Title
How Superadditive Can a Risk Measure Be?
Abstract
In this paper, we study the extent to which any risk measure can lead to superadditive risk assessments, implying the potential for penalizing portfolio diversification. For this purpose we introduce the notion of extreme-aggregation risk measures. The extreme-aggregation measure characterizes the most superadditive behavior of a risk measure by yielding the worst-possible diversification ratio across dependence structures. One of the main contributions is demonstrating that, for a wide range of risk measures, the extreme-aggregation measure corresponds to the smallest dominating coherent risk measure. In our main result, it is shown that the extreme-aggregation measure induced by a distortion risk measure is a coherent distortion risk measure. In the case of convex risk measures, a general robust representation of coherent extreme-aggregation measures is provided. In particular, the extreme-aggregation measure induced by a convex shortfall risk measure is a coherent expectile. These results show that, in the presence of dependence uncertainty, quantification of a coherent risk measure is often necessary, an observation that lends further support to the use of coherent risk measures in portfolio risk management.
Year
DOI
Venue
2015
10.1137/140981046
SIAM JOURNAL ON FINANCIAL MATHEMATICS
Keywords
Field
DocType
distortion risk measures,shortfall risk measures,expectiles,dependence uncertainty,risk aggregation,diversification
Spectral risk measure,Coherent risk measure,Financial economics,Distortion risk measure,Dynamic risk measure,Deviation risk measure,Risk measure,Mathematics,Expected shortfall,Entropic value at risk
Journal
Volume
Issue
ISSN
6
1
1945-497X
Citations 
PageRank 
References 
1
0.39
8
Authors
3
Name
Order
Citations
PageRank
Ruodu Wang14711.75
Valeria Bignozzi210.39
Andreas Tsanakas310.72