Offering no specific reason for his early departure, Grant Thornton says Mike McGuire is stepping aside as CEO.

McGuire will become “CEO emeritus” effective Aug. 1, 2019, and his duties will be assumed immediately by interim CEO-elect Bradley Preber. McGuire will serve as a “brand ambassador” for the firm, focusing on leadership transition, business development, and supporting key client relationships, the firm said. 

McGuire was appointed CEO in 2015. In 2018, the firm’s partnership board voted to extend his term until July 31, 2021, his mandatory retirement date. He was credited then with leading the firm successful on several fronts, including financial results, culture, innovation, and quality.

Grant Thornton’s partnership board thanked McGuire for his vision and leadership, saying he has “taken our firm from the ‘now’ to the ‘next’ and on to the ‘new.’ ” McGuire said in a statement he has been honored to lead the firm over the past five years and he’s proud of what has been accomplished.

“As fast as the marketplace is changing, I believe we now need to transition as quickly as possible to new leadership that can take us on the next leg of our journey to become the ‘firm of the future’ over the next five years or more,” said McGuire. “I will do everything in my power in the coming years to help the firm navigate this transition and continue to succeed.”

Preber was elected chairman of the firm’s partnership board in December 2018, according to his online professional profile. He has served as national managing partner of business risk services and as managing partner of the firm’s Phoenix office. He joined the firm in 2009, a few years after departing Arthur Anderson in 2002, where he was a partner.