. and nasdaq , inc . an investment of $ 100 ( with reinvestment of all dividends ) is assumed to have been made in our class a common stock , in the peer group and the s&p 500 index on december 31 , 2012 , and its relative performance is tracked through december 31 , 2017 . comparison of 5 year cumulative total return* among cme group inc. , the s&p 500 index , and a peer group 12/12 12/13 12/14 12/15 12/16 cme group inc