CME Group

( Nancy Stone/Chicago Tribune / May 10, 2012 )

The world's biggest futures exchange company has its headquarters in Chicago, but its executive chairman, Terry Duffy, expressed concerns on Wednesday about Illinois' corporate tax rate and said it might move somewhere else. CME Group has other worries, as well -- since the beginning of the financial crisis, the company's shares have lost 25 percent of their value, underperforming the broader market as well as exchange sector peers like Deutsche Boerse AG and NYSE Euronext.

Pictured above are CME Group's offices at 30 S. Wacker Drive in Chicago.