Understanding the Implied Volatility Surface for Options on a Diversified Index

This paper describes a two-factor model for a diversified index that attempts to explain both the leverage effect and the implied volatility skews that are characteristic of index options. Our formulation is based on an analysis of the growth optimal portfolio and a corresponding random market activity time where the discounted growth optimal portfolio is expressed as a time transformed squared Bessel process of dimension four. It turns out that for this index model an equivalent risk neutral martingale measure does not exist because the corresponding Radon-Nikodym derivative process is a strict local martingale. However, a consistent pricing and hedging framework is established by using the benchmark approach. The proposed model, which includes a random initial condition for market activity, generates implied volatility surfaces for European call and put options that are typically observed in real markets. The paper also examines the price differences of binary options for the proposed model and their Black-Scholes counterparts. Mathematics Subject Classification: primary 90A12; secondary 60G30; 62P20 JEL Classification: G10, G13     

Conditioning manager alphas on economic information: another look at the persistence of performance

This article presents evidence on persistence in the relativeinvestment performance of large, institutional equity managers.Similar to existing evidence for mutual funds, we find persistentperformance concentrated in the managers with poor prior-periodperformance measures. A conditional approach, using time-varyingmeasures of risk and abnormal performance, is better able todetect this persistence and to predict the future performanceof the funds than are traditional methods.     

A Comparison of Two Quadratic Approaches to Hedging in Incomplete Markets

This paper provides comparative theoretical and numerical results on risks, values, and hedging strategies for local risk-minimization versus mean-variance hedging in a class of stochastic volatility models. We explain the theory for both hedging approaches in a general framework, specialize to a Markovian situation, and analyze in detail variants of the well-known Heston (1993) and Stein and Stein (1991) stochastic volatility models. Numerical results are obtained mainly by PDE and simulation methods. In addition, we take special care to check that all of our examples do satisfy the conditions required by the general theory.     

Unique but integrated: The role of individuation and assimilation processes in teen opinion leadership

Opinion leaders propel the diffusion of innovation and exert a significant influence on the marketplace. This influence is especially pronounced during adolescence, a period marked by increasing reliance on peers and the emergence of a tension between two countervailing needs: assimilation and individuation. A survey of 1142 adolescents reveals that these developmental needs affect adolescent opinion leadership in the critical clothing market. Adolescent opinion leadership relies on a balance between desires for assimilation (i.e., centrality within the peer network) and individuation (i.e., need for uniqueness); adolescents' susceptibility to peers' normative influence and gender moderate these relationships. Adolescents who occupy central positions within their peer network tend to be opinion leaders, though only if they are not susceptible to normative influence. Position within the peer network is a key for girls, whereas need for uniqueness is a key for boys. These differences implicate different approaches for managers targeting adolescent males and females.     

US domestic airline alliances: does the national welfare impact turn on strategic international gains?

The six largest U.S. airlines announced in the beginning of 1998 the formation of three domestic alliances, but the size and scope of these alliances spurred significant public interest concerns. GAO analysis suggests a rough equivalence between the domestic costs and benefits of alliances, yet the international competitive effects have not been considered. I argue that the national welfare merits of domestic airline alliances turn on positive international competitive effects. Empirical tests - run on comprehensive panel data covering the international airline markets among 21 nations over the 1983–1992 period - support domestic market concentration resulting in strategic international gains; hence, domestic airline alliances likely improve national welfare.     

An Adversarial Ethic for Business: or When Sun-Tzu Met the Stakeholder

In the economic literature on the firm, especially in the transaction–cost tradition, a sharp distinction is drawn between so-called “market transactions” and “administered transactions.” This distinction is of enormous importance for business ethics, since market transactions are governed by the competitive logic of the market, whereas administered transactions are subject to the cooperative norms that govern collective action in a bureaucracy. The widespread failure to distinguish between these two types of transactions, and thus to distinguish between adversarial and non-adversarial relations, has led many business ethicists to develop a “uniform” moral code. Yet in market transactions, the checks and balances built into the system of commercial exchange are such as to permit more instrumental forms of behavior. In administered transactions, by contrast, these checks and balances are absent, and thus the institutional context calls for much greater exercise of moral restraint. In this paper, I begin the task of developing an adversarial ethic for business. According to this view, the competitive environment licenses a greater range of “self-interested” behavior, but also imposes its own constraints on the strategies that firms may adopt in the pursuit of their interests. Joseph Heath is Associate Professor in the Department of Philosophy and the Centre for Ethics at the University of Toronto. He is the author of three books: Communicative Action and Rational Choice (MIT Press, 2001), The Efficient Society (Penguin, 2001), and with Andrew Potter. The Rebel Sell (HarperCollins, 2004). His research focuses on practical rationality, normative economics, and critical theory.     

A Documentary Theory of States and Their Existence as Quasi-Abstract Entities

This article is concerned with the existence of states as a matter of fact, and it approaches that subject within the context of the ontology of social reality as a whole. It argues, first, that states do not have a place in the traditional Platonist duality of the concrete and the abstract. Second, that states belong to a third category – the quasi-abstract – that has received philosophical attention with a recently emerging theory of documentality. Documentality, derived from Austin’s theory of performative utterances, claims that documents acts can bring quasi-abstract objects, such as states into being. Third and finally, it argues that the existence of quasi-abstract states should not be rejected on the basis of the Principle of Parsimony, because geopolitical theories that recognise the existence of quasi-abstract states will have greater explanatory power than theories that deny their existence.