X0202 4/A 2007-06-01 2007-06-04 0 0001038357 PIONEER NATURAL RESOURCES CO PXD 0001034310 RAMSEY CHARLES E JR 5205 N. O'CONNOR BLVD., SUITE 200 IRVING TX 75039 1 0 0 0 Common Stock 2007-06-01 4 M 0 3625 0.00 A 25619 D The original Forms 4, filed by the reporting person on May 17, 2007 and June 4, 2007, reporting acquisitions that occurred on May 16, 2007 and June 1, 2007, overstated the number of shares beneficially held by the reporting person following each transaction by 2,000 shares. By: Mark H. Kleinman, Attorney-in-Fact For: Charles E. Ramsey, Jr. 2007-06-12