Portfolio Selection Under Systemic Risk
52 Pages Posted: 1 Apr 2020 Last revised: 16 Mar 2021
Date Written: March 25, 2020
This paper proposes a novel methodology to construct optimal portfolios that explicitly incorporates the occurrence of systemic events. Investors maximize a modiﬁed Sharpe ratio that is conditional on a systemic event, with the latter interpreted as a low market return environment. We solve the portfolio allocation problem analytically under the absence of short-selling restrictions and numerically when short-selling restrictions are imposed. This approach for obtaining an optimal portfolio allocation is made operational by embedding it in a multivariate dynamic setting using dynamic conditional correlation and copula models. We evaluate the out-of-sample performance of our portfolio empirically on the US stock market over the period 2007 to 2020 using ex-post wealth paths and systemic risk metrics against mean-variance, equally-weighted, and global minimum variance portfolios. Our portfolio maximizing a modiﬁed Sharpe ratio outperforms all competitors under market distress and remains competitive in non-crisis periods.
Keywords: Conditional Volatility Models, Portfolio Allocation, Sharpe Ratio, Systemic Risk, Conditional Tail Risk
JEL Classification: C15, C32, C53, C61, G01, G11
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