“…Several factors have been advanced to explain the portfolio under-diversification problem, such as risk aversion, taxation, financial literacy, household ownership status, age, wealth, and so on (Agarwal & Chua, 2020;Dimmock et al, 2016;Flavin & Yamashita, 2002;Guiso et al, 2000;Poterba, 2002;Von Gaudecker, 2015;Xiao & Tao, 2021;Zhang, Song, et al, 2021;Zhang, Wei, et al, 2021). In addition, lack of information is a crucial factor for under-diversification.…”