In this paper we estimate the mean-variance portfolio in the high-dimensional case using the recent results from the theory of random matrices. We construct a linear shrinkage estimator which is distribution-free and is optimal in the sense of maximizing with probability $1$ the asymptotic out-of-sample expected utility, i.e., mean-variance objective function for different values of risk aversion coefficient which in particular leads to the maximization of the out-of-sample expected utility and to the minimization of the out-of-sample variance. One of the main features of our estimator is the inclusion of the estimation risk related to the sample mean vector into the high-dimensional portfolio optimization. The asymptotic properties of the new estimator are investigated when the number of assets $p$ and the sample size $n$ tend simultaneously to infinity such that $p/n \rightarrow c\in (0,+\infty)$. The results are obtained under weak assumptions imposed on the distribution of the asset returns, namely the existence of the $4+\varepsilon$ moments is only required. Thereafter we perform numerical and empirical studies where the small- and large-sample behavior of the derived estimator is investigated. The suggested estimator shows significant improvements over the existent approaches including the nonlinear shrinkage estimator and the three-fund portfolio rule, especially when the portfolio dimension is larger than the sample size. Moreover, it is robust to deviations from normality.

翻译：在本文中,我们使用随机矩阵理论的最新结果来估计高维假设的平均值组合。我们用随机矩阵理论的最新结果来估计高维假设值的平均值组合。我们建造了一个线性缩缩缩估计值,该估计值是无分布性的,最优化的,其含义是将高维组合的预期效用最大化,概率为1美元。当资产数量(美元)和抽样规模(美元)往往同时到不精确时,对风险转换系数的不同值的平均值(美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元)的平均值。根据对资产回报分布的薄弱假设,即将与样本平均矢量矢量矢量矢量矢量矢量相关的估计风险纳入高度组合的优化中。当资产数量(美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元/美元