equilibrium in an ambiguity averse mean variance investors market abstract in a financial market composed of n risky assets and a riskless asset where short sales are allowed and mean variance investors can be ambiguity averse i e diffident about mean return estimates where confidence is represented using ellipsoidal uncertainty sets we derive a closed form portfolio rule based on a worst case max min criterion then in a market where all investors are ambiguity averse mean variance investors with access to given mean return and variance covariance estimates we investigate conditions regarding the existence of an equilibrium price system and give an explicit formula for the equilibrium prices in addition to the usual equilibrium properties that continue to hold in our case we show that the diffidence of investors in a homogeneously diffident with bounded diffidence mean variance investors market has a deflationary effect on equilibrium prices with respect to a pure mean variance investors market in equilibrium deflationary pressure on prices may also occur if one of the investors in an ambiguity neutral market with no initial short position decides to adopt an ambiguity averse attitude we also establish a capm like property that reduces to the classical capm in case all investors are ambiguity neutral

optimal shared savings contracts in supply chains linear contracts and double moral hazard in many supply chains consumption of indirect materials sold by a supplier to a customer for use in her production process can be reduced by efforts exerted by either party since traditional supply contracts provide no incentive for the supplier to exert such effort shared savings contracts have been proposed as a way to improve incentives in the channel leading to more efficient effort choices by the two parties such shared savings contracts typically combine a fixed service fee with a variable component based on consumption volume we formalize this situation using the double moral hazard framework in which both parties decide how much effort to exert by trading off the cost of their effort against the benefits that they will obtain from reduced consumption we also extend the double moral hazard framework to analyze a broader class of cost of effort functions than considered so far including the linear cost of effort functions commonly found in practice we show that the supplier can still always induce the optimal second best equilibrium with a linear shared savings contract under this broader class of functions however the behavior of the optimal contract as a function of the problem parameters becomes more complex we illustrate how small changes in the problem parameters can turn profits from being a well behaved to a poorly behaved function of the contract and provide some theoretical characterization of this phenomenon the practical significance of this is that simple linear contracts are sufficient in many double moral hazard contexts even for the broader class of functions we consider but care must be taken in selecting the optimal contract parameters

a general mean variance approximation to expected utility for short holding periods the mean variance model is precisely consistent with the expected utility hypothesis only in the special cases of normally distributed security returns or quadratic utility functions there is little evidence however that security returns follow normal distributions see 13 for references and quadratic preferences can be shown to generate implausible results exhibiting increasing absolute risk aversion in the pratt ll arrow 1 2 sense and displaying negative marginal utility after some finite wealth level in addition hakansson 4 has shown that single period mean variance efficient portfolios can have disastrous consequences over time even when return distributions are stationary such criticisms of the mean variance approach within the von neumann morgenstern framework have prompted several writers to suggest that investors maximize the expected value of utility functions with more realistic properties while others have criticized the single period focus of the model one popular alternative utility function is the logarithmic function which exhibits decreasing absolute risk aversion and conveniently leads to myopic decision processes through time i e investors treat each period as if it were the last basing investment decisions on that period s wealth and return distributions only 8 4 other utility functions with constant relative risk aversion such as the power function also imply myopic decision rules within a multiperiod setting

optimal joint pricing and lot sizing with fixed and variable capacity this paper examines previously unexplored fixed and variable capacity problems of jointly determining an item s price and lot size for a profit maximizing firm facing constant but price dependent demands over a planning horizon we apply geometric programming to these constrained nonlinear maximization problems with nonconcave objective functions and obtain global optimal solutions using kuhn tucker condition marginal and sensitivity analyses we investigate model interactions provide managerial implications on the optimal capacity decisions and explore the postoptimal behavior of the price lot size and capacity expansion and reduction size some findings cast interesting insights different from previous just in time management studies without pricing consideration

current account deficits and debt accumulation in latin america debate and evidence abstract in this paper i examine competing explanations for the behavior of latin america s current account in the 1970s and 1980s after briefly reviewing the focus of various economists on internal or external factors i outline a financial breakdown view which stresses the role of the changing availability of capital during this period of time i then turn to econometric work which 1 establishes the plausibility of viewing capital availability as a constraint on the current account and 2 offers some support for all three views of the determinants of latin america s current account

when not all conflict is bad manufacturing marketing conflict and strategic incentive design researchers and managers broadly agree that coordination and harmony between manufacturing and marketing improve firm performance by eliminating suboptimal practices within the firm in this paper we present a contrasting view of the manufacturing marketing interface we model a duopoly in which the firms compete on price and quality dimensions the manufacturing and marketing managers within each firm are presented with conflicting incentives focused on cost minimization and revenue maximization respectively these managers bargain with each other before arriving at compromise decisions regarding price and quality while frequently encountered in practice this conflicting objectives puzzle is surprising because one expects that centralized coordination by the owners of the firm towards profit maximization would lead to higher profits in this paper we resolve the conflicting objectives puzzle and demonstrate that surprisingly the firm s resulting profits in this setting of conflict can be higher than those obtained when the decisions of the managers are perfectly coordinated we also analyze the equilibrium in incentive plans when the owners can choose between compromise and perfect coordination our results offer a new interpretation of manufacturing marketing conflict as a strategic tool that can enhance firm profits

an alternative test of the capital asset pricing model reply in our 1980 paper we tested the joint hypothesis that prices are determined by the mean variance mv capital asset pricing model capm and that beliefs are stationary by focusing on the invariance law of prices we avoided the questionable practice of estimating ex ante expectations with ex post returns moreover we circumvented the need to identify the true market portfolio and hence avoided the ambiguity noted by richard roll 1977 in the traditional security market line sml tests of the same joint hypothesis however stuart turnbull and ralph winter t w and richard sweeney point to a further inconsistency in the joint hypothesis that they believe can be removed by relaxing the stationarity assumption this new concern is fundamental in that it applies to all empirical tests which assume stationarity of the return distribution whether they are simply tests of the capm or tests employing the capm the concern would apply a fortiori to tests that assume stationary betas as well both comments also suggest that the ad hoc addition of a random error term to our invariance law equation and the subsequent statistical tests of it are unnecessary we first address these two criticisms and then address some further criticisms raised separately by t w and sweeney

coordination of internal supply chains in vertically integrated high tech manufacturing organizations htmos abstract this paper uses economic mechanisms to coordinate supply chains within high tech manufacturing organizations htmos it models the one shot initial production and allocation decisions involved in the production and marketing of new technologies these decisions are driven by the economic objectives of the firm and of the employees with private information the experts it analyzes and compares the efficiency of three coordination policies centralized command and control centralized revelation and decentralized revelation it shows that decentralized policies introduce an additional cost and it proposes rules of thumb for coordinating supply chains within firms that use many experts

multivariate stochastic volatility via wishart processes financial models for asset and derivatives pricing risk management portfolio optimization and asset allocation rely on volatility forecasts time varying volatility models such as generalized autoregressive conditional heteroscedasticity and stochastic volatility svol have been successful in improving forecasts over constant volatility models we develop a new multivariate svol framework for modeling financial data that assumes covariance matrices stochastically varying through a wishart process in our formulation scalar variances naturally extend to covariance matrices rather than to vectors of variances as in traditional svol models model fitting is performed using markov chain monte carlo simulation from the posterior distribution because of the model s complexity an efficiently designed gibbs sampler is described that produces inferences with a manageable amount of computation our approach is illustrated on a multivariate time series of monthly industry portfolio returns a test of the ec

target pricing demand side versus supply side approaches abstract the practice of target pricing has been a key factor in the success of japanese manufacturers in the more commonly known demand side approach the target price for the supplier equals the manufacturer s market price less a percent margin for the manufacturer but no cost improvement expenses are shared in the supply side approach cost improvement expenses are shared and the target price equals the supplier s cost plus a percent margin for the supplier using a general oligopoly and cournot duopoly models we characterize the equilibrium and optimal policy for each approach under various conditions we find that sharing cost reduction expenses allows the manufacturer using the supply side approach to attain competitive advantage in the form of increased market share and higher profit particularly in industrial conditions where margins are thin and price sensitivities are high

normality solvency and portfolio choice this paper examines whether investors with power utility functions choose mean vari ance mv efficient portfolios when returns are approximately normally distributed and there is borrowing or lending at a riskless interest rate the results show that the unlevered portfolios of power utility investors plot very closely to the mv efficient frontier how ever there are marked differences in the mix of risky assets regardless of whether the portfolios are highly concentrated or widely diversified such differences allow power investors to remain solvent even when they lever their optimal portfolios to a greater ex tent than less risk averse mv investors who risk bankruptcy it is concluded that the investment policies of power utility and mv investors with similar risk aversion measures are not as similar as is commonly believed this is particularly true for high power inves tors unless explicit solvency constraints are imposed on the mv problem and for low power investors when quadratic utility approximations are made to the power utility func tions these differences in the investment policies of power utility and mv investors lead us to question the widely accepted assertion that the assumptions of homogeneous beliefs normality a riskless asset and risk averse investors imply the simple mv capm where all investors including power utility investors hold combinations ofthe market portfolio and the riskless asset

the mean variance optimization puzzle security portfolios and food portfolios the markowitz mean variance optimization framework presents a puzzle although it is the standard model of portfolio construction investors rarely use it and when used it is constrained so much that portfolios reflect the constraints more than the optimization why do investors dislike unadulterated optimized mean variance portfolios the typical answer focuses on biases introduced by estimation errors more important is the fact that investors goals are quite different from mean variance optimization people care about more than cost and nutrition when they construct their diets they also care about palatability similarly investors care about more than expected returns and variance as they construct their securities portfolios they also care about the investment equivalent of palatability we use an analogy between security portfolios and food portfolios to explore the nature of the gap between intuitively appealing portfolios and mean variance optimized portfolios

leadtime reduction in a q r inventory system an agency perspective abstract we examine the problem of designing and implementing a continuous review q r inventory system from an agency perspective in which the agent s effort influences the item s replenishment leadtime our results are as follows if the agent is risk neutral a linear or quadratic contract achieves first best for a risk averse agent with an exponential utility function assuming a normal leadtime distribution we determine the optimal linear contract extensive numerical experiments suggest that ignoring the possible influence of the agent on the replenishment leadtime can be costly but that the cost penalty of ignoring agency can be significantly reduced by a simple contract

robust consumption and portfolio policies when asset prices can jump abstract we study the consumption portfolio allocation problem in continuous time when asset prices follow levy processes and the investor is concerned about potential model misspecification we derive optimal consumption and portfolio policies that are robust to uncertainty about the hard to estimate drift rate jump intensity and jump size parameters we also provide a semi closed form formula for the detection error probability and compare various portfolio holding strategies including robust and non robust policies our quantitative analysis shows that ignoring uncertainty leads to significant wealth loss for the investor

a note on portfolio selection with restrictions on leverage abstract this note focuses on a mean variance asset allocation framework having restrictions on leverage namely where investors are constrained either to hold funds in a risk free asset i e to lend or to hold debt i e to borrow it is shown that the optimal portfolio in a constrained leverage situation will not have the same composition as the optimal portfolio in an unconstrained situation we give formal justification for the intuitive notion that the more debt an investor is constrained to hold the more the investor should tilt the remaining investments towards a portfolio of less risky assets conversely the greater the proportion an investor is constrained to hold in a risk free asset the more the investor should tilt remaining investment towards a portfolio of more risky assets

on the sensitivity of mean variance efficient portfolios to changes in asset means some analytical and computational results tbis paper investigates the sensitivity of meanvariance mv efficientportfolios to changes in the means of individual assets when only a budget constraint is imposed on the investment problem the analytical results indicate that an mv efficient portfolio s weights mean and variance can be extremely sensitive to cbanges in asset means when nonnegativity constraints are also imposed on the problem the computational results confirm that a positively weigbted mv efficient portfolio s weigbts are extremely sensitive to cbanges in asset means but the portfolio s returns are not a surprisingly small increase in the mean of just one asset drives balf the securities from the portfolio yet the portfolio s expected return and standard deviation are virtually uncbanged this paper supersedes should investors hold well diversified portfolios financial support from the natural science and engineering research council of canada is gratefully acknowledged we also acknowledge the most capable assistance of ruth cornale simon ng jean marc potier and frederick shen the paper was presented at simon fraser university and the western finance association meetings in san diego we thank the participants especially stephen brown john herzog john heaney ray koopman and bruce lehmann and the editors jon ingersoll and chester spatt for

dutch disease government policy and import demand in nigeria the effects of sectoral changes and government policies on import demand in nigeria are examined in the context of the oil shocks of the 1970s and 1980s a two equation model is estimated to determine real import demand and the real exchange rate the results show that import demand increased significantly in response to the boom induced squeeze on the agricultural sector furthermore by inducing and sustaining real exchange rate overvaluation expansionary government policies contributed to higher import demand even after the collapse in oil prices

evaluating the impact of inequality constraints and parameter uncertainty on optimal portfolio choice we present new analytical results for the impact of portfolio weight constraints on an investor s optimal portfolio when parameter uncertainty is taken into account while it is well known that parameter uncertainty and imposing weight constraints results in reduced certainty equivalent returns in the general case there are no analytical results in a special case commonly used in the funds management literature we derive analytical expression for the certainty equivalent loss that does not depend on the risk aversion parameter we illustrate our theoretical results using hedge fund data from the perspective of a fund of fund manager our contribution is to formalize the framework to investigate this problem as well as providing tractable analytical solutions that can be implemented using either simulated or asset manager returns

time diversification and estimation risk the recommendation that investors with long investment horizons tilt their portfolios toward stocks is commonplace we used a nonparametric bootstrap approach to investigate whether in a mean variance efficient portfolio the weights for u s stocks and u s t bills vary in a systematic manner with investment horizon this approach allowed us to analyze the impact of estimation risk on the optimal weights of stocks and fixed income securities the results show that an investor can gain from time diversification the weights for stocks in an efficient portfolio were significantly larger for long investment horizons than a one year horizon

an examination of resampled portfolio efficiency we examined the out of sample performance of using resampled portfolio efficiency an approach proposed in 1998 in international asset allocation strategies for the period january 1983 to may 2000 for most models we used to estimate expected returns using strategies based on resampled portfolio efficiency provided some benefits in terms of improved sharpe ratios and abnormal returns over using traditional mean variance strategies we found little evidence however that active mean variance strategies or resampled efficiency strategies would have generated significantly positive abnormal returns for the time period we considered

bayesian estimation of the global minimum variance portfolio in this paper we consider the estimation of the weights of optimal portfolios from the bayesian point of view under the assumption that the conditional distribution of the logarithmic returns is normal using the standard priors for the mean vector and the covariance matrix we derive the posterior distributions for the weights of the global minimum variance portfolio moreover we reparameterize the model to allow informative andnon informative priors directly for the weights of the global minimum variance portfolio the posterior distributions of the portfolio weights are derived in explicit form for almost all models the models are compared by using the coverage probabilities of credible intervals in an empirical study we analyze the posterior densities of the weights of an international portfolio

coordination mechanisms of supply chain systems supply chain management scm has become an important management paradigm as supply chain members are often separate and independent economic entities a key issue in scm is to develop mechanisms that can align their objectives and coordinate their activities so as to optimize system performance in this paper we provide a review of coordination mechanisms of supply chain systems in a framework that is based on supply chain decision structure and nature of demand this framework highlights the behavioral aspects and information need in the coordination of a supply chain the identification of these issues points out several directions of future research in this area

portfolio management with robustness in both prediction and decision a mixture model based learning approach abstract we develop in this paper a novel portfolio selection framework with a feature of double robustness in both return distribution modeling and portfolio optimization while predicting the future return distributions always represents the most compelling challenge in investment any underlying distribution can be always well approximated by utilizing a mixture distribution if we are able to ensure that the component list of a mixture distribution includes all possible distributions corresponding to the scenario analysis of potential market modes adopting a mixture distribution enables us to 1 reduce the problem of distribution prediction to a parameter estimation problem in which the mixture weights of a mixture distribution are estimated under a bayesian learning scheme and the corresponding credible regions of the mixture weights are obtained as well and 2 harmonize information from different channels such as historical data market implied information and investors subjective views we further formulate a robust mean cvar portfolio selection problem to deal with the inherent uncertainty in predicting the future return distributions by employing the duality theory we show that the robust portfolio selection problem via learning with a mixture model can be reformulated as a linear program or a second order cone program which can be effectively solved in polynomial time we present the results of simulation analyses and primary empirical tests to illustrate a significance of the proposed approach and demonstrate its pros and cons

competitive and cooperative inventory policies in a two stage supply chain we investigate a two stage serial supply chain with stationary stochastic demand and fixed transportation times inventory holding costs are charged at each stage and each stage may incur a consumer backorder penalty cost e g the upper stage the supplier may dislike backorders at the lower stage the retailer we consider two games in both the stages independently choose base stock policies to minimize their costs the games differ in how the firms track their inventory levels in one the firms are committed to tracking echelon inventory in the other they track local inventory we compare the policies chosen under this competitive regime to those selected to minimize total supply chain costs i e the optimal solution we show that the games nearly always have a unique nash equilibrium and it differs from the optimal solution hence competition reduces efficiency furthermore the two games equilibria are different so the tracking method influences strategic behavior we show that the system optimal solution can be achieved as a nash equilibrium using simple linear transfer payments the value of cooperation is context specific in some settings competition increases total cost by only a fraction of a percent whereas in other settings the cost increase is enormous we also discuss stackelberg equilibria

risk forecasting models and optimal portfolio selection this study analyses from an investor s perspective the performance of several risk forecasting models in obtaining optimal portfolios the plausibility of the homoscedastic hypothesis implied in the classical markowitz model is dicussed and more general models which take into account assymetry and time varying risk are analysed specifically it studies whether arch type based models obtain portfolios whose risk adjusted returns exceed those of the classical markowitz model the same analysis is performed with models based on the lower partial moment lpm which take into account the assymetry in the distribution of returns the results suggest that none of the models achieve a clearly superior average performance it is also found that models based on semivariance perform as well as those based on the variance but not better than even if the evaluation criterion is based on the reward to semivariance ratio when attention turns to the analysis of worst case performance the results are clearly differ

calibration of agricultural risk programming models abstract positive mathematical programming pmp is one of the most commonly used methods for calibrating activity programming models in this article we consider pmp as a calibration method for risk programming models with a mean variance e v specification we argue that the restrictive theoretical assumptions employed by typical linear e v models limit their applicability in analyzing the effects of decoupled payments on agricultural production decisions furthermore the requirement for eliciting a risk aversion coefficient renders such models incompatible with the pmp method for this reason we propose a nonlinear e v specification and develop a pmp based procedure for its calibration which does not aim at introducing further nonlinearities in the objective function but at recovering the true distribution of wealth that will allow the final model to reproduce base year observations we also examine how our approach relates to the recent pmp developments on calibration against elasticity priors and we show how such priors can be used for the calibration of the nonlinear e v model

marketing production decisions in an industrial channel of distribution this paper presents a model that considers the interface between marketing and production decisions in a channel of distribution of industrial goods comprised of a manufacturer and a distributor the key issue investigated is the nature of the coordination within the channel in light of an unstable pattern of seasonal demand the investigation which focuses on dynamic issues considers production activities such as product delivery and inventory policy and their link to marketing strategies such as pricing policies the focus here is on the dynamic nature of the coordinational aspects of the various policies for example the following questions are addressed what is the distributor s pricing strategy throughout the season what is the nature of the contractual price in the channel under what conditions should the distributor carry no inventory throughout the seasonal period under what conditions should the manufacturer carry no inventory what is the impact of the seasonal parameters and differing h

there is no silver bullet the value of diversification in planning invasive species surveillance abstract in this study we demonstrate how the notion of diversification can be used in broad scale resource allocation for surveillance of invasive species we consider the problem of short term surveillance for an invasive species in a geographical environment we find the optimal allocation of surveillance resources among multiple geographical subdivisions via application of a classical portfolio framework which allocates investments among multiple financial asset types with uncertain returns in a portfolio that maximizes the performance and by meeting the desired diversification targets protects against errors in estimating the portfolio s performance we illustrate the approach with a case study that applies a spatial transmission model to assess the risk of spread of the emerald ash borer eab a significant pest in north america with infested firewood that may be carried by visitors to campground facilities in central canada adding the diversification objective yields an expected survey performance that is comparable with undiversified optimal allocation but more importantly makes the geographical distribution of survey priorities less subject to possible errors in the spread rate estimates overall diversification of pest surveillance can be viewed as a viable short term strategy for hedging against uncertainty in expert and model based assessments of pest invasion risk

an investigation of the equal commission rate policy for a multi product salesforce for a multi product sales force the policy of paying commissions as an equal percentage of realized gross margins is shown to be in general nonoptimal from the firm s profit maximization point of view for a homogeneous salesforce the nonoptimality results from the fact that earlier research while taking into account the effect of commission rates on a salesperson s allocations of total time to the multiple products has not incorporated the effect of commission rates on salesperson s total selling time resulting from his her trading off income vs total time to maximize utility the equal commission rate policy is however optimal for the cases of i salesperson with a fixed total selling time and a minimum income requirement and ii fair income salesperson whose total selling time is merely a function of income and not based on rate of change of income as in the utility maximization case if the salesforce is heterogeneous e g different salespersons have differing sales responses to selling time this makes the equal commission rate policy to be in general nonoptimal even for the restrictive cases i and ii it is suggested that the commission rates be set higher for products with greater elasticities relating quantities sold to selling times the common practice of paying commissions as a percentage of total dollar sales rather than gross margins is shown to be optimal under certain assumptions

60 years of portfolio optimization practical challenges and current trends abstract the concepts of portfolio optimization and diversification have been instrumental in the development and understanding of financial markets and financial decision making in light of the 60 year anniversary of harry markowitz s paper portfolio selection we review some of the approaches developed to address the challenges encountered when using portfolio optimization in practice including the inclusion of transaction costs portfolio management constraints and the sensitivity to the estimates of expected returns and covariances in addition we selectively highlight some of the new trends and developments in the area such as diversification methods risk parity portfolios the mixing of different sources of alpha and practical multi period portfolio optimization

do constraints improve portfolio performance the discrete time dynamic investment model using only historical data in various asset allocation settings often produces significant abnormal returns however the model does not choose the diversified portfolios that theory suggests it should therefore in this paper we compare the investment policies and returns of the model with and without constraints on the mix of risky assets the constraints lead to appreciably more diversification and less realized risk but only at the cost of less realized return visual comparisons of compound return standard deviation plots and statistical comparisons of jensen s alpha suggest that the reduction in return is not worth the reduction in risk for more risk averse investors ex post utility and certainty equivalent returns suggest that it is the results however illustrate the problems associated with using ex post utility to measure performance 2000 elsevier science b v all rights reserved

asset allocation with correlation a composite trade off abstract we assess the ability of minimum variance portfolio allocation strategies accounting for time varying correlation between assets to provide performance benefits relative to an equally weighted portfolio prior to transaction costs correlation based strategies emphatically outperform the equally weighted benchmark this finding is strongest for short horizon correlation forecasts and attributed to dynamic correlation as opposed to variance forecasts thus estimation error is not found to be the primary obstacle to successful portfolio optimization rather frequent rebalancing and associated transaction costs pose a significant challenge limiting portfolio turnover through short selling restrictions and greater rebalancing error tolerance results in regular outperformance of the correlation based strategies even for large transaction costs taken together these findings provide evidence of a trade off between optimal portfolio performance forecasting horizon rebalancing frequency and transaction costs

how many stocks make a diversified portfolio we show that a well diversified portfolio of randomly chosen stocks must include at least 30 stocks for a borrowing investor and 40 stocks for a lending investor this contradicts the widely accepted notion that the benefits of diversification are virtually exhausted when a portfolio contains approximately 10 stocks we also contrast our result with the levels of diversification found in studies of individuals portfolios

the effects of imf programs in the third world debate and evidence from latin america abstract this article reviews the debate about the effects of imf sponsored stabilization programs in the third world after examining recent studies by fund economists results of a new study on a latin american country set are presented in this research imf programs are associated with insignificant changes in the current account significant improvements in the overall balance of payments increases in inflation mixed effects on growth and a strong and consistent pattern of reduction in labor share of income the latter result is incorporated into a distribution oriented critique of fund policy

decentralizing cross functional decisions coordination through internal markets a firm faces many problems that are inherently cross functional to solve them successfully requires the coordinated actions of many functional representatives acting in a decentralized setting functional managers however respond to their own individual incentives and may consequently fail to maximize the overall profits of the firm we examine this issue in a setting in which the output of early actions limits the range of later actions and we propose an incentive scheme that allows the system to be successfully decentralized our mechanism is based on linear transfer prices for the intermediate output that are implemented through an internal market a market maker buys the output from one function and sells it to another she is not obliged to sell at the same price at which she bought and may set prices solely to provide incentives we illustrate the flexibility of the scheme by applying it to several models in the operations management literature

portfolio selection under distributional uncertainty a relative robust cvar approach robust optimization one of the most popular topics in the field of optimization and control since the late 1990s deals with an optimization problem involving uncertain parameters in this paper we consider the relative robust conditional value at risk portfolio selection problem where the underlying probability distribution of portfolio return is only known to belong to a certain set our approach not only takes into account the worst case scenarios of the uncertain distribution but also pays attention to the best possible decision with respect to each realization of the distribution we also illustrate how to construct a robust portfolio with multiple experts priors by solving a sequence of linear programs or a second order cone program

the benefits of differential variance based constraints in portfolio optimization abstract the main problem of portfolio optimization is parameter estimation error various methods have been suggested to mitigate this problem among which are shrinkage resampling bayesian updating naive diversification and imposing constraints on the portfolio weights this study suggests two substantial extensions of the constrained optimization approach the variance based constraints vbc and the global variance based constraints gvbc methods by the vbc method the constraint imposed on the weight of a given stock is inversely proportional to its standard deviation the higher a stock s sample standard deviation the higher the potential estimation error of its parameters and therefore the tighter the constraint imposed on its weight gvbc employs a similar idea but instead of imposing a sharp boundary constraint on each stock a quadratic cost is assigned to deviations from the naive 1 n weight and a single global constraint is imposed on the total cost of all deviations comparing ten optimization methods we find that the two new suggested methods typically yield the best performance as measured by the sharpe ratio gvbc ranks first these results are obtained for two different datasets and are also robust to the number of assets under consideration

active portfolio management with benchmarking adding a value at risk constraint abstract we examine the impact of adding a value at risk var constraint to the problem of an active manager who seeks to outperform a benchmark while minimizing tracking error variance tev by using the model of roll 1992 a mean variance analysis of tracking error journal of portfolio management 18 13 22 we obtain three main results first portfolios on the constrained mean tev boundary still exhibit three fund separation but the weights of the three funds when the constraint binds differ from those in roll s model second the constraint mitigates the problem that when an active manager seeks to outperform a benchmark using the mean tev model he or she selects an inefficient portfolio finally when short sales are disallowed the extent to which the constraint reduces the optimal portfolio s efficiency loss can still be notable but is smaller than when short sales are allowed

external disturbances domestic policy responses and debt accumulation in nigeria abstract this paper provides a case study of the link between external shocks domestic policy responses and external debt accumulation in nigeria the indonesian experience during 1970 1989 is provided as a contrast for policy comparison a significant part of the increase in external debt in the two countries corresponds to financing of capital flight after 1981 current account deficits assumed greater importance in the accumulation of external debt the growth in external debt was caused in part by adverse external conditions the results of this study show that the nigerian debt crisis was exacerbated by inappropriate policy responses indonesia avoided a crisis by applying prudent real exchange rate management and fiscal restraint

salesforce compensation plans in environments with asymmetric information in this paper we present a theory of salesforce compensation plans to provide insights into why it may be advantageous for a profit maximizing firm to offer members of its salesforce the opportunity to choose from a menu of compensation plans although such contractual arrangements are not commonly used in the industry they have been introduced and implemented by firms such as ibm and st regis paper as in our previous work on salesforce compensation plans basu lal srinivasan and staelin basu a k r lal v srinivasan r staelin 1985 salesforce compensation plans an agency theoretic perspective marketing sci 4 fall 267 291 we use an agency theory framework in this paper we relax the assumptions of information symmetry and salesforce homogeneity and show the conditions under which it is optimal to offer a menu of compensation plans we also show that even when these assumptions are relaxed there are situations where offering a single plan characterized by basu lal srinivasan and staelin basu a k r lal v srinivasan r staelin 1985 salesforce compensation plans an agency theoretic perspective marketing sci 4 fall 267 291 is still optimal insights gained from the analyses are discussed in the context of an existing compensation scheme

general uncertainty in portfolio selection a case based decision approach abstract often a portfolio investor can hardly imagine all states of nature relevant to his investment problem causing general uncertainty concerning an asset allocation model we quantify general uncertainty as the weakness of an investor s belief in a conventional portfolio procedure then we develop the case based decision making approach for determining the optimal belief degree the economic effect of the proposed case based methodology is investigated in the empirical study the empirical results suggest two successful patterns of case based decisions that could be linked to the issue of market efficiency moreover our case based modeling reflects some behavioral phenomena observed on financial markets

impossible frontiers a key result of the capital asset pricing model capm is that the market portfolio the portfolio of all assets in which each asset s weight is proportional to its total market capitalization lies on the mean variance efficient frontier the set of portfolios having mean variance characteristics that cannot be improved upon therefore the capm cannot be consistent with efficient frontiers for which every frontier portfolio has at least one negative weight or short position we call such efficient frontiers impossible and show that impossible frontiers are difficult to avoid in particular as the number of assets n grows we prove that the probability that a generically chosen frontier is impossible tends to one at a geometric rate in fact for one natural class of distributions nearly one eighth of all assets on a frontier is expected to have negative weights for every portfolio on the frontier we also show that the expected minimum amount of short selling across frontier portfolios grows linearly with n and even when short sales are constrained to some finite level an impossible frontier remains impossible using daily and monthly u s stock returns we document the impossibility of efficient frontiers in the data

coordinating supply chains with competition capacity allocation in semiconductor manufacturing abstract this paper motivated by the experiences of a major us based semiconductor manufacturer presents an integrated model of incentive problems arising in forecasting and capacity allocation our model involves multiple product managers and multiple manufacturing managers who forecast the means of their respective demand and capacity distributions a central coordinator is responsible for allocating capacities to product lines when these distributions are unknown to the central coordinator and capacity is scarce the managers misrepresent their forecasts a product manager inflates his forecast to gain a greater allocation of the capacity a manufacturing manager deflates his forecast to cover for the uncertainties in production we propose a game theoretic model and design a mechanism a bonus scheme for all managers and an allocation rule to allocate realized capacity to the product managers that elicits truthful reporting by all managers the results herein show that the structure of the truth eliciting bonus schemes is rather simple with easily calculable parameters we also show that large classes of allocation rules including the current allocation practice of the firm are manipulable a bonus is often required for elicitation of truthful information we synthesize the implications of our results for the practitioners

allocating spending between advertising and information technology in electronic retailing this study examines coordination issues that occur in allocating spending between advertising and information technology it in electronic retailing electronic retailers run the risk of overspending on advertising to attract customers but underspending on it thus resulting in inadequate processing capacity at the firm s website in this paper we present a centralized joint marketing it model to optimally allocate spending between advertising and it and we discuss an uncoordinated case where marketing and it make suboptimal advertising and capacity decisions we show how these decisions can be coordinated either by reducing the value of a customer session or by designing an optimal processing contract between marketing and it both the coordination methods can be implemented with only local knowledge of the it function yet they generate a solution that almost matches the quality of the centralized solution we extend our basic model to consider demand uncertainty lagged advertising effects and uncertainties in the lead time to acquire it capacity with demand uncertainty electronic retailers should reduce spending on advertising and increase it capacity if there is potential for a demand upswing and the cost of it capacity is relatively low the value of a customer session should be further reduced when uncertainties exist this is required to share the risk of excess or inadequate it capacity

reducing incremental costs associated with the delegation of incentive contracting decisions an analysis of planning and control decisions in a manufacturing setting in the presence of moral hazard abstract we compare and contrast two specific regimes involving the centralization and delegation of the incentive contracting decision in manufacturing organizations in the centralization regime a single individual simultaneously makes the allocation of demand to production facilities and determines the incentive compensation scheme for the managers at the facilities under the delegation regime the demand allocation is decided upon initially by a superior and the incentive contracting decision is subsequently made by a subordinate who is neither of the two managers in charge of the production facilities using the principal agent paradigm which assumes that the managerial efforts are unobservable we demonstrate that the centralization regime performs no worse than the delegation regime for situations where strategic or other requirements necessitate firms to opt for the delegation of the incentive contracting decision we propose a heuristic that significantly increases the likelihood of mimicking the allocation and contracting decisions made under the centralized regime

revisiting latin america s debt crisis some lessons for the periphery of the eurozone a domar pasinetti model of an emerging market open economy with output growth endogenous to aggregate demand is presented with foreign debt interest and exchange rates playing a relevant role in the dynamics of the debt to gdp ratio d the model is used to assess the macroeconomic effects of the orthodox policy fiscal austerity implemented by policy makers to cope with the foreign debt crisis of latin america in the 1980s such policy involved high costs in terms of welfare job and output losses to no avail since the region s financial fragility remained largely unresolved in the end resulting in the so called lost decade the main policy insight of domar s and pasinetti s analysis we argue posits a pro growth expansionary policy as the most efficient strategy to abate and bring d to a sustainable path finally we contend that latin america s experience provides insight for dealing with the ongoing crisis of the periphery of the eurozone

risk information and incentives in telecom supply chains supply chain management involves the selection coordination and motivation of independently operated suppliers the central planner s perspective in operations management translates poorly to vertically separated chains where suppliers recurrently seem to object to benevolent information sharing and centralized decision rights seen from the supplier s perspective such resistance may very well be rational a downstream assembly line disclosing reliable information on actual and forecasted sales puts itself at a disadvantage when bargaining on share of chain profits in this paper we use a minimal agency model to contrast known optimal mechanisms with the actual practice in the telecommunications industry a three stage supply chain under stochastic demand and varying coordination and information asymmetry is modeled a two period investment production game addresses the information sharing and specific investment problem in the telecom industry the observed price quantity contracts under limited commitment are shown to be inadequate under realistic asymmetric information assumptions more a result of gradually evolving changes in bargaining power than coordination efforts the upstream urge to coordinate may further deteriorate performance in terms of our model c 2003 elsevier science b v all rights reserved

information sharing in a long term supply chain relationship the role of customer review strategy in this paper we study the practice of forecast sharing and supply chain coordination with a game theoretical model we find that in a one shot version of the game forecasts are not shared truthf

asymmetric information incentives and intrafirm resource allocation this paper considers the question how should a firm allocate a resource among divisions when the productivity of the resource in each division is known only to the division manager obviously if the divisions as represented by their managers are indifferent among various allocations of the resource the headquarters can simply request the division managers to reveal their private information on productivity knowing that the managers have no incentive to lie the resource allocation problem can then be solved under complete or at least symmetric information this aspect is a flaw in much of the recent literature on this topic i e there is nothing in the models considered which makes divisions prefer one allocation over another thus although in some cases elaborate allocation schemes are proposed and analyzed they are really unnecessary in the model we develop a division can produce the same output with less managerial effort if it is allocated more resources and effort is costly to the manager we further assume that this effort is unobservable by the headquarters so that it cannot infer divisional productivity from data on divisional output and managerial effort given these assumptions we seek an optimal resource allocation process our results show that certain types of transfer pricing schemes are optimal in particular if there are no potentially binding capacity constraints on production of the resource then an optimal process is for each division to choose a transfer price from a schedule announced by the headquarters division managers receive a fixed compensation minus the cost of the resource allocated to them at the chosen transfer price resources are allocated on the basis of the chosen transfer prices if there is a potentially binding constraint on resource production a somewhat more complicated but similar scheme is required

the sampling error in estimates of mean variance efficient portfolio weights this paper presents an exact finite sample statistical procedure for testing hypotheses about the weights of mean variance efficient portfolios the estimation and inference procedures on efficient portfolio weights are performed in the same way as for the coefficients in an ols regression ols t and f statistics can be used for tests on efficient weights and when returns are multivariate normal these statistics have exact t and f distributions in a finite sample using 20 years of data on 11 country stock indexes we find that the sampling error in estimates of the weights of a global efficient portfolio is large

keynes meets markowitz the trade off between familiarity and diversification we develop a model of portfolio choice to nest the views of keynes who advocates concentration in a few familiar assets and markowitz who advocates diversification we use the concepts of ambiguity and ambiguity aversion to formalize the idea of an investor s familiarity toward assets the model shows that for any given level of expected returns the optimal portfolio depends on two quantities relative ambiguity across assets and the standard deviation of the expected return estimate for each asset if both quantities are low then the optimal portfolio consists of a mix of familiar and unfamiliar assets moreover an increase in correlation between assets causes an investor to increase concentration in familiar assets flight to familiarity alternatively if both quantities are high then the optimal portfolio contains only the familiar asset s as keynes would have advocated in the extreme case in which both quantities are very high no risky asset is held nonparticipation this paper was accepted by brad barber teck ho and terrance odean special issue editors

on manufacturing marketing incentives stereotypically marketing is mainly concerned about satisfying customers and manufacturing is mainly interested in factory efficiency using the principal agent agency paradigm which assumes that the marketing and manufacturing managers of the firm will act in their self interest we seek incentive plans that will induce those managers to act so that the owner of the firm can attain as much as possible of the residual returns one optimal incentive plan can be interpreted as follows the owner subcontracts to pay the manufacturing manager a fixed rate for all capacity he delivers each marketing manager receives all of the returns from his product in turn all managers pay a fixed fee to the owner under this plan the marketing managers will often complain about the stock level decisions even though these levels are announced in advance under a revised plan the owner can eliminate such complaints by delegating the stocking decisions to the respective marketing managers without any loss this plan is interpreted as requiring the owner to make a futures market for manufacturing capacity paying the manufacturing manager the expected marginal value for each unit of capacity delivered receiving the realized marginal value from the marketing managers and losing money on average in the process

percentage rent contracts between co stores abstract high rental rates and space scarcity in popular retail areas are encouraging retailers to share available space creating co stores co stores with complementary products enjoy a boost in foot traffic thus higher sales when the space is owned by one a common practice for retailers is to engage in a revenue sharing agreement we study the optimal design of a percentage rent contract between two co stores each having his her own random sales dependent on effort levels of both retailers since the effort level exerted by a retailer is often unverifiable it results in a double moral hazard problem we show that a linear percentage rent which is composed of a sales share and a based rent achieves the second best effort levels the landlord may also find it optimal to set a fixed rent by setting the sales share to zero with cobb douglas sales and power disutility of effort functions we obtain closed form expressions for the optimal contract we show that the landlord charges a high sales share for a tenant with low demand externality and a high sales scale the landlord is better off renting out space to a small but high revenue generating retailer rather than one generating larger traffic but with lower sales scale when the landlord s externality potential is low but he is successful in generating sales optimal sales share is low but the base rent is high the percentage rent can increase the landlord profit by up to 13 compared to the conventional fixed rent

implications of breach remedy and renegotiation design for innovation and capacity amanufacturer writes supply contracts with n buyers then the buyers invest in innovation and the manufacturer builds capacity finally demand is realized and the firms renegotiate the supply contracts to achieve an efficient allocation of capacity among the buyers the court remedy for breach of contract specific performance versus expectation damages affects how the firms share the gain from renegotiation and hence how the firms make investments ex ante the firms may also engage in renegotiation design inserting simple clauses into the supply contract to shape the outcome of renegotiation for example when a buyer grants a financial hostage to the manufacturer or is charged a per diem penalty for delay in bargaining the manufacturer captures the gain from renegotiation tradable options which grant buyers the right to trade capacity without intervention from the manufacturer return the gain from renegotiation to the buyers this paper proves that under surprisingly general conditions the firms can coordinate their investments with the simplest of supply contracts fixed quantity contracts this may require renegotiation design and certainly requires that the firms understand the breach remedy and set their contract parameters accordingly

linking advertising and quantity decisions in the single period inventory model abstract the single period problem spp also known as the newsboy or news vendor problem is to find the order quantity which maximizes the expected profit in a single period probabilistic demand framework interest in the spp remains unabated and many extensions to it have been proposed in the last decade an important aspect of the spp is the effect of advertising on sales in this paper we extend the spp to a case in which advertising leads to increases in sales we assume that the mean demand is increasing and concave in advertising expenditure and address three cases of demand variance as a function of advertising expenditure 1 demand has constant variance 2 demand has constant coefficient of variation and 3 demand has an increasing coefficient of variation we deal with two objectives a maximizing the expected profit and b maximizing the probability of achieving a target profit we provide closed or near closed form solutions to the problem under uniform exponential and normal demand distributions we illustrate the results using numerical examples and provide some insights into the effect of advertising

multiple lot sizing and value of probabilistic information in production to order of an uncertain size abstract a make to order batch manufacturer knows that an order for items with some particular specifications is forthcoming but does not yet know the exact size of the order due to production lead times work needs to start immediately but some units produced may fail to meet required tolerances that is the yield of each batch is random each new run involves a costly setup and each unit attempted involves material and other variable costs if a subjective probability distribution for the order size can be formed the following related questions arise 1 a what is the optimal run size 2 b when should production stop to answer these questions this paper formulates a new model whose main new feature is the ability to handle uncertain demand within a multiple lot sizing setting it is proved that the optimal policy for this scenario is one of control limit stop if and only if the stock of good units is larger than some critical value a computer program was developed for solving the problem for binomial yields and optimal policies for several examples are reported due to the effort required to form and communicate probabilistic forecasts a common practice is to express a forecast as a single number corresponding perhaps to the mean or median of the unarticulated distribution we compute the extra profit expected from forming and using probabilistic forecasts we also show how to compute the profit s variance for any policy

an analytic derivation of admissible efficient frontier with borrowing the admissible efficient portfolio selection problem for risky assets has been discussed by zhang and nie in this paper the admissible efficient portfolio model is proposed under the assumption that there exists the borrowing money or a risk free asset case the admissible efficient frontiers are developed by the spreads of expected return and risk from admissible errors the analytic forms of the admissible efficient frontiers when short sales are not allowed on all risky assets are derived from two cases the borrowing with an upper bound constraint or without an upper bound constraint the influence on the admissible efficient frontier is explained under the different interest rates of the borrowing the differences between the results with the borrowing and the results without the borrowing is revealed by a real numerical example

comparison of alternative utility functions in portfolio selection problems this paper examines the effect of alternative utility functions and parameter values on the optimal composition of a risky investment portfolio normally distributed assets are the setting for the theoretical and empirical analyses the results agree well with the available theory and imply utility functions and parameter values that are appropriate for investors with particular risk bearing attitudes the results give strong empirical support to the proposition that utility functions having different functional forms and parameter values but similar absolute risk aversion indices have similar optimal portfolios these results suggest that over horizons up to one year one can safely substitute convenient surrogate utility functions for other utility functions for reasons of tractability or otherwise the results also provide guidance regarding the significance of the magnitude and change of particular numerical values of the risk aversion index moreover theoretical exact results are obtained using rubinstein s measure of global risk aversion

salesforce incentives market information and production inventory planning salespeople are the eyes and ears of the firms they serve they possess market knowledge that is critical for a wide range of decisions a key question is how a firm can provide incentives to its salesforce so that it is in their interest to truthfully disclose their information about the market and to work hard many people have considered this question and provided solutions perhaps the most well known solution is due to gonik 1978 who proposed and implemented a clever scheme designed to elicit market information and encourage hard work the purpose of this paper is to study gonik s scheme and compare it with a menu of linear contracts a solution often used in the agency literature in a model where the market information possessed by the salesforce is important for the firm s production and inventory planning decisions

product warranties and double moral hazard this article explores a model of warranties in which moral hazard problems play a key role the goal is to understand the important characteristics of warranties including their provision of incomplete insurance and the relationship between product quality and coverage we analyze a model in which buyers and sellers take actions that affect a product s performance since these actions are not cooperatively determined an incentives problem arises we characterize the optimal warranty contract and undertake comparative statics to determine the predicted correlation of warranty coverage and product quality

optimal hedging with a subjective view an empirical bayesian approach the standard optimal hedging model has been the preferred theoretical model of normative hedging behavior in empirical applications the model is often implemented with the parameter certainty equivalent pce procedure however the pce procedure completely ignores parameter estimation risk and subjective views we develop an empirical bayesian optimal hedging model that not only effectively accommodates parameter estimation risk but also provides hedgers with a theoretically intuitive yet quantitatively rigorous framework to blend their subjective views and a marketwide or firmwide consensus in determining optimal hedging positions ratios

capital asset pricing compatible with observed market value weights we show that the set of expected return vectors for which an observed portfolio is mean variance mv efficient is a two parameter family we identify ten ways to specify the time series behavior of the two parameters the result highlights a number of inconsistencies involved in mv modelling for each of the cases it permits the inference of the time series of expected return vectors as well as all the other capital asset pticing model capm variables compatible with a known covariance matrix and the observed time series of market value weights the empirical work shows that there are substantial case to case differences in the time series of mean vectors and many of them are quite different from the constant mean vector envisioned in tests of

contracting over multiple parameters capacity allocation in semiconductor manufacturing abstract this paper is a generalization of mallik and harker mallik s harker p t 2004 coordinating supply chains with competition capacity allocation in semiconductor manufacturing european journal of operational research 159 330 347 that presented an integrated model of incentive problems arising in forecasting and capacity allocation in that model multiple product managers and multiple manufacturing managers forecast the means of their respective demand and capacity distributions and a central coordinator allocates capacities based on these forecasts a mechanism that elicits truthful information from the managers was the main contribution of that paper the objective of this paper is to generalize our previous results to multiple statistics reporting this work assumes that the central coordinator can ask the managers to report multiple statistics mean and variance for example about their respective distributions we propose a game theoretic model and design a mechanism a bonus scheme and an allocation rule that elicits truthful reporting of all statistics by all managers it turns out that the structure of the optimal bonus schemes are rather simple with easily calculable parameters we also show that a large class of allocation rules are manipulable a bonus is often required for elicitation of truthful information we compare our results of multiple statistics reporting with those from mallik and harker 2004 we also characterize under what conditions the reporting of the extra information is of limited use

the latin american debt burden consequences for international adjustment and agricultural trade this paper attributes the origins of the latin american external debt problem to the oil price and real interest rate increases and debtor country and international bank policies next it briefly examines the implications of economic adjustments to service the debt finally in order to facilitate research on the linkages between debt and agricultural trade the paper suggests some factors to consider in modeling import behavior and international borrowing

marketing production coordination in channels of distribution abstract in this paper we analyze the effects of functional horizontal decentralization by a channel member on the performance of an industrial channel of distribution we use the model of eliashberg j steinberg r 1987 management science 33 981 1000 which describes a channel of distribution consisting of a manufacturer and a value adding distributor we allow the distributor to decentralize decision making between his marketing and production functions our results show that functional decentralization at the distributor level increases the price sensitivity of the distributor concerning the price he faces from the manufacturer causes a shift in the distributor s demand curve increases the distributor s inventory activities in terms of both quantity and time frame and under certain conditions increases the manufacturer s inventory as expected the decentralized distributor has a less coordinated pricing policy vis a vis the production policy using numerical means we show that functional decentralization can improve the overall channel profitability i e for both manufacturer and distributor this counter intuitive result suggests that in our non repeated perfect information game setting functional decentralization can yield a pareto dominant equilibrium outcome where both the distributor and manufacturer are better off even though it is only the distributor who is changing his organizational decision making

the long run creditworthiness of developing countries theory and practice this paper analyzes the determinants of developing country long run creditworthiness focusing on the process of capital accumulation relative to external debt creditworthiness depends on the actual capital stock compared with a critical level representing the gross wealth just sufficient to ensure that interest payments to foreigners never exhaust national output given expected gross inflows and existing outstanding debt hence the probability of rescheduling is linked to debt service capital net inflows capital investment rates and income levels the empirical results based on a probit analysis of historical rescheduling incidents are quite robust and supportive of the theoretical framework

supply chain choice on the internet internet companies extensively use the practice of drop shipping where the wholesaler stocks and owns the inventory and ships products directly to customers at retailers request under the drop shipping arrangement the supply chain benefits from risk pooling because the inventory for multiple retailers is stocked at the same location the wholesalers another more traditional channel alternative on the internet is one in which retailers stock and own the inventory these two supply chain structures which predominate on the internet result in different inventory risk allocation stocking decisions and profits for channel members moreover the two channel alternatives can be combined into a dual strategy whereby the retailer uses local inventory as a primary source and relies on drop shipping as a backup we model the dual strategy as a noncooperative game among the retailers and the wholesaler analyze it and obtain insights into the structural properties of the equilibrium solution to facilitate development of recommendations for practicing managers finally we characterize situations in which each of three channels is preferable by specifying appropriate ranges of critical parameters including demand variability the number of retailers in the channel wholesale prices and transportation costs

improving diversification opportunities for socially responsible investors socially responsible investment sri has grown enormously and has expanded globally in recent years it allows sri investors to reduce their portfolio risk assumptions through international diversification in this context the aim of this paper is twofold i to examine price and volatility linkages among the most representative sri indexes for north america europe and asia pacific employing a multivariate approach and ii to provide the out of sample performance of an optimal portfolio constructed on the basis of time varying return and volatility forecasts from this specification approach our overall results show that using this technique it is possible to reduce risk and out perform the naive rule which is usually employed in this type of investment these findings are relevant not only for academics but also for practitioners especially for professional managers of sri portfolios

dynamic business share allocation in a supply chain with competing suppliers this paper studies a repeated game between a manufacturer and two competing suppliers with imperfect monitoring we present a principal agent model for managing long term supplier relationships using a unique form of measurement and incentive scheme we measure a supplier s overall performance with a rating equivalent to its continuation utility the expected total discounted utility of its future payoffs and incentivize supplier effort with larger allocations of future business we obtain the vector of the two suppliers ratings as the state of a markov decision process and we solve an infinite horizon contracting problem in which the manufacturer allocates business volume between the two suppliers and updates their ratings dynamically based on their current ratings and the current performance outcome our contributions are both theoretical and managerial we propose a repeated principal agent model with a novel incentive scheme to tackle a common but challenging incentive problem in a multiperiod s

value of information in portfolio selection with a taiwan stock market application illustration abstract despite many proposed alternatives the predominant model in portfolio selection is still mean variance however the main weakness of the mean variance model is in the specification of the expected returns of the individual securities involved if this process is not accurate the allocations of capital to the different securities will in almost all certainty be incorrect if however this process can be made accurate then correct allocations can be made and the additional expected return following from this is the value of information this paper thus proposes a methodology to calculate the value of information a related idea of a level of disappointment is also shown how value of information calculations can be important in helping a mutual fund settle on how much to set aside for research is discussed in reference to a taiwan stock exchange illustrative application in which the value of information appears to be substantial heavy use is made of parametric quadratic programming to keep computation times down for the methodology

the dynamic black litterman approach to asset allocation abstract we generalize the black litterman bl portfolio management framework to incorporate time variation in the conditional distribution of returns in the asset allocation process we evaluate the performance of the dynamic bl model using both standard performance ratios as well as other measures that are designed to capture tail risk in the presence of non normally distributed asset returns we find that the dynamic bl model outperforms a range of different benchmarks moreover we show that the choice of volatility model has a considerable impact on the performance of the dynamic bl model

setting the right incentives for global planning and operations we study incentive issues seen in a firm performing global planning and manufacturing and local demand management the stochastic demands in local markets are best observed by the regional business units and the firm relies on the business units forecasts for planning of global manufacturing operations we propose a class of performance evaluation schemes that induce the business units to reveal their private demand information truthfully by turning the business units demand revelation game into a potential game with truth telling being a potential maximizer an appealing refinement of nash equilibrium moreover these cooperative performance evaluation schemes satisfy several essential fairness notions after analyzing the characteristics of several performance evaluation schemes in this class we extend our analysis to include the impact of effort on demand

more possessions more worry abstract a common wisdom asserts that the wider the universe of assets to choose from the greater the investor s welfare we show that this is not the case in practice where parameters have to be estimated even when the estimates are unbiased surprisingly risk aversion plays a crucial role corresponding to the desirability of asset expansion by dividing investors in three groups investors with very low risk tolerance and investors with very high risk tolerance are better off with asset expansion and investors with moderate risk tolerance are worse off despite the option to refrain from investing in the additional asset

why empirical international portfolio models fail evidence that model misspecification creates home asset bias abstract international portfolio models consistently predict that investors should put much more of their wealth into foreign assets than they actually do a result known as home asset bias we use actual international portfolio data to show how model misspecification contributes to this bias we find that three widely used simplifying assumptions produce optimal portfolio weights that are significantly different from the weights produced by an unsimplified model in particular imposing the invalid assumption that ppp holds exaggerates the degree of home asset bias these findings suggest that researchers should pay greater attention to empirical model specification in the future