People: Pioneer Natural Resources Co (PXD)

Mr. Mark Stephen Berg is Executive Vice President, General Counsel of Pioneer Natural Resources Co. Mr. Berg was also elected Executive Vice President, General Counsel and Assistant Secretary of Pioneer GP in June 2007. Prior to joining the Company, Mr. Berg served as Executive Vice President, General Counsel and Secretary of American General Corporation, a Fortune 200 diversified financial services company, from 1997 through 2002. Subsequent to the sale of American General to American International Group, Inc., Mr. Berg joined Hanover Compressor Company as Senior Vice President, General Counsel and Secretary. He served in that capacity from May 2002 through April 2004. Mr. Berg began his career in 1983 with the Houston-based law firm of Vinson & Elkins L.L.P. He was a partner with the firm from 1990 through 1997. Mr. Berg graduated Magna Cum Laude and Phi Beta Kappa with a Bachelor of Arts degree from Tulane University in 1980. He earned his Juris Doctorate with honors from The University of Texas Law School in 1983.