CEO Aubrey McClendon remains confident in Chesapeake's future

Williams said he hopes McClendon will continue to use his entrepreneurial skills to build on his legacy in Oklahoma City after he leaves Chesapeake.

Chesapeake's board has retained executive search firm Heidrick & Struggles to find McClendon's successor. The search is expected to include internal and external candidates, with input from McClendon.

In the interim, McClendon will work closely with top Chesapeake executives Steve Dixon and Nick Dell'Osso to hand off some of his day-to-day responsibilities at the company.

In his email Tuesday, Dunham told employees that Dixon, Chesapeake's chief operating officer, and Dell'Osso, the company's chief financial officer, will be able to address any rumors that arise with the news of McClendon's retirement.

Dunham also expressed his optimism about the company's future.

“We are at an important transition point for our company, but it is also a point of great opportunity,” Dunham wrote.

Chesapeake said McClendon will remain an important partner because he still owns company stock and interests in some of its wells through the Founders Well Participation Program, which will remain in place through June 2014.

The participation program had been part of McClendon's compensation package since 1993, but he agreed to negotiate an early end to it in April after it was reported he had secured more than $1 billion in loans to fund his share of the company's well costs. Shareholders had approved it to run through 2015.