On Dec 5, we issued an updated research report on quick-casual and fresh Mexican food restaurant chains operator, Chipotle Mexican Grill, Inc. ( CMG - Free Report ). Chipotle has underperformed the Zacks categorized Retail–Food & Restaurants industry year to date with an average negative return of 17.4% compared with a decline of 0.2% witnessed by the latter. We note that Chipotle has been reeling under negative publicity related to the E. coli and norovirus outbreak since the end of 2015. As a safety measure, the fast casual chain was forced to close several outlets.