further results on asset pricing with incomplete information abstract this paper extends the analysis of asset pricing when information is incomplete by relaxing some of the restrictive assumptions of the gaussian model studied earlier in the literature for the information structure considered the posterior beliefs of the investor the conditional distribution of the current state given the past observations are characterized by two sets of sufficient statistics implementable in the form of a filter i the vector of conditional means and ii a set of sufficient statistics for the conditional variance covariance matrix a separation theorem is demonstrated and used to produce a closed form solution for the interest rate process when the investor s utility function is logarithmic in this context we examine the informational efficiency properties of the interest rate and analyze the stochastic shifts in the volatility of the interest rate process

a two person dynamic equilibrium under ambiguity this paper describes a pure exchange continuous time economy with two heterogeneous agents and complete markets a novel feature of the economy is that agents perceive some security returns as ambiguous in the sense often attributed to frank knight the equilibrium is described completely in closed form after identifying agents as countries the model is applied to address the consumption home bias and equity home bias puzzles 2002 elsevier science b v all rights reserved jel classi cation d81 g11 g12 g15

disagreement and asset prices abstract how do differences of opinion affect asset prices do investors earn a risk premium when disagreement arises in the market despite their fundamental importance these questions are among the most controversial issues in finance in this paper we use a novel data set that allows us to directly measure the level of disagreement among wall street mortgage dealers about prepayment speeds we examine how disagreement evolves over time and study its effects on expected returns return volatility and trading volume in the mortgage backed security market we find that increased disagreement is associated with higher expected returns higher return volatility and larger trading volume these results imply that there is a positive risk premium for disagreement in asset prices we also show that volatility in and of itself does not lead to higher trading volume instead only when disagreement arises in the market is higher uncertainty associated with more trading finally we are able to distinguish empirically between two competing hypotheses regarding how information in markets gets incorporated into asset prices we find that sophisticated investors appear to update their beliefs through a rational expectations mechanism when disagreement arises

the proper scope of government theory and an application to prisons when should a government provide a service in house and when should it contract out provision we develop a model in which the provider can invest in improving the quality of service or reducing cost if contracts are incomplete the private provider has a stronger incentive to engage in both quality improvement and cost reduction than a government employee has however the private contractor s incentive to engage in cost reduction is typically too strong because he ignores the adverse effect on noncontractible quality the model is applied to understanding the costs and benefits of prison privatization

consensus consumer and intertemporal asset pricing with heterogeneous beliefs le fichier attache est egalement edite dans les cahier de la chaire les particuliers face aux risques de l institut de finance de dauphine cahier n 7 mars 2007

financial market innovation and security design an introduction abstract the article describes in the context of theory and practice this special issue of the journal of economic theory on financial market innovation and security design the main focus is on security design in incomplete financial markets possibly with asymmetrically informed traders we first survey the general equilibrium literature which emphasizes the spanning role of securities we then provide a unified framework encompassing the literature that employs a cara guassian setting to study the impact of financial innovation on risk sharing and information aggregation journal of economic literature classification numbers g10 d52

effects of financial innovations on market volatility when beliefs are heterogeneous abstract consider a model with two logarithmic utility maximizer agents that observe aggregate consumption but disagree about its expected rate of change markets are incomplete we first show that volatility of the interest rate in an economy with additional information is higher in a complete markets economy with no additional information there are two differences in volatility with the previous the first one due to the increase in volatility of the wealth share of the individuals is always positive the second difference is the change in covariance between the components of the interest rate volatility and can be positive or negative

optimal innovation of futures contracts this article presents a simple model of the innovation of new futures contracts by transaction volume maximizing futures exchanges in incomplete markets under uncertainty with mean variance preferences and proportional transactions costs we characterize the set of nash equilibria for a number of exchanges simultaneously or sequentially choosing contracts the optimal monopolistic contract design is shown to be pareto optimal an example shows the failure of pareto optimality for aparticularnash equilibrium likewise in a monopolistic multiperiod setting an example shows the failure of pareto optimality given an incentive for the exchange to induce turnover

divergence of opinion in complete markets a note we consider an arrow debreu model with agents who have different subjective probabilities in general asset prices will depend only on aggregate consumption and the distribution of subjective probabilities in each state of nature if all agents have identical preferences then an asset with more dispersed subjective probabilities will have a lower price than an asset with less dispersed subjective probabilities if risk aversion does not decline too rapidly it seems that this condition is likely to be met in practice so that increased dispersion of beliefs will generally be associated with reduced asset prices in a given arrow debreu equilibrium there have been several recent investigations concerning the effect of heterogeneous probability beliefs on asset prices most of these investigations have taken place in the context of capm like mean variance models see for example lintner 5 miller 7 williams 10 jarrow 4 and mayshar 6 comparatively little has been done in the analysis of differences of opinion in an arrow debreu contingent claims context rubinstein 8 breeden and litzenberger 2 and breeden 1 have presented nice analyses of asset price determination in an arrow debreu model but most of their results have assumed commonly held probability beliefs in this paper we analyze the impact of divergence of opinion on asset prices in an arrow debreu economy the results serve to generalize the findings of rubinstein and breeden litzenberger to the case of different probability beliefs among the results we establish are 1 in equilibrium asset prices depend only on aggregate consumption and the distribution of subjective probability beliefs 2 asset values are an increasing function of any one individual s probability beliefs 3 an increase in the spread of the probability beliefs of investors may increase or decrease equilibrium asset values depending on the value of a parameter of the utility function however the most likely effect is to decrease the asset values these results are especially interesting in light of the recent empirical work of cragg and malkiel 3 they studied the relationship between ex post return and various measures of risk for common stocks and found that the measure of risk that performed best in their analysis was a measure of divergence of opinion

rural income and poverty in a time of radical change in malawi abstract malawi is one of the poorest countries in africa there is widespread though not universal agreement about the shape of poverty in the country and the policy challenge this sets agriculture continues to be the most obvious means to stimulate broad based rural growth and to provide levels of food security and income needed for the majority rural population a longitudinal study over a decade during which radical policy and political changes occurred provides the data and basis for discussing the appropriate policy directions for reducing poverty

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

a welfare criterion for models with distorted beliefs this paper proposes a welfare criterion for economies in which agents have heterogeneously distorted beliefs instead of taking a stand on whose belief is correct our criterion asserts an allocation to be belief neutral ine cient if it is ine cient under any convex combination of agents beliefs while this criterion gives an incomplete ranking of social allocations it can identify negative sum speculation in a broad range of prominent models with distorted beliefs

the persistence of risk adjusted mutual fund performance the authors examine predictability for stock mutual funds using risk adjusted returns they find that past performance is predictive of future risk adjusted performance applying modern portfolio theory techniques to past data improves selection and allows the authors to construct a portfolio of funds that significantly outperforms a rule based on past rank alone in addition they can form a combination of actively managed portfolios with the same risk as a portfolio of index funds but with higher mean return the portfolios selected have small but statistically significant positive risk adjusted returns during a period where mutual funds in general had negative risk adjusted returns copyright 1996 by university of chicago press

differences in beliefs and currency risk premiums this paper studies the importance of heterogeneous beliefs for the dynamics of asset prices we focus on currency markets where the absence of short selling constraints allows us to perform sharper tests of theoretical predictions using a unique data set with detailed information on foreign exchange forecasts we construct an empirical proxy for differences in beliefs we show that this proxy has a strong effect on the implied volatility of currency options beyond the volatility of macroeconomic fundamentals we document that differences in beliefs impact also on the shape of the implied volatility smile on the volatility risk premiums and on future currency returns

a risk centric model of demand recessions and speculation we provide a continuous time risk centric representation of the new keynesian model which we use to analyze the interactions between asset prices financial speculation and macro economic outcomes when output is determined by aggregate demand in principle interest rate policy is highly effective in dealing with shocks to asset valuations however in practice monetary policy faces a wide range of constraints if these constraints are severe a decline in risky asset valuations generates a demand recession this reduces earnings and generates a negative feedback loop between asset prices and aggregate demand in the recession phase average beliefs matter not only because they affect asset valuations but also because they determine the strength of the amplification mechanism in the ex ante boom phase belief disagreements or heterogeneous asset valuations matter because they induce investors to speculate this speculation exacerbates the crash by reducing high valuation investors wealth when the economy transitions to recession which depresses wealth weighted average beliefs macroprudential policy that restricts speculation in the boom can pareto improve welfare by increasing asset prices and aggregate demand in the recession

international good market segmentation and financial innovation abstract while international capital flows are now well liberalized markets for goods remain segmented to investigate how financial innovation may relieve the effects of this segmentation on risk sharing we examine a series of two country economies with internationally segmented good markets distinguished by the available financial securities sufficient conditions for efficiency include complete international financial markets together with liberalized international financial flows under these conditions heterogeneous agents from the same country may use securities as a substitute for the international shipment of goods this allows them to partially circumvent the segmentation allowing for efficient risk sharing

option smiling when investors estimates of asset volatility disagree this study sheds light on why heterogeneous beliefs in volatility manifest the smile effect of options and how the degree of belief disagreement influences option implied volatility it is found that when investors level of heterogeneous beliefs increases agents who over estimate volatility raise their subjective probability about those outer dividend states and hence increase more consumption to those states as a result an increase of consumption causes a decrease of their marginal rate of transformation in outer states the raising subjective probability increases the prices of outer states while the lower marginal rate of transformation decreases the prices of that however the influence of the former dominates the latter causing a fatter tail of the state price density as a consequence the values increase for those call options with high strike prices and put options with low strike prices leading to a u shaped implied volatility and hence causes a smell effect

market timing and mutual fund performance an empirical investigation the evaluation of investment performance is of importance for allocating investment funds efficiently and setting appropriate management fees because actively managed mutual funds are an important form of investment in the united states a valid question is whether the active management has achieved a sufficient increase in returns to offset the associated costs of information and transactions as well as the management fees charged as a corollary the ability to earn superior returns based on superior forecasting ability would be a violation of the efficient markets hypothesis and would have far reaching implications for the theory of finance 2 henriksson and merton 1981 present statistical techniques for testing forecasting ability with a particular emphasis on the market timing ability of investment managers the tests are derived from the basic model of market timing developed by merton 1981 where the forecaster predicts when stocks will outperform riskless securities and when riskless securities will outperform stocks but does not predict the magnitude of the relative returns the evaluation of the performance of investment managers is a topic of considerable interest to practitioners and academics alike using both the parametric and nonparametric tests for the evaluation of forecasting ability presented by henriksson and merton the market timing ability of 116 open end mutual funds is evaluated for the period 1968 80 the empirical results do not support the hypothesis that mutual fund managers are able to follow an investment strategy that successfully times the return on the market portfolio

labor shortages on small landholdings in malawi implications for policy reforms abstract a simple linear programming model of representative smallholder households is used to investigate the sources of relative scarcity of labor and land in malawi the paradox of on farm labor shortages on small landholdings can be explained by the multiple constraints smallholders face these multiple constraints including lack of finance concerns for food security and others lead to suboptimal allocations of household resources in turn the low returns to labor and land contribute to household food insecurity and a vicious cycle of poverty the findings of the paper provide a clear signal to policymakers and research and extension institutions that these constraints are all linked and addressing one cannot be effective without addressing the others

an intertemporal general equilibrium model of asset prices this paper develops a continuous time general equilibrium model of a simple but complete economy and uses it to examine the behavior of asset prices in this model asset prices and their stochastic properties are determined endogenously one principal result is a partial differential equation which asset prices must satisfy the solution of this equation gives the equilibrium price of any asset in terms of the underlying real variables in the economy in this paper we develop a general equilibrium asset pricing model for use in applied research an important feature of the model is its integration of real and financial markets among other things the model endogenously determines the stochastic process followed by the equilibrium price of any financial asset and shows how this process depends on the underlying real variables the model is fully consistent with rational expectations and maximizing behavior on the part of all agents our framework is general enough to include many of the fundamental forces affecting asset markets yet it is tractable enough to be specialized easily to produce specific testable results furthermore the model can be extended in a number of straightforward ways consequently it is well suited to a wide variety of applications for example in a companion paper cox ingersoll and ross 7 we use the model to develop a theory of the term structure of interest rates many studies have been concerned with various aspects of asset pricing under uncertainty the most relevant to our work are the important papers on intertemporal asset pricing by merton 19 and lucas 16 working in a continuous time framework merton derives a relationship among the equilibrium expected rates of return on assets he shows that when investment opportunities are changing randomly over time this relationship will include effects which have no analogue in a static one period model lucas considers an economy with homogeneous individuals and a single consumption good which is produced by a number of processes the random output of these processes is exogenously determined and perishable assets are defined as claims to all or a part of the output of a process and the equilibrium determines the asset prices our theory draws on some elements of both of these papers like merton we formulate our model in continuous time and make full use of the analytical tractability that this affords the economic structure of our model is somewhat similar to that of lucas however we include both endogenous production and

equilibrium interest rates and multiperiod bonds in a partially observable economy this paper analyzes the market for financial assets in a production and exchange economy with several realized outputs and a single unobservable source of nondiversifiable risk the paper demonstrates that for a large class of diffusion outputs and preferences optimizing consumers first estimate the realizations of the unobservable factor and then use these estimates to determine portfolio and consumption rules moreover the explicit consideration of this unobservable productivity factor affects equilibrium demands and prices the equilibrium spot rate of interest emerges as the best estimate of the unobservable factor and multiperiod default free bonds arise as the optimal hedge for the unobservable changes of the stochastic investment opportunity set this paper analyzes the market for financial assets in a production and exchange economy with several realized outputs and a single unobservable source of nondiversifiable risk the paper poses and answers three questions 1 how do consumers determine equilibrium demands and prices when their investment opportunities are unobservable 2 in equilibrium what financial assets provide an optimal hedge for the

trading in derivatives when the underlying is scarce abstract regulatory restrictions and market frictions can constrain the aggregate quantity of long and short positions in a security when these constraints bind we refer to the security as scarce and its price becomes distorted relative to its value in a frictionless market we show that an otherwise redundant derivative can reduce the price distortion of the underlying security by relaxing its scarcity we also show that it is especially important to analyze the underlying and derivative markets jointly when evaluating the impact of regulation such as short sales bans and position limits in derivatives that restricts trade

learning from prices and the dispersion in beliefs i study whether investors use an asset s price to update their beliefs about its payos i show that in a dynamic economy the relationship between the dispersion in investor beliefs and returnvolume characteristics can be used to empirically answer this question when investors have rational expectations re and condition on the price i show that belief dispersion is positively related to expected returns return volatility and correlation between volume and absolute returns but negatively related to return autocorrelation when investors do not use the price as in a dierence of opinions do model these relationships are reversed i test these predictions using the crosssection of returns volume and analyst forecast dispersion over dierent horizons the results are consistent with the re model at quarterly and longer horizons but reject both models at the monthly horizon i show that a hybrid model with some do investors and some re investors can match the short horizon evidence the empirical results are consistent with the idea that while some investors do not use the price in the short run they increase their conditioning on the price over time

of tournaments and temptations an analysis of managerial incentives in the mutual fund industry we test the hypothesis that when their compensation is linked to relative performance managers of investment portfolios likely to end up as losers will manipulate fund risk differently than those managing portfolios likely to be winners an empirical investigation of the performance of 334 growth oriented mutual funds during 1976 to 1991 demonstrates that mid year losers tend to increase fund volatility in the latter part of an annual assessment period to a greater extent than mid year winners furthermore we show that this effect became stronger as industry growth and investor awareness of fund performance increased over time

efficiency with costly information a study of mutual fund performance 1965 1984 if information is costly to collect and implement then it is efficient for trades by informed investors to occur at prices sufficiently different from full information prices to compensate them for the cost of becoming informed this notion is tested by evaluating investment performance in the mutual fund industry over a 20 year period the study finds evidence that is consistent with optimal trading in efficient markets risk adjusted returns in the mutual fund industry net of fees and expenses are comparable to returns available in index funds and portfolio turnover and management fees are unrelated to fund performance

portfolio performance evaluation old issues and new insights this article presents a model that provides insights about various measures of portfolio performance the model explores several criticisms of these measures these include the problem of identifying an appropriate benchmark portfolio the possibility of overestimating risk because of market timing ability and the failure of informed investors to earn positive risk adjusted returns because of increasing risk aversion the article argues that these need not be serious impediments to performance evaluation

exploring seasonal poverty traps the six week window in southern malawi conventional wisdom in malawi holds that seasonal food deficits force smallholders to hire out their labour to buy food during the critical first six weeks after planting thereby reducing maize yields on their own fields and reinforcing poverty this model was tested empirically for the blantyre shire highlands using evidence from a panel survey and household case studies results showed no significant relationship between the supply of hired labour ganyu and the timeliness of weeding for maize and that timely weeding was not a significant determinant of household maize deficits this puzzle is explained by the diversification of the rural economy that has allowed households to develop alternative livelihood strategies to cope with maize deficits livelihood diversity helped poor households avoid the seasonal poverty trap and also helps explain the paradox of why the poorest region in malawi escaped the 2001 2002 famine

the consumption based capital asset pricing model the paper provides conditions on the primitives of a continuous time economy under which there exist equilibria obeying the consumption based capital asset pricing model ccapm the paper also extends the equilibrium characterization of interest rates of cox ingersoll and ross 1985 to multi agent economies we do not use a markovian state assumption this work provides sufficient conditions on agents primitives for the validity of the consumption based capital asset pricing model ccapm of breeden 1979 as a necessary condition breeden showed that in a continuous time equilibrium satisfying certain regularity conditions one can characterize returns on securities as follows the expected instantaneous rate of return on any security in excess of the riskless interest rate the security s expected excess rate of return is a multiple common to all securities of the instantaneous covariance of this excess return with aggregate consumption increments this common multiple is the arrow pratt measure of risk aversion of a representative agent rubinstein 1976 published a discrete time precursor of this result the exis tence of equilibria satisfying breeden s regularity conditions had been an open issue we also show that the validity of the ccapm does not depend on breeden s assumption of markov state information and present a general asset pricing model extending the results of cox ingersoll and ross 1985 as well as the discrete time results of rubinstein 1976 and lucas 1978 to a multi agent environment since the ccapm was first proposed much effort has been directed at finding sufficient conditions on the model primitives the given assets the agents preferences the agents consumption endowments and in a production econ omy the feasible production sets conditions sufficient for the existence of continuous time equilibria were shown in duffie 1986 but the equilibria demonstrated were not shown to satisfy the additional regularity required for the ccapm in particular breeden assumed that all agents choose pointwise interior consumption rates in order to characterize asset prices via the first order conditions of the bellman equation interiority was also assumed by huang 1987 in demonstrating a representative agent characterization of equilibrium an approach exploited here the use of dynamic programming and the bellman equation aside from the difficulty it imposes in verifying the existence of interior 1 financial support from the national science foundation is gratefully acknowledged we thank

optimal consumption and portfolio policies when asset prices follow a diffusion process abstract we consider a consumption portfolio problem in continuous time under uncertainty a martingale technique is employed to characterize optimal consumption portfolio policies when there exist nonnegativity constraints on consumption and on final wealth we also provide a way to compute and verify optimal policies our verification theorem for optimal policies involves a linear partial differential equation unlike the nonlinear partial differential equation of dynamic programming the relationship between our approach and dynamic programming is discussed we demonstrate our technique by explicitly computing optimal policies in a series of examples in particular we solve the optimal consumption portfolio problem for hyperbolic absolute risk aversion utility functions when the asset prices follow a geometric brownian motion the optimal policies in this case are no longer linear when nonnegativity constraints on consumption and on final wealth are included by these examples one can see that our approach is much easier than the dynamic programming approach

efficiency with costly information a reinterpretation of evidence from managed portfolios we investigate the informational efficiency of mutual fund performance for the period 1965 84 results are shown to be sensitive to the measurement of performance chosen we find that returns on s p stocks returns on non s p stocks and returns on bonds are significant factors in performance assessment once we correct for the impact of non s p assets on mutual fund returns we find that mutual funds do not earn returns that justify their information acquisition costs this is consistent with results for prior periods coauthors are martin j gruber sanjiv das and matthew hlavka article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

intertemporal asset pricing with heterogeneous beliefs abstract we examine the behaviour of the interest rate asset prices and asset holdings in an economy with heterogeneous rationally updated beliefs about the expected rate of production growth the equilibrium interest rate is a weighted average of the interest rates that would prevail in economies populated by homogeneous agents with the beliefs of the respective agents in the heterogeneous model the weights are given by the fractions of total wealth held financial innovation affects the dynamics of allocations and prices but preserves the aggregate output process and the structure of equilibrium asset prices also display the wealth weighted average characterization journal of economic literature classification numbers c60 d52 d91 g12

bureaucratic inefficiency failure to capture the efficiencies of outsourcing this paper analyzes the political economy ofoutsourcing by 16 federal bureaus during 1981 96 inan era of restricted budgets and budget balancing thepaper questions why federal bureaus did not exploitfully the efficiencies of outsourcing it proves thatfederal bureaus can achieve technical and costefficiency through outsourcing when contracts can benearly fully specified federal bureaus outsource byobtaining inputs to their production processes throughcontracts with competitive market producing units econometric results substantiate the hypothesis that institutions matter and reveal that bureausachieve varying levels of technical efficiency throughdifferent levels of outsourcing

an intertemporal general equilibrium asset pricing model the case of diffusion information this paper provides sufficient conditions for the equilibrium price system and a vector of exogenously specified state variable processes to form a diffusion process in a pure exchange economy the conditions involve smoothness of agents utility functions and certain nice properties of the aggregate endowment process and the dividend processes of traded assets in place of the dynamic programming a martingale representation technique is utilized to characterize equilibrium portfolio policies this technique is useful even when there does not exist a finite dimensional markov structure in the economy and thus the markovian stochastic dynamic programming is not applicable a gents are shown to hold certain hedging mutual funds and the riskless asset in contrast to earlier results the market portfolio does not have a special role in hedging since the markets are dynamically complete when there exists a finite dimensional markov system in the economy the dimension of the hedging demand identified through the markovian dynamic programming may be much larger than that identified by the martingale method copyright 1987 by the econometric society

using cost observation to regulate firms the paper emphasizes the use of accounting data in regulatory or procurement contracts when the supplier 1 has superior information about the cost of the project and 2 invests in cost reduction the main result states that under risk neutrality the supplier announces an expected cost and is given an incentive contract linear in cost overruns this optimal contract moves toward a fixed price contract as the announced cost decreases an investment choice is then introduced and the use of a rate of return regulation is studied

the determinants of poverty in malawi 1998 abstract poverty reduction efforts aim at changing those household characteristics that are judged important determinants of household welfare and poverty status we model the determinants of poverty for malawian households by conducting an empirical multivariate analysis of household welfare primarily using data from the 1997 98 malawi integrated household survey using this model to simulate the effects of changes in key household characteristics we are able to assess the likely impact on poverty of a number of poverty reduction policy interventions the simulations show that higher levels of educational attainment especially for women and the reallocation of household labor away from agriculture and into the trade and services sector of the economy will prove effective in reducing poverty in malawi

hot hands in mutual funds short run persistence of relative performance 1974 1988 the relative performance of no load growth oriented mutual funds persists in the near term with the strongest evidence for a one year evaluation horizon portfolios of recent poor performers do significantly worse than standard benchmarks those of recent top performers do better though not significantly so the difference in risk adjusted performance between the top and bottom octile portfolios is six to eight percent per year these results are not attributable to known anomalies or survivorship bias investigations with a different previously used data set and with some post 1988 data confirm the finding of persistence

optimal portfolio choice under incomplete information models of asset pricing generally assume that the variables which characterize the state of the economy are observable however the distributional properties of asset prices that are relevant for portfolio decisions are in general not observable and therefore must be estimated the estimation of expected returns is a particularly difficult problem and estimation errors are likely to be substantial in this light it is reasonable to examine whether the assumption of observability of expected returns and other relevant state variables causes significant mis specification in equilibrium models of asset prices this paper has three main objectives first to derive optimal estimators for the unobservable expected instantaneous returns using observations of past realized returns second to establish that estimation and portfolio choice can be solved in two separate steps third to analyze the impact of estimation error on investment choices the estimators of expected returns are in general not consistent i e the estimation error does not tend to disappear asymptotically the effects of the estimation error therefore cannot be ignored even if realized returns are observed continuously over an infinite time period

a model of competitive stock trading volume a model of competitive stock trading is developed in which investors are heterogeneous in their information and private investment opportunities and rationally trade for both informational and noninformational motives i examine the link between the nature of heterogeneity among investors and the behavior of trading volume and its relation to price dynamics it is found that volume is positively correlated with absolute changes in prices and dividends i show that informational trading and noninformational trading lead to different dynamic relations between trading volume and stock returns

a theory of optimal timing and selectivity abstract we solve an extended optimal portfolio problem in continuous time for any horizon where we allow the mean and variance of returns to be stochastic introduce fund flows to and from the portfolio permit differential investor preferences for dividend versus growth stocks and allow the investor to buy costly information on the random mean and variance of the portfolio to improve his portfolio choice set this model provides analytical results especially useful in understanding the expenditure on timing and selection information a mutual fund undertakes in attempting to improve performance relative to a benchmark we examine this proposition for growth and income funds long and short investment horizons and also account for fund inflows and outflows we also combine our model of costly learning with the traditional model of incomplete information to understand the interaction between costly and costless learning the approach taken is a purely theoretical one and in this regard the paper is normative in spirit we anticipate that the propositions in this paper will provide two byproducts i a framework for fund managers to think about how to allocate information expenses between timing and selection skills and ii give academics especially empirical researchers a theoretical backdrop against which to examine the mutual fund industry

on the risk of stocks in the long run a familiar proposition is that investing in common stocks is less risky the longer an investor plans to hold them if this proposition were true then the cost of insuring against earning less than the risk free rate of interest should decline as the investment horizon lengthens this paper shows that the opposite is true even if stock returns are mean reverting in the long run the case for young people investing more heavily than older people in stocks cannot therefore rest solely on the long run properties of stock returns for guarantors of money fixed annuities the proposition that stocks in their portfolios are a better hedge the longer the maturity of their obligations is unambiguously wrong

off farm labor supply and correlated shocks new theoretical insights and evidence from malawi abstractwe offer new conceptual insights into the understanding of occupational choice in uncertain rural environments with a focus on its ex ante before a shock and ex post after a shock consequences for farmers belonging to different portions of the asset distribution we model theoretically the choice between relatively safe subsistence farming higher return but higher risk cash crop activities and off farm labor conditional on preexisting asset allocation and look at the general equilibrium labor market implications of correlated shocks our results backed by evidence from malawi challenge some stylized perceptions in the literature on consumption smoothing via off farm labor supply

differential information and dynamic behavior of stock trading volume this article develops a multiperiod rational expectations model of stock trading in which investors have differential information concerning the underlying value of the stock investors trade competitively in the stock market based on their private information and the information revealed by the market clearing prices as well as other public news we examine how trading volume is related to the information flow in the market and how investors trading reveals their private information article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

vulnerability seasonality and poverty in ethiopia most studies examining the dynamics of welfare have found large fluctuations in consumption over relatively short periods suggesting substantial short run movements in and out of poverty the consequence is that cross section poverty research may not be able to identify the poor in this study we explore this short run variability further we use a data set on a panel of 1450 households in different communities in rural ethiopia surveyed thrice over 18 months on average year to year poverty is very similar however we find high variability in consumption and poverty over the seasons and year by year econometric analysis suggests that consumption is affected by idiosyncratic and common shocks including rainfall and household specific crop failure while households respond to seasonal incentives related to changing labour demand and prices the results imply that a larger number of households are vulnerable to shocks than implied by the standard poverty statistics while some of the non poor in the

arbitrage short sales and financial innovation the authors describe a model of general equilibrium with incomplete markets in which firms can innovate by issuing arbitrary costly securities when short sales are prohibited firms behave competitively and equilibrium is efficient when short sales are allowed these classical properties may fail if unlimited short sales are allowed imperfect competition may persist even when the number of potential innovators is large if limited short sales are allowed perfect competition may obtain in the limit but equilibrium can be inefficient because of the presence of an externality the private benefits of innovation for firms differ from the social benefits copyright 1991 by the econometric society

market timing selectivity and mutual fund performance an empirical investigation this article empirically examines market timing and selectivity performance of a sample of mutual funds it uses a very simple regression technique to separate stock selection ability from timing ability this technique first suggested by treynor and mazuy and later refined by bhattacharya and pfleiderer uses a modified security market line approach to produce individual measures of timing and stock selection ability the inputs to the model are only the returns earned on the fund and those earned on the market portfolio the empirical results indicate that at the individual fund level there is some evidence of superior micro and macroforecasting ability on the part of the fund manager copyright 1990 by the university of chicago

asset pricing in a production economy with incomplete information this paper analyzes an economy in which investors operate under partial information about technology relevant state variables it is shown that for gaussian information structures under incomplete observations the consumer s problem can be transformed into an equivalent program with a completely observed state the conditional expectation of the underlying unobservable state variables a consequence of this transformation is that classic results in finance remain valid under an appropriate reinterpretation of the state variables the static capital asset pricing model capm of sharpe 24 lintner 16 and mossin 20 states that the expected premium on any risky asset is proportional to the premium on the market as a whole this theoretical linear relationship however is subject to criticisms on two grounds first it does not seem to be supported by the empirical evidence second it is based on the premises of a constant opportunity set merton 19 subsequently relaxes this assumption and shows that when the opportunity set fluctuates over time due to changes in the state of the economy individual securities are also priced with respect to selected portfolios funds providing a hedge against unanticipated fluctuations 2 more recently breeden 3 has extended merton s results by emphasizing the role of aggregate consumption in pricing relationships in this paper we seek to further our understanding of asset pricing by relaxing the assumption that investors observe the state of the economy in the mertonbreeden framework observed state variables affect the means and variances of asset returns implying deformations of the opportunity set over time from a practical point of view it seems that this complete information assumption is violated investors in financial markets operate under partial knowledge of the microvariables which influence production and the returns on assets their decisions rely mostly on information through noisy channels such as newspapers technical reviews or weather reports in this paper we attempt to model such

consumption and portfolio policies with incomplete markets and short sale constraints the infinite dimensional case abstract we employ a martingale approach to study a dynamic consumption portfolio problem in continuous time with incomplete markets and short sale constraints we introduce a notion of minimax local martingale and transform the dynamic problem into a static problem of maximizing expected utility over the consumption bundles that satisfy a single budget constraint formed using that measure we establish the existence of and characterize the minimax local measure provide sufficient conditions for the dynamic consumption portfolio problem to have a solution and relate the optimal policies to the solution of quasi linear partial differential equation

are more risk averse agents more optimistic insights from a rational expectations model we analyze the link between pessimism and risk aversion we consider a model of partially revealing competitive rational expectations equilibrium with diverse information in which the distribution of risk aversion across individuals is unknown we show that when a high individual level of risk aversion is taken as a signal for a high average level of risk aversion more risk averse agents are more optimistic this correlation between individual risk aversion and optimism leads to a pessimistic consensus belief hence to an increase in the market price of risk risk sharing schemes and welfare implications are analyzed we show that agents welfare may increase upon the receipt of more precise information

collateral motivated financial innovation collateral frictions have a profound effect on our economic landscape ranging from the design of financial securities laws and institutions to various rules and regulations we analyze a model with disagreement where securities and collateral requirements are endogenous it shows that the security that isolates the variable with disagreement is optimal in the sense that alternative securities cannot generate any trading in an economy with n states investors may introduce more than n securities and markets are still incomplete the model has several novel predictions on the behavior of basis the spread between the prices of an asset and its replicating portfolio

relating seasonal hunger and prevention and coping strategies a panel analysis of malawian farm households relative to chronic hunger seasonal hunger in rural and urban areas of africa is poorly understood this paper examines the extent and potential correlates of seasonal hunger in malawi using panel data from 2011 2013 we find that both urban and rural households report seasonal hunger in the pre harvest months certain strategies to smooth consumption including crop storage and livestock ownership are associated with fewer months of hunger in addition we find that malawian households that experience seasonal hunger harvest their crops earlier than average a short term coping mechanism that can reduce the crop s yield and nutritional value possibly perpetuating hunger