Chipotle Mexican Grill’s Board of Directors named company founder Steve Ells the fast-casual restaurant chain’s sole CEO. Ells will also remain chairman of Chipotle’s board. Monty Moran has stepped down from the co-CEO role and from his board seat effective immediately, and will retire from Chipotle in 2017.

As Chairman and CEO, Ells will directly oversee restaurant operations, strategic initiatives, and innovation projects at the company.

Ells, a classically trained chef, started Chipotle in 1993. He served as chairman and CEO from 1993 until 2009 when Ells became co-CEO, sharing the title with Moran. The company went public in 2006.

“Steve founded Chipotle more than 23 years ago with a powerful vision to use great ingredients prepared skillfully by hand, but served very fast,” said Neil Flanzraich, lead director of Chipotle’s board. “This approach has proven to be a very successful formula, but as the company grew, operations became more complicated and less consistent. Given the ongoing challenges facing the company, the board felt strongly that it was best for Steve to resume leadership of the company going forward. This will ensure that his high standards for the guest experience and his unyielding commitment to the company’s mission are top priorities.”