Performance of robust portfolio optimization in crisis periods

We examin empirical performances of two alterna- tive robust optimization models, namely the worst-case conditional value-at-risk (worst-case CVaR) model and the nominal conditional value-at-risk (CVaR) model in crisis periods. Both models are based on historical value-at-risk methodology. These performances are compared by using a portfolio constructed on the basis of daily clos- ing values of different stock indices in developed markets using data from 1990 to 2013. An empirical evidence is produced with Ro- bustRisk software application. Both a Monte-Carlo simulation and an out-of-sample test show that robust optimization with worst-case CVaR model outperforms the nominal CVaR model in the crisis peri- ods. However, the trade-off between model misspecification risk and return maximization depending on the market movements should be optimized in a robust model selection.