“…However, this method has some shortcomings. First, financial time series is assumed to follow normal distribution when the correlation is calculated by the Pearson correlation coefficient, whereas numerous studies have shown that the return on financial markets is not subject to normal distribution (Bae, Karolyi, & Stulz, 2003;Durante, Foscolo, Jaworski, & Wang, 2014;Wang, Xie, Zhang, Han, & Chen, 2014). Second, the Pearson correlation coefficient only reveals linear correlations, and it ignores the heterogeneity of financial data at different times; therefore, it is difficult to accurately measure the tail correlation in a booming market and a recession market .…”