Scott D. Sheffield currently serves as President and Chief Executive Officer of Pioneer Natural Resources, now the second-largest crude producer in Texas. Mr. Sheffield is an energy industry leader who played significant roles in the American shale revolution and in lifting the US crude oil export ban. He began his career as a Reservoir Engineer with Amoco Production Co. In 1979, Sheffield joined Parker & Parsley Petroleum Co. By 1985, he was the company’s CEO, and he became its Chairman in 1991. When Parker & Parsley merged with MESA, Inc., in 1997 to form Pioneer Natural Resources, Mr. Sheffield became its founding CEO, later becoming Chairman of the Board in 1999. He retired from Pioneer in 2016 but returned as President and CEO in 2019 and continues to serve on the board. His board affiliations include The Williams Companies, Inc., the Center for Global Energy Policy at Columbia University, and the Energy Council of CSL Capital Management, LLC. The Permian Basin Petroleum Association honored Mr. Sheffield with its prestigious Top Hand award, and he is a 2013 inductee into the Permian Basin Petroleum Museum Hall of Fame, among numerous awards recognizing his leadership and philanthropic efforts. Mr. Sheffield holds a Bachelor of Science degree in petroleum engineering from the University of Texas.