Shares of Chipotle Mexican Grill Inc fell 3.5 percent in extended trading on Monday, after Boston College said students, including members of the men's basketball team, fell ill after dining at the popular burrito chain.
The college said the students complained of gastrointestinal symptoms and that the common factor among the students is that they had all eaten at the Chipotle restaurant in Cleveland Circle.
The Massachusetts Department of Public Health has been notified, and is working to determine if there is a link to an outbreak of E. coli linked to the burrito chain, the college said in a statement.
Federal health investigators on Friday said the E. coli outbreak linked to Chipotle had expanded to nine states, with 47 of the 52 people sickened having reported eating at the chain.
Chipotle shares were down $19.05 at $532.