Bill Ackman, founder and CEO of hedge fund Pershing Square Capital Management, posted his very first tweet on Wednesday from a Chipotle Mexican Grill (CMG - Get Report) . 

Eating our own cooking @ChipotleTweets and making my own mix at https://t.co/CiNtycYWhP pic.twitter.com/rYad7uKuI3

— Bill Ackman (@BillAckman1) July 19, 2017

Ackman's Pershing Square is the largest holder of Chipotle shares, and his debut on Twitter (TWTR - Get Report)  comes just a day after the company's stock fell as much as 7.5% after reports surfaced of a store closure where multiple customers fell ill.

Pershing Square lost about $74 million at midday Tuesday. Chipotle shares are slightly higher in afternoon trading.

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