smoothing outcome we modify lucas and stokey s economy to permit only risk free debt having only risk free debt confronts the ramsey planner with additional constraints on equilibrium allocations beyond one imposed by lucas and stokey s assumption of complete markets the ramsey outcome blends features of barro s model with lucas and stokey s in our model the contemporaneous effects of exogenous government expenditures on the government deficit and taxes resemble those in lucas and stokey s model but incomplete markets put a near unit root component into government debt and taxes an outcome like barro s however we show that without ad hoc limits on the government s asset holdings outcomes can diverge in importa

the effect of climate change on electricity expenditures in massachusetts abstract climate change affects consumer expenditures by altering the consumption of and price for electricity previous analyses focus solely on the former which implicitly assumes that climate induced changes in consumption do not affect price but this assumption is untenable because a shift in demand alters quantity and price at equilibrium here we present the first empirical estimates for the effect of climate change on electricity prices translated through the merit order dispatch of existing capacity for generating electricity climate induced changes in daily and monthly patterns of electricity consumption cause non linear changes in electricity prices a 2 c increase in global mean temperature increases the prices for and consumption of electricity in massachusetts usa such that the average household s annual expenditures on electricity increase by about 12 commercial customers incur a 9 increase these increases are caused largely by higher prices for electricity whose impacts on expenditures are 1 3 and 3 6 fold larger than changes in residential and commercial consumption respectively this suggests that previous empirical studies understate the effects of climate change on electricity expenditures and that policy may be needed to ensure that the market generates investments in peaking capacity to satisfy climate driven changes in summer time consumption

trading under market impact crossing networks interacting with dealer markets abstract we use a model with agency frictions to analyze the structure of a dealer market that faces competition from a crossing network traders are privately informed about their types e g their portfolios which is something the dealer must take into account when engaging his counterparties instead of participating in the dealer market the traders may take their business to a crossing network the dealer must take into consideration that traders have this alternative when choosing a pricing schedule we show that the presence of a crossing network may benefit traders even if they do not trade in it furthermore it results in more traders being serviced by the dealer and the book s spread shrinking under certain conditions we allow for the pricing on the dealer market to determine the structure of the crossing network which itself influences the structure of the dealer market this results in a feedback look that under the same conditions that lead to a reduction of the spread yields an equilibrium book crossing network pair

international business cycles with endogenous incomplete markets backus kehoe and kydland 1992 baxter and crucini 1995 and stockman and tesar 1995 find two major discrepancies between standard international business cycle models with complete markets and the data in the models cross country correlations are much higher for consumption than for output while in the data the opposite is true and cross country correlations of employment and investment are negative while in the data they are positive this paper introduces a friction into a standard model that helps resolve these anomalies the friction is that international loans are imperfectly enforceable any country can renege on its debts and suffer the consequences for future borrowing to solve for equilibrium in this economy with endogenous incomplete markets the methods of marcet and marimon 1999 are extended incorporating the friction helps resolve the anomalies more than does exogenously restricting the assets that can be traded

a global game with strategic substitutes and complements abstract we study a global game in which actions are strategic complements over some region and strategic substitutes over another region an agent s payoff depends on a market fundamental and the actions of other agents if the degree of congestion is sufficiently large agents strategies are non monotonic in their signal about the market fundamental in this case a signal that makes them believe that the market fundamental is more favorable for an action may make them less likely to take the action because of the risk of overcrowding

optimal fiscal and monetary policy in an economy without capital abstract this paper is concerned with the structure and time consistency of optimal fiscal and monetary policy in an economy without capital in a dynamic context optimal taxation means distributing tax distortions over time in a welfare maximizing way for a barter economy our main finding is that with debt commitments of sufficiently rich maturity structure an optimal policy if one exists is time consistent in a monetary economy the idea of optimal taxation must be broadened to include an inflation tax and we find that time consistency does not carry over an optimal inflation tax requires commitment by rules in a sense that has no counterpart in the dynamic theory of ordinary excise taxes the reason time consistency fails in a monetary economy is that nominal assets should from a welfare maximizing point of view always be taxed away via an immediate inflation in a kind of capital levy this emerges as a new possibility when money is introduced into an economy without capital

opportunity and social mobility the fact that the children of rich parents have better economic prospects than the children of poor parents unequal opportunity is generally thought to be one of the weak points of modem capitalist societies the ability of the descendants of poor families to eventually become rich and the descendants of rich families to eventually become poor social mobility is commonly considered to be one of the strong points of these societies here i argue that both of these characteristics are in fact necessary implications of an efficient societal arrangement when incentives to work hard must be provided i argue this point using a generational version of the model of phelan and townsend 1991 an infinitely repeated general equilibrium economy with incentive constraints in my model each household s stochastic output is a function of its level of effort since effort is assumed to be costly and privately observed households can shirk higher than minimal effort levels must be induced by making a household s present or future consumption dependent on the household s observed output history a large literature considers models similar to this including green 1987 atkeson and lucas 1992 phelan 1994 1995 wang 1995 hopenhayn and nicolini 1997 khan and ravikumar 2002 the main difference between the economies in that literature and here is that here instead of a household consisting of a single infinitely lived individual a household consists of a sequence of altruistically linked individuals a familial dynasty each of whom lives for one period this difference affects the appropriate societal ranking of allocations when households consist of a single infinitely lived individual allocations can be ranked according to their implied distributions of ex ante lifetime utilities if one allocation delivers a distribution of ex ante utilities dominated by another allocation then the first allocation is inefficient however if a household consists of a sequence of altruistically linked individuals then the appropriate ranking of allocations is no longer obvious how those in the first generation rank allocations will in general differ from how their descendants rank allocations this paper addresses this conflict between generations by ranking allocations according to a rawlsian veil of ignorance criterion rawls 1971 that is here society seeks to maximize the expected dynastic utility utility including altruism toward descendants of an individual who does not know into which generation he will be born and the identity or output levels of his ancestors 1 i argue that this corresponds to a societal ranking which does

what do we learn from the weather the new climate economy literature a rapidly growing body of research applies panel methods to examine how temperature precipitation and windstorms influence economic outcomes these studies focus on changes in weather realizations over time within a given spatial area and demonstrate impacts on agricultural output industrial output labor productivity energy demand health conflict and economic growth among other outcomes by harnessing exogenous variation over time within a given spatial unit these studies help credibly identify i the breadth of channels linking weather and the economy ii heterogeneous treatment effects across different types of locations and iii nonlinear effects of weather variables this paper reviews the new literature with two purposes first we summarize recent work providing a guide to its methodologies datasets and findings second we consider applications of the new literature including insights for the damage function within models that seek to assess the potential economic effects of future climate change jel c51 d72 o13 q51 q54

efficiency and equality in a simple model of efficient unemployment insurance abstract this paper describes the efficient allocation of consumption and work effort in an economy in which workers face idiosyncratic employment risk and considerations of moral hazard prevent full insurance we impose a lower bound on the expected discounted utility that can be assigned to any agent from any date onward and show with this feature added that the efficient unemployment insurance scheme induces an invariant cross sectional distribution of individual entitlements to utility the paper thus provides a simple prototype model suited to the study of the normative question what is the trade off between equality and efficiency in resource allocation journal of economic literature classification numbers d31 d63 d82 j65

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

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

temperature and seasonality influences on spanish electricity load abstract deregulation of the spanish electricity market in 1998 and the possible listing of electricity or weather derivative contracts have encouraged the study of the relationship between electricity demand and weather in spain in this paper a transfer function intervention model is developed for forecasting daily electricity load from cooling and heating degree days the influence of weather and seasonality is proved and is significant even when the autoregressive effects and the dynamic specification of the temperature are taken into account the estimated general model shows a high predictive power the results and information presented in this paper could be of interest for current users and potential traders in the deregulated spanish electricity market

liquidity based competition for order flow we present a microstructure model of competition for order flow between exchanges based on liquidity provision we find that neither a pure limit order market plm nor a hybrid specialist limit order market hm structure is competition proof a plm can always be supported in equilibrium as the dominant market i e where the hybrid limit book is empty but an hm can also be supported for some market parameterizations as the dominant market we also show the possible coexistence of competing markets order preferencing that is decisions about where orders are routed when investors are indifferent is a key determinant of market viability welfare comparisons show that competition between exchanges can increase as well as reduce the cost of liquidity active competition between exchanges for order flow in cross listed securities is intense in the current financial marketplace examples include rivalries between the new york stock exchange nyse crossing networks and ecns and between the london stock exchange the paris bourse and other continental markets for equity trading and between eurex and london international financial futures and options exchange liffe for futures volume while exchanges compete along many dimensions e g payment for order flow transparency execution speed liquidity and price improvement will in our view be the key variables driving competition in the future over time high cost markets should be driven out of business as investors switch to cheaper trading venues moreover market structure is increasingly singled out by regulators exchanges and other market participants as a major determinant of liquidity 1

competitive equilibria with limited enforcement we show how to decentralize constrained efficient allocations that arise from enforcement constraints between sovereign nations in a pure exchange economy these allocations can be decentralized with private agents acting competitively and taking as given government default decisions on foreign debt in an economy with capital these allocations can be decentralized if the government can tax capital income as well as default on foreign debt the tax on capital income is needed to make private agents internalize a subtle externality the decisions of the government can arise as an equilibrium of a dynamic game between governments

a theory of financing constraints and firm dynamics there is widespread evidence supporting the conjecture that borrowing constraints have important implications for firm growth and survival in this paper we model a multiperiod borrowing lending relationship with asymmetric information we show that borrowing constraints emerge as a feature of the optimal long term lending contract and that such constraints relax as the value of the borrower s claim to future cash flows increases we also show that the optimal contract has interesting implications for firm dynamics in agreement with the empirical evidence as age and size increase mean and variance of growth decrease and firm survival increases

optimal indirect and capital taxation we consider an environment in which agents skills are private information and follow arbitrary stochastic processes we prove that it is typically pareto optimal for an individual s marginal benefit of investing in capital to exceed his marginal cost of doing so this wedge is consistent with a positive tax on capital income we also prove that it is pareto optimal for the marginal rate of substitution between any two consumption goods to equal the marginal rate of transformation this lack of a wedge is consistent with uniform taxation of consumption goods within a period

on the long run implications of repeated moral hazard abstract this paper analyzes the effects of moral hazard on long run consumption or utility given exponential utility it is shown that the utility of those with unobservable endowments becomes arbitrarily negative as long as any positive fraction of otherwise identical agents have observable endowments next it is shown that assuming a finite number of agents results in essentially the same outcomes as with a continuum of agents finally it is shown that the key characteristic determining whether the utility of almost all agents becomes arbitrarily low is whether lim c u c is bounded away from zero journal of economic literature classification numbers d30 d31 d80 d82

comment on markets versus governments by acemoglu golosov and tsyvinski one of the oldest and most fundamental debates in economics pertains to the role of markets andgovernment in the allocation of resources there are two dimensions to this debate the rst is inherentlynormative and revolves around the question what role should markets and governments play in the allocationof resources the second dimension is motivated by the varied combinations of markets and governmentsobserved in different economies this leads to a series of positive questions what factors can account for thesedifferent combinations of markets and governments what is the role of political institutions and socialpreferences or culture in shaping the particular combinations that we observe what are the properties of theallocations being implemented by these different arrangements what are the resulting welfare implications this paper seeks to contribute to the normative debate and explores the conditions that make markets moredesirable than governments since markets and governments are viewed as alternative allocation mechanisms the outcome of this comparison depends crucially on the economic environment here the presence ofidiosyncratic risk in labor productivity implies that the ability to enable risk sharing plays a key role in theranking of markets and governments this ability in turn depends on the particular way in which markets andthe government are modelled there are many possible strategies to evaluate the comparative performance of different allocationmechanisms one is to endow the economic environment with a primitive friction such as private informationor limited commitment and ask how close the market and the government can get to the best allocation thatcan be achieved given that friction this paper instead presumes that markets and the government arecharacterized by a different set of frictions in the market setting anonymity or lack of enforcement imply thatthe equilibrium allocation cannot in general sustain full risk sharing on the other hand the government sability to provide insurance is limited by two different frictions first individual abilities are privateinformation second the ruler is not benevolent and can appropriate rents this approach implies that thecomparison of markets and government boils down to a race between frictions the resulting analysisteaches us about the properties of optimal allocations under different sets of frictions but it is silent about theintrinsic comparative advantages of markets and governments since the issue of what government andmarkets can best accomplish is not addressed the question of what role they should play in resource allocationremains open

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

characterising equilibrium selection in global games with strategic complementarities abstract global games are widely used to predict behaviour in games with strategic complementarities and multiple equilibria we establish two results on the global game selection first we show that for any supermodular complete information game the global game selection is independent of the payoff functions chosen for the game s global game embedding second we give a simple sufficient criterion to derive the selection and establish noise independence in many action games by decomposing them into games with smaller action sets to which we may often apply simple criteria we also report in which small games noise independence may be established by counting the number of players or actions

a note on incomplete factor taxation abstract optimal capital taxes may be positive in the steady state in ramsey models with an incomplete set of factor taxes i show this possibility crucially depends on how fiscal policy is constrained at date t 0 if the government is barred from manipulating the value of initial assets the chamley judd result reappears the optimal capital tax is always zero in the steady state

currency crises with the threat of an interest rate defence while virtually all currency crisis models recognise that the decision to abandon a peg depends on how tenaciously policy makers defend it this is seldom modelled explicitly we add the threat of an interest rate defence to the global game model of morris and shin american economic review 88 1998 with an endogenous defence actions of speculators may become strategic substitutes instead of the usual complements nevertheless our generalised model remains tractable and has a unique threshold equilibrium it provides additional insights for instance the threat of an interest rate defence makes speculation riskier and this may be sufficient to keep speculators out when fundamentals are still relatively strong

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

should capital income be taxed in the steady state this paper provides a new economic interpretation of the well known dynamic optimal taxation principle that capital income should not be taxed in the steady state we show that the result is related to the minimization of distortions at the intratemporal margin when every factor of production can be taxed at the optimal rate capital income should not be taxed in the steady state but when there are restrictions on the taxation of production factors the tax rate on capital income in the steady state is different from zero

sequential equilibria in a ramsey tax model this paper presents a full characterization of the equilibrium value set of a ramsey tax model more generally it develops a dynamic programming method for a class of policy games between the government and a continuum of households by selectively incorporating euler conditions into a strategic dynamic programming framework we wed two technologies that are usually considered competing alternatives resulting in a substantial simplification of the problem

impact of temperature on electricity demand evidence from delhi and indian states abstract electricity for cooling improves health and quality of life and is an important mode of adapting to extreme weather conditions and to climate change this study measures the change in electricity demand in response to weather shocks at the household level in delhi and at various aggregate levels in india our econometric analysis uses a semi parametric model to capture the nonlinearity of short run temperature response on average aggregate electricity demand in india increases by 11 or more at temperatures above 30 c from demand at temperatures of 21 24 c with substantial heterogeneity across states aggregate demand in delhi increases by 30 or more at temperatures above 30 c using rich micro data on electricity demand in delhi we do a first of its kind estimation of household level temperature response we find evidence that low income consumers especially those living in slums show limited incremental response to high temperatures likely due to an absence of cooling options these findings underscore the need to improve our understanding of the constraints posed by poverty on climate change adaptation and for interventions to mitigate risks of heat stress among the poor this also suggests rising affluence will lead to sharp increases in electricity demand for cooling

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

the risk free rate in heterogeneous agent incomplete insurance economies abstract why has the average real risk free interest rate been less than one percent the question is motivated by the failure of a class of calibrated representative agent economies to explain the average return to equity and risk free debt i construct an economy where agents experience uninsurable idiosyncratic endowment shocks and smooth consumption by holding a risk free asset i calibrate the economy and characterize equilibria computationally with a borrowing constraint of one year s income the resulting risk free rate is more than one percent below the rate in the comparable representative agent economy

multimarket trading and market liquidity when a security trades at multiple locations simultaneously an informed trader has several avenues in which to exploit his private information the greater the proportion of liquidity trading by large traders who can split their trades across markets the larger is the correlation between volume in different markets and the smaller is the informativeness of prices we show that one of the markets emerges as the dominant location for trading in that security when informed traders can use their information for more than one trading period the timely release of price information by market makers at one location adversely affects the profits informed traders expect to make subsequently at other locations market makers competing to offer the lowest cost of trading at their location consequently deter informed trading be voluntarily making the price information public and by cracking down on insider trading article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

optimal taxation of capital income in general equilibrium with infinite lives this paper analyzes the optimal tax on capital income in general equilibrium models of the second best agents have infinite lives and utility functions which are extensions from the koopmans form the population is heterogeneous the important property of the models is the equality between the social and the private discount rates in the long run i find that the optimal tax rate is zero in the long run for a special case of additively separable utility functions i then determine the tax rates along the dynamic path and conditions that are sufficient for the local stability of the steady state

optimal fiscal policy with redistribution i study the optimal taxation oflabor and capital in a dynamic economy subject to government expenditure and technology shocks unlike representative agent ramsey models workers are heterogenous and lump sum taxation is not ruled out i consider two tax scenarios a linear taxation with a lump sum intercept and b nonlinear mirrleesian taxation when taxes are linear i derive a partial equivalence result with ramsey settings that provides a reinterpretation of such analyses i find conditions for perfect tax smoothing oflabor income taxes and zero capital taxation implications that contrast with ramsey are derived for public debt management for the nature of the time inconsistency problem and for the viability of replicating complete markets without state contingent bonds shifts in the distribution of skills provide a novel source for variations in tax rates for the nonlinear tax scenario i show that taxation based on income averages is optimal

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

income fluctuation and asymmetric information an example of a repeated principal agent problem we examine a simple repeated principal agent model with discounting there are a risk averse borrower with an unobservable random income and a risk neutral lender the efficient contract is characterized it tends to the first best constant consumption contract as the discount factor tends to one and the time horizon extends to infinity if the time horizon is infinite and the contract is legally enforceable the borrower s utility becomes arbitrarily negative with probability one if the borrower has constant absolute risk aversion consumption is transferred between any two states at a constant interest rate which is less than the rate of time preference

on repeated moral hazard with discounting in this paper we analyze optimal contracts in an infinitely repeated agency model in which both the principal and agent discount the future we show that there is a stationary representation of the optimal contract when the agent s conditional discounted expected utility is used as a state variable this representation reduces the multi period problem to a static variational problem which can be analyzed using standard variational techniques this reduction is used to obtain several properties of the contract

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

optimal fiscal and monetary policy with sticky prices in this paper i consider the role of state contingent inflation as a fiscal shock absorber in an economy with nominal rigidities i study the ramsey equilibrium in a monetary model with distortionary taxation nominal non state contingent debt and sticky prices with sticky prices the ramsey planner must balance the shock absorbing benefits of state contingent inflation against the associated resource misallocation costs for government spending processes resembling post war experience introducing sticky prices generates striking departures in optimal policy from the case with flexible prices for even small degrees of price rigidity optimal policy displays very little volatility in inflation tax rates display greater volatility compared to the model with flexible prices with sticky prices tax rates and real government debt exhibit behavior similar to a random walk for government spending processes resembling periods of intermittent war and peace optimal policy displays extreme inflation volatility even when the degree of price rigidity is large as the variability in government spending increases smoothing tax distortions across states of nature becomes increasingly important and the shock absorber role of inflation is accentuated

inequality and social discounting we explore steady state inequality in an intergenerational model with altruistically linked individuals who experience privately observed taste shocks when the welfare function depends only on the initial generation efficiency requires immiseration inequality grows without bound and everyone s consumption converges to zero we study other efficient allocations in which the welfare function values future generations directly placing a positive but vanishing weight on their welfare the social discount factor is then higher than the private one and for any such difference we find that consumption exhibits mean reversion and that a steady state cross sectional distribution for consumption and welfare exists with no one trapped at misery

risk and wealth in a model of self fulfilling currency attacks market participants risk attitudes wealth and portfolio composition in uence their positions in a pegged foreign currency and therefore may have important efiects on the sustainability of currency pegs we analyze such efiects in a global game model of currency crises with continuous action choices generating a rich set of theoretical comparative static predictions related to often discussed but rarely modelled accounts of the onset and timing of currency crises the model can be solved in closed form and the methods could be used to study other economic issues in which coordination and risk aversion play important roles

political economy of mechanisms we study the optimal mirrlees taxation problem in a dynamic economy in contrast to the standard approach where the taxation mechanism is operated by a benevolent planner with full commitment power we focus on economies in which policy decisions are made by self interested politicians who cannot commit to policies the society controls politicians using elections we show that the provision of incentives to politicians can be partly separated from redistribution across agents and that political economy constraints can be modeled as introducing additional aggregate distortions in the dynamic mirrlees problem we provide conditions under which the political economy distortions persist or disappear in the long run if the politicians are as patient as the agents the best sustainable mechanism leads to an asymptotic allocation where the aggregate distortions arising from political economy disappear in contrast when politicians are less patient than the citizens positive aggregate labor and capital taxes remain even asymptotically we conclude by providing a brief comparison of centralized

optimal fiscal policy in a stochastic growth model although most neoclassical growth models focus on competitive equilibria which are pareto optimal and ignore the role of government recent works by romer 28 29 judd 20 baxter and king s and bizer and judd 7 have shown that government can be introduced into and suboptimal equilibria can be studied in these models as well their studies however are positive analyses of the effects of fiscal policy in competitive equilibria the purpose of this paper is to apply ramsey s 27 theory of optimal taxation to the normative study of fiscal policy in a stocastic growth model ramsey studied a static representative consumer economy with many goods in his formulation a government consumes a fixed amount of these goods which it purchases at market prices and finances by levying flat rate excise taxes prices and quantities are determined in a competitive equilibrium the government is benevolent and its objective is to choose the optimal tax rates to maximize the representative consumer s utility a number of economists among them kydland and prescott 23 barro 3 turnovsky and brock 31 and lucas and stockey 26 have noted that ramsey s formulation can be applied to dynamic economies with uncertainty if one reinterprets the goods in static problems as dated state contingent goods in this framework a fiscal policy is a rule which specifies state contingent tax rates and the amount of public debt issue in each date the optimal fiscal policy is defined as the one which leads to a quantity