estimation methods in portfolio selection and the effectiveness of short sales restrictions uk evidence forecasting the mean returns vector and the covariance matrix is a key feature in implementing portfolio theory the performance of the bayes stein method for forecasting these parameters for use in the markowitz model with and without short sales was compared with that of seven other estimation methods and three alternative portfolio selection techniques this paper represents the first large scale empirical investigation of the usefulness of the bayes stein approach using historical data this data was drawn from the london stock exchange in contrast to earlier studies the relative performance of bayes stein was mixed while it produced reasonable estimates of the mean returns vector there were superior methods e g overall mean for estimating the covariance matrix when short sales were permitted when short sales were prohibited actual portfolio performance was clearly improved although there was little to choose between the various estimation methods

are household portfolios efficient an analysis conditional on housing in this paper we argue that standard tests of portfolio efficiency are biased towards rejection because they neglect the existence of illiquid wealth in the case of household portfolios the most important illiquid asset is housing if housing stock adjustments are costly and therefore infrequent we show how the dynamic optimization problem produces optimal portfolios in periods of no adjustment that are affected by housing price risk through a hedge term when the housing stock is not adjusted we argue that tests for portfolio efficiency of financial asset must then be run conditionally upon housing wealth in our application we use italian household portfolio data from shiw 1998 and time series data on financial asset and housing stock returns to assess whether actual portfolios are efficient we first consider purely financial portfolios and portfolios that also treat the housing stock as another asset we then consider the consequences of treating the housing stock as given and test for efficiency in this framework our empirical results support the view that the presence of illiquid wealth can explain portfolio choice by home owners

forward exchange bias hedging and the gains from international diversification of investment portfolios abstract the gains to the us investor from international diversification of investment portfolios are examined for portfolio strategies that hedge and strategies that do not hedge exchange rate risk via the interbank forward market using the sharpe performance index and stochastic dominance as performance measures almost all the unhedged strategies outperformed the hedged strategies for 1985 1988 the opposite held for 1981 1984 the results are explained by the biasedness of forward rates in predicting future spot rates jel f30

possible impact of 2020 bioenergy targets on european union land use a scenario based assessment from national renewable energy action plans proposals according to the renewable energy directive 2009 28 ec the european union member states should increase by 2020 the use of renewable energy to 20 of gross final energy consumption and to reach a mandatory share of 10 renewable energy in the transport sector this study aims to quantify the impact of 2020 bioenergy targets on the land use in the eu based on the projections of the national renewable action plans in four scenarios scenario 1 bioenergy targets according to nreaps scenario 2 bioenergy targets according to nreaps no second generation biofuels scenario 3 bioenergy targets according to nreaps reduced import of biofuels and bioliquids scenario 4 bioenergy targets according to nreaps high imports of biofuels and bioliquids this study also considers the credit for co products generated from biofuel production the analysis reveals that the land used in the eu for bioenergy would range between 13 5 mha and 25 2 mha in 2020 this represent between 12 2 and 22 5 of the total arable land used and 7 3 and 13 5 of the utilised agricultural area uaa in the nreaps scenario about 17 4 mha would be used for bioenergy production representing 15 7 of arable land and 9 4 of uaa the increased demand from biofuels would lead to an increased generation of co products replacing conventional fodder for animal feed considering the co products the land used for bioenergy would range between 8 8 mha and 15 0 mha in 2020 in the various scenarios this represent between 7 9 and 13 3 of the total arable land used in the eu and 4 7 and 8 0 of the uaa in the nreaps scenario when co products are considered about 10 3 mha would be used for biofuels bioliquids and bioenergy production representing 9 3 of arable land and 5 6 of agricultural land this study further provides detailed data on the impact on land use in each member state

co firing of imported wood pellets an option to efficiently save co2 emissions in europe abstract in this paper the energy and carbon footprints of pellet imports from australia west canada and russia for co firing in europe are investigated their ecologic and economic performances are proven by applying the belgian and uk co firing subsidy systems which require dedicated sustainability evaluations based on the modelling of different subsidy schemes and price scenarios the present paper identifies favourable conditions for the use of biomass co firing in germany and austria which currently do not have dedicated co firing incentives the present paper shows that under present conditions co firing has a narrow financial gap to coal with 3 to 4 cent kwh el and has low co 2 mitigation costs compared to other renewables moreover it is shown that co firing is one of the most cost attractive options to reach the eu 2020 targets for policy makers the support of co firing is found to be very efficient in terms of cost benefit ratio it is proven that the co firing subsidy schemes might direct supply chain decisions towards options with low energy and carbon impacts

on representative social capital abstract this paper analyzes the behavior of subjects randomly drawn from the dutch population who reveal their capacity to provide and sustain social capital by their propensity to invest and reward investments in an economic experiment we find that heterogeneity in behavior is characterized by several asymmetries men the young and elderly and low educated individuals invest relatively less but reward significantly more investments the age effects are found to corroborate existing findings whereas those of gender and education do not higher expected levels of investments by others are found to have a positive and significant effect on own investments finally a laboratory experiment with student subjects is found to provide a lower bound of the population level of social capital

determinants of technical efficiency in the bioenergy industry in the eu28 region most previous bioenergy industry research has concentrated on how to implement a certain level of yield however few articles have paid attention to rational resource allocation to increase efficiency to enhance bioenergy production through proper use of available resources this study identified the effects of internal country specific and external macroeconomic determinants of technical efficiency level in the bioenergy industry for the eu28 region the study was established based on a conceptual framework suggesting a correlation between input use and level of technical efficiency a panel data analysis method was employed for the analysis and a panel regression analysis framework based on the fixed effect fe model and random effect re model was used to examine the potential determinants of technical efficiency level in the bioenergy industry for the eu28 region for the period between 1990 and 2013 the results indicate that the technical efficiency level of the bioenergy industry in developing countries is higher than in developed countries the empirical findings also suggest that technical efficiency has greater influence on pure technical efficiency levels capital input labor input gross domestic product inflation and interest rate significantly affected the technical efficiency of the bioenergy industry in the developing and developed countries in the eu28 region during the period of this study the findings clearly call for regulators and decision makers to review the technical efficiency level of the bioenergy industry within the eu28 region this study also provides better information and guidance to the boards of the bioenergy industry as they need to have a clear understanding of the influence technical efficiency has on bioenergy production performance moreover the results of this study have implications for investors who focus mainly on profits from their investments

improved estimates of higher order comoments and implications for portfolio selection in the presence of nonnormally distributed asset returns optimal portfolio selection techniques require estimates for variance covariance parameters along with estimates for higher order moments and comoments of the return distribution this is a formidable challenge that severely exacerbates the dimensionality problem already present with mean variance analysis this article extends the existing literature which has mostly focused on the covariance matrix by introducing improved estimators for the coskewness and cokurtosis parameters we find that the use of these enhanced estimates generates a significant improvement in investors welfare we also find that it is only when improved estimators are used that portfolio selection with higher order moments dominates mean variance analysis from an out of sample perspective the author 2009 published by oxford university press on behalf of the society for financial studies all rights reserved for permissions please email journals permissions oxfordjournals org oxford university press

measuring price risk in rating revenue coverage bs or no bs the black scholes bs option pricing model has been a cornerstone of modern financial theories since its introduction by black and scholes 1973 and its subsequent refinement by merton 1973 the model has realized widespread adoption for a number of purposes inherent in the model are a number of assumptions an important and potentially restrictive assumption is that the underlying asset price is log normally distributed among the many diverse uses of the bs model the model and underlying theory are used to derive measurements of the variance of expected harvest time prices for use in rating revenue coverage in the federal crop insurance program revenue coverage currently accounts for about 80 of the total liability insured in the program this liability frequently exceeds 100 billion and thus the accuracy of revenue premium rates is of vital importance the use of the bs model by the risk management agency rma of the usda has been the focus of recent criticisms of the program critics have argued in favor of retrospective measures of price variability that are based on historical price movements or have recommended other approaches to measuring price risk this article reports on a contracted review of revenue insurance rating methodology commissioned by rma we evaluate a number of alternative approaches to measuring expected price variability including several approaches recommended by critics of the federal program our results suggest that the bs model is preferred to recommended alternatives on the basis of numerous criteria

the behavior of flexible exchange rates evidence and implications for predicting currency price movements furthermore variations in nominal exchange rates are dominated by changes in real rates past rate changes will not be useful for predicting inflation or vice versa changes in money supplies real incomes interest rates and current or trade accounts appear not to be systematically related to changes in exchange rates in the absence of any systematic component that could be exploited for forecasting purposes what means are available for controlling exchange rate risk hedging can be used with some effect but the optimal hedging policy is still a matter of debate given the relatively low correlations between euromarket interest rates and returns on common stock indexes and relative changes in exchange rates diversification across international markets offers considerable potential for risk reduction

political risk and the benefits of international portfolio diversification this paper examines the benefits of portfolio investment in the stock markets of politically risky countries by evaluating the effects of political risk constraints on the performance of a portfolio of international stocks we use monthly data on political risk ratings and stock returns for a sample of thirty six countries from april 1982 to december 1991 ex post and ex ante portfolio selection strategies are developed to assess the gains from international diversification efficient sets are derived using a quadratic programming technique we use four ex ante portfolio strategies whose optimal portfolio weights are those of the equally weighted portfolio the minimum variance portfolio the certainty equivalence tangency portfolio and the bayes stein portfolio the empirical findings based on the performance tests of jobson and korkie 1981 suggest that diversification among politically risky countries improves the risk return characteristics of optimal portfolios however the most striking benefit of the inclusion of politically risk countries in an international portfolio is the reduction in overall portfolio risk

global land use implications of first and second generation biofuel targets recently an active debate has emerged around greenhouse gas emissions due to indirect land use change iluc of expanding agricultural areas dedicated to biofuel production in this paper we provide a detailed analysis of the iluc effect and further address the issues of deforestation irrigation water use and crop price increases due to expanding biofuel acreage we use globiom an economic partial equilibrium model of the global forest agriculture and biomass sectors with a bottom up representation of agricultural and forestry management practices the results indicate that second generation biofuel production fed by wood from sustainably managed existing forests would lead to a negative iluc factor meaning that overall emissions are 27 lower compared to the no biofuel scenario by 2030 the iluc factor of first generation biofuels global expansion is generally positive requiring some 25 years to be paid back by the ghg savings from the substitution of biofuels for conventional fuels second generation biofuels perform better also with respect to the other investigated criteria on the condition that they are not sourced from dedicated plantations directly competing for agricultural land if so then efficient first generation systems are preferable since no clear technology champion for all situations exists we would recommend targeting policy instruments directly at the positive and negative effects of biofuel production rather than at the production itself

monetary conditions and international investing we examine the relationship between monetary conditions and global stock returns previous studies established that u s stock returns during expansive u s monetary periods are significantly higher than returns during restrictive periods we found that this pattern prevails in non u s markets furthermore the pattern exists relative to both local and u s monetary conditions by examining several investment strategies we show that investors could have improved portfolio performance in the period studied by using both u s and local monetary conditions to guide their portfolio allocations using monetary conditions to determine portfolio composition would have been consistently beneficial throughout the past 30 years

optimal portfolio of foreign currencies with borrowing and lending until the late sixties most american corporations held their liquid assets in the form of cash short term government notes and other highly liquid marketable securities since the early seventies more and more firms have begun to hold their current assets in foreign currencies beyond what would be required to conduct normal foreign operations in the last few years companies have accumulated and retained much more cash than they held in the past in order to understand the magnitude of this issue realize that at the end of 1977 cash and short term securities held by international business machines amounted to 5 4 billion by exxon 4 2 billion and ford and general motors held well above 3 billion obviously with this cash pile up most companies devote much attention to cash management even a slight improvement in the management of these assets means a substantial profit and firms have responded with highly trained staff in particular people familiar with the international money market and the investment opportunities available the change in attitude toward cash management may be summarized by the following quotation from a senior adviser to the j henry schroder bank and trust company companies are no longer looking at a bank balance they re looking at a

hedging crude oil using refined product a regime switching asymmetric dcc approach abstract in this paper we explore the strategy on hedging crude oil using refined product we develop a regime switching asymmetric dcc rs adcc model by taking into account both of regime switching and asymmetry in correlations our out of sample findings indicate that rs adcc displays greater hedging effectiveness than some conventional multivariate garch heating oil can better hedge crude oil than gasoline

on the diversification observability and measurement of estimation risk this paper reexamines how risk return relationships are affected by investor uncertainty about the exact parameters of the joint rate of return distribution we attempt to clarify results relating to three central issues first we address the issue of diversification focusing on an apt factor model framework second we discuss the observability of estimation risk and describe research experimental designs that should encompass the existence of estimation risk and reveal it in the data finally we suggest exploiting contemporaneous return observations on high and low information securities to aid in the measurement of return parameters for low information securities

massaging mean variance inputs returns from alternative global investment strategies in the 1980s this paper explores the impact of adjustments to the inputs on total returns terminal wealth and portfolio turnover in an unconstrained monthly mean variance mv asset allocation over time it is well known that mv allocations are very sensitive to small forecast errors in the means and covariances this sensitivity is especially pronounced for errors in means one way to control this sensitivity to forecast errors is to use stein estimation we examined three naive applications of stein estimation for six individual country stock indexes five country bond indexes and five cash indexes this study has two major conclusions first any of the suggested adjustments to inputs dominate the results of an unadjusted input mv optimization adjusted input portfolios have higher mean return less variance and greater terminal wealth than unadjusted input portfolios second these improvements become even greater with transaction costs

international diversification of investment portfolios u s and japanese perspectives in this paper we analyze the gains from international diversification of investment portfolios from the japanese as well as the u s perspectives the major findings of this paper include first the potential gains from international as opposed to purely domestic diversification are much greater for u s investors than for japanese investors for u s investors the gains accrue not so much in terms of lower risk as in terms of higher return and the opposite holds for japanese investors second using various ex ante international investment strategies designed to control parameter uncertainty u s investors can realize substantial gains from international diversification in out of sample periods japanese investors however can gain relatively little third hedging exchange risk generally allows the u s but not japanese investors to benefit more from international diversification for u s investors the international bond diversification with exchange risk hedging offers a superior risk return trade off than the international stock diversification with or without hedging

renewable energy policy framework and bioenergy contribution in the european union an overview from national renewable energy action plans and progress reports abstract the use of renewable energy is projected to increase substantially in the european union to reach a share of 20 in final energy consumption and 10 renewable energy in transport by 2020 the renewable energy contribution is further expected to increase to 55 75 of gross final energy consumption in 2050 according to the latest reports the european union has made significant progress since 2005 and is on track to reach its 2020 renewable energy targets this paper provides a review of the policy framework for renewable energy in the european union and an analysis of the progress made by the use of renewable energy as well as the expected developments until 2020 and beyond it focusses on the contribution of bioenergy the major source among renewables in the european union as biomass availability is a critical issue for the bioenergy production this paper provides an analysis of the biomass demand for reaching the 2020 targets in relation with the expected domestic supply and biomass potential

money bonds and foreign exchange in the theory of finance capital markets provide securities which allow the ownership of productive assets to be allocated among investors according to their willingness to bear risk in exchange for return and independently of their tastes for the productive services provided by the assets this paper uses the theory of finance to study the role of money as a productive asset and the transformation of money into a portfolio asset true to its purpose the capital market provides securities nominal bonds that allow an allocation of the current services of the money supply according to its current productivity and without regard for its future purchasing power risk and an allocation of the future purchasing power risk of the money supply according to the willingness of investors to bear this risk in exchange for return and without regard for investor needs for the future transactions services of money in open

a dynamic globally diversified index neutral synthetic asset allocation strategy an investor with the ability to assess the prospective return and risk structure of the global capital markets can construct portfolios that over time will not only outperform actively or passively managed domestic asset portfolios but will also outperform passively managed global portfolios a bayesian approach to dynamic seemingly unrelated regression dsur is a robust and effective means to forecast the one step ahead conditional distribution of asset returns this approach recognizes the time varying nature of the global capital markets the predictive moments are used to derive a single factor return model once an index portfolio is specified the index portfolio represents an investor s underlying portfolio given the factor model that assesses the relative attractiveness and risk of the assets in relation to the index an index neutral portfolio is constructed as an overlay to enhance the returns of the index portfolio this portfolio is mean variance optimal is notional neutral i e the sum of the asset exposures is zero and has returns that are designed to be uncorrelated with the returns of the index portfolio the implementation of such an index neutral portfolio using derivative securities is simulated over the period january 1988 to december 1993

bayes stein estimation for portfolio analysis in portfolio analysis uncertainty about parameter values leads to suboptimal portfolio choices the resulting loss in the investor s utility is a function of the particular estimator chosen for expected returns so this is a problem of simultaneous estimation of normal means under a well specified loss function in this situation as stein has shown the clas sical sample mean is inadmissible this paper presents a simple empirical bayes estimator that should outperform the sample mean in the context of a portfolio simulation analysis shows that these bayes stein estimators provide significant gains in portfolio selection problems

disagreement portfolio optimization and excess volatility disagreement a key factor inducing trading has been receiving ever increasing attention in recent years most research has focused on disagreement about the expected returns several authors have shown that if the average belief coincides with the true expected return in the portfolio context prices are unaffected by disagreement in this paper we study the pricing effects of disagreement about return variances we show that i disagreement about variances has systematic and significant pricing effects more disagreement leads to higher prices and ii prices are very sensitive to the degree of disagreement even if the average belief about the variance is constant tiny fluctuations in the disagreement about the variance lead to substantial price fluctuations this second result may offer an explanation for the excess volatility puzzle when small changes in the degree of disagreement occur they induce relatively large price changes yet the changes in disagreement may be hard to directly detect empirically leading to apparent excess volatility

an empirical and forecasting analysis of the bioenergy market in the eu28 region evidence from a panel data simultaneous equation model this study improves upon and applies a comprehensive panel data simultaneous equation model to the european union eu28 region s bioenergy market the goals are to estimate bioenergy quantities in domestic and international markets for the period from 1990 to 2013 and to apply a forecasting analysis for the eu28 s domestic and international bioenergy markets for the period of 2014 2020 the results demonstrate that biomass harvest and the domestic price in a domestic market have a significant influence on the supply function additionally domestic price has a negative relationship with the bioenergy market domestic demand in international markets competitive import prices play a primary role in the development of the bioenergy market import demand export prices and gdp also have primary influences on the export demand for bioenergy moreover the exchange rate has a positive and significant effect on export demand the results of a forecasting analysis for the future period of 2014 2020 has predicted slight increases in domestic supply domestic demand and import trends on the other hand it also predicted a sharp decline in the export demand trend between those same years this study contributes to the literature by providing policymakers and other energy policy stakeholders a reliable forward looking analysis of the potential condition of the domestic and international bioenergy markets in the eu28 region through the end of 2020

eu bioenergy development to 2050 abstract bioenergy is the eu s leading renewable energy source at present understanding bioenergy s contribution to the future eu energy mix is strategically relevant for mid to long term climate targets this review consolidates recent projections of both supply and demand dynamics for eu bioenergy to 2050 drawing from resource focused demand driven and integrated assessment approaches projections are synthesised to identify absolute ranges determine cohesion with policy and draw insights on the implications for the scale of development trade and energy security supply side studies have undergone methodological harmonisation efforts in recent years despite this due to assumptions on key uncertainties such as feedstock yields technical potential estimates range from 9 to 25 ejyr 1 of eu domestically available biomass for energy in 2050 demand side projections range between 5 and 19 ejyr 1 by 2050 this range is primarily due to variations in study assumptions on key influential developments such as economic competitivity of bioenergy eu energy efficiency gains within the power sector flexibility for meeting mitigation targets and technological portfolios upper bound technical supply estimates are able meet future demand wholly from the domestic resource base holding the potential to reduce total eu primary energy import dependency 22 points from the current eu roadmap trajectory however due to part of this domestic resource base being deemed economically inaccessible or of insufficient quality interregional imports are projected to increase from current 4 to 13 76 emergence of non energy applications are projected to compete for at least 10 of the biomass needed to fulfil bioenergy demand in 2050

future bioenergy trade in the eu modelling trading options from a cost effectiveness perspective the purpose of this paper is to analyse under what conditions with respect to co2 emission reduction and biofuels for transport targets the trading in the eu of co2 credits and solid and or liquid biofuels is cost effective from the perspective of an optimisation energy systems model we use the peep model covering the eu27 except bulgaria malta and cyprus to generate insights about the cost effectiveness of different options under different policy scenarios trade in co2 credits is a cost effective option in all relevant policy scenarios trade in some biofuels mainly from central and eastern european countries to the eu15 is cost effective in all assessed scenarios in the case of co2 targets whether national or at the eu level there is trade in solid biofuels when biofuels for transport targets are also implemented trading both solid and liquid biofuels is cost effective

portfolio selection an alternative approach this paper provides a solution to the portfolio diversification problem based on finding optimal weights that will result in maximizing the risk adjusted return of the underlying portfolio subject to the budget constraint contrary to the standard approach that aims at finding the required weights based on minimizing the variance of the portfolio subject to the budget constraint a mathematical proof is given for the suggested solution an application is provided to the portfolio diversification opportunity between all the share market indexes of the two largest economies in the world the results show that the portfolio created by our suggested approach leads to almost one percent increase in the risk adjusted return compared to the portfolio created by the standard method

hedging with futures does anything beat the naive hedging strategy this paper investigates out of sample performance of the naive hedging strategy relative to that of the minimum variance hedging strategy in which the covariance parameters are estimated from 18 e

performance of portfolios optimized with estimation error we explain the poor out of sample performance of mean variance optimized portfolios developing theoretical bias adjustments for estimation risk by asymptotically expanding future returns of portfolios formed with estimated weights we provide closed form non bayesian adjustments of classical estimates of portfolio mean and standard deviation the adjustments significantly reduce bias in international equity portfolios increase economic gains and are robust to sample size and to nonnormality dominant terms grow linearly with the number of assets and decline inversely with the number of past time periods under suitable conditions sharpe ratio maximizing tangency portfolios become more diversified using these approximation methods it may be possible to assess before investing the effect of statistical estimation error on portfolio performance

cvar models with selective hedging for international asset allocation abstract we develop an integrated simulation and optimization framework for multicurrency asset allocation problems the simulation applies principal component analysis to generate scenarios depicting the discrete joint distributions of uncertain asset returns and exchange rates we then develop and implement models that optimize the conditional value at risk cvar metric the scenario based optimization models encompass alternative hedging strategies including selective hedging that incorporates currency hedging decisions within the portfolio selection problem thus the selective hedging model determines jointly the portfolio composition and the level of currency hedging for each market via forward exchanges we examine empirically the benefits of international diversification and the impact of hedging policies on risk return profiles of portfolios we assess the effectiveness of the scenario generation procedure and the stability of the model s results by means of out of sample simulations we also compare the performance of the cvar model against that of a model that employs the mean absolute deviation mad risk measure we investigate empirically the ex post performance of the models on international portfolios of stock and bond indices using historical market data selective hedging proves to be the superior hedging strategy that improves the risk return profile of portfolios regardless of the risk measurement metric although in static tests the mad and cvar models often select portfolios that trace practically indistinguishable ex ante risk return efficient frontiers in successive applications over several consecutive time periods the cvar model attains superior ex post results in terms of both higher returns and lower volatility

international effects of a compression of euro area yield curves abstract in this paper we use a bayesian global vector autoregressive model to analyze the macroeconomic effects of a flattening of euro area yield curves our findings indicate positive effects on real activity and prices both within the euro area as well as in neighboring economies spillovers transmit through an exchange rate channel and a broad financial channel we complement our analysis by conducting a portfolio optimization exercise our results show that multi step ahead forecasts conditional on the euro area yield curve shock improve sharpe ratios relative to other investment strategies

international portfolio diversification the basket peg regime abstract the paper compares and contrasts optimal investment strategies in two alternative monetary arrangements namely in the regime with freely floating bilateral exchange rates and the basket peg system it is shown that in the basket peg arrangement investors can form a domestic currency denominated risk free asset of the foreign risk free assets without entering into the forward currency markets furthermore investors have an incentive to hold fewer assets and the structure of capital flows tends to be more volatile but also more predictable in the basket peg system than in the regime with freely floating bilateral exchange rates

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

the benefits from international diversification for nordic investors abstract in this paper we investigate the magnitude of the benefits from international diversification from the nordic point of view special attention is paid to whether potentially increased co movement of stock markets together with more volatile nordic currencies have resulted in decreased benefits from international diversification towards the end of the 1980s moreover the paper presents evidence on the benefits from international diversification for a currency which has recently started its free float the finnish markka fim we find significant increases in stock market co movement both unhedged ex ante strategies as well as strategies hedged for exchange rate risk are investigated revealing substantial benefits from international diversification for the nordic countries however we obtain mixed results concerning the question of the optimality of hedging

were the returns from stocks and bonds of different countries really different in the 1980 s we analyzed the total equity returns of indexes from australia canada germany japan the uk and the us and total fixed income returns of indexes from all but australia excluded due to lack of data to see if the returns of stocks and bonds were statistically different across markets during the 1980s at the end of 1989 these countries represented over 87 of the market capitalization of the morgan stanley capital international msci world equity index and over 88 of the salomon brothers world bond index this study used monthly observations from january 1980 through december 1989 and examined returns based in local currency and hedged and unhedged us dollars we found that sample mean stock and bond returns during the 1980s were statistically indistinguishable across countries however because the sample variances were so large relative to the sample means it would have been difficult to detect differences in population means by any test we found evidence of variance heterogeneity which may be

the anatomy of distributional preferences with group identity abstract the increasing diversity of societies raises questions about the consequences for redistributive preferences this paper assesses the impact of social identity on distributional preferences in a modified dictator game i estimate individual level utility functions with two parameters that govern the trade offs between equity and efficiency and giving to self and to other subjects on average put less weight on income of the out group the out group treatment also changes the distribution of equity efficiency concerns however the experiment also uncovers a large individual heterogeneity of preferences an analysis of garp violations reveals that choices in both treatments overwhelmingly stem from well behaved yet systematically different underlying utility functions hence the evidence presented here suggests that the rational choice approach is a useful tool for understanding the effect of social identity on preferences

exchange rate uncertainty forward contracts and international portfolio selection in this paper ex ante efficient portfolio selection strategies are developed to realize potential gains from international diversification under flexible exchange rates it is shown that exchange rate uncertainty is a largely nondiversiflable factor adversely affecting the performance of international portfolios therefore it is essential to effectively control exchange rate volatility for that purpose two methods of exchange risk reduction are simultaneously employed multicurrency diversification and hedging via forward exchange contracts the empirical findings show that international portfolio selection strategies designed to control both estimation and exchange risks almost consistently outperform the u s domestic portfolio in out of sample periods since grubel 11 applied modern portfolio theory mpt to international investment various authors such as levy and sarnat 17 solnik 20 and lessard 16 have examined the gains from international diversification of investment portfolios for the purpose of establishing the gains from international diversification these studies constructed international portfolios using historical risk and return data from a period of fixed or relatively stable exchange rates and showed that internationally diversified portfolios dominated purely domestic portfolios in terms of mean variance efficiency from the standpoint of today s investors however the previous studies fail to offer operational guidance for international diversification for two important reasons first it is now questionable whether the past findings are still relevant under the current flexible exchange rate regime second by being ex post in nature the past studies ignored the issue of estimation risk or parameter uncertainty and therefore may have overstated the realizable portion of the potential gains from international diversification fluctuating exchange rates are likely to mitigate the potential gains from international diversification by making investment in foreign securities more risky as will be shown later a fluctuating exchange rate contributes to the risk of foreign investment not only through its own variance but also through its positive covariances with the local stock market returns during our sample period of 1980 through 1985 for example exchange rate volatility is found to account for about fifty percent of the volatility of dollar returns from investment in the stock markets of such major countries as germany japan and the u k furthermore the exchange rate changes vis a vis the u s dollar are found to be

systemic risk and international portfolio choice returns on international equities are characterized by jumps moreover these jumps tend to occur at the same time across countries leading to systemic risk we capture these stylized facts using a multivariate system ofjump diffusion processes where the arrival of jumps is simultaneous across assets we then determine an investor s optimal portfolio for this model of returns systemic risk has two effects one it reduces the gains from diversification and two it penalizes investors for holding levered positions we find that the loss resulting from diminished diversification is small while that from holding very highly levered positions is large returns on international equities are characterized by jumps 1 moreover these jumps tend to occur at the same time across countries implying that conditional correlations between international equity returns tend to be higher in periods of high market volatility or following large downside moves 2 our objective in

parameter based decision making under estimation risk an application to futures trading this study shows how the standard portfolio model of futures trading should be modified when there is less than perfect information about the relevant parameters estimation risk the standard and the optimal decision rules for futures trading in the presence of estimation risk are compared and discussed an operational model of futures trading for use under estimation risk is advanced in the presence of relevant prior and sample information the model can be used to optimally blend both types of information many of the contributions of economic theory to the study of financial markets involve the use of parameters that are assumed known or estimable by the economic agents examples include the risk premium coefficient 18 and the security market lines that underlie the capital asset pricing model the volatility measures required for option pricing and the minimum variance hedge ratio and expected basis used to construct portfolios of futures contracts and cash positions generally it is left to practitioners to provide estimates of these parameters which are then directly substituted for the actual parameter values of the theoretical model whenever textbooks demonstrate how these parameters can be estimated there is usually a cookbook formula provided that requires some relatively straightforward analysis of the relevant data e g marshall 1989 chapters 6 and 7 cox and rubinstein 1985 chapter 6 the problems with the procedure described above are twofold first the theory has been slow to acknowledge that the practical application of the model almost always involves parameter estimates generally the additional risk of not knowing the true parameters is completely neglected second practitioners or the market participants will often have some type of nonsample information such as insider information or subjective priors that seems relevant for decision making however this potentially important information is ignored altogether when only sample data are used to obtain the parameter estimates

daily exchange rate behaviour and hedging of currency risk textabstractwe construct models which enable a decision maker to analyze the implications of typical time series patterns of daily exchange rates for currency risk management our approach is bayesian where extensive use is made of markov chain monte carlo methods the effects of several model characteristics unit roots garch stochastic volatility heavy tailed disturbance densities are investigated in relation to the hedging strategies consequently we can make a distinction between statistical relevance of model specifications and the economic consequences from a risk management point of view we compute payoffs and utilities from several alternative hedge strategies the results indicate that modelling time varying features of exchange rate returns may lead to improved hedge behaviour within currency overlay management

confidence in the familiar an international perspective one striking feature of intemrnational portfolio investment is the extent to which equity portfolios are concentrated in the domestic equity market of the investor the home bias puzzle i examine the role of investors perception of foreign investment risk on their portfolio choices the expected retumrns and risk of foreign investment are specified through an asset pricing model with the home portfolio being the benchmark asset pastor s 2000 domestic capm the model serves as a reference point around which investors can center their prior beliefs i focus on investors prior beliefs that are consistent with the literature on confidence in the familiar foreign equities in terms of both expected returns and risk being viewed less favorably than domestic equities these prior beliefs are then combined with the data on g7 equities and the revised beliefs are used to obtain the global optimal asset allocation to hold predominantly domestic equities each g7 investor has to believe that the risk of foreign investment is several times higher than the actual risk the home bias is more of a puzzle for a u s investor during the 1970s specifying investors prior beliefs around the world capm does not help resolve the puzzle

bayesian and capm estimators of the means implications for portfolio selection abstract this paper compares active investment policies under three alternative models for estimating expected stock returns the historical sample mean a shrinkage or bayesian estimator and a capm based estimator the out of sample performance of actively managed u s industry portfolios is analyzed for these three estimators over the period 1931 to 1987 it is found that the classical method based on historical means and covariances leads to the worst forecasts and out of sample performance and is generally outperformed by shrinkage estimators an active portfolio with expected returns based on the capm produced the best results among all actively managed portfolios this strategy as we show closely matches a simple buy and hold the market rule

developments in international solid biofuel trade an analysis of volumes policies and market factors abstract this paper presents and analyses international solid biofuel trade and concludes upon interactions with bioenergy policies and market factors it shows that trade has grown from about 56 to 300 pj between 2000 and 2010 wood pellets grew strongest i e from 8 5 to 120 pj other relevant streams by 2010 included wood waste 77 pj fuelwood 76 pj wood chips 17 pj residues 9 pj and roundwood 2 4 pj intra eu trade covered two thirds of global trade by 2010 underlying markets are highly heterogeneous generally though trade evolved whenever supply side market factors coincided with existing emerging demand patterns market factors and policies both defined trade volumes though policy changes did not have as prominent effects on trade developments as in the liquid biofuel sector economic viability is the key limiting factor main exporting countries have low feedstock costs and already existing wood processing industries trade relevant aspects are the commodity s monetary value determined by its homogeneity heating value and bulk density consumer markets are diverse in residential heating demand trade patterns have been influenced by local biofuel availability and short term price signals i e mainly price competitiveness and investment support for boilers stoves commodities are mainly sourced regionally but price differences have triggered a growing trade the industrial segment is greatly influenced by policy frameworks but more mature e g established routes trade is strictly linked to margins defined mainly by policies and combustion technologies uncertainties in the analysis are due to data gaps across and within databases regarding import export declarations to estimate bioenergy related trade anecdotal data was indispensable we believe datasets should be streamlined across international institutions to eventually enable reporting of global trade beyond digit 6 level research is needed to provide further insights into informal markets interrelations between trade factors are particularly relevant when mapping future trade streams under different policy trade regime scenarios

efficient portfolios when housing needs change over the life cycle abstract we address the issue of the efficiency of household portfolios in the presence of housing risk we treat housing stock as an asset and rents as a stochastic liability stream over the life cycle households can be short or long in their net housing position efficient financial portfolios are the sum of a standard markowitz portfolio and a housing risk hedge term that multiplies net housing wealth our empirical results show that net housing plays a key role in determining which household portfolios are inefficient the largest proportion of inefficient portfolios obtains among those with positive net housing who should invest more in stocks

productivity developments in european agriculture relations to and opportunities for biomass production abstract this paper discusses if how fast and to what maximum yield improvements can be realized in europe in the coming decades and what the opportunities and relations are to biomass production the starting point for the analysis is the historic context of developments in european agriculture over the past five decades historic developments in european crop and animal protein productivity between 1961 and 2007 show an average mean annual growth rate of 1 6 in relative terms developments are slower on average in the netherlands and france at 1 0 y 1 than in poland and ukraine ussr at 2 2 y 1 in absolute figures however growth has been considerable in wec and modest in the ceec yield trends further show that significant yield changes can be realized over a short period of time positive growth rates of 3 5 y 1 were reached in several countries and for several crops in several decades in eastern european countries during their transition in the 1990s negative growth rates as low as 7 y 1 occurred outcomes suggest that productivity levels can be actively steered rather than being just the result of autonomous developments current yield gaps differ greatly between western europe france 1 high yielding lignocellulosic crops could double this potential it is concluded that the potential to free up agricultural lands for the production of bioenergy crops in europe is considerable the degree to and the pace at which yields develop will determine how much of the potential is opened up agricultural policy and technological development are key to open up the potential

sensitivity analysis for mean variance portfolio problems this paper shows how to perform sensitivity analysis for mean variance mv portfolio problems using a general form of parametric quadratic programming the analysis allows an investor to examine how parametric changes in either the means or the right hand side of the constraints affect the composition mean and variance of the optimal portfolio the optimal portfolio and associated multipliers are piecewise linear functions of the changes in either the means or the right hand side of the constraints the parametric parts of the solution show the rates of substitution of securities in the optimal portfolio while the parametric parts of the multipliers show the rates at which constraints are either tightening or loosening furthermore the parametric parts of the solution and multipliers change in different intervals when constraints become active or inactive the optimal mv paths for sensitivity analyses are piecewise parabolic as in traditional mv analysis however the optimal paths may contain negatively sloping segments and are characterized by types of kinks i e points of nondifferentiability not found in mv analysis

review of solid and liquid biofuel demand and supply in northwest europe towards 2030 a comparison of national and regional projections biomass is the largest source of renewable energy carrier in the european union eu contributing to over 60 of renewable energy with the majority of supply coming from domestic sources however an increasing significant amount of feedstock is imported either due to domestic undersupply or higher production costs within the country this article provides an up to date view of bioenergy supply demand and trade in northwest europe to 2030 projections of the energy system model green x are compared to recent national studies concerning bioenergy imports the results show that there is a sizeable gap of the projection bandwidths after the 2020 horizon projections might under or overestimate biomass potential in certain cases depending on whether they are derived from national reports or regional models whether future policy developments were taken into account etc the ranges of biomass consumption are multiple times apart by 2020 already and the gap increases by 2030 total biomass imports in the region can range between 14 and 44 3 mt by 2020 and 18 5 60 mt by 2030

in defense of optimization the fallacy of 1 n previous research has shown that equally weighted portfolios outperform optimized portfolios which suggests that optimization adds no value in the absence of informed inputs this article argues the opposite with naive inputs optimized portfolios usually outperform equally weighted portfolios the ostensible superiority of the 1 n approach arises not from limitations in optimization but rather from reliance on rolling short term samples for estimating expected returns this approach often yields implausible expectations by relying on longer term samples for estimating expected returns or even naively contrived yet plausible assumptions optimized portfolios outperform equally weighted portfolios out of sample

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

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

a rational explanation for home country bias abstract while modern portfolio theory predicts that investors should diversify across international markets corporate equity is essentially held by domestic investors french and poterba 1991 french k poterba j 1991 investor diversification and international equity markets american economic review 81 222 226 suggest that in order for this bias to be justified investors must hold optimistic expectations about their domestic markets and pessimistic expectations about their foreign markets tesar and werner 1995 tesar l l werner i m 1995 home bias and high turnover journal of international money and finance 14 467 492 find existing explanations for the home equity bias unsatisfactory and conclude that the issue poses a challenge for portfolio theory we develop a model that incorporates both the foregone gains from diversification and the informational constraints of international investing and shows that home equity bias is consistent with rational mean variance portfolio choice specifically we prove that the nature of estimation risk in international markets can be responsible for this phenomenon we show that when the cross market variability in the estimation errors of international markets means far exceeds the cross market variability in the means themselves domestic dedication dominates international diversification an examination of 11 international markets returns over the last 25 years from the perspective of german japanese and us investors provides evidence consistent with this explanation

risk reduction by diversification in the nordic stock markets empirical examination of the ex post potential gains of risk reduction through international portfolio diversification started with grubel 1968 levy and sarnat 1970 solnik 1974 and lessard 1974 in their survey of international finance adler and dumas 1983 p 938 summed up the results the potential for international diversification to reduce risk seems unquestionable in the wake of increasing liberalization for international portfolio investment more recent contributions include jorion 1985 1989 grauer and hakansson 1987 and levy and lerman 1988 the results of the pioneers have been corroborated by contemporary research and according to jorion 1989 p 54 international diversification extolled by grubel as early as 1968 seems to have delivered on its promises despite the long tradition of studies in international portfolio diversification there has been no such work regarding the nordic markets this paper fills the gap through an analysis of potential gains from international diversification for different nordic investors danish finnish norwegian and swedish if they invest in all the nordic equity markets until the beginning of the 1980s nordic investors particularly in finland and sweden faced legal restrictions on investment abroad see nordiska radet 1987 adler and dumas 1983 have pointed out that such restrictions would lead to partially or fully segmented markets and hietala 1989 has shown the existence of premiums in the finnish stock market in our study we do not make any direct test of whether the nordic equity markets have been segmented or integrated but our results might provide some indirect evidence the nordic countries are generally viewed as fairly homogeneous from a social political and economic point of view while international diversifi

the empirical minimum variance hedge decision making under unknown true parameters estimation risk is discussed along with bayes and parameter certainty equivalent pce criteria bayes criterion incorporates estimation risk in a manner consistent with expected utility maximization the pce method which is the most commonly used is not consistent with expected utility maximization bayes criterion is employed to solve for the minimum variance hedge ratio empirical application of bayes minimum variance hedge ratio is addressed and illustrated simulations shoe that discrepancies between prior and sample parameters may lead to substantial differences between bayesian and pce minimum variance hedges

performance of currency portfolios chosen by a bayesian technique 1967 1985 abstract this paper is about normative currency portfolio rules it assumes logarithmic investors who maximize the expected utility from lognormal currency returns with and without short sales restrictions a number of implementable portfolio diversification policies are tried out on a large body of data covering nine major currencies and eighteen years of weekly observations in doing so we present ways of dealing with the estimation risk in an international context the necessary mean and covariance inputs are provided by a bayesian prior on the means and by sample means and covariance matrices which are estimated from weekly sample data while some policies do produce abnormal returns over and beyond proper reward for risk none does so in a statistically significant way this means that the evidence does not allow one to conclude that market participants are improperly diversified as a byproduct of this investigation techniques are found which would allow portfolio managers to earn a proper reward for risk by following a purely mechanical procedure such techniques may be valuable in a multi country world where the aggregate portfolio of currencies and securities is unknown and is not supposed to be efficient

selective hedging strategies for oil stockpiling abstract as a feasible option for improving the economics and operational efficiency of stockpiling by public agency this study suggests simple selective hedging strategies using forward contracts the main advantage of these selective hedging strategies over the previous ones is not to predict future spot prices but to utilize the sign and magnitude of basis easily available to the public using the weekly spot and forward prices of west texas intermediate for the period of october 1997 august 2002 this study adopts an ex ante out of sample analysis to examine selective hedging performances compared to no hedge and minimum variance routine hedging strategies to some extent selective hedging strategies dominate the traditional routine hedging strategy but do not improve upon the expected returns of no hedge case which is mainly due to the data characteristics of out of sample period used in this analysis

international portfolio diversification with estimation risk international portfolio diversification has long been advocated as a way of enhancing average returns while reducing portfolio risk for the investor who considers diversifying into foreign securities this proposition however relies on the assumption that the required inputs to the classical mean variance analysis are known with certainty typically expected returns variances and covariances are simply replaced by their ex post sample values and the optimal portfolio is derived without mentioning the uncertainty inherent in these parameter values but the rational investor should take this uncertainty into account when forming expectations and probably will consider estimators that are less subject to estimation error than the classical sample mean this paper investigates alternative estimators of expected returns and their implications for the alleged gains from diversification an important observation is the crucial influence that errors in estimating expected returns have on portfolio analysis a closer examiprevious studies of international portfolio diversification have relied on ex post meanvariance analysis without considering the problem of estimation risk typically past averages are substituted for expected returns and no allowance is made for the uncertainty inherent in these parameter values first i demonstrate the shortcomings of such an approach and second i investigate another method of estimating expected returns initially proposed by stein by shrinking the sample averages toward a common mean i find that the out of sample performance of the optimal portfolio is substantially increased one of the implications of this method is that the classical conclusions vastly overestimate the possible gains in average returns instead benefits from diversification are more likely to accrue from a reduction in risk this paper draws on part of my dissertation at the university of chicago i am grateful to arnold zellner michael mussa george constantinides and especially john bilson for useful discussions and comments numerous improvements were also suggested by the referee this research received the generous financial support of the college interuniversitaire d etudes doctorales dans les sciences du management

future perspectives of international bioenergy trade abstract according to the iea world energy outlook 2012 primary demand for bioenergy will strongly increase up to the year 2035 the demand for biofuels and biomass for electricity is expected to triple these changes will have an impact on the regional balance of demand and supply of bioenergy leading to both increasing trade flows and changes in trade patterns the gfpm timer and poles models have been selected for a detailed comparison of scenarios and their impact on global bioenergy trade in ambitious scenarios 14 26 of global bioenergy demand is traded between regions in 2030 the model scenarios show a huge range of potential bioenergy trade for solid biomass in ambitious scenarios bioenergy trade ranges from 700 mt to more than 2 500 mt in 2030 for liquid biomass the ambitious scenarios show a bioenergy trade in the range of 65 360 mt in 2030 considering the currently very small share of internationally traded bioenergy this would result in huge challenges and require tremendous changes in terms of production pretreatment of biomass and development of logistic chains

a general equilibrium model of international portfolio choice we investigate in a two country general equilibrium model whether a bias in consumption towards domestic goods will necessarily lead to a preference for domestic securities we develop a model where investors are constrained to consume only from their domestic capital stock and where it is costly to transfer capital across countries in this model investors less risk averse than an investor with log utility bias their portfolios towards domestic assets investors more risk averse than log however prefer foreign assets thus this model suggests that it is unlikely that the portfolios observed empirically can be explained by the high proportion of domestic goods in total consumption we investigate in a two country general equilbrium model whether a bias in consumption toward domestic goods will necessarily lead to a preference for domestic assets in an investor s optimal portfolio we constrain investors to consume only from their domestic capital stock and introduce a proportional cost for transferring goods from one country this cost gives rise to endogenous deviations from the law of one price lop thus the home and foreign investors do not hold identical portfolios we show that an investor s optimal portfolio is biased towards domestic equity only if she is less risk averse than an investor with log utility investors with relative risk aversion greater than one exhibit a preference for the foreign asset this is because the exchange rate derived endogenously is negatively correlated with the return on the foreign asset and therefore the translated return on the foreign stock is less risky than that on the domestic stock thus the results of this model suggest that it is unlikely that the preference for domestic assets that is observed empirically can be explained by the high proportion of domestic goods in total consumption there exists a considerable body of literature documenting the gains from international diversification grubel 1968 was the first to propose that international diversification allows investors to attain lower return variances than those achievable by diversifying domestically this proposition relies on the correlation between stock indices across countries being significantly less

combining equilibrium resampling and analyst s views in portfolio optimization abstract this paper proposes the use of a portfolio optimization methodology which combines features of equilibrium models and investor s views as in black and litterman 1992 and also deals with estimation risk as in michaud 1998 in this way our combined methodology is able to meet the needs of practitioners for stable and diversified portfolio allocations while it is theoretically grounded on an equilibrium framework we empirically test the methodology using a comprehensive sample of developed countries fixed income and equity indices as well as sub samples stratified by geographical region time period asset class and risk level in general our proposed combined methodology generates very competitive portfolios when compared to other methodologies considering three evaluation dimensions financial efficiency diversification and allocation stability by generating financially efficient stable and diversified portfolio allocations our methodology is suitable for long term investors such as central banks and sovereign wealth funds

international bioenergy trade a review of past developments in the liquid biofuel market policies aimed to promote biofuels locally had tremendous effects on global market developments across the past decade this article develops insights into the interaction of these policies and market forces via a comprehensive collection and analysis of international production and trade data it shows that world biofuel production and trade has grown exponentially from below 30 pj in 2000 to 572 pj in 2009 for biodiesel from 340 pj in 2000 to over 1540 pj in 2009 for fuel ethanol the eu has dominated world biodiesel whereas the us and brazil have led fuel ethanol production world net biofuel trade reached 120 130 pj in 2009 and was directed towards the most lucrative markets for biodiesel this has been the eu whose imports rose to 92 pj in 2008 and remained at 70 pj in 2009 regarding fuel ethanol both the us and the eu have been prime destinations for competitively priced exports the vast majority of which originated in brazil international biofuel trade is both supply and demand driven the demand side was shaped by support policies which generally increased the domestic market value of biofuels trade developed wherever these policies prices were not accompanied by respective measures it is found that import duties largely influenced trade volumes whereas trade routes were mainly driven by tariff preferences trade regimes appear to have been designed and adapted unilaterally along national interests causing market disruptions trade inefficiencies and disputes to avoid these it is important to explicitly consider international trade implications of national trade policies a prerequisite is to improve the understanding of the underlying complex and interwoven links within the market the current lack of adequate homogeneous international reporting of biofuel production and trade statistics could be bridged via internationally standardized custom clarifications trade factor interrelations also need to be investigated further

cluster analysis for portfolio optimization we consider the problem of the statistical uncertainty of the correlation matrix in the optimization of a financial portfolio by assuming idealized conditions of perfect forecast ability for the future return and volatility of stocks and short selling we show that the use of clustering algorithms can improve the reliability of the portfolio in terms of the ratio between predicted and realized risk bootstrap analysis indicates that this improvement is obtained in a wide range of the parameters n number of assets and t investment horizon the predicted and realized risk level and the relative portfolio composition of the selected portfolio for a given value of the portfolio return are also investigated for each considered filtering method we also show that several of the results obtained by assuming idealized conditions are still observed under the more realistic assumptions of no short selling and mean return and volatility forecasting based on historical data

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

sustainability constraints in determining european bioenergy potential a review of existing studies and steps forward abstract this paper reviews european land and bioenergy potential studies to 1 identify shortcomings related to how they account for agricultural intensification and its associated environmental effects and sustainability constraints and 2 provide suggestions on how these shortcomings can be improved in future assessments the key shortcomings are the environmental impacts of intensification are nearly always ignored in the reviewed studies while these impacts should be accounted for if intensification is required to make land available for energy cropping future productivity developments of crops and livestock and the associated land use and environmental effects are currently limited to conventional intensification measures whereby the proportion between inputs and outputs is fixed sustainable intensification measures which increase land productivity with similar or lower inputs are ignored in the reviewed studies livestock productivity developments livestock specific intensification measures and their environmental effects are poorly or not at all covered in the reviewed studies most studies neglect sustainability constraints other than ghg emissions in the selection of energy crops this includes limitations to rainfed energy crop cultivation a minimum number of crop species the structural diversity within cropping areas and the integration of energy crops in existing or new crop rotations while simultaneously considering the effects on subsequent crops these shortcomings suggest that the identification of sustainable pathways for european bioenergy production requires a more integrative approach combining land demand for food feed and energy crop production including different intensification pathways and the consequent direct and indirect environmental impacts a better inclusion of management practices into such approach will improve the assessment of intensification its environmental consequences and the sustainable bioenergy potential from agricultural feedstocks

discrimination in the laboratory a meta analysis of economics experiments abstract economists are increasingly using experiments to study and measure discrimination between groups in a meta analysis containing 441 results from 77 studies we find groups significantly discriminate against each other in roughly a third of cases discrimination varies depending upon the type of group identity being studied it is stronger when identity is artificially induced in the laboratory than when the subject pool is divided by ethnicity or nationality and higher still when participants are split into socially or geographically distinct groups in gender discrimination experiments there is significant favouritism towards the opposite gender there is evidence for both taste based and statistical discrimination tastes drive the general pattern of discrimination against out groups but statistical beliefs are found to affect discrimination in specific instances relative to all other decision making contexts discrimination is much stronger when participants are asked to allocate payoffs between passive in group and out group members students and non students appear to discriminate equally we discuss possible interpretations and implications of our findings

variance vs downside risk is there really that much difference abstract the popularity of downside risk among investors is growing and mean return downside risk portfolio selection models seem to oppress the familiar mean variance approach the reason for the success of the former models is that they separate return fluctuations into downside risk and upside potential this is especially relevant for asymmetrical return distributions for which mean variance models punish the upside potential in the same fashion as the downside risk the paper focuses on the differences and similarities between using variance or a downside risk measure both from a theoretical and an empirical point of view we first discuss the theoretical properties of different downside risk measures and the corresponding mean downside risk models against common beliefs we show that from the large family of downside risk measures only a few possess better theoretical properties within a return risk framework than the variance on the empirical side we analyze the differences between some us asset allocation portfolios based on variances and downside risk measures among other things we find that the downside risk approach tends to produce on average slightly higher bond allocations than the mean variance approach furthermore we take a closer look at estimation risk viz the effect of sampling error in expected returns and risk measures on portfolio composition on the basis of simulation analyses we find that there are marked differences in the degree of estimation accuracy which calls for further research

delegated portfolio management and optimal allocation of portfolio managers in this article we investigate whether the application of the mean variance framework on portfolio manager allocation offers any out of sample benefits compared to a naive strategy of equal weighting based on an exclusive data set of high net worth hnw investors we utilize a wide variety of methodologies to estimate the input parameters including exponentially weighted moving average ewma generalized autoregressive conditional heteroscedasticity garch and bayes stein shrinkage estimation we apply nine different mean variance models but find that none of these present any consistent benefit over a naive strategy of equal weighting

gains from international diversification 1968 85 returns on portfolios of stocks and bonds this paper applies the multi period investment model to a universe of international securities on the basis of the simple probability assessment approach our principal findings are 1 the gains from including non u s asset categories in the universe were remarkably large in some cases statistically significant especially for the highly risk averse strategies 2 the gains from removing the no leverage constraint were more substantial than they were in the absence of non u s securities and 3 there is strong evidence of market segmentation in that the optimal levels of investment in u s securities were mostly zero in the presence of the non u s asset categories

market timing with option implied distributions a forward looking approach we address the empirical implementation of the static asset allocation problem by developing a forward looking approach that uses information from market option prices to this end we extract constant maturity s p 500 implied distributions and transform them to the corresponding risk adjusted ones then we form optimal portfolios consisting of a risky and a risk free asset and evaluate their out of sample performance we find that the use of risk adjusted implied distributions times the market and makes the investor better off than if she uses historical returns distributions to calculate her optimal strategy the results hold under a number of evaluation metrics and utility functions and carry through even when transaction costs are taken into account not surprisingly the reported market timing ability deteriorated during the recent subprime crisis an extension of the approach to a dynamic asset allocation setting is also presented this paper was accepted by wei xiong finance

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