“…Various efforts have been made to mitigate the sensitivity of the optimal solution of the Markowitz mean-variance model to parameter fluctuations. (See, e.g., Yao, Li, and Li (2016), Huang, Li, and Yao (2018), Yang, Wen, Liu, Li, and Huang (2019)). Wolf (2003, 2004a) proposed a method utilizing the weighted average of a low-variance target estimator matrix, b Σ target , and the sample covariance matrix rather than the sample covariance matrix.…”