Chipotle Replacing Its C.E.O., Founder Steve Ells

Chipotle Mexican Grill said on Wednesday that it was looking for a new leader “with demonstrated turnaround expertise” to replace Steve Ells, the current chief executive and founder of the fast casual chain.

Mr. Ells, who started the company in Denver in 1993 and now oversees more than 2,350 restaurants, will become executive chairman once his successor is found. Montgomery F. Moran stepped down as co-chief executive of Chipotle late last year after several food safety failures at the chain, which caused an exodus of customers and a pummeling on Wall Street.

“While we are continuing to make progress, it is clear that we need to move faster to make improvements,” Mr. Ells said in a statement. “Simply put, we need to execute better to ensure our future success.”