The Zacks Mid Cap Core Index selection methodology is designed to identify companies with potentially superior risk-return profiles as determined by Zacks. The objective of the Index is to select a diversified group of stocks with the potential to outperform on a risk-adjusted basis the S&P Mid Cap 400 Index and other benchmark indices. The Index constituent selection methodology utilizes multi-factor proprietary selection rules to identify those stocks that offer the greatest potential from a risk/return perspective while maintaining industry diversification. The approach is specifically designed to enhance investment applications and investability. Index reconstitution will begin quarterly after the close of the last business day of March, June, September, and December.