Score-driven copula models for portfolios of two risky assets

ABSTRACT

The precise measurement of the association between asset returns is important for financial investors and risk managers. In this paper, we focus on a recent class of association models: Dynamic Conditional Score (DCS) copula models. Our contributions are the following: (i) We compare the statistical performance of several DCS copulas for several portfolios. We study the Clayton, rotated Clayton, Frank, Gaussian, Gumbel, rotated Gumbel, Plackett and Student's t copulas. We find that the DCS model with the Student's t copula is the most parsimonious model. (ii) We demonstrate that the copula score function discounts extreme observations. (iii) We jointly estimate the marginal distributions and the copula, by using the Maximum Likelihood method. We use DCS models for mean, volatility and association of asset returns. (iv) We estimate robust DCS copula models, for which the probability of a zero return observation is not necessarily zero. (v) We compare different patterns of association in different regions of the distribution for different DCS copulas, by using density contour plots and Monte Carlo (MC) experiments. (vi) We undertake a portfolio performance study with the estimation and backtesting of MC Value-at-Risk for the DCS model with the Student's t copula.     

The influence of low-fare airlines on vacation choices of students: Results of a stated portfolio choice experiment

This paper reports the results of a portfolio model of vacation choices of students. The portfolio model concerns the combined choice of destination type, transport mode, duration, accommodation, and travel party for vacations. In addition to usual transport modes such as airline, train, bus and car, a distinction was made between low-fare airlines, as these may be especially appealing to students, and regular airlines. Stated choice data were used to estimate the model. The attributes of the transport modes were systematically varied in the experiment, while respondents were faced with free options for the other choice facets. Estimation results indicated that the developed model of portfolio choice performs satisfactory. In substantive terms, it seems that transport mode predominantly influences the portfolio choices. The attributes that are significant tend to amplify the specific role of transport modes in general and low-fare airlines in particular.     

What if women earned more than their spouses? An experimental investigation of work-division in couples

Female specialization on household work and male specialization on labor-market work is a widely observed phenomenon across time and countries. This absence of gender neutrality with respect to work-division is known as the “work-division puzzle”. Gender differences regarding characteristics (preferences, productivity) and context (wage rates, social norms) are generally recognized as competing explanations for this fact. We experimentally control for context and productivity to investigate preferences for work-division by true co-habiting couples, in a newly developed specialization task. Efficiency in this task comes at the cost of inequality, giving higher earnings to the “advantaged” player. We compare behavior when men (or women) are in the advantaged position, which corresponds to the traditional (or power) couple case where he (or she) earns more. Women and men contribute equally to the household public good in all conditions. This result allows us to rule out some of the standard explanations of the work-division puzzle.     

Mandatory versus voluntary labelling of genetically modified food: evidence from an economic experiment

Opponents of the voluntary labelling scheme for genetically modified (GM) food products often argue that consumers have the “right to know” and therefore advocate mandatory labelling. In this article, we argue against this line of reasoning. Using experimental auctions we show that the quality of the signal generated by a mandatory labelling scheme is affected by the number of labels in the market. If there are two labels, one for GM products and one for non‐GM products, mandatory and voluntary labelling schemes generate a similar degree of uncertainty about the quality of products that do not carry a label.     

Efficiency analysis of East European electricity distribution in transition: legacy of the past?

This paper provides a cross-country efficiency analysis of electricity distribution companies in the East European transition countries of Poland, the Czech Republic, Slovakia and Hungary. We use common nonparametric efficiency measurement such as Data Envelopment Analysis (DEA) and Free Disposal Hull (FDH) under different assumptions and apply recent developments of statistical inference in nonparametric frontier models to test our hypotheses. We discuss the empirical problems of cross-country benchmarking approaches, in particular the comparability of different structures of electricity distribution companies. Our results suggest that Poland’s distribution companies are still inefficiently small; the Czech Republic features the highest efficiency; and Slovakia and Hungary occupy the middle range. We also note that privatization has had a positive effect on technical efficiency in the four countries. We use the phrase “legacy of the past” to describe the four countries in comparison to the efficiency of electricity distribution companies we studied in Germany.

Technology management and collaboration profile: virtual companies and industrial platforms in the high‐tech biotechnology industries

In this paper we discuss collaboration in the area of technology management. We propose the concept of collaboration profile to describe various forms of networks along key differentiating characteristics. The collaboration profile is then applied using two examples to illustrate different forms of collaboration in the biotechnology industries, the ‘virtual company’ and the ‘industrial platform’. Based on interviews with members of a virtual company as well as members of industrial platforms and drawing conclusions from theoretical insights, the advantages and disadvantages of these forms and their suitability for different stages of the technology life cycle will be discussed. Specifically, we address the following questions: What kind of collaboration profile applies to virtual companies and industrial platforms? How does the suitability of collaboration forms vary with the stage of technology development? Furthermore, we demonstrate the usefulness of the collaboration profile for analysing features and potential problems of collaborations by describing two examples. Focusing on the key characteristics of a collaboration helps to check the appropriateness of the collaboration form and to identify and manage respective problems.     

Work and Wage Dynamics around Childbirth

In this paper, we investigate how the wage processes of women who are well established in the labour market are affected by having children. We estimate a flexible fixed‐effects wage regression model extended by post‐childbirth fixed effects. We use register data on West Germany, and we exploit the expansionary family policy during the late 1980s and 1990s for identification. On their return to work after childbirth, the wages of mothers drop by 3–5.7 per cent per year of leave. We find negative selection back to full‐time work after childbirth. We discuss the policy implications regarding statistical discrimination and the results concerning the family gap.