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.     

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.     

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.     

媒体情绪与房价波动*

本文使用2000—2015年中国112个大中城市媒体报道和房价月度指数研究了媒体异质性对房价波动的影响。研究发现,纸媒情绪对房价波动的影响大于网媒情绪,中央媒体情绪对房价波动的影响大于地方媒体情绪,明星微博情绪对房价波动的影响大于普通微博情绪,媒体语气确定性和报道篇幅对房价波动有正影响,明星城市媒体情绪较非明星城市更易引起房价波动。据此,为防范非理性房价波动,应加强对不同媒体报道的监管。     

Analysis of the Service Dominant Logic network,authors, and articles

The present study analyses research conducted in Service Dominant Logic (S-D logic), providing an overview of its intellectual structure. For that purpose, a structured approach was adopted through the implementation of bibliometric methods, using co-citation analysis combined with performance analysis and an integrative science mapping approach, which considered a timeline, a graph, and a distance-based perspective. This allowed the identification of the leading authors and of six clusters of articles based on bibliographic coupling, along with the most prominent research themes clustered in five subdomains of research based on co-occurrence of terms. The networks extracted show the associations between the main articles and concepts treated by the S-D logic community, unveiling the salient challenges and prospective expansion facing its future theoretical and practical context.     

From global start-ups to the borderless firm: Why and how to build a worldwide value system

Although the original concept of international new ventures included the geographic configuration of value activities, the subsequent development of the literature has gradually abandoned the concern about the geographic configuration of both input sourcing and output marketing to concentrate almost exclusively on the latter. Therefore, this paper argues that there is a need to re-focus the research so as to figure out how and why some companies are borderless. Borderless firms are defined as the result of the combination, early on, of geographically dispersed resources and capabilities, defying the home-base logic. A borderless firm presents the following characteristics (or a combination of them) from inception (or shortly thereafter): (i) value-added activities dispersed across different countries and regions; (ii) entrepreneurs not bounded by a home base; (iii) multinational founders and/or management teams; and (iv) a multinational workforce. To enquiry into this issue, the study uses five case studies of borderless firms. The results advance the understanding of the motives and processes behind the development, early on, of a borderless configuration of value activities.