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

an equilibrium model of asset trading with sequential information arrival in an effort to better understand the dynamic market price adjustment process this paper develops a model which describes the impact of new information on a financial market the primary emphasis is on the price change volume relationship in the presence of a margin requirement we find that the margin requirement significantly affects the relation of price change to volume furthermore this relationship is shown to be affected by the number of investors in the market the degree of information dissemination differences in interpretation of information and the implicit cost of the margin requirement

international portfolio choice and political instability risk a multi objective approach abstract the benefits derived from international portfolio diversification into foreign nations including the less developed countries are well documented yet this practice is discouraged due to market imperfections such as political instability in practice nations may be differentiated further by many aspects such as border controls or political and social trends which constrain private transactions and financial decisions this paper attempts to examine 1 whether the home asset bias in a portfolio holding is associated with higher political instability risk and 2 to what extent international diversification among stocks in the presence of such risk outperforms domestic stock portfolios using alternative instability risk proxies in the context of a discrete time version of mean variance framework we corroborate the impact of this type of risk on international portfolio investment decisions

financial portfolio management through the goal programming model current state of the art abstract since markowitz 1952 formulated the portfolio selection problem many researchers have developed models aggregating simultaneously several conflicting attributes such as the return on investment risk and liquidity the portfolio manager generally seeks the best combination of stocks assets that meets his her investment objectives the goal programming gp model is widely applied to finance and portfolio management the aim of this paper is to present the different variants of the gp model that have been applied to the financial portfolio selection problem from the 1970s to nowadays

a minimax portfolio selection strategy with equilibrium a new minimax model on optimal portfolio selection with uncertainty of both randomness and estimation in inputs is established and the corresponding optimal portfolio is derived analytically based on this result a sufficient condition for the existence and uniqueness of a nonnegative equilibrium price system under which the total demand and supply of each asset are equal is provided and an explicit formula for such a price system is obtained furthermore some properties of the equilibrium are discussed

modeling purchase timing and brand switching behavior incorporating explanatory variables and unobserved heterogeneity the authors use a continuous time semi markov approach to analyze in a single framework the purchase timing and brand switching decisions of households for a frequently purchased product the analysis provides more insights into the dynamics of household purchase behavior than could be obtained from conventional discrete choice models such as logit or probit the authors find that the probability distribution of interpurchase times is not the same for various switching between brands revealing extra information about the purchase timing decisions further they find that though the marketing mix and household demographic variables explain a large part of the variation in the brand switching rates they account for only a small part of the variation in the repeat purchase rates another finding from the analysis is that the rates of switching between brands due to promotional activities such as special displays and price reductions are in reverse order to the share of purchases of the various brands

note extending the rotterdam model to test hierarchical market structures two issues that have implications across a firm s marketing activities are the estimation of the market response functions and the determination of the structure of the market in which its products compete in a recent paper clements and selvanathan clements k w e a selvanathan 1988 the rotterdam demand model and its application to marketing marketing sci 7winter 60 75 describe how the rotterdam demand system can be used to study these two issues in a joint framework in this note we extend their model to test hierarchical market structures using data at the brand form level we also incorporate idiosyncratic response coefficients that capture the effects of advertising and or other nonprice marketing mix variables separate from the effects of a price change these extensions provide additional insights into the nature and extent of competition among brands within a product class

realized volatility transmission the role of jumps and leverage effects this paper is the first to employ a multivariate extension of the lhar cj model for realized volatility of corsi and reno 2012 considering continuous and jump volatility components and leverage effects the model is applied to financial s p 500 commodity wti crude oil and forex us eur intraday futures data and allows new insights in the transmission mechanisms among these markets besides significant leverage effects we find that the jump components of all considered assets do not contain incremental information for the one step ahead realized volatility the volatility of s p 500 and us eur exchange rate futures exhibits significant spillovers to the realized volatility of wti moreover decreasing equity prices appear to increase volatility in other markets while strengthening of the us seems to calm down the crude oil market

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 impact of heterogeneity in purchase timing and price responsiveness on estimates of sticker shock effects the notion that individuals have an internal reference price against which they compare observed prices is well supported by several psychological theories empirically several papers in the marketing literature employing scanner panel data have modeled the impact of reference prices on brand choice via the sticker shock formulation in which consumers evaluate choice alternatives using differences between shelf prices and reference prices most of the studies reported thus far have not accounted for heterogeneity in price response among consumers and have typically imputed reference prices from the shelf prices of brands that a consumer is supposed to have observed on previous purchases in the category since category marketing activity can differentially affect the purchase timing of households we argue that this measure of reference price may follow certain systematic patterns across consumers and when combined with unaccounted for price response heterogeneity may result in a spurious sticker shock effect specifically we show that estimates of sticker shock are biased upward if households that are price sensitive in the brand choice decision are also more responsive to category promotion activity in their purchase timing decision we discuss some general conditions under which the bias occurs and conduct a simulation experiment to confirm our specific hypotheses our simulation results show that changes in purchase timing are a critical determinant of the bias in the sticker shock effect we also show that unaccounted for price response heterogeneity can in itself result in a biased sticker shock parameter however this requires very large differences in price sensitivities across consumers far greater than what is normally observed we develop a hierarchical bayes version of the nested logit model which models heterogeneity via individual level parameters in a continuous random effects framework we estimate the model on scanner panel data from the yogurt and ketchup categories we find in both categories that the 95 probability interval of the posterior distribution of the mean sticker shock coefficient contains the value zero therefore at least for the data used in this study there is no evidence for the sticker shock effect at the aggregate level in contrast the corresponding coefficient from a standard model which ignores this heterogeneity is highly significant and supports the existence of a possibly spurious sticker shock effect consistent with our explanation of the underlying cause of the bias households that are more price sensitive in the choice decision are also found to be more responsive to category promotion activity in their decision to purchase in the category the results highlight the measurement problems associated with imputing reference prices from past prices since the frequency duration and price level of a retailer s promotional program depend on its size and prevalence accurate estimates of the sticker shock effect are essential for formulating optimal promotion strategies an adequate accounting of consumer heterogeneity is critical to this effort

the dynamics of stock index and stock index futures returns in rational efficiently functioning markets the returns on stock index and stock index futures contracts should be perfectly contemporaneously correlated this study investigates the time series properties of 5 minute intraday returns of stock index and stock index futures contracts and finds that sp however the effect is not completely unidirectional with lagged stock index returns having a mild positive predictive impact on futures returns

modeling and explaining the dynamics of european union allowance prices at high frequency in this paper we model the adjustment process of european union allowance eua prices to the releases of announcements at high frequency controlling for intraday periodicity volatility clustering and volatility persistence we find that the high frequency eua price dynamics are very well captured by a fractionally integrated asymmetric power garch process the decisions of the european commission on second national allocation plans have a strong and immediate impact on eua prices on the other hand our results suggest that eua prices are only weakly connected to indicators about the future economic development as well as the current economic activity

portfolio optimization under a minimax rule this paper provides a new portfolio selection rule the objective is to minimize the maximum individual risk and we use an l function as the risk measure we provide an explicit analytical solution for the model and are thus able to plot the entire efficient frontier our selection rule is very conservative one of the features of the solution is that it does not explicitly involve the covariance of the asset returns

inertia and variety seeking in a model of brand purchase timing previous research on state dependence indicates that a brand s purchase probabilities vary over time and depend on the levels of inertia and variety seeking and on the identity of the previously purchased brand brand choice probabilities obtained from models such as the logit and the probit are however fixed over time conditional on the previous brand purchased and on the levels of marketing variables consequently state dependence has largely been studied as a time invariant phenomenon in brand choice models with the levels of inertia and variety seeking assumed to be constant over time to account for the time varying nature of state dependence would require a model in which brand switching probabilities depend upon interpurchase times one modeling framework that can account for this dependence is based on the hazard function approach the proposed approach works as follows all other factors being equal an inertial household purchasing a brand on a particular occasion is most likely to repurchase that brand on the next occasion if the household switches it will be to a brand located perceptually close in attribute space to the previously purchased brand in other words an inertial household has the highest switching hazard for the same origin and destination brands with a progressively lower hazard rate for brands perceptually located farther and farther away from the origin brand the amount by which the hazard is lowered depends upon the perceptual distance and the inertia level of the household on the other hand if the household is variety seeking the most likely brand purchased would be a brand located farthest away from the previously purchased brand in attribute space in other words the hazard rate of repurchase is the lowest with the rate increasing with the distance of the destination brand from the origin brand and the level of that household s variety seeking tendency the effects of inertia and variety seeking are therefore incorporated at the attribute level into a brand purchase timing model in doing so we attempt to provide greater insight into the nature of state dependence in models of purchase timing our model and estimation procedure will enable us to distinguish between households that are inertial and those that are variety prone in addition to accounting for state dependence the model also accounts for the effects of unobserved heterogeneity among households in their brand preferences and in their sensitivities to marketing activities a majority of studies in marketing using the hazard function approach to investigate purchase timing have not accounted for heterogeneity in marketing mix effects the study integrates recent methods that incorporate the effects of inertia and variety seeking in brand choice models with a semi markov model of purchase timing and brand switching the proposed model enables us to 1 infer market structure via a perceptual map for the sample households and 2 investigate implications for the introduction of a line extension we provide empirical applications of the proposed method using three different household level scanner panel data sets we find that differing levels of inertia and variety seeking characterize the three data sets the findings are consistent with prior beliefs regarding these categories in addition our results indicate that the nature of interbrand purchase timing behavior depends upon the extent of inertia or variety seeking in the data we are also able to characterize the structure of the three product markets studied this provides implications for interbrand rivalry in the market further we demonstrate how the model and results can be used to predict the location of a line extension in the perceptual space of households finally we obtain implications for the timing of brand promotions

investigating household purchase timing decisions a conditional hazard function approach the purchase timing decision is an important component of the dynamics of a household s purchase behavior this decision is influenced by marketing and other variables and the modeling of this dependence has recently received attention in the literature in this paper we build on previous studies and develop a comprehensive stochastic model that incorporates the major factors influencing interpurchase times specifically we use a generalized version of cox s proportional hazard model to test among competing probability distributions for the interpurchase times while incorporating effects due to marketing variables observed household characteristics and unobserved heterogeneity across households the empirical finding from analyzing the iri coffee data suggests that the interpurchase times cannot be adequately described by probability distributions such as exponential erlang 2 or weibull the effects of unobserved heterogeneity are significant and they impact the estimates of the effects of the covariates we also find that a nonparametric procedure for estimating the effects of unobserved heterogeneity provides the best overall fit to the data and yields covariate estimates that are more consistent with prior expectations our model is validated by replicating the substantive empirical findings on an additional product category

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

realized volatility transmission between crude oil and equity futures markets a multivariate har approach this paper differs from extant literature because it studies volatility co movements with a multivariate orthogonalized har model a flexible specification for the time series of realized volatility which is able to identify short mid and long term spillover effects we examine volatility transmission mechanisms using high frequency data of the stock index futures on s p 500 nikkei 225 ftse 100 and the futures on the west texas intermediate crude oil during the period from september 2002 to september 2012 considering the full sample the short term volatility of the equity futures contains information about future oil volatility incremental to the information inherent in the time series of oil volatility on the other hand weekly and monthly volatilities do not exhibit a significant spillover effect breaking the whole sample into three subsamples no significant granger causalities are observed in the pre crisis period while in the crisis time and its aftermath we document that the us and uk equity market volatilities to granger cause the oil futures volatility which itself leads the japanese market in terms of magnitude we observe an increase in the short term volatility spillover over time studying the residuals of the har transmission models within a ccc dcc garch framework reveals increasing instantaneous correlation between the energy and equity volatilities in the course of time

intraday trading volume and return volatility of the djia stocks a note abstract we examine the contemporaneous correlation as well as the lead lag relation between trading volume and return volatility in all stocks comprising the dow jones industrial average djia we use 5 minute intraday data and measure return volatility by the exponential generalized autoregressive conditional heteroscedasticity method contrary to the mixture of distribution hypothesis the vast majority of the djia stock shows no contemporaneous correlation between volume and volatility however we find evidence of significant lead lag relations between the two variables in a large number of the djia stocks in accordance with the sequential information arrival hypothesis

testing competitive market structures an accurate understanding of the structure of competition is important in the formulation of many marketing strategies for example in new product launch product reformulation or positioning decisions the strategist wants to know which of his competitors will be most affected and hence most likely to respond many marketing science models have been proposed to identify market structure in this paper we examine the managerial problem and propose a criterion by which to judge an identified market structure basically our criterion is a quantification of the intuitive managerial criterion that a submarket is a useful conceptualization if it identifies which products are most likely to be affected by our marketing strategies we formalize this criterion within the structure of classical hypothesis testing so that a marketing scientist can use statistical statements to evaluate a market structure identified by 1 behavioral hypotheses 2 managerial intuition or 3 market structure identification algorithms mathematically our criterion is based on probabilities of switching to products in the situation where an individual s most preferred product is not available submarkets are said to exist when consumers are statistically more likely to buy again in that submarket than would be predicted based on an aggregate constant ratio model for example product attributes e g brand form size use situations e g coffee in the morning versus coffee at dinner and user characteristics e g heavy versus light users are specified as hypotheses for testing alternate competitive structures measurement and estimation procedures are described and a convergent approach is illustrated an application of the methodology to the coffee market is presented and managerial implications of six other applications are described briefly

modeling purchases as repeated events we put forward a statistical model for interpurchase times that incorporates all current and past information available for all purchases as time runs along the calendar time scale it delivers forecasts for the number of purchases in the next period as well as for the timing of subsequent and consecutive purchases purchase occasions are viewed as a counting process that counts the recurrent purchases for each house hold as they evolve over time we illustrate our model for yogurt purchases and highlight its managerial implications

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

a maxmin policy for bond management a simple immunization problem is formulated as a maxmin optimal control problem and analytically solved by means of dynamic programming the optimal control law namely the immunization policy turns out to be quite different from any duration based immunization policy moreover it is seemingly able to discriminate between favourable and unfavourable changes in the yield curve

investigating consumers purchase incidence and brand choice decisions across multiple product categories a theoretical and empirical analysis we propose a framework to investigate consumers brand choice and purchase incidence decisions across multiple categories where both decisions are modeled as an outcome of a consumer s basket utility maximization we build the model from first principles by theoretically explicating a general model of basket utility maximization and then examining the reasonable restrictions that can be placed to make the solution tractable without sacrificing its flexibility comparing with prior models we show why prior multicategory purchase incidence models overemphasize the role of the cross effects of a market mix of brands in other categories on the purchase incidence decision of a given category additionally we show that prior single category models are a special case of the proposed model when further restrictions are placed on the basket utility structure we estimate the model on household basket data for the laundry family of categories we show i why prior single category and multicategory models would systematically bias the estimates of the own and cross price promotional purchase incidence elasticities and ii how the market mix of each brand in each category affects the purchases across all categories which can help retailers make promotional decisions across a portfolio of products

true and spurious duration dependence the identifiability of the proportional hazard model lancaster and nickell 1980 have argued that in the proportional hazard model the effects of time dependence true duration dependence and unobserved sample heterogeneity spurious duration dependence cannot be distinguished we show that both effects can be distinguished if the model allows for observed explanatory variables in the hazard we also discuss the application of our result to practical situations

intraday volume and volatility relations with and without public news this paper reexamines the dynamic relation between intraday trading volume and return volatility of large and small nyse stocks in two partitioned samples with and without identifiable public news we argue that the sequential information arrival hypothesis siah can be tested only in periods containing public news after partitioning the sample into periods with and without public news we find bi directional granger causality between volume and volatility in the presence of public information as hypothesized by the siah our analysis further suggests that return volatility is higher in the periods with public news while trading volume is significantly higher in the no news period perhaps owing to the importance of private information for trading stocks using the sample without public news we find evidence that volume granger causes volatility without feedback these results are broadly consistent with behavioral models like the overconfidence and biased self attribution model of daniel k hirshleifer d subrahmanyam a 1998 investor psychology and security market under and over reactions journal of finance 53 1839 1885 it appears that overconfident investors overrate the precision of their private news signals and therefore trade too aggressively in the absence of public news when public news arrives investors biased self attribution triggers excessive return volatility

volatility volume causality across single stock spot futures markets in india abstractthis study examines the causal relationships between volatility and volume across spot and futures market for the 50 constituent stocks of the cnx nifty index granger non causality tests implemented using vector autoregression var and asymmetric var models indicate the presence of significant causal relations from both the spot and futures volume to both the spot and futures volatility bidirectional causal relationships between spot and futures volume were observed for almost all stocks but few stocks displayed a similar relationship between volatilities the results highlight the importance of volume in absorbing information and its behaviour as the conduit of information

return on roller coasters a model to guide investments in theme park attractions despite the economic significance of the theme park industry and the huge investments needed to set up new attractions no marketing models exist to guide these investment decisions this study addresses this gap in the literature by estimating a response model for theme park attendance the model not only determines the contribution of each attraction to attendance but also how this contribution is distributed within and across years the model accommodates saturation effects which imply that the impact of a new attraction is smaller if similar attractions are already present it also captures reinforcement effects meaning that a new attraction may reinforce the drawing power of similar extant attractions especially when these were introduced recently the model is calibrated on 25 years of weekly attendance data from the efteling a leading european theme park our return on investment calculations show that it is more profitable to invest in multiple smaller attractions than in one big one this finding is in remarkable contrast with the current arms race in the industry furthermore even though thrill rides tend to be more effective than theme rides there are conditions under which one should consider to switch to the latter

predicting future random events based on past performance there are many situations where one is interested in predicting the expected number of events in period 2 given that x events occurred in period 1 for example insurance companies must decide whether or not to cancel the insurance of drivers who had 3 or more accidents during the previous year in analyzing marketing research data an analyst may wish to predict the number of future purchases to be made by those customers who made x purchases in the previous 3 months the owner of a baseball team may wish to estimate the number of home runs a batter will hit this year given he hit say 40 home runs last year when the events e g accidents purchase occasions home runs can be assumed to occur randomly over time a very general result due to robbins robbins h 1977 prediction and estimation for the compound poisson distribution proc national acad sci usa74 2670 2671 is available this approach has certain advantages and disadvantages with respect to the negative binomial model that is commonly used to analyze purchasing and accident data the robbins result is particularly appropriate for predicting what the zero class in period 1 will do in period 2 the main purpose of this paper is to present the robbins result in a form that can be readily understood by applied researchers in a variety of disciplines data on consumer purchases motor vehicle violations and accidents are analyzed and applications to other areas are discussed

customer lifetime value measurement the measurement of customer lifetime value is important because it is used as a metric in evaluating decisions in the context of customer relationship management for a firm it is important to form some expectations as to the lifetime value of each customer at the time a customer starts doing business with the firm and at each purchase by the customer in this paper we use a hierarchical bayes approach to estimate the lifetime value of each customer at each purchase occasion by jointly modeling the purchase timing purchase amount and risk of defection from the firm for each customer the data come from a membership based direct marketing company where the times of each customer joining the membership and terminating it are known once these events happen in addition there is an uncertain relationship between customer lifetime and purchase behavior therefore longer customer lifetime does not necessarily imply higher customer lifetime value we compare the performance of our model with other models on a separate validation data set the models compared are the extended nbd pareto model the recency frequency and monetary value model two models nested in our proposed model and a heuristic model that takes the average customer lifetime the average interpurchase time and the average dollar purchase amount observed in our estimation sample and uses them to predict the present value of future customer revenues at each purchase occasion in our hold out sample the results show that our model performs better than all the other models compared both at predicting customer lifetime value and in targeting valuable customers the results also show that longer interpurchase times are associated with larger purchase amounts and a greater risk of leaving the firm both male and female customers seem to have similar interpurchase time intervals and risk of leaving however female customers spend less compared with male customers

growing growing gone cascades diffusion and turning points in the product life cycle research on the product life cycle plc has focused primarily on the role of diffusion this study takes a broader theoretical perspective on the plc by incorporating informational cascades and developing and testing many new hypotheses based on this theory on average across 30 product categories the authors find that i new consumer durables have a typical pattern of rapid growth of 45 per year over 8 years ii this period of growth is followed by a slowdown when sales decline by 15 and stay below those of the previous peak for 5 years iii slowdown occurs at 34 population penetration and about 50 of ultimate market penetration iv products with large sales increases at takeoff tend to have larger sales declines at slowdown v leisure enhancing products tend to have higher growth rates and shorter growth stages than nonleisure enhancing products time saving products tend to have lower growth rates and longer growth stages than nontime saving products vi lower probability of slowdown is associated with steeper price reductions lower penetration and higher economic growth vii a hazard model can provide reasonable predictions of the slowdown as early as the takeoff the authors discuss the implications of these findings

an empirical investigation of returns to search using data on search and choice behavior from a local automobile market we estimate monetary returns to search in terms of lower prices resulting from additional time invested in price search for our analytical framework we adapt a model developed in the job search literature to the problem of consumer search this framework is especially useful for illuminating the relationship between time spent searching the outcome of search and demand and supply side variables our results indicate that for this particular sample of buyers marginal returns to search are broadly consistent with what one might expect if consumers balance costs and benefits of search and that potential gains from additional search for lower car prices do not appear to be large for most consumers our study highlights many of the methodological difficulties involved in estimating returns to search including isolating returns to different outcomes of search and sensitivity of results to model specification and sampling error we deal with these problems by trying to isolate time spent searching for price from other uses of search time by deriving our model used in estimation from a specific conceptual framework and by extensive specification testing

futures trading with information asymmetry and otc predominance another look at the volume volatility relations in the european carbon markets this paper constitutes the first exercise of analysing the european carbon market efficiency from a double perspective combining both nature of execution venues screen vs otc trading and their volatility liquidity relations using a bivariate asymmetric gjr garch model we first document that otc exchange traded trading volume shows consistent bi uni directional granger causality to our volatility estimates consistent with greater responsiveness of the otc exchange traded market to changes in market wide idiosyncratic risks second we report significant contemporaneous and lagged positive causality of otc derivatives volume on spot futures volatility confirming that the sequential information arrival hypothesis siah applies third we find that the one way causality from otc to futures volumes is mainly driven by heterogeneous investor beliefs trading volume provides an indication on how private information is dispersed and held at different levels rather than proxying information signal itself after rejecting execution venues substitutability we advocate for systematic clearing and netting of otc positions through a unique clearing house and reporting rules to identify speculation in line with mifid art 59 proposals

portfolio selection and skewness evidence from international stock markets abstract this paper finds that the returns of the world s 14 major stock markets are not normally distributed and that the correlation matrix of these stock markets was stable during the january 1988 december 1993 time period polynomial goal programming in which investor preferences for skewness can be incorporated is utilized to determine the optimal portfolio consisting of the choices of 14 international stock indexes the empirical findings suggest that the incorporation of skewness into an investor s portfolio decision causes a major change in the construction of the optimal portfolio the evidence also indicate that investors trade expected return of the portfolio for skewness

estimation risk in portfolio selection the mean variance model versus the mean absolute deviation model konno and yamazaki konno h k yamazaki 1992 mean absolute deviation portfolio optimization model and its applications to tokyo stock market management sci 39 519 531 propose the mean absolute deviation mad model as an alternative to the mean variance mv model they claim it retains all the positive features of the mv model saves the investor computing time and does not require the covariance matrix this paper shows that ignoring the covariance matrix results in greater estimation risk that outweighs the benefits in both models estimation error is more severe in small samples small observations relative to the number of assets and for investors with high risk tolerance the mv model s lower estimation risk is most striking in small samples and for investors with a low risk tolerance

theoretical models of sales promotions contributions limitations and a future research agenda our objective in this paper is to review theoretical models of sales promotions we highlight the key contributions of these models discuss their limitations and outline an agenda for future research managerial questions examined in these models include some very fundamental issues such as why firms resort to the use of sales promotions in mature markets and why the use of sales promotions has increased dramatically during the last two decades also included in this review are models that address firm level strategic issues such as the allocation of dollars between advertising and sales promotions and the relative emphasis on trade promotions vis a vis consumer promotions we also review theoretical models that explain how consumers respond to price promotions and what type of sales promotion tools may be superior to others in a particular market the review concludes with a possible agenda for future research

a segment level hazard approach to studying household purchase timing decisions the increasing availability of customer level data and the willingness of marketers to customize the timing of their offers to consumers makes the accurate segment level description of household purchase timing decisions a compelling issue in this paper we employ a finite mixture accelerated failure time model to identify and characterize household segments in terms of their purchasing rates and their propensity to accelerate purchases due to marketing mix activities such an approach also promises to alleviate possible aggregation problems arising from the use of a common hazard rate for all households an application to household panel data suggested that infrequent buyers show higher propensity to accelerate than frequent buyers do and that positive duration effects are underestimated when not accounting for segment specific hazard rates copyright 2002 john wiley sons ltd

existence of equilibrium in capm abstract in the mean variance capital asset pricing model capm non monotonicity of preferences may lead to satiation and short selling as well as satiation may lead to non existence of equilibrium this paper identifies several sets of sufficient conditions for equilibrium to exist the nature of the central conditions is to impose bounds on the investors degree of risk aversion as measured by the marginal rate of substitution between mean and standard deviation of return these bounds do not need to hold globally but only in a relevant range of portfolios or combinations of mean and standard deviation