Zhengyang Bao1,2,3, Difang Huang4. 1. Department of Finance, School of Economics, Xiamen University, Xiamen, China. 2. Wang Yanan Institute for Studies in Economics, Xiamen University, Xiamen, China. 3. MOE Key Laboratory of Econometrics, Xiamen University, Xiamen, China. 4. Department of Econometrics and Business Statistics, Monash University, Melbourne, Victora, Australia. difang.huang@monash.edu.