portfolio resampling review and critique a well understood fact of asset allocation is that the traditional portfolio optimization algorithm is too powerful for the quality of the inputs recently a new concept called resampled efficiency has been introduced into the asset management world to deal with estimation error the objective of this article is to describe this new technology put it into the context of established procedures and point to some peculiarities of the approach even though portfolio resampling is a thoughtful heuristic some features make it difficult to interpret by the inexperienced portfolio resampling review and critique a comment

the impact of skewness and fat tails on the asset allocation decision the authors modeled the non normal returns of multiple asset classes by using a multivariate truncated levy flight distribution and incorporating non normal returns into the mean conditional value at risk m cvar optimization framework in a series of controlled optimizations they found that both skewness and kurtosis affect the m cvar optimization and lead to substantially different allocations than do the traditional mean variance optimizations they also found that the m cvar optimization would have been beneficial during the 2008 financial crisis

year end tax induced sales and stock market seasonality the paper relates two phenomena in the stock market the high return during the month of january and the apparent existence of widespread sales of stocks for tax purposes towards the end of the fiscal year the findings suggest that due to the taxinduced sales the price of many stocks over the last 35 years was temporarily depressed in december but recovered in the following january this price recovery is a major contributor to the high returns observed in january the tax effect is present in firms of all sizes but much more pronounced for small firms the analysis also indicates that a more precise identification of the tax switch candidates may prove that the taxinduced sales are in fact the sole contributor to the high january s returns the issue of seasonality in the stock market has attracted the attention of researchers for some time rozeff and kinney 13 present evidence of seasonality in the market index with the months of january and july having a peak return the seasonal movements in the average return in the market could not be fully accounted for by a corresponding seasonal pattern in the market risk they offer three explanations to this phenomenon tax induced sales release of accounting information and seasonal demand for cash the first explanation has received some support from recent research dyl 4 studied the effects of capital gain taxes on trading volumes of common stocks and concluded that capital gain taxes affect investors year end portfolio decisions and that this effect is in turn reflected in the trading volumes of common stocks in december p 174 mcenally 10 and branch 2 studied the effects of the tax induced trading on securities return and found that depressed stocks at the end of the year are likely to bounce back immediately after year end the existence of a pronounced seasonal behavior in the market might suggest some form of market inefficiency a strategy under which stocks are bought towards the end of the year and sold at the beginning of the following year might yield an abnormal return despite the seasonal behavior of stock returns it would be indeed surprising if this regularity which has not gone unnoticed by the financial community could be exploited to bring a risk adjusted excess return the objective of this paper is to examine jointly the two phenomena tax

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

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

the turn of the year in canada a number of investigators have reported that january stock returns in the u s exceed returns for other months of the year this paper documents a similar finding for canadian stocks over the period 1951 1980 however canada did not introduce a capital gains tax until 1973 and the paper reports that january returns in canada exceed returns for other months of the year before and after this date thus these data do not support the tax loss selling pressure hypothesis as the entire explanation for the turnof the year effect in stock returns nor by implication do they support the tax lossselling pressure hypothesis as the complete explanation for the small firm effect in u s stocks returns recently keim 9 has reported that returns on nyse and ase firms with small market values exceed by significant margins returns on firms with large market values this result was previously reported by banz 1 and reinganum 11 but keim s analysis shows that most of the excess return for small firms is concentrated in january indeed it is concentrated in the first two weeks in january roll 13 also documents this phenomenon and investigates a number of possible explanations for it 2 after rejecting several possible nonexploitable explanations roll is left with year end tax loss selling pressure of the sort discussed by branch 2 dyl 5 and givoly and ovadia 6 as the most likely explanation of this result according to the tax loss selling pressure hypothesis toward the end of the year stockholders sell stocks that have declined in price during the year investors do this to take advantage of the opportunity to write off capital losses against ordinary income in computing their federal income taxes the year end sell off exerts downward pressure on stock prices as soon as the tax and calendar year ends the selling pressure is relieved and stock prices quickly rebound to their equilibrium levels roll 13 presents some evidence consistent with this hypothesis specifically he finds a negative correlation between stock returns in january and returns over the previous 12 months that is stocks that decrease in value during the year tend to be big gainers in january roll also finds that

a direct test of roll s conjecture on the firm size effect empirical research indicates that small firms earn higher average rates of return than large firms even after accounting for beta risk roll conjectured that the small firm effect might be attributed to improper estimation of security betas the evidence shows that while the direction of the bias in beta estimation is consistent with roll s conjecture the magnitude of the bias appears to be too small to explain the firm size effect

the japanese equity market past and present this paper discusses matters of economic interest related to the japanese equity market among other things it emphasizes the futures market in shares of the companies that managed the stock exchanges as an important element of the pre wwii market the stock market crisis of 1965 as an event that conditioned the subsequent course of public policy and institutional developments the zaraba continuous auction method as the microstructure of the exchanges and the uneven distribution of stock ownership and trading the poor performance of investment trusts and the high degree of concentration in the securities industry as the key contemporary features

an empirical investigation of international asset pricing we investigate several asset pricing models in an international setting we use data on a large number of assets traded in the united states japan the united kingdom and france the models together with the hypothesis of capital market integration imply testable restrictions on multivariate regressions relating asset returns to various benchmark portfolios we find that multifactor models tend to outperform single index models in both domestic and international forms especially in their ability to explain seasonality in asset returns we also find that the behavior of the models is affected by changes in the regulatory environment in international markets

seasonal fluctuations in industrial production and stock market seasonals february and august peaks in the growth rates of the seasonally unadjusted industrial production index follow the stock market peaks documented by rozeff and kinney 1976 by one month coefficients on one month lead growth rates in industrial production for small firms are positive and significant in time series regressions even in the presence of the market factor moreover whereas returns on large firms stocks unidirectionally gran ger cause i e predict future growth rates in industrial production at least six months in advance returns on small firms stocks reflect one month lead as well as past growth rates in industrial production for these reasons we argue that seasonal real growth provides a partial explanation for the january stock seasonal among small firms

misspecification of capital asset pricing this study documents empirical anomalies which suggest that either the simple one period capital asset pricing model capm is misspecified or that capital markets are inefficient in particular portfolios based on firm size or earnings price e p ratios experience average returns systematically different from those predicted by the capm furthermore the abnormal returns persist for at least two years this persistence reduces the likelihood that these results are being generated by a market inefficiency rather the evidence seems to indicate that the equilibrium pricing model is misspecified however the data also reveals that an e p effect does not emerge after returns are controlled for the firm size effect the firm size effect largely subsumes the e p effect thus while the e p anomaly and value anomaly exist when each variable is considered separately the two anomalies seem to be related to the same set of missing factors and these factors appear to be more closely associated with firm size than e p ratios

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

japan s shift from process to product patents in the pharmaceutical industry an event study of the impact on japanese firms in 1975 japan expanded the scope of its patent law by introducing product patents for newly developed chemical and pharmaceutical products we use rate of return data from the tokyo stock exchange for japanese pharmaceutical companies to examine the impact of the change in the patent law our empirical findings indicate that the passage of the new patent law induced an excess return of approximately 26 percent to a portfolio of large pharmaceutical companies companies with r d programs specializing in new product development experienced large gains while companies with r d programs specializing in imitative process patents experienced no gains

in defense of portfolio optimization what if we can forecast author response we thank richard o michaud david n esch and robert o michaud for their interest in our paper in their letter they suggest that our results are inconsistent with the canonical literature beca

weekly patterns in japanese stock returns this study investigates the day of the week effect in the japanese stock returns low tuesday and high wednesday returns are observed most of the positive returns arise during the nontrading period the monday effect is also observed in the week whose previous week is closed by friday trading low tuesday returns appear to be related to low monday returns in the u s the weekly pattern is more pronounced for the returns of smaller firms a reverse size effect is observed during the trading period

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

some empirical tests of the theory of arbitrage pricing we estimate the parameters of ross s arbitrage pricing theory apt using daily return data during the 1963 78 period we compare the evidence on the apt and the capital asset pricing model capm as implemented by market indices and find that the apt performs well the theory is further supported in that estimated expected returns depend on estimated factor loadings and variables such as own variance and firm size do not contribute additional explanatory power to that of the factor loadings

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

event study methodologies and the size effect abstract this study of 862 press recommendations demonstrates that the size effect can distort longer term performance measures and hence event studies relative to similar sized companies post publication performance is neutral however market adjustments the capm and market model with equally or capitalization weighted indexes all produce biased results event studies are most exposed to such bias when the measurement interval is long event securities differ systematically in size or weighting from the index constituents the size effect is large and or volatile and when capm type methodologies are used these distortions are avoided by explicitly controlling for size

portfolio analysis with a large universe of assets covariance matrix optimization algorithms are applied to a large number of assets a previous paper by burgess and bey 1988 suggests that attempting to optimize a large number of securities with the traditional covariance matrix model is not practical an alternative approach ranks the securities with the reward to volatility reward to beta ratio and then optimizes a smaller subset of securities with the covariance matrix model this study proposes additional screening methods such as stochastic dominance reward to variability r v ratios reward to lower partial moment r lpm ratios and the optimization of subgroups and provides an empirical test of the various screening methodologies the results indicate that the full covariance critical line optimization algorithm is surprisingly robust compared to the other techniques

latin american hydropower a century of uneven evolution abstract latin america is home to a number of the largest countries powered by hydroelectricity in the world today both in absolute and per capita levels this region accounts for over 20 per cent of the world s hydropower and has by far the largest share of hydroelectricity over total electricity generation in the world excluding china latin american hydropower exhibits the fastest growth in the world over the last 30 years despite these records latin america s large hydroelectric potential began to be realised late in comparison to most advanced countries and its advance has been notably uneven across time and space this article provides a succinct survey of the evolution of hydropower for 20 latin american countries over the past century and offers a unique quantitative comparative perspective into the past and present of hydroelectricity in the region we investigate the role played by the different domestic energy endowments in the way hydroelectricity developed across the region we conclude that the gross theoretical hydroelectric potential is a necessary but not sufficient condition for understanding the historical evolution of hydroelectricity in different countries we used panel data analysis to examine the role of alternative sources of energy electric demand and each nation s capacity to supply electricity infrastructure our model explicitly accounts for the effects of different gross theoretical potentials and the effect of time passage overall we report that latin american hydropower followed an uneven path over the 20th century

playing the turn of the year effect with index futures the turn of the year effect is a well documented stock market phenomenon in which low capitalization small stocks receive relatively higher returns than high capitalization big stocks on the last trading day of december and the first 8 trading days of january the difference in returns during this period is of the order of 10 strategies for buying and selling these small stocks may be profitable but may also incur large transaction costs that eliminate most or all of the projected gains in this paper we show a preferable way to invest in order to exploit this anomaly use a futures spread that is long in the small stocks and short in the big stocks the optimal investment which uses a modification of the capital growth criterion is large and has a substantial expected gain with minimal risk we have used this analysis successfully in managing investment accounts

seasonal and size anomalies in the japanese stock market little attention has been paid by the academic community in the united states to the japanese stock market and its structure japan has the second largest economy in the western world and the tokyo stock exchange tse is second only to the new york stock exchange nyse in terms of aggregate market values and sales volume analysis of the japanese stock market is useful given its relative importance but in addition examination of the japanese market may offer insights into controversies surrounding u s markets this study focuses on two such current controversies the january and size anomalies