This paper introduces a new approach to constructing optimal mean-variance portfolios. The approach relies on a novel unconstrained regression representation of the mean-variance optimization problem combined with high-dimensional sparse-regression methods. Our estimated portfolio, under a mild sparsity assumption, controls for risk and attains the maximum expected return as both the numbers of assets and observations grow. The superior properties of our approach are demonstrated through comprehensive simulation and empirical analysis. Notably, using our strategy, we find that investing in individual stocks, in addition to the Fama-French three-factor portfolios, leads to substantially improved performance. Received October 6, 2014; editorial decision July 13, 2018 by Editor Andrew Karolyi.

This study evaluates the link between CEO governance heterogeneity, power structure of the firm, and product market competition on various facets of post-IPO cash policy. Our results suggest that post-IPO cash holdings as well as marginal value of cash reserves are higher under a founder CEO governance regime relative to non-founder CEOs. Concentrating board power in the hands of founder CEOs however, reduces their ability to maintain higher post-IPO cash reserves. Our results also suggest that product market competition influences both the level and marginal value of cash reserves in the hands of founder CEOs. Further, we find that stronger internal governance reduces the tendency of IPO firms to deploy excess cash reserves to fund internal investments in excess of industry rivals. Finally, our results suggest that excess cash reserves in competitive industry environments lead to superior post-IPO operating performance.