With the ink still wet on the Chicago Mercantile Exchange (CME) purchase of Chicago Board of Trade (CBoT), speculation is already being raised that Chicago Board Options Exchange (CBOE) could be the next marketplace in the sights of the newly formed CME Group.CME CEO Craig Donohue said that the current integration between CME and CBoT will take priority adding that the exchange landscape is changing more rapidly than it did when CME originally announced the CBoT deal last October. How and when CME plans to add to the accelerated consolidation is what shareholders and industry participants are now examining. The most obvious next choice for CME is...