Hedge fund firm takes 9.9% stake in Chipotle

Bill Ackman's Pershing Square hedge fund management yesterday disclosed a 9.9 percent stake in Chipotle Mexican Grill, resulting in the restaurant chain's shares climbing in after-hours trade.

Pershing indicated in a filing it intends to engage in discussions with the fast-casual restaurant company's board and management.

Chipotle - damaged by food-borne illness breakouts and a class-action lawsuit filed by employees - experienced a stock drop of 26.5 percent during the first half of the year.

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