Chesapeake Energy Corporation and Bronco Drilling Company Announce Entry into an Agreement in Principle in Shareholder Lawsuit

Chesapeake Energy Corporation

and Bronco Drilling Company, Inc.

today announced that they entered into an agreement in principle on May 27, 2011 as to the key terms of the settlement agreement in connection with the putative consolidated class action, captioned Shriver v. Bronco Drilling Company, Inc., et al., filed in the District Court of Oklahoma County, Oklahoma. Pursuant to that agreement, Nomac Acquisition, Inc., Chesapeake's indirect wholly owned subsidiary, has extended its cash tender offer to purchase all outstanding shares of common stock of Bronco.