Portfolio choice and equilibrium in capital markets with safety-first investors

This paper develops optimal portfolio choice and market equilibrium when investors behave according to a generalized lexicographic safety-first rule. We show that the mutual fund separation property holds for the optimal portfolio choice of a risk-averse safety-first investor. We also derive an explicit valuation formula for the equilibrium value of assets. The valuation formula reduces to the well-known two-parameter capital asset pricing model (CAPM) when investors approximate the tail of the portfolio distribution using Tchebychev's inequality or when the assets have normal or stable Paretian distributions. This shows the robustness of the CAPM to safety-first investors under traditional distributional assumptions. In addition, we indicate how additional information about the portfolio distribution can be incorporated to the safety-first valuation formula to obtain alternative empirically testable models.     

The effect of estimation risk on optimal portfolio choice

This paper determines the effect of estimation risk on optimal portfolio choice under uncertainty. In most realistic problems, the parameters of return distributions are unknown and are estimated using available economic data. Traditional analysis neglects estimation risk by treating the estimated parameters as if they were the true parameters to determine the optimal choice under uncertainty. We show that for normally distributed returns and ‘non-informative’ or ‘invariant’ priors, the admissible set of portfolios taking the estimation uncertainty into account is identical to that given by traditional analysis. However, as a result of estimation risk, the optimal portfolio choice differs from that obtained by traditional analysis. For other plausible priors, the admissible set, and consequently the optimal choice, is shown to differ from that in traditional analysis.     

A Model of Household Grocery Shopping Behavior

The shopping trip to the grocery store is one of the most basic elements of consumer behavior. The authors seek to provide an understanding of the factors that account for variations in shopping behavior across households. They present a model of shopping behavior that assumes that households seek to minimize the travel cost associated with shopping and the cost of holding goods in inventory. As in the classic EOQ model, observed shopping behavior reflects the manner in which households balance these costs while meeting their consumption needs. A number of propositions derived from the model are tested using data on shopping trips made by households over a one-year period. The results support the model and indicate that the relationship between household characteristics and shopping behavior can be fairly complex: for some households shopping may have a recreational aspect while for others it may compete directly with wage-earning activity.     

The covariates of regularity in purchase timing

An examination of the timing of consumers' purchases for coffee reveals that consumers vary a great deal in terms of the regularity of their purchasing behavior. Some consumers make purchases at seemingly random time intervals, while others purchase at highly regular intervals. The measurement of regularity in purchase timing, as well as the identification of its covariates, is important in many contexts such as modeling purchase incidence and sales forecasting. We measure the degree of regularity among a sample of coffee purchasers and identify several consumer characteristics that vary with the degree of regularity in purchase timing. Results show that regularity in purchase timing is related to brand loyalty, store loyalty and deal proneness, as well as to certain pattern of routinization by the households, and that regularity may be used, along with other aspects of purchase behavior, to provide a basis for market segmentation.The authors wish to acknowledge the support of Information Resources Inc. for providing the data, and are grateful to Professor Jane T. Landwehr, University of Delaware, for her help.     

The effect of limited information and estimation risk on optimal portfolio diversification

This paper analyzes the optimal portfolio choice problem when security returns have a joint multivariate normal distribution with unknown parameters. For the case of limited, but sufficient (sample plus prior) information, we show that for a general family of conjugate priors, the optimal portfolio choice is obtained by the use of a mean-variance analysis that differs from traditional mean-variance analysis due to estimation risk. We also consider two illustrative cases of insufficient sample information and minimal prior information and show that in these cases it is asymptotically optimal for an investor to limit diversification to a subset of the securities. These theoretical results corroborate observed investor behavior in capital markets.     

LOW-INCOME HOUSING IN INDIAN CITIES: SOME CONSIDERATIONS FOR POLICY

Across cities in India, migrant groups, squatters and the urban poor residing in slums have played a crucial role in developing low-income housing. This form of housing is closely connected to the economic activity of the poor, which in turn contributes to the wider urban economy. It also enables the poor to consolidate their position in the city and make claims on the city administration for infrastructure. However, such housing has been bracketed as 'informal' and lacks legitimacy. Policies concerning low-income housing must address this issue while enabling the poor to further their economic and entrepreneurial initiatives.     

Assessment of the road safety performance of four roundabouts in Kumasi,Ghana

Upgrade of the Ejisu-Kumasi section of the N6 saw the construction of roundabouts at selected intersections. Their use appears challenging particularly for vehicles with elevated Centre-of-Gravity. The objective of this study was to establish the relative risk of traffic accident deaths or hospitalized injuries at the roundabouts. Five-year crash data covering a 100 m stretch upstream and downstream of the roundabouts were analysed. A total of 119 crashes occurred with 18% casualty hospitalization and 12%fatalities. Compared with the Ejisu roundabout, fatal or hospitalized injuries were significantly higher at the Boadi (OR = 25.6, p = 0.0021) and Kwame Nkrumah University of Science and Technology Police Station Junctions (OR = 48.2, p < 0.001). Occupants of buses, heavy goods vehicles and riders of two wheelers were at elevated risk of deaths or serious injuries. Crash severity at the round abouts was aggravated by night-time, steep gradients and adverse cambers. It is recommended that, signalization and grade separation should be used in the current arrangement where appropriate.     

Optimal rules for ordering uncertain prospects

In this paper, we obtain the optimal selection rule for ordering uncertain prospects for all individuals with decreasing absolute risk averse utility functions. The optimal selection rule minimizes the admissible set of alternatives by discarding, from among a given set of alternatives, those that are inferior (for each utility function in the restricted class) to a member of the given set. We show that the Third Order Stochastic Dominance (TSD) rule is the optimal rule when comparing uncertain prospects with equal means. We also show that in the general case of unequal means, no known selection rule uses both necessary and sufficient conditions for dominance, and the TSD rule may be used to obtain a reasonable approximation to the smallest admissible set. The TSD rule is complex and we provide an efficient algorithm to obtain the TSD admissible set. For certain restrictive classes of the probability distributions (of returns on uncertain prospects) which cover most commonly used distributions in finance and economics, we obtain the optimal rule and show that it reduces to a simple form. We also study the relationship of the optimal selection rule to others previously advocated in the literature, including the more popular mean-variance rule as well as the semi-variance rule.     

A nested logit model of brand choice incorporating variety-seeking and marketing-mix variables

We model the effects of variety-seeking and marketing-mix variables on consumers' purchases of coffee using a nested logit model. We premise that on any given purchase occasion, the utilities of brands other than the one purchased on the previous occasion may be correlated due to the consumer's tendency to seek variety or to avoid variety. This results in a two-level hierarchical model where choice on any purchase occasion is conditioned on the brand purchased on the immediately preceding occasion. Such a structure accounts for variety seeking and inertia tendencies of consumers and is consistent with a hierarchical decision process, where consumers first decide whether or not to make a repeat purchase and then decide which brand size to purchase. The assumed hierarchical structure is shown to be consistent with observed coffee purchase behavior, and the model is shown to outperform a nonhierarchical logit model in predicting consumers' brand choices.     

Influences on consumer response to direct mail coupons: An integrative review

A substantial and growing body of research on coupons and coupon effectiveness has emerged in the marketing literature. The objective of this paper is to review and consolidate the findings of previous studies to provide a better understanding of the factors that influence consumer response to direct mail coupons. The effects of coupon, brand, product category, and consumer characteristics on redemption behavior and incremental sales are examined, and their implications for the effectiveness of direct mail coupon promotions are discussed. Based on the findings of prior studies, a theoretical model of coupon effects on purchase behavior is proposed. Several key issues that need to be addressed in future research are identified. © 1996 John Wiley & Sons, Inc.