the effects of fiscal policies when incomes are uncertain a contradiction to ricardian equivalence this paper shows that when future earnings are uncertain the substitution of deficit fin ance for tax finance or the introduction of an unfunded social secur ity program can raise consumption even if all bequests reflect inter generational altruism an operative bequest motive therefore need not imply ricardian equivalence this conclusion follows from the result derived in the paper that the uncertainty of future income makes t he existence of a future bequest uncertain to the prospective donor copyright 1988 by american economic association

real exchange rates and real interest rate differentials a present value interpretation although the real exchange rate real interest rate reri relationship is central to most open economy macroeconomic models empirical support for the relationship is generally found to be rather weak in this paper we re investigate the reri relationship using bilateral us real exchange rate data spanning the period 1978 2007 instead of testing one particular model we build on campbell and shiller 1987 cointegration tests of present value models journal of political economy 95 1062 1088 to propose a metric of the economic significance of the relationship our empirical results provide robust evidence that the reri link is economically significant and that the real interest rate differential is a reasonable approximation of the expected rate of depreciation over longer horizons

the effect of social security on the steady state distribution of consumption abstract abel has shown that the introduction of a fully funded social security ss would decrease the variances of the steady state distribution of young period and old period consumptions eckstein et al have shown that a perfect ss would increase the steady state expected utility of consumptions we intend to give a caveat on their positive results by showing that the assumptions from which the above propositions are derived have some unrealistic implications and that by replacing these assumptions with more reasonable ones we may obtain very different results the only positive conclusion we are certain of is that a marginal ss insurance in the no insurance situation can always reduce the steady state coefficient of variation of both young and old period consumption distributions

the distribution of wealth with imperfect altruism abstract in this paper we study the distribution of wealth in an economy with infinitely lived families individual generations of each family may or may not be altruistic this is represented as a preference shock which follows a first order markov process within each family a feature representingimperfect altruism altruistic individuals care about the welfare of their children and are likely to leave bequests selfish ones do not this results in a non trivial distribution of wealth among families at any point in time we study an economy with a risk free linear production technology and show that a stationary distribution of wealth exists this distribution is discrete and approximates the pareto distribution under additional restrictions we also characterize conditions on the production technology which yields perpetual growth with increasing inequality journal of economic literatureclassification numbers d31 d91 e21

optimal life insurance purchase and consumption investment under uncertain lifetime abstract in this paper we consider optimal insurance and consumption rules for a wage earner whose lifetime is random the wage earner is endowed with an initial wealth and he also receives an income continuously but this may be terminated by the wage earner s premature death we use dynamic programming to analyze this problem and derive the optimal insurance and consumption rules explicit solutions are found for the family of crra utilities and the demand for life insurance is studied by examining our solutions and doing numerical experiments

non constant discounting and consumption portfolio and life insurance rules consumption portfolio and life insurance rules are studied for an investor with an arbitrary but known distribution of lifetime with time inconsistent preferences solutions are found for naive and sophisticated agents for the family of cara and crra utility functions effects of non constant discounting are illustrated numerically

macro economic shocks the erm and tri polarity the authors use the comparative behavior of real output growth and inflation behavior of members and nonmembers of the exchange rate mechanism erm to analyze the importance of erm membership on macroeconomic performance an econometric procedure for identifying temporary and permanent shocks to output is proposed and executed the results confirm that the erm has acted as a vehicle for macropolicy coordination between members the authors also investigate several issues relating to the hypothesis of global economic tri polarity between the united states germany and japan copyright 1995 by mit press

comment on kotlikoff shoven and spivak in the absence of perfect annuity markets individual consumers generally undertake precautionary saving to provide resources for their future consumption in the event that they live longer than expected kotlikoff shoven and spivak in this issue hereafter kss have provided us with a well conceived and well executed study of the effects of various annuity arrangements on individual and aggregate saving in the presence of lifetime uncertainty each of these authors has had a long standing interest in this area and their current paper reflects their accumulated expertise their results indicate that a potentially sizable fraction of u s household wealth represents precautionary saving resulting from the absence of perfect annuity markets the strategy of the kss paper is to develop simple models of individual saving behavior on the basis of utility maximization and then to aggregate the behavior of individuals both intraand intertemporally by comparing the results of models that differ in the specification of bequest motives and opportunities for creating annuities kss provide insights about the effects of various annuity arrangements on saving and capital accumulation although the models are all conceptually simple analytic solutions cannot be obtained in many cases therefore kss provide numerical solutions to their models in addition because the models are conceptually

the family as an incomplete annuities market families can self insure against uncertain dates of death through implicit or explicit agreements with respect to consumption and interfamily transfers interfamily transfers need have nothing to do with altruistic feelings they may simply reflect risk sharing behavior of completely selfish family members although family annuity markets are incomplete even small families can substitute by more than 70 percent for perfect market annuities given adverse selection and transaction costs family risk pooling may be preferred to public market annuities in the absence of public annuities these risk sharing arrangements provide powerful incentives for marriage and family formation

determinants of the current account balance in the united states this article studies the role of public and private imbalances in the behaviour of the current account balance in the united states in the context of an intertemporal model the estimation evaluates the effects of public and private imbalances on the dynamics of the current account correlation coefficients support the ricardian equivalence higher budget deficit correlates with a reduction in private consumption and an increase in private savings government saving does not vary significantly with macroeconomic variables in the short or in the long run in contrast fluctuations in government investment vary significantly with a number of economic variables in the long and in the short run accordingly fluctuations in the budget deficit are likely to be driven by fluctuations in public investment in contrast to government savings private savings vary significantly with macro variables in the long and in the short run fluctuations in private investment appear less evident compared to that in privat

the dynamic effects of aggregate demand and supply disturbances we interpret fluctuations in gnp and unemployment as due to two types of disturbances disturbances that have a permanent effect on output and disturbances that do not we interpret the first as supply disturbances the second as demand disturbances demand disturbances have a hump shaped mirror image effect on output and unemployment the effect of supply disturbances on output increases steadily over time peaking after two years and reaching a plateau after five years

international capital mobility amongst the major industrialised countries too little or too much this paper examines capital flows among the major industrialized countries with a view to assessing m feldstein and c horioka s 1980 claim that international capital mobility is limited it argues that saving investment correlation tests are inherently flawed and proposes an alternative methodology for testing the degree of international capital mobility it finds that capital flows have been excessive in the sense that they are driven by speculative forces rather than by economic fundamentals copyright 1995 by royal economic society

what drives china s current account the paper offers an empirical taxonomy of the factors driving china s current account a simple present value model with non tradeable goods explains more than 70 percent of current account variability over the period 1982 2007 including the persistent surpluses since 2001 it also correctly predicts the decline of china s current account since 2008 expected increases in the prices of non tradeables e g housing and medical care and expected declines in net output gdp less investment and government spending are the main channels of external adjustment much of china s current account surplus seems driven by shocks that have global effects by persistently depressing the world real interest rate this is consistent with recent theoretical models that suggest that factors related to china s domestic financial development are key in understanding global imbalances

exchange intervention policy in a multiple country world abstract intervention policy is examined in a three country model employment and output in each country depend upon the domestic currency value of a natural basket of currencies called the sally each country will find it desirable to intervene to stabilize its sally rate if capital movements are more volatile than trade flows this is a natural generalization of well known small country results however in this general equilibrium setting it is clear that such a policy can destabilize employment in another country and lead to retaliation currency unions are also examined and found to have similar spillover problems

new evidence on the ricardian equivalence theorem a multicointegration approach this paper derives major theoretical constructs which underlie richardian equivalence and using multicointegration methodology empirically tests whether they bear out results indicate that government spending and revenues are cointegrated however the cointegrating scalar is less than one therefore in order for government to obey its intertemporal budget constraint debt and government revenue must be multicointegrated they are not additional evidence indicates that saving and debt may be weakly cointegrated the findings suggest that failure of richardian equivalence may be due to public rather than private sector failure

capital accumulation and annuities in an adverse selection economy this paper suggests that adverse selection problems in competitive annuity markets can generate quantity constrained equilibria in which some agents whose length of lifetime is uncertain find it advantageous to accumulate capital privately this occurs despite the higher rates of return on annuities the welfare properties of these allocations are analyzed it is shown that the level of capital accumulation is excessive in a paretian sense policies that eliminate this inefficiency are discussed copyright 1987 by university of chicago press

distribution and growth in models of imperfect capital markets abstract a full analysis of the distribution of income should include both the inequality in income between different generations of the same family what is usually called intergenerational ocial mobility and the inequality in income between different families in the same generation becker tomes 1979 p 1154

estate taxation with intended and accidental bequests abstract in this paper we examine the properties of the optimal estate tax in the presence of a complete set of tax instruments available to the social planner we allow for both types of bequest motives namely altruistic and accidental we examine the case for estate taxation which seems to be the strongest but not impeccable with accidental bequests in general the estate tax is highly sensitive to the relative importance of the two bequest motives

what drives us foreign borrowing evidence on external adjustment to transitory and permanent shocks the joint dynamics of us net output consumption and valuation adjusted foreign assets and liabilities characterized empirically following lettau and ludvigson 2004 is shown to be strikingly consistent with current account theory while us consumption is virtually insulated from transitory shocks these contribute considerably to the variation in net output and even more so in gross foreign positions arguably smoothing temporary variations in returns a single permanent shock naturally interpreted as a productivity shock raises consumption swiftly while causing net output to adjust only gradually this leads to persistent procyclical external deficits but interestingly moves gross assets and liabilities in the same direction

uncertainty and optimal social security systems this paper examines the annuity aspect of social security within the framework of an overlapping generations model the duration of life is assumed to be uncertain under a fully funded system demand for social security is determined by each generation so as to maximize expected lifetime utility taking into account the welfare of future generations under a pay as you go system with intergenerational transfers demand for retirement benefits by the working population takes into account taxes paid by descendants it is shown that the two modes of finance are equivalent in terms of all real aggregates effects of changes in expected lifetime and in the birth rate are analyzed starting at the optimal level a compulsory balanced increase in social security taxes and benefits is shown to increase short run savings

consumption and portfolio rules for time inconsistent investors abstract this paper extends the classical consumption and portfolio rules model in continuous time merton r c 1969 lifetime portfolio selection under uncertainty the continuous time case review of economics and statistics 51 247 257 merton r c 1971 optimum consumption and portfolio rules in a continuous time model journal of economic theory 3 373 413 to the framework of decision makers with time inconsistent preferences the model is solved for different utility functions for both naive and sophisticated agents and the results are compared in order to solve the problem for sophisticated agents we derive a modified hjb hamilton jacobi bellman equation it is illustrated how for crra functions within the family of hara functions logarithmic and power utilities the optimal portfolio rule does not depend on the discount rate but this is not the case for a general utility function such as the exponential cara utility function

the distribution of wealth and welfare in the presence of incomplete annuity markets this paper examines the implications of the absence of complete annuity markets on the distribution of wealth and welfare of agents whose saving decisions are obtained under uncertainty regarding the length of their life the absence of annuities is shown to yield a unique nondegenerate intragenerational distribution of wealth which is fully characterized this characterization is then used to evaluate the pareto desirability of an annuity system alternative welfare criteria that can be used when the proposed change has differential impacts on the initial state of subsequent generations are considered

forecasting oil price movements with crack spread futures abstract in oil markets the crack spread refers to the crude product price relationship refiners are major participants in oil markets and they are primarily exposed to the crack spread in other words refiner activity is substantially driven by the objective of protecting the crack spread moreover oil consumers are active participants in the oil hedging market and they are frequently exposed to the crack spread from another perspective hedge funds are heavily using crack spread to speculate in oil markets based on the high volume of crack spread futures trading in oil markets the question we want to raise is whether the crack spread futures can be a good predictor of oil price movements we investigated first whether there is a causal relationship between the crack spread futures and the spot oil markets in a vector error correction framework we found the causal impact of crack spread futures on spot oil market both in the long and the short run after april 2003 where we detected a structural break in the model to examine the forecasting performance we use the random walk model rwm as a benchmark and we also evaluate the forecasting power of crack spread futures against the crude oil futures the results showed that a both the crack spread futures and the crude oil futures outperformed the rwm and b the crack spread futures are almost as good as the crude oil futures in predicting the movements in spot oil markets

international macroeconomic fluctuations and the current account intertemporal models of the current account generally assume that global shocks do not affect the current account we use this assumption to identify global and country specific shocks in a bivariate var we test the quality of the identification using evidence from g7 data in accordance with the theory we observe a link between the global shock and a measure of the world real interest rate we also find that long term output growth is driven by global factors in most countries that country specific shocks are less persistent in smaller economies and generally less volatile than global shocks

capital accumulation and uncertain lifetimes with adverse selection this paper examines the implications of adverse selection in the private annuity market for the pricing of private annuities and the consequent effects on constrption and bequest behavior with privately known heterogeneous mortality probabilities adverse selection causes the rate of return on private annuities to be less than the actuarially fair rate based on population average mortality however a fully funded social security system with compulsory participation can offer an implied rate of return equal to the actuarially fair rate based on population average mortality thus since social security offers a higher rate of return than private annuities consumers cannot completely offset the effects of social security by transacting in the private annuity market using an overlapping generations model with uncertain lifetimes we demonstrate that the introduction of actuarially fair social security reduces the steady state rate of return on annuities and raises the steady state levels of average bequests and average consumption of the young the steady state national capital stock rises or falls according to the strength of the bequest motive this abstract was borrowed from another version of this item

uncertain lifetimes and the welfare enhancing properties of annuity markets and social security this paper explores the implications of social security programs and annuity markets through which agents who are characterized by different distributions of length of lifetime share deathrelated risks when annuity markets operate a non discriminatory social security program affects only the intragenerational allocation of resources in the absence of private information regarding individual survival probabilities such a program will lead to a non optimal intragenerational allocation of resources however the presence of adverse selection considerations gives rise to a pareto improving role for a mandatory non discriminatory social security program

an upper bound for wealth distribution in a model of accidental bequests abstract an explicit upper bound is calculated for wealth distribution in a model of overlapping generations with uncertain lifetimes and an imperfect annuities market

the effects of annuities bequests and aging in an overlapping generations model of endogenous growth we examine the effects of introducing actuarially fair annuity markets into an overlapping generations model of endogenous growth the complete annuitisation of agents wealth is not in general dynamically optimal the degree of annuitisation that is dynamically optimal depends nonmonotonically on the expected length of retirement and on the pay as you go social security tax rate the government has an incentive to restrict the availability of actuarially fair annuities contracts and can often move the economy from a pay as you go to a fully funded social security system via voluntary contributions to a government sponsored actuarially fair pension today accompanied by reductions in social security taxes tomorrow

international evidence on the size of the random walk in output this paper contributes three extensions of cochrane s work on measuring the relative stability of long term growth it estimates variance ratios for nine oecd countries over the period 1871 1985 presents an improved approximation to the distribution of the variance ratio and considers the comovements of long growth cycles across countries the evidence indicates that the relative stability of long term growth found by cochrane is unique to the united states relative to the united states most countries have more variable dynamics at low frequencies and smoother dynamics at frequencies traditionally associated with business cycles

precautionary saving and accidental bequests this paper presents a simple general equilibrium model of precautionary saving and accidental bequests this model is used to analyze the implications of individual lifetime uncertainty for aggregate consumption and capital accumulation a precautionary demand for saving arises because an individual consumer does not know in advance the date at which he will die and he wants to avoid low levels of consumption in the event that he lives longer than expected an implication of this precautionary saving is that when death does occur the consumer is generally holding some wealth which is then passed on to his heirs in the form of an accidental bequest even if all consumers have the same ex ante mortality probabilities there will be some intracohort variation in the date of death consequently there will be a nondegenerate distribution of bequests left by consumers in a cohort this nondegenerate distribution of bequests left by one generation induces variation in the distributions of wealth consumption and bequests of subsequent generations the importance of bequests in aggregate saving has been established by laurence kotlikoff and lawrence summers 1981 who reported that 80 percent of u s household wealth is inherited wealth one interpretation of this finding is that the simple life cycle model without bequest motives is an inadequate description of saving behavior in the united states but the model i present demonstrates that accidental bequests by selfish consumers can account for a potentially sizeable fraction of aggregate wealth although some part of bequests especially by the wealthy undoubtedly results from an explicit bequest motive accidental bequests also play a role in the intergenerational transfer of wealth as well as in the intragenerational variation in wealth in order to focus on the role of accidental bequests i purposely exclude a bequest motive from the specification of the utility function the effects of lifetime uncertainty on individual consumption behavior were first examined formally in a seminal paper by menachem yaari 1965 yaari s model provided the basic framework for virtually all subsequent work on uncertain lifetimes including well known papers by nils hakansson 1969 stanley fischer 1973 robert barro and james friedman 1977 david levhari and leonard mirman 1977 and kotlikoff and avia spivak 1981 however all of these papers focused on the consumption decision of an individual and ignored the effect of accidental bequests on the behavior of the recipients of these accidental bequests 2 as will be shown at various points in this paper changes in the economic environment can have effects on aggregate behavior which differ sharply from the effects on individual behavior because of the endogenous adjustment of bequests the effects of department of economics harvard university cambridge ma 02138 this paper is a revised version of bequests and social security with uncertain lifetimes nber working paper no 1372 june 1984 i thank olivier blanchard john burbidge christopher cavanagh robert clower stanley fischer benjamin friedman elhanan helpman mervyn king nobuhiro kiyotaki laurence kotlikoff robert mcdonald james pesando julio rotemberg lawrence summers lars svensson mark watson and jeffrey wolcowitz for valuable conversations and correspondence i also thank the participants in seminars at boston university columbia university cornell university federal reserve board harvard university university of iowa mit university of minnesota university of montreal national bureau of economic research north carolina state university the wharton school and yale university and two anonymous referees for their helpful comments i also thank the national science foundation for financial support 1 in the presence of perfect annuity and life insurance markets there may or may not be bequests depending on the presence or absence of a bequest motive but there would be no accidental bequests 2 kotlikoff and spivak focus on the role of the family in providing an incomplete annuities market but stop short of a full scale overlapping generations model in which the distribution of bequests is determined endogenously

informational diversity over time and the optimality of monetary equilibria abstract the temporal realizations of a random state variable in an overlapping generations model create an informational diversity between members of different generations and require a reexamination of the optimality that competitive equilibria might display in such an environment using an optimality criterion that reflects this informational diversity we prove the optimality of competitive equilibrium in a model with a fixed stock of fiat money a single spot market and good endowments that follow a markov process the need for an optimality criterion that incorporates informational diversity is further motivated by studying the same model with the operation of complete contingent commodities markets

testing a present value model of the current account evidence from us and canadian time series abstract this paper presents a simple model of current account determination based upon the permanent income hypothesis of private consumption behavior under rational expectations the model employs a representative national agent who is forward looking and can borrow and lend at a constant world interest rate a present value relationship for the current account is derived and its implications are tested on post war data for the united states and canada testing is done using the framework developed by campbell and shiller 1987 which allows the forcing variables in the model to be difference rather than trend stationary our empirical results indicate the most stringent restrictions of the present value model are strongly rejected by the us and canadian data however less formal procedures suggest the consumption smoothing model has some ability to track the dynamic behavior of the us current account jel f32

an existence theorem on the stationary state of income distribution and population growth through a utility maximizing process individuals derive their optimal fertility and bequest decisions both as functions of their initial socioeconomic backgrounds the combination of these two decisions form a multi type galton watson process under weak assumptions it is proved that the economy will converge to a unique stationary state which implies both a constant population growth rate and a time invariant income distribution as such this paper extends the becker willis static micro level fertility demand model to a dynamic macro level population growth model alternatively our model can be viewed as a generalization of laitners stochastic income theory where no differential fertility is allowed excerpt

the relative dynamics of investment and the current account in the g7 economies this paper contributes to the empirics of the intertemporal approach to the current account we use a cointegrated var framework to identify permanent and transitory components of country specific and global shocks our approach allows us to investigate empirically the sensitivity to persistence implied by many forward looking models and our results shed new light on the excess volatility of investment encountered by glick and rogoff 1995 in g7 data we find the relative current account and investment response to be in line with the intertemporal approach

present value tests of an intertemporal model of the current account abstract this paper first demonstrates that in a simple intertemporal open economy model the current account is equal to the expected decline of the present discounted value of net output of a country net output is defined as gross domestic product less the sum of investment plus government spending it then uses econometric methods for present value models to analyze the current account for four countries in two of these countries the model does a satisfactory job of explaining the current account

risk bearing and the theory of income distribution this paper develops the stochastic theory of distribution with a dynamic model which focuses on the role of incomplete insurance in generating inequality unlike previous work our approach takes explicit account of the reason for market incompleteness in modeling agents behaviour in particular the amount of risk borne is endogenous using a model of growth with altruism in which agents are risk averse and there is moral hazard we show that lineage wealth follows a markov process which converges globally to an ergodic distribution this also represents the long run population distribution of wealth we discuss the role of particular assumptions such as availability of production loans and unboundedness of utility in yielding the qualitative properties of the distribution of wealth the choice of occupation and the prevention of poverty traps