Board of Directors

Audit Committee

Compensation and Leadership Development Committee

Nominating and Corporate Governance Committee

Health, Safety and Environment Committee

Chairman of the Board, President and CEO, Pacific Star Energy LLC

Former Managing Director, Credit Suisse First Boston

Chairman and CEO, ProPetro Holding Corp.

Retired Dean, Mewbourne College of Earth and Energy, University of Oklahoma

Executive Consultant

Retired Vice President, Shell Oil Company

Retired Vice President and Treasurer, Exxon Mobil Corporation

Chief Executive Officer

Retired Vice Chairman and Chief Financial Officer, Brown-Forman Corporation

Chief Legal Officer, Reata Pharmaceuticals, Inc.