Stochastic Models of Implied Volatility Surfaces

We propose a market–based approach to the modelling of implied volatility, in which the implied volatility surface is directly used as the state variable to describe the joint evolution of market prices of options and their underlying asset. We model the evolution of an implied volatility surface by representing it as a randomly fluctuating surface driven by a finite number of orthogonal random factors. Our approach is based on a Karhunen–Loeve decomposition of the daily variations of implied volatilities obtained from market data on SP500 and DAX options.
We illustrate how this approach extends and improves the accuracy of the well–known 'sticky moneyness' rule used by option traders for updating implied volatilities. Our approach gives a justification for the use of 'Vegas' for measuring volatility risk and provides a decomposition of volatility risk as a sum of independent contributions from empirically identifiable factors.
(J.E.L.: G130, C14, C31).     

Towards a Theory of Organizational Improvisation: Looking Beyond the Jazz Metaphor

abstract This paper calls for research on organizational improvisation to go beyond the currently dominant jazz metaphor in theory development. We recognize the important contribution that jazz improvisation has made and will no doubt continue to make in understanding the nature and complexity of organizational improvisation. This article therefore presents some key lessons from the jazz metaphor and then proceeds to identify the possible dangers of building scientific inquiry upon a single metaphor. We then present three alternative models – Indian music, music therapy and role theory. We explore their nature and seek to identify ways in which the insights they generate complement those from jazz. This leads us to a better understanding of the challenges of building a theory of organizational improvisation.     

Is globalization a road to duopoly?

In global markets, the market shares of the two or three biggest firms sum up more than 90 percent and firms do marketing efforts. However, the classical neo-walrasiano theoretical framework only is able to justify these stylized facts with particular firms’ cost structures, being one reason the presumption that there are no information costs. Towards the rationalization of those stylized facts, I study the evolution of the market structure in a model of price advertising with a variable that controls the degree of openness of regional markets. The main result of the model is that in equilibrium the structure of a global market is the duopoly.     

Perceptions of poverty attributions in Europe: a multilevel mixture model approach

The perception of the causes of poverty has long been recognized as a very important factor in the broader study of this social phenomenon. This study covers 15 European Union countries and considers three types of poverty attributions: individualistic, societal, and fatalistic. The individualistic view perception believes the poor are responsible for their situation, the societal perspective blames society for poverty and the fatalistic view considers poverty to be the result of bad luck or fate. A multilevel mixture model with three clusters of countries and six clusters of individuals was identified. Despite the generalization of the social explanations of poverty at the individual or micro level, there are also groups that emphasize more individualistic explanations, blaming the poor for their condition. At the country or macro level, the most developed cluster believes in the individualistic and fatalistic causes of poverty, whereas the least developed clusters explain poverty based on the injustices of society. There is diversity in the way these countries perceive poverty.     

Does Inter‐jurisdictional Competition Engender a “Race to the Bottom”? A Meta‐Regression Analysis

A growing literature documents the existence of strategic political reactions to public expenditure between rival jurisdictions. These interactions can potentially create a downward expenditure spiral (“race to the bottom”) or a rising expenditure spiral (“race to the top”). However, in the course of identifying the existence of such interactions and ascertaining their underlying triggers, the empirical evidence has produced markedly heterogeneous findings. Most of this heterogeneity can be traced back to study design and institutional differences. This article contributes to the literature by applying meta‐regression analysis to quantify the magnitude of strategic inter‐jurisdictional expenditure interactions, controlling for study, and institutional characteristics. We find several robust results beyond confirming that jurisdictions do engage in strategic expenditure interactions, namely that strategic interactions: (i) are weakening over time, (ii) are stronger among municipalities than among higher levels of government, and (iii) appear to be more influenced from tax competition than yardstick competition, with capital controls and fiscal decentralization shaping the magnitude of fiscal interactions.     

Effort Elicitation,Wage Differentials and Income Distribution in A Wage‐Led Growth Regime

Motivated by the empirical evidence on endogenous labor effort and wage differentials, this paper explores implications for distribution and growth of firms using different strategies to elicit effort from workers. The frequency distribution of effort‐elicitation strategies across firms is governed by a replicator dynamic that generates wage differential as a long‐run equilibrium. Although firms willing to elicit more effort have to compensate workers with a higher wage rate, a larger proportion of firms adopting such strategy will not necessarily produce a higher wage share and thereby a higher growth rate. The intuition is that, depending on the accompanying rise in labor productivity, the wage share may not vary positively with the proportion of firms paying higher wages.     

Capital services estimates in Portuguese industries, 1977–2003

This paper presents capital services estimates for 26 Portuguese industries for the 1977–2003 period. The estimation procedure follows an integrated approach under which the flows of capital services are approximated as a proportion of the capital stock converted into standard efficiency units. Our findings suggest a close proximity between the evolution of capital flows and the observed fluctuations of Portuguese macroeconomic growth. TFP growth estimates based on growth accounting reveal, furthermore, a very disappointing performance of the Portuguese economy during the period under study, with an average annual rate of TFP growth of 0.8% being observed. Performance varies across industries, but the bulk of activities show very modest rates of TFP growth.     

Editors’ note

Portuguese Economic Journal -