Mean–variance and mean–semivariance portfolio selection: a multivariate nonparametric approach

While univariate nonparametric estimation methods have been developed for estimating returns in mean-downside risk portfolio optimization, the problem of handling possible cross-correlations in a vector of asset returns has not been addressed in portfolio selection. We present a novel multivariate nonparametric portfolio optimization procedure using kernel-based estimators of the conditional mean and the conditional median. The method accounts for the covariance structure information from the full set of returns. We also provide two computational algorithms to implement the estimators. Via the analysis of 24 French stock market returns, we evaluate the in-sample and out-of-sample performance of both portfolio selection algorithms against optimal portfolios selected by classical and univariate nonparametric methods for three highly different time periods and different levels of expected return. By allowing for cross-correlations among returns, our results suggest that the proposed multivariate nonparametric method is a useful extension of standard univariate nonparametric portfolio selection approaches.     

Accelerators as start-up infrastructure for entrepreneurial clusters

ABSTRACT

Infrastructure is commonly conceptualized as a set of facilities that play a critical role in facilitating activities by individuals and organizations. Conventionally, infrastructure is tightly linked to publicly funded projects that facilitate access to key resources and enable diverse activities. Within entrepreneurial clusters research, infrastructure includes universities, research institutions and telecommunication technologies that facilitate entrepreneurial activities. These capital-intensive investments seek to facilitate start-ups emergence by aiding access to markets and development of ideas. Accelerators facilitate the same activities and have only recently been conceptualized as start-up infrastructure. This study builds upon this research stream by elaborating on how accelerators can play this meaningful role at the cluster level. Specifically, and by relying on the analysis of empirical evidence from three distinct studies, we uncover how accelerators provide tangible and intangible dimensions of start-up infrastructure to form a positively reinforcing cycle of entrepreneurial activities. Additionally, our findings allow us to push further the idea that start-up infrastructure development can be an endogenous process involving multiple actors within the cluster. Our empirical findings and the theoretical insights derived from them have meaningful implications for the aforementioned literature, as well as start-up practitioners and policymakers linked to the funding of entrepreneurial clusters.     

中华苏维埃共和国国家银行的创建

<正>新中国金融体系的历史渊源,可以追溯到大革命时期中国共产党领导的金融事业。这个体系从萌发到中华苏维埃共和国国家银行的创建、抗日根据地银行和解放区银行的建立,以及中国人民银行的建立,历经中国共产党领导的中国革命各个历史时期,始终伴随着中国革命的不断胜利而发展壮大。     

Digital Transformation Through Exploratory and Exploitative Internet of Things Innovations: The Impact of Family Management and Technological Diversification*

This study examines the impact of family management on digital transformation with specific regard to the firm’s development of Internet of Things (IoT) innovations. Drawing on the distinctive characteristics of firms with family managers, such as the focus on family‐centered noneconomic goals, long tenure, emotional ties to existing assets, and rigid mental models, it hypothesizes that increasing family involvement in the top management team is negatively related to the development of IoT innovations that are distant from a firm’s existing technology base (i.e., exploratory IoT innovations) compared to exploitative IoT innovations. Further, the study proposes that the firm’s degree of technological diversification, especially in unrelated forms, reinforces this relationship. The longitudinal analysis between 2002 and 2013 on a sample of publicly traded German firms allows us to test our hypotheses from the beginning of the emergence of the IoT concept. Our findings show that due to the particular characteristics of their managers, family‐managed firms do not welcome the risks related to exploratory IoT innovations, and the benefit of risk diversification from technological diversification is lower than the cost of abandoning family‐centered goals. As our results imply that the involvement of family managers constrains the development of exploratory IoT innovation, the top management team composition in firms that intend to be at the forefront of the digital transformation should be accurately designed by avoiding a high proportion of family members.     

Organisatie en financiering van de Nederlandse gezondheidszorg

Bespreking van D. Dolman, Subsidies en gezondheidszorg, een feitelijk onderzoek naar financieringsstructuren, ac. proefschrift, Universiteit van Amsterdam 1964, H. E. Stenfert Kroese N.V., Leiden, 240 blz.     

De Proliferatie van Economische Modellen

Bespreking vanE. Scheele, Einkommensverteilung und Wirtschaftswachstum, J. C. B. Mohr (Paul Siebeck), Tübingen 1965, 263 blz. enE. Heuss, Die Verbindung von mikroökonomischer und makroökonomischer Verteilungstheorie. Walter Eucken Institut. VortrÄge und AufsÄtze. J. C. B. Mohr (Paul Siebeck), Tübingen 1965, 40 blz.     

Bijdragen Tot De Geschiedenis Van Het Centrale Bankwezen

Vervolg van het artikel in de aflevering van mei, blz. 289 e.v.