This paper starts from examining the performance of equally weighted 1/N stock portfolios over time. During the last four decades these portfolios outperformed the market. The construction of these portfolios implies that their constituent stocks are in general older than those in the market as...

We show that even when a covariance matrix is poorly estimated, it is still possible to obtain a robust maximum Sharpe ratio portfolio by exploiting the uneven distribution of estimation errors across principal components. This is accomplished by approximating an investor's view on future asset...

We identify a few sample eigenvalues adjustment patterns that lead to an improvement in the out-of-sample portfolio Sharpe ratio when the population covariance matrix admits a high-dimensional factor model. These patterns unveil the key to portfolio performance improvement and shed light on the...

The first principal component of stock returns is often identified with the market factor. If this portfolio is to represent the market portfolio, then all its weights must be positive. From the classical Perron-Frobenius theorem, a sufficient condition for the dominant eigenvector to be...

The limiting distributions of two unit-root test statistics are derived and discussed for data that have both cross-sectional and time-series dimensions.

Abstract Numerical challenges inherent in algorithms for computing worst Value-at-Risk in homogeneous portfolios are identified and solutions as well as words of warning concerning their implementation are provided. Furthermore, both conceptual and computational improvements to the Rearrangement...

We study the problem of ?finding the worst-case joint distribution of a set of risk factors given prescribed multivariate marginals and a nonlinear loss function. We show that when the risk measure is CVaR, and the distributions are discretized, the problem can be conveniently solved using...

Numerical challenges inherent in algorithms for computing worst Value-at-Risk in homogeneous portfolios are identified and words of warning concerning their implementation are raised. Furthermore, both conceptual and computational improvements to the Rearrangement Algorithm for approximating...