| 1 | Packard Gas Company | Irving, TX 75063 | Oil & Gas Operator | Nov 2006 |
| 2 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 3 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 4 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 5 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 6 | Perdido Energy, LLC | Houston, TX 77251 | Oil & Gas Operator | Dec 2024 |
| 7 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2024 |
| 8 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Aug 2024 |
| 9 | Petroleum Capital, L.C. | Dallas, TX 75367 | Oil & Gas Operator | Dec 2024 |
| 10 | Phillips 66 Company | Bartlesville, OK 74004 | Oil & Gas Operator | Aug 1997 |
| 11 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 12 | Pioneer Natural Res. (GPC), Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 1998 |
| 13 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | Dec 2024 |
| 14 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 15 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 16 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 17 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 18 | Prayer Oil & Gas Production, LLC | Hallsville, TX 75650 | Oil & Gas Operator | Dec 2024 |
| 19 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 20 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Dec 2024 |
| 21 | Progenies Operating LLC | Austin, TX 78746 | Oil & Gas Operator | Dec 2024 |