Optimal Portfolio Selection and Cutoff Rates of Security Performance: A Multi-Index Case*

The present study performs portfolio analysis using a multi-index model in the diagonal form. In a mean-variance framework, an alternative solution to a portfolio optimization problem is derived, providing analytical and computational improvements. This leads to a proof of a crucial functional property of cutoff rates of security performance in the solution, thus providing formal justification for a nonranking procedure of optimal portfolio selection. The robustness of the above functional property, and hence the nonranking procedure, is demonstrated numerically when the underlying normality assumption of security returns is replaced by a more general assumption of stable Paretian distributions.