Chesapeake Energy Corporation and Bronco Drilling Company, Inc. Announce Entry into a Memorandum of Understanding in Shareholder Lawsuit

Chesapeake Energy Corporation

and Bronco Drilling Company, Inc.

today announced that they have entered into a memorandum of understanding on May 17, 2011 as to the key terms of the settlement agreement in connection with the putative consolidated class action, captioned In Re: Bronco Drilling Company, Inc. Shareholder Litigation, pending in the Court of Chancery of the State of Delaware. Pursuant to the memorandum of understanding, Chesapeake and Bronco have entered into an amendment to the pending merger agreement and 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. The cash tender offer was previously scheduled to expire at 12:00 midnight, New York City time, on Monday, May 23, 2011 and will now expire at 12:00 midnight, New York City time, on Tuesday, May 31, 2011, unless further extended in accordance with the merger agreement, applicable rules and regulations and the procedures described in the Offer to Purchase. Pursuant to the cash tender offer, Nomac Acquisition, Inc. is offering to purchase all outstanding Bronco shares for $11.00 per share in cash, without interest and less any required withholding taxes.