| 1 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 2 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 3 | Pemberton, W. C. Oil Co., Inc. | Cameron, TX 76520 | Oil & Gas Operator | Dec 2024 |
| 4 | Penn VIrginia Oil & Gas Corp | Houston, TX 77024 | Oil & Gas Operator | Dec 2018 |
| 5 | Penroc Oil Corp. | Hobbs, NM 88241 | Oil & Gas Operator | Sep 2024 |
| 6 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2024 |
| 7 | Petrogas Operating Corporation | Garland, TX 75043 | Oil Operator | Feb 2010 |
| 8 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 9 | Pierce Junction Petroleum Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2010 |
| 10 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 11 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 12 | Pomykal, Verde Oil Co | Brenham, TX 77833 | Oil & Gas Operator | Dec 2024 |
| 13 | Powell-McCarroll Partnership | Sachse, TX 75048 | Oil & Gas Operator | Dec 2024 |
| 14 | Prime Natural Resources, Inc. | Houston, TX 77042 | Oil & Gas Operator | Jun 2007 |
| 15 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |