analyst forecasting errors additional evidence analyst forecasting errors are approximately as large as dreman and berry 1995 documented and an optimistic bias is evident for all years from 1985 through 1996 in contrast to their findings i show that analyst forecasting errors and bias have decreased over time moreover the optimistic bias in quarterly forecasts was absent for sp 2 firms with comparatively large amounts of market capitalization absolute value of earnings forecast and analyst following and 3 firms in certain industries

malthus living in a slum urban concentration infrastructure and economic growth abstract the link between urban concentration primacy and economic growth at country level is not straightforward as there are benefits as well as costs associated with urban primacy recent empirical evidence suggests a differential negative effect of concentration in sub saharan africa compared to the rest of the world this paper revisits the literature on urban concentration and economic growth to shed some light on these recent results the main contribution of the paper is to show how differentiated effects of urban primacy on economic growth can be accounted for by considering a role for the quality of the urban environment in terms of urban infrastructure the role of urban infrastructure is found to be robust to a long list of controls different specifications different estimation techniques and potential bias from simultaneity and measurement error

more on estimation risk and simple rules for optimal portfolio selection for the risk averse investor consideration of estimation risk is important in selecting an expected utility maximizing portfolio it has previously been shown that the composition of the tangency portfolio is unaffected by the recognition of estimation risk if the full covariance model is used alternatively if the market model is used the composition of the tangency portfolio has been shown to be affected by the recognition of estimation risk however as is demonstrated in this paper the effect will generally not be as substantive as previously believed and in many situations can be safely ignored in order to determine the composition and location of an efficient frontier from which an optimal portfolio will be selected the investor must employ estimates of expected returns variances and covariances for the set of securities under consideration if the investor simply treats the estimated parameter values for the securities as true parameter values then estimation risk will have been ignored and as shown by barry 1 and klein and bawa 14 15 a suboptimal portfolio will most likely have been selected bawa brown and klein 6 and klein and bawa 14 discuss the effects of estimation risk on the selection of an optimal portfolio from a set of risky assets and note that the location but not the composition of the efficient frontier changes when estimation risk is recognized if security returns are generated by a stationary multivariate normal distribution for which the investor has a diffuse prior furthermore brown 8 has shown these results to be robust for severe misspecification of the underlying multivariate distribution of returns e g assuming it to be normal when in actuality it is student t with small degrees of freedom this paper is concerned with the effects of estimation risk on the composition of the tangency portfolio derived from a set of risky assets and a risk free asset under the assumption that the investor has a diffuse prior 1 barry 2 bawa and brown 4 and brown 7 have shown analytically that the composition of the tangency portfolio is unaffected by estimation risk if the full covariance model is used chen and brown 10 have expanded upon the work of brown 9 and have argued that if security returns are generated by the market model then the composition of the tangency portfolio will be substantively different when estimation risk is recognized

the effect of experience on security analyst underreaction abstract we examine if analysts more fully incorporate prior earnings and returns information in their current quarter forecasts as their experience following a firm increases we measure analyst firm specific forecasting experience as the number of prior quarters for which the analyst has issued an earnings forecast for the firm we find that analysts underreact to prior earnings information less as their experience increases suggesting one reason why analysts become more accurate with experience

short sales are almost instantaneously bad news evidence from the australian stock exchange this paper investigates the market reaction to short sales on an intraday basis in a market setting where short sales are transparent immediately following execution we find a mean reassessment of stock value following short sales of up to 0 20 percent with adverse information impounded within fifteen minutes or twenty trades short sales executed near the end of the financial year and those related to arbitrage and hedging activities are associated with a smaller price reaction trades near information events precipitate larger price reactions the evidence is generally weaker for short sales executed using limit orders relative to market orders this article analyzes the intraday price behavior surrounding short sales executed using market and limit orders within a transparent setting a number of recent studies have focused on daily or monthly stock price behavior surrounding short selling activity in u s markets e g senchack and starks 1993 figlewski and webb 1993 conrad 1994 hanley and seyhun 1994 asquith and meulbroek 1996 and dechow et al 1997 this research has been motivated by the continued interest of market regulators i n short selling activity and the controversy surrounding the desirability restrictions and disclosure requirements related to short selling see janvey 1992 and ramsay 1993 in particular several studies such as that by figlewski and webb 1993 have examined the relationship between short positions and subsequent abnormal returns without finding a strong relationship asquith and meulbroek 1996 in contrast focus on firms with large short positions and find a strong and consistent relationship dechow et al 1997 find a correlation between short selling strategies and strategies based on fundamental analysis these results are consistent with short sellers being able to identify

the labour market participation of northern ireland university students this paper seeks to examine what factors are associated with student labour force participation in northern ireland in both term time and vacation making use of quarterly labour force survey data for the period march 1998 february 1999 the results suggest female students are more likely to work than male students mature students are less likely to work than non mature students roman catholic students are less likely to work than non roman catholic students students living at home are more likely to work than student living away from home and an increase in the actual or predicted wage increases the probability of labour force participation the author suggests that some of these results are due to the particular nature of the northern ireland socio economic situation while others are likely to be true for the rest of the united kingdom

urbanization mortality and fertility in malthusian england the modern world is the product of two momen tous changes the industrial revolution of 1800 which brought sustained efficiency advances in economies and the demographic transition of 1900 which channeled those efficiency advances mainly into increased income per capita instead of increases in population how these revolutions were connected has been a persistent unsolved puzzle in the history of growth the demographic transition was achieved without any improve ment in contraceptive technologies from those of 1800 and earlier it was a possibility for all preindustrial societies why did it occur only after the industrial revolution the key component of the malthusian econ

comparisons and combinations of long and long short strategies market neutral long short strategies get their returns from alphas and short rebates long strategies get their returns from alpha and the market differing return and risk sources complicate their comparison partly because of the strong market referenced focus of conventional performance analysis compelling theoretical advantages of active return per unit of active risk suggest that long short strategies are better able to deliver excess return than are conventional institutional long strategies long short strategies even with tiny positive alphas are seen to improve investors efficient frontiers when added to a traditional t bill long portfolio mix mostly because their risk sources are uncorrelated surprisingly the improvement occurs even if long short strategies are sharpe ratio inferior to long strategies these results provide theoretical support for including long short strategies in most investors mix of assets

the efficiency gains of long short investing long short strategies have generated controversy and institutional interest for more than 10 years we analyzed the efficiency gains of long short investing where we defined efficiency as the information ratio of the implemented strategy the optimal portfolio relative to the intrinsic information ratio of the alphas the efficiency advantage of long short investing arises from the loosening of the surprisingly important long only constraint long short and long only managers need to understand the impact of this significant constraint long short implementations offer the most improvement over long only implementations when the universe of assets is large asset volatility is low and the strategy has high active risk the long only constraint induces biases particularly toward small stocks limits the manager s ability to act on upside information by not allowing short positions that could finance long positions and reduces the efficiency of traditional high risk long only strategies relative t

a new approach to understanding labour supply of disabled people abstractthe main interest of this article is to propose an individual utility maximization model to explain the low participation of disabled people we account for heterogeneity of preferences and

portfolio selection under institutional procedures for short selling normative and market equilibrium considerations abstract in view of the acceptance of short selling of stocks as an investment tool in the portfolio context by a growing number of institutional investors in recent years the present study considers both normative and market equilibrium aspects of portfolio selection with short selling under the full information covariance structure of security returns the study accurately captures institutional procedures for short selling without sacrificing analytical tractability while short selling enhances the portfolio s risk return trade off from a normative perspective the equilibrium analysis reveals that there is a continuum of market clearing prices within two boundaries for each security economic implications of the equilibrium pricing relationship are also explored in the study

short sale constraints divergence of opinion and asset values evidence from the laboratory the overvaluation hypothesis miller 1977 predicts that a stocks are overvalued when there are short selling restrictions and that b the overvaluation is increasing in the degree of divergence of opinion we design an experiment that allows us to test these predictions in the laboratory our results support the hypothesis that prices are higher in the presence of short selling constraints the overvaluation does not depend on the degree of divergence of opinion

whisper forecasts of quarterly earnings per share abstract we compare first call analyst forecasts of earnings to unofficial forecasts commonly referred to as whispers our analysis indicates that whispers are more accurate proxies for market expectations of earnings than are first call forecasts consistent with the claim in the professional press that whispers are increasingly becoming the true market expectation of earnings further trading strategies based on the relation between whisper and first call forecasts earn abnormal returns this suggests that whispers contain information not contained in first call forecasts and that at least part of this information is impounded in price prior to the earnings release

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

the capital gain lock in effect and perfect substitutes abstract this paper analyses the effect of investors accrued capital gains on optimal portfolio composition and equilibrium returns under the assumption that investors are able to re balance with perfect substitute securities no dominance arguments are used to show that pricing differences because of accrued capital gains do not arise among securities which are perfect substitutes these arguments are insufficient however to prevent pricing differences because of accrued capital gains among securities which are not perfect substitutes trading rules are developed which outline the conditions necessary for the realisation of accrued capital gains and the deferral of capital losses these trading rules also provide guidance on which securities investors should sell given their tax basis when re balancing their portfolios

short interest and stock price crash risk abstract using a large sample of u s public firms we find robust evidence that short interest is positively related to one year ahead stock price crash risk the evidence is consistent with the view that short sellers are able to detect bad news hoarding by managers additional findings show that the positive relation between short interest and future crash risk is more salient for firms with weak governance mechanisms excessive risk taking behavior and high information asymmetry between managers and shareholders empirical support is provided showing that the relation between short interest and crash risk is driven by bad news hoarding

optimal portfolio selection under institutional procedures for short selling abstract this study presents and formally justifies a simple ranking approach for optimal portfolio selection under institutional procedures for short selling it also provides economic insights of the explicit solution of the portfolio problem the analysis is applicable to different treatments of the short sale proceeds and any margin deposits in contrast to previous approaches it does not require assumptions that overstate short sale benefits for maintaining analytical tractability and it can easily identify and filter out securities that are undesirable for investing or for short selling thus this study can enhance the usefulness of portfolio modeling for assisting practical investment decisions

equivalence scale relativities and the extent of inequality and poverty most inequality and poverty theory analyzes equivalent income distributions for homogeneous populations incomes are assumed to be deflated by an equivalence scale that accounts for differences in needs between households yet in practice there is no consensus about what the appropriate equivalence scale is the authors analyze how the choice of equivalence scale affects inequality and poverty measures and show that there is a systematic relationship between equivalence scale generosity and the extent of inequality and poverty they consider most of the measures in common use and provide some empirical illustrations copyright 1992 by royal economic society

the relationship between short interest and stock returns in the canadian market abstract this paper provides new insight into the relationship between short sales and stock market returns using a sample of stocks sold short in canada short interest is defined in relation to trading volume the results strongly support the assertion that short sales and excess returns are contemporaneously negatively correlated in canada the paper further finds that excess returns are more negative for small firms because the supply of shortable shares is constrained for these firms excess returns are less negative for stocks with associated options and convertible bonds importantly the evidence is consistent with the proposition that informed traders short sell canadian interlisted stocks in canada rather than the us to exploit lower execution costs together the results suggest that less restrictive regulation of short sales will improve the efficiency of markets

the impact of export strategy on export sales performance export sales are an important route to growth for the small to medium sized firm this article reports the results of an extensive empirical study of the export strategies of a large sample of high technology electronics firms and the performance results of adopting alternate export strategies six strategy scenarios were identified the results show that the types of foreign markets selected segmentation strategies and product strategies all have a pronounced impact on export sales and export growth the best performers a group of firms called the world marketers and representing 13 5 of the sample achieved a dramatic 188 annual growth in exports and exported 52 5 of their output the profiles of firms that elected each strategy scenario were determined also

loss function assumptions in rational expectations tests on financial analysts earnings forecasts abstract prior research concludes that financial analysts do not process public information efficiently in generating their earnings forecasts the ordinary least squares ols regression based tests used in prior studies assume implicitly that analysts face a quadratic loss function in contrast we argue that analysts likely face a linear loss function and hence try to minimize their absolute forecast errors we conduct and compare rational expectations tests using these two alternative loss functions we reproduce most prior findings of forecast inefficiency with ols regressions but find virtually no evidence of forecast inefficiency with least absolute deviation regressions where we explicitly assume a linear loss function

portfolio optimization with factors scenarios and realistic short positions this paper presents fast algorithms for calculating mean variance efficient frontiers when the investor can sell securities short as well as buy long and when a factor and or scenario model of covariance is assumed currently fast algorithms for factor scenario or mixed factor and scenario models exist but except for a special case of the results reported here apply only to portfolios of long positions factor and scenario models are used widely in applied portfolio analysis and short sales have been used increasingly as part of large institutional portfolios generally the critical line algorithm cla traces out mean variance efficient sets when the investor s choice is subject to any system of linear equality or inequality constraints versions of cla that take advantage of factor and or scenario models of covariance gain speed by greatly simplifying the equations for segments of the efficient set these same algorithms can be used unchanged for the long short portfolio selection problem provided a certain condition on the constraint set holds this condition usually holds in practice

short sale restrictions and market reaction to short interest announcements according to the diamond verrecchia hypothesis if increases in short interest are correlated with information that is not yet public they should precipitate a price adjustment stocks with unexpected increases in short interest are found to generate statistically significant but small negative abnormal returns for a short period around the announcement date when the sample is divided into stocks with and without tradable options nonoptioned stocks closely mimic these results but the optioned stocks do not in a cross sectional analysis of individual firms the short term negative abnormal returns are found to be 1 more negative the higher the degree of unexpected short interest and 2 less negative if the firm has tradable options

capital asset prices with and without negative holdings prize lecture to the memory of alfred nobel december 7 1990 this abstract was borrowed from another version of this item

disability insurance benefits and labor supply a critical input for assessing the optimal size of disability insurance programs is the elasticity of labor force participation with respect to the generosity of benefits unfortunately this parameter has been difficult to estimate in the context of the u s disability insurance program since all workers face an identical benefits schedule i surmount this problem by studying the experience of canada which operates two distinct disability insurance programs for quebec and for the rest of canada the latter program raised its benefits by 36 percent in january 1987 whereas benefits in quebec were constant i find a sizable labor supply response to the policy change my central estimates imply an elasticity of labor force nonparticipation with respect to disability insurance benefits of 0 28 0 36

married women s hours and participation revisited elasticity estimates are presented for participation and hours of work for a sample of married women in the social change and economic life initiative sceli 1986 data set a logit model is used to estimate the participation function and a tobit model is employed to estimate an hours of work equation the results are in agreement with the evidence available for the uk the own wage hours of work elasticity is found to be relatively elastic with negligible effects detected for non labour income and the husband or spouse s wage the effects on participation of an unemployed husband or spouse were examined and found to have a strong negative effect

do individual short sellers make money evidence from korea abstract we use a proprietary trade and account level dataset of short sales to investigate the profitability of individual investors short selling in the korean stock market from august 1 2007 to may 31 2010 using actual data on short covering transactions we find that the average profit is 26 810 korean won roughly usd 24 4 per trade per hour and about 44 of shorted trades are covered within a day we also find that the profitability of short selling decreases as the hours to cover increases account level analyses show that investors who sell short more firms make higher profits than those who sell short fewer firms and that the profitability of short selling is persistent we attribute the profitability to short sellers ability to exploit short run price reversals and information processing skills

trimability and fast optimization of long short portfolios optimization of long short portfolios through the use of fast algorithms takes advantage of models of covariance to simplify the equations that determine optimality fast algorithms exist for widely applied factor and scenario analysis for long only portfolios to allow their use in factor and scenario analysis for long short portfolios the concept of trimability is introduced the conclusion is that the same fast algorithms that were designed for long only portfolios can be used virtually unchanged for long short portfolio optimization provided the portfolio is trimable which usually holds in practice

the rewards to meeting or beating earnings expectations abstract this paper finds that firms that meet or beat current analysts earnings expectations mbe enjoy a higher return over the quarter than firms with similar quarterly earnings forecast errors that fail to meet these expectations further such a premium to mbe although somewhat smaller exists in the cases where mbe is likely to have been achieved through earnings or expectations management the findings also indicate that the premium to mbe is a leading indicator of future performance this premium and its predictive ability are only marginally affected by whether the mbe is genuine or the result of earnings or expectations management

short selling and efficient sets the effect of short selling on the composition and location of the efficient set has been analyzed in a variety of ways however the situation typically facing investors where the initial margin requirement is less than 100 percent and the riskfree interest rate that is paid on the short proceeds is less than the rate paid on initial margin has not previously been considered the elton gruber padberg algorithm 1976 1978 subject to certain modifications is shown here to be capable of identifying the efflcient set under such conditions when harry markowitz 1952 developed the notion of efficient sets as a method of identifying an investor s optimal portfolio he did so in a setting where short selling was prohibited since then the effect of short selling on the composition and location of the efficient set has been considered in a variety of ways for example lintner 1965 suggested that short sales be treated from the perspective of a broker dealer where an amount of money equal to the short proceeds must be put up as initial margin with the short seller receiving riskfree interest on both the short proceeds and the margin alternatively black 1972 and merton 1972 assumed that the short seller did not have to put up any initial margin and that the short seller actually got the use of the short proceeds more recently dyl 1975 has assumed that the short seller must put up initial margin that is less than the short proceeds but receives no interest on either the margin or short proceeds this paper is concerned with the generation of efficient sets where short selling is allowed but with certain restrictions attached to it referred to hereafter as restricted short selling in particular initial margin is required but can be met by depositing interest bearing securities with the brokerage firm where the short seller s account is kept furthermore the model allows the short seller to earn interest on the short proceeds accordingly the model

the information content of short interest a natural experiment an increase in the cost of selling short should increase the bearish information content of short interest announcements by driving relatively uninformed short sellers out of the market we extend the diamond and verrecchia 1987 model to include short selling against the box and test the extended model using a natural experiment based around the taxpayer relief act of 1997 tra97 tra97 made short selling more costly for those shorting against the box consistent with the implications of our extended model this increase in short selling costs strengthens the negative relationship between short interest and subsequent stock price performance post tra97

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

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

estimation risk and simple rules for optimal portfolio selection elton gruber and padberg egp 6 7 have recently simplified the process of constructing optimal portfolios by developing simple criteria for optimal portfolio selection which do not involve use of mathematical programming their simple decision rules permit one to determine easily which securities to include in an optimal portfolio and how much to invest in each however in practical applications of theoretical models sample estimators are usually treated as if they were true values of unknown parameters as a result the effect of the standard errors of sample estimators on decision rules are completely ignored bawa brown and klein 1 have shown that what is optimal in the absence of estimation risk is not necessarily optimal or even approximately optimal in the presence of estimation risk moreover brown 4 examined optimal portfolio choice under uncertainty for various portfolio selection procedures the diffuse bayes rule the markowitz certainty equivalent ce rule the aggregation ce rule and the equal weight rule 1 and found that the diffuse bayes rule uniformly dominates the markowitz ce rule in repeated samples for the quadratic utility case as the sample size increases the bayes rule becomes superior to the aggregation ce and the equal weight rules in addition the result holds even where the probability distribution of returns is seriously misspecified thus brown s 4 study has clearly indicated that without taking estimation risk into account portfolio selection rules other than the bayes rule can lead investors to select suboptimal portfolios this paper shows by using the single index model for the return generating process that the simple decision rules for optimal portfolio selection derived by elton gruber and padberg 7 are not identical under the bayesian and the traditional methods of analysis 2 moreover in the case where short sales are not

transaction costs and the pricing of assets the existence of transaction costs explains why investors do not fully diversify their portfolios this paper examines the implications of such limited diversification oi equilibrium asset prices in the framework of the capital asset pricing model in the pricing equation obtained here an asset s risk premium depends on a weighted average of its covariance with the market and its own variance the absence of transaction costs in the sharpe lintner capital asset pricing model capm is often claimed to be only a minor idealization which hardly affects the substantive implications of the model this paper aims to demonstrate that this is not the case incorporating transaction costs into the capm leads to a major reformulation of its basic asset pricing equation in contrast with the capm formula

optimal stock trading with personal taxes implications for prices and the abnormal january returns abstract the tax law confers upon the investor a timing option to realize capital losses and defer capital gains with the tax rate on long term gains and losses being about half the short term rate the law provides a second timing option to realize losses short term and gains long term if at all our theory and simulation over the 1962 1977 period establish that taxable investors should realize long term gains in high variance stocks and repurchase stock in order to realize potential future losses short term tax trading does not explain the small firm anomaly but predicts a seasonal pattern in trading volume which maps into a seasonal pattern in stock prices the january anomaly only if investors are irrational or ignorant of the price seasonality

consensus expectations and international equity returns numerous studies of u s markets have shown that stock selection models have been able to isolate securities that earn returns above those predicted by a simple market model models examining the relation between analyst expectations and returns have been particularly useful unexpected earnings changes in analysts earnings per share forecasts the number of analysts revising their forecasts all these measures have been found to be useful in predicting abnormal returns in u s equity markets at least two of these measures changes in analysts eps forecasts and the number of analysts changing their forecasts are also related to abnormal returns in several international markets

technological change and inequality in the very long run abstract in this paper we investigate the impact of technological change on inequality in the presence of a landed elite using a standard unified growth model we measure inequality by the ratio between land rent and wages and show that before the onset of the fertility transition technological progress increased inequality directly through land biased technological change and indirectly through increasing population growth the fertility transition and the child quantity quality trade off eventually disabled the malthusian mechanism and technological progress triggered education and benefited workers if the elasticity of substitution between land and labor is sufficiently high the rent wage ratio declines such that inequality is hump shaped in the very long run we use the publication of new farming book titles as a measure of technological progress in agriculture and provide evidence for technology driven inequality in britain between 1525 and 1895 we confirm these results for a panel of european countries over the period 1265 1850 using agricultural productivity as a measure of technology finally using patents in the period 1800 1980 we find a technology driven inequality reversal around the onset of the fertility transition

future lending income and security value i test the duffie g rleanu and pedersen hypothesis that security prices incorporate expected future securities lending income to determine whether institutional investors anticipate gains from future lending of securities i examine their trading behavior around loan fee increases the evidence suggests that institutions buy shares in response to an increase in lending fees and that this could explain the premium associated with high lending fee stocks expected future lending income affects stock prices although the effect seems to be attenuated by the negative information that arises from short selling

multidimensional welfare distributions empirical application to household panel data from vietnam this article explores the empirical application of theoretical multidimensional welfare distribution analysis techniques to real household welfare distributions the article operationalizes recent conceptual developments in multidimensional distribution theory and assesses their usefulness for the measurement of multidimensional household inequality the results strongly highlight the importance of bringing nonmonetary aspects of household welfare into the forefront of inequality analysis agreement over the various approaches to the measurement of multidimensional inequality entails however nontrivial decisions that may limit the practical usefulness of these measures we suggest that the use of multidimensional inequality ranges and the application of restrictive dominance criteria to multidimensional welfare distributions may open significant scope for further developments in the empirical analysis of multidimensional inequality

on the optimal selection of portfolios under limited diversification abstract we address the problem of selecting portfolios which maximize the ratio of the average excess return to the standard deviation among all those portfolios which comprise at most a pre specified number k of securities under the assumptions of constant pairwise correlations and no short selling we argue that the simple ranking procedure of elton gruber and padberg effectively solves the problem for all values of k and that as a function of k the optimal ratio increases at a decreasing rate we also clarify why further generalization or extension of our results to other situations is improbable

labour market discrimination on the basis of health an application to uk data an analysis of wage discrimination is carried out on the basis of health on uk data with a number of important modifications first selection is controlled for into both health and labour market status second the direct effect of health upon productivity is accounted for and third discrimination is examined with regard to participation as well as wages the question of selection into health status is found to be of little empirical importance but taking account of selection into labour market status and the direct impact of health upon productivity leads to a fall in measured discrimination the paper finds similar results with regard to participation it is also examined whether these effects differ across age and gender

short interest explanations and tests cross sectional and time series tests are performed to explain levels and changes in short interest explanatory variables and tests are chosen based on tax arbitrage and speculative reasons for going short short interest is found to follow a seasonal pattern that is weakly consistent with tax based trading stocks with high betas and the existence of convertible securities or options tend to have higher levels of short interest which is con sistent with arbitrage efforts for firms with traded options there is a positive association between the month to month changes in option open interest and short interest prior months returns and changes in short interest are positively related but there is no rela tionship between changes in short interest and returns in the subsequent month

the informational effects of restrictions on short sales some empirical evidence in a world of heterogeneous investors a competitive financial market has two major functions first it is the mechanism by which ownership of the existing supply of risky assets is distributed among investors this is the role which is analyzed in detail by the standard capital asset pricing model capm and its many extensions the second important market function is to aggregate the diverse information held by different investors into a single price most versions of the capm eliminate the information aggregation function by assuming that investors hold homogeneous beliefs with respect to the probability distribution of asset returns exceptions which deal with some aspects of the problem are lintner 7 grossman 4 grossman and stiglitz 5 and figlewski 1 3

short sale restrictions implications for stock index arbitrage abstract this paper offers a study of relevant transaction costs when examining the efficiency of stock index futures markets we suggest that a different transaction cost estimate should be used when testing the upper side of the cost of carry model than when testing the lower side of the model empirical evidence indicates that this explains most of the underpricing observed in the finnish stock index futures market

short selling and exchange traded funds returns evidence from the london stock exchange abstractan exchange traded fund etf is a security that tracks a basket of stocks an etf investor gains immediate exposure to the basket by taking either a long or short position on this instrument both hedgers and speculators can short etfs making the informational content of increases in etf short interest difficult to interpret using high frequency daily short interest data for etfs traded on the london stock exchange between june 2006 and april 2010 we examine the price impact on etfs of increases in short interest contrary to most of the previous empirical evidence for individual stocks we find that large increases in etf short interest are associated with subsequent over performance relative to a benchmark index and this pattern is most pronounced during pre financial crisis period

how variation in signal quality affects performance the information coefficient ic the correlation between forecasted and realized return is a popular measure of signal quality as shown in this article variation in ic is an important source of active risk and ic variation has an effect on optimal portfolio structure contrary to popular belief the ability to take short positions in equity portfolios does not necessarily lead to superior performance managers who can maintain a stable ic over time will benefit from short extensions but managers who have an unstable ic may see their performance deteriorate from increased short positions

the determinants of subsistence income in a malthusian world abstract this study constructs a simple two sector malthusian model with agriculture and industry and uses it to identify the determinants of income in a malthusian equilibrium we make standard assumptions about preferences and technologies but in contrast to existing studies we assume that children and other consumption goods are gross substitutes consistent with the conventional malthusian model the present theory shows that productivity growth in agriculture has no effect on equilibrium income more importantly we also show that equilibrium income varies not just with the death rate as has recently been demonstrated in the literature but also with the level of productivity in the industrial sector an empirical analysis using data for pre industrial england lends support to both hypotheses

dynamics and stagnation in the malthusian epoch this paper examines the central hypothesis of the influential malthusian theory according to which improvements in the technological environment during the pre industrial era had generated only temporary gains in income per capita eventually leading to a larger but not significantly richer population exploiting exogenous sources of cross country variations in land productivity and the level of technological advancement the analysis demonstrates that in accordance with the theory technological superiority and higher land productivity had significant positive effects on population density but insignificant effects on the standard of living during the time period 1 1500 ce

on the optimality of long short strategies we consider the optimality of portfolios not subject to short selling constraints and derive conditions that a universe of securities must satisfy for an optimal active portfolio to be dollar neutr

a note on simple criteria for optimal portfolio selection using sharpe s 7 single index model elton gruber and padberg egp 4 5 have established some simple ranking criteria for optimal portfolio selection a further extension has been made by chen and brown 2 and alexander and resnick 1 to incorporate the risk associated with the estimation of input parameters this note explores the economic rationale underlying the portfolio formation process based on the single index model in so doing we seek to enhance the intuitive appeal of the simplified portfolio criteria developed in the above studies to practitioners to this end we restate the egp solution with short sales allowed as

20 myths about long short popular conceptions of long short investing are distorted by a number of myths many of which appear to result from viewing long short from a conventional investment perspective long short portfolios differ fundamentally from long only portfolios in construction in the measurement of their risk and return and in their implementation costs furthermore long short portfolios allow greater flexibility in security selection asset allocation and overall plan structure

the three horsemen of riches plague war and urbanization in early modern europe how did europe escape the iron law of wages we construct a simple malthusian model with two sectors and multiple steady states and use it to explain why european per capita incomes and urbanization rates increased during the period 1350 1700 productivity growth can only explain a small fraction of the rise in output per capita population dynamics changes of the birth and death schedules were far more important determinants of steady states we show how a major shock to population can trigger a transition to a new steady state with higher per capita income the black death was such a shock raising wages substantially because of engel s law demand for urban products increased and urban centers grew in size european cities were unhealthy and rising urbanization pushed up aggregate death rates this effect was reinforced by diseases spread through war financed by higher tax revenues in addition rising trade also spread diseases in this way higher wages themselves reduced population pressure we show in a calibration exercise that our model can account for the sustained rise in european urbanization as well as permanently higher per capita incomes in 1700 without technological change wars contributed importantly to the rise of europe even if they had negative short run effects we thus trace europe s precocious rise to economic riches to interactions of the plague shock with the belligerent political environment and the nature of cities

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

long term determinants of the demographic transition 1870 2000 abstract this paper analyzes the long term economic determinants of the demographic transition using a large panel of countries since 1870 a simple theoretical framework accounts for the possibly nonmonotonic variations of fertility in the course of economic development as predicted by unified growth theory i find that primary schooling rather than income or health related variables is the most robust determinant of the fertility transition as regards the health transition both education and income are significant determinants of mortality rates but education alone accounts for the bulk of their time variation over the twentieth century thus education can be viewed as the main long term determinant of the demographic transition

individual analyst characteristics and forecast error the purpose of the study reported here was to investigate how characteristics of analysts affect their forecast errors previous research has found positive serial correlation in forecast errors which can be attributed to underreaction to new information especially to bad news the relationship between an analyst s behavior and that analyst s characteristics is not clear however because most previous work was based solely on consensus estimates by using detailed historical data i found a stronger serial correlation among the herd to consensus analysts that is the group with a small average distance between their forecasts and the consensus forecast than among other analysts moreover average distance to consensus itself has a positive serial correlation and it may be attributed to an analyst s personality optimistic or pessimistic i found strong positive serial correlation in the average distance to consensus among the herd to consensus analysts these results show that herd to consensus ana

portfolio constraints and the fundamental law of active management active portfolio management is typically conducted within constraints that do not allow managers to fully exploit their ability to forecast returns constraints on short positions and turnover for example are fairly common and materially restrictive other constraints such as market capitalization and value growth neutrality with respect to the benchmark or economic sector constraints can further restrict an active portfolio s composition we derive ex ante and ex post correlation relationships that facilitate the performance analysis of constrained portfolios the ex ante relationship is a generalized version of a previously developed fundamental law of active management and provides an important strategic perspective on the potential for active management to add value the ex post correlation relationship represents a practical decomposition of performance into the success of the return prediction process and the noise associated with portfolio constraints we verify the accuracy of these relati

short selling and common stock prices an analysis of overall market data and of individual companies traded on the nyse amex and otc markets indicates a positive but statistically insignificant relation between changes in short position and stock prices even after accounting for market movements and risk short sellers on average do not earn abnormal returns furthermore the relation between short selling and stock price does not seem to be materially affected by whether the stock is traded on the nyse or amex or over the counter the results provide strong evidence refuting the popular notion that short sellers earn abnormal profits at the expense of less informed traders short sellers do not appear to drive prices down through their short sales in fact if anything short sellers provide market liquidity by shorting into up markets and reducing short positions in down markets

disability in italian households income poverty and labour market participation this article studies the economic effects of disabled members on italian households with the aim of identifying a suitable target group for welfare policies survey of households income and wealth data for the year 2000 is used preliminary results show significant differences in levels of income and poverty diffusion to the detriment of households with disabled members we propose an exogenous explanation the replacement ratio between disability benefits and expected labour income shows that disability benefits do not compensate the potential incomes of the disabled person and of the possible carer except in households with severe socioeconomic disadvantages we also propose an endogenous explanation applying a logit model we show that the labour market participation of the possible carer is reduced in households with disabled persons in order to increase the income of the households with disabled members policy recommendations include the provision of care services and structural policies to impro

information quality and options microstructure researchers have long understood that information quality has an effect on price formation in the underlying asset market however option researchers have largely ignored the fact that information quality might also impact the options market this article characterizes the nature of the impact by showing how option prices and implied volatility levels are related to the forward looking information quality path this result follows from a noisy rational expectations model that abandons the normal distribution in favor of the gamma distribution but maintains the standard assumption of exponential utility thus the new model bridges the gap between the microstructure literature that relies so heavily on the normal exponential framework and the options literature that relies exclusively on models that are consistent with the limited liability of stock prices the model s tractability allows for a robustness check against the standard framework and provides a viable setting for analyzing the empirical implications of information quality for the options market jel d8 gl

performance attribution and the fundamental law the reported study operationalized the fundamental law of active management in the context of a factor based performance attribution system the system incorporates factor payoffs in the linear regression framework that many portfolio managers and external reviewers use to judge what is being rewarded in the market the study indicates that parameters of the fundamental law can be used to approximate and interpret the results of the regression based performance attribution system the procedure is illustrated by the use of security holdings returns and factor exposure data for two portfolios benchmarked to the s p 500 index for april 1995 to march 2004

a note on market neutral portfolio selection abstract long short equity strategies allow investors to benefit potentially from both undervalued and overvalued securities the present study develops a normative portfolio model under the practical conditions that a market neutral strategy entails the offsetting long and short equity holdings are established jointly and without any constraints by the underlying market index while accurately capturing institutional procedures for short selling the model contains the analytical and economic properties as required for a ranking approach to filter out any undesirable securities under consideration in view of its practical features the analysis should be of interest to practitioners for assisting their long short investment decisions

options short sales and market completeness this paper presents empirical evidence that trading in options contributes to both transactional and informational efficiency of the stock market by reducing the effect of constraints on short sales the significantly higher average level of short interest exhibited by optionable stocks supports the argument that options facilitate short selling we also find significant effects on option prices related to the short interest in the underlying stock we then present evidence that options also increase information efficiency earlier work that is replicated and extended here has suggested that short sale constraints cause stock prices to underweight negative information options appear to reduce that effect

the demand for food and calories we investigate nutrition and expenditure in rural maharashtra in india we estimate that the elasticity of calorie consumption with respect to total expenditure is 0 3 0 5 a range that is in accord with conventional wisdom the elasticity declines only slowly with levels of living and is far from the value of zero suggested by a recent revisionist literature in these indian data the calories necessary for a day s activity cost less than 5 percent of the daily wage which makes it implausible that income is constrained by nutrition rather than the other way around

how relevant is malthus for economic development today the malthusian model of population and economic growth has two key components first there is a positive effect of the standard of living on the growth rate of population resulting either from a purely biological effect of consumption on birth and death rates or a behavioral response on the part of potential parents to their economic circumstances second because of the existence of some fixed resource such as land there is a negative feedback from the size of population to the standard of living these two components generate a number of predictions specifically in the absence of technological change or expansion in the stock of the fixed resource population will be stable around a constant level second without changes in the function generating population growth technological improvements or increases in the stock of resources will eventually result in more people but not a higher standard of living as a description of population income interactions the malthusian model had a long period of success covering most of human history in most of the world until the beginning of the industrial revolution in this paper we ask whether the model has any relevance to the world today for the first part of the model the positive causality running from income to population growth the answer is clearly no for reasons that have not fully been determined countries that get richer now see falling rather than rising rates of population growth regarding the second part of the model whether higher population lowers the standard of living some further clarification is required before we can even pursue this issue first it important to differentiate among the different channels through which population affects economic outcomes we will characterize as non malthusian those channels that work through the growth rate or demographic structure of the population these include the effect of population growth in diluting capital per worker the effect of the population age structure itself a function of fertility on the ratio of working age adults to dependents the association of lower fertility with higher human capital investment via a quality quantity mechanism and the effect of lower fertility in freeing up female labor for output production we reserve the term malthusian for channels having to do with the size of the population such as the congestion of fixed resources this channel was the one malthus thought about and it is also the only one that pins down the level of population in steady state which matches historical experience thus in our typology it is perfectly possible for reductions in population growth to raise income per capita even though the malthusian channel is irrelevant a second issue to be clarified is at what geographic scale we are looking it is possible that in a world with trade a high level of population in a single country will not lower that country s income relative to others but that a world with more people will be worse off because of congestion of productive resources or the environment we do not pursue that possibility here instead we ask whether there are countries or subnational regions in the world where the local version of malthusianism hold true the likeliest place to look for malthusian effects is among poor countries for several reasons first poor countries have had and are continuing to have the largest increases in population the population of africa is expected to multiply by a factor of 9 8 between 1950 and 2050 in india during the century of most rapid population growth 1920 2020 population is expected to multiply by a factor of 5 5 by contrast in europe over the period 1800 1900 roughly the century of fastest population growth population increased by a factor of 2 2 if the initial population in these regions represented some equilibrium in the relation between population and resources given available technology the more rapid population growth is more likely to result in a disequilibrium in this relationship second poor countries are least able to use trade as a means of avoiding resource constraints finally as discussed further below poor countries empirically have much higher shares of natural resource rents in national income than do rich countries the idea that poor countries might suffer negative economic effects from overpopulation has a long pedigree however in recent decades the malthusian perspective has fallen out of favor among development economists who have stressed the substitutability of technology capital and labor for fixed factors as well as the productive benefits of density per se or of the technological and institutional changes induced by population pressure see allen c kelley 2001 we take as an operative test of the malthusian channel the answer to the question if a country had fewer people but was otherwise unchanged in terms institutions human and physical capital per capita productivity terms of trade etc would it be significantly better off in per capita terms

portfolio analysis using single index multi index and constant correlation models a unified treatment in this study a simple common algorithm which is applicable to seven models is proposed for optimal portfolio selection disallowing short sales of risky securities the models considered in the analysis consist of a single index model four multi index models and two constant correlation models unlike the previous approach the proposed algorithm does not require explicit ranking of securities therefore it is particularly useful for two multi index models with orthogonal indices which do not provide any ranking criterion also because of its algorithmic efficiency as demonstrated in a simulation study on models with multiple groups the approach here can enhance their usefulness in portfolio analysis in a series of publications elton and gruber 2 and elton gruber and padberg hereafter egp 3 8 have considered extensively portfolio optimization problems using a variety of index models and constant correlation models these models are sharpe s 12 single index model cohen and pogue s 1 multi index model in the diagonal form a multi index model with orthogonal indices 8 a constant correlation model with a single group 3 and a constant correlation model with multiple groups 7 hereafter sim mim di mim or ccm s and ccm m respectively using these models egp have developed some ranking procedures to reach optimal portfolios disallowing short sales of risky securities all securities in each group are ranked according to their performance as measured by a ratio of excess return to risk they are sequentially added to feasible portfolios following the ranking hierarchy until the optimal portfolio is reached for models where explicit ranking criteria can be established the egp approach is easy to implement and it clearly explains why a security belongs or does not belong to a portfolio besides the above models it is also applicable to cohen and pogue s 1 multi index model in the covariance form hereafter mim co however it does not work well for models lacking appropriate criteria to rank securities in order to overcome ranking difficulties in mim or egp 8 have introduced a market portfolio with zero residual risk to establish an alternative ranking criterion unfortunately as egp have indicated this causes internal inconsistency in the analysis in the present study a simple algorithm for optimal portfolio selection disal

the micro evidence for the malthusian system france 1670 1840 abstract i test the assumptions of the malthusian model at the individual cross sectional level for france 1650 1820 using husband s occupation from the parish records of 41 french rural villages i assign three different measures of status there is no evidence for the existence of the positive check infant deaths are unrelated to status however the preventive check operates strongly acting through female age at first marriage the wives of rich men are younger brides than those of poorer men this drives a positive net fertility gradient in living standards however the strength of this gradient is substantially weaker than it is in pre industrial england

short sales restrictions and kinks on the mean variance frontier with a short sales restriction there may be switching points along the mean variance frontier corresponding to changes in the set of assets held traditional wisdom holds that each switching point corresponds to a kink while ross has claimed that kinks never occur this paper shows that the truth lies between the two views since the efficient frontier may or may not be kinked at a switching point there is some indication that kinks are rare since a kink corresponds to a portfolio in which all assets have the same expected return

malthus to solow a unified growth theory is developed that accounts for the roughly constant living standards displayed by world economies prior to 1800 as well as the growing living standards exhibited by modern industrial economies our theory also explains the industrial revolution which is the transition from an era when per capita incomes are stagnant to one with sustained growth the authors use a standard growth model with several technologies the first denoted the malthus technology requires land labor and reproducible capital as inputs the second denoted the solow technology does not require land the authors show that in the early stages of development only the malthus technology is used and due to population growth living standards are stagnant despite technological progress eventually technological progress causes the solow technology to become profitable and both technologies are employed at this point living standards improve since population growth has less influence on per capita income growth in the limit the economy behaves like a standard solow growth model excerpt

on back testing zero investment strategies zero investment strategies typically involve forming a long portfolio in one set of securities and a short portfolio in another with the two identified by the use of some trading rule when back testing such strategies the ex post difference in their abnormal returns represents an unbiased estimate of their economic profitability in perfect markets and thus serves as an indication of market efficiency however regulation t s short selling constraints are a potentially significant imperfection facing retail and institutional investors after development of a procedure that recognizes these constraints in measuring returns the impact of these constraints on economic profitability is analyzed copyright 2000 by university of chicago press