| 1 | Abel, M.D. Co. | Lampasas, TX 76550 | Oil & Gas Operator | Jun 2017 |
| 2 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Jun 2025 |
| 3 | Abraxas Production Corporation | San Antonio, TX 78270 | Oil & Gas Operator | Sep 1999 |
| 4 | Accell Natural Gas Company | Houston, TX 77042 | Oil & Gas Operator | Sep 1998 |
| 5 | Aeg Operating, LLC | Austin, TX 78746 | Oil Operator | Jun 2012 |
| 6 | Aghorn Operating, Inc. | Odessa, TX 79768 | Oil & Gas Operator | Jun 2025 |
| 7 | Ajax Resources, LLC | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 8 | Allar Co., The | Graham, TX 76450 | Oil & Gas Operator | Dec 2004 |
| 9 | Alpine Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 10 | Alta Energy Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1995 |
| 11 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 12 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 13 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 14 | Amerind Oil Company, LTD. | Midland, TX 79701 | Oil & Gas Operator | Nov 2004 |
| 15 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 16 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 17 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Mar 2025 |
| 18 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 19 | Antelope Production Co. | Midland, TX 79701 | Oil & Gas Operator | Oct 1995 |
| 20 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 21 | Arch Petroleum Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2008 |
| 22 | Arco Oil & Gas Company | Plano, TX 75086 | Oil & Gas Operator | Mar 2006 |
| 23 | Arco Permian | Houston, TX 77079 | Oil & Gas Operator | Dec 2001 |
| 24 | Arkland Producing Co Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2023 |
| 25 | Aroc (Texas) Inc | Houston, TX 77090 | Oil & Gas Operator | Dec 2014 |
| 26 | Arrington,David H. Oil & Gas,Inc | Midland, TX 79702 | Oil & Gas Operator | Jun 2025 |
| 27 | Arya Resources, LLC | Midland, TX 79710 | Oil & Gas Operator | Jun 2025 |
| 28 | Asher Resources | Boerne, TX 78006 | Oil & Gas Operator | May 2015 |
| 29 | Aspen Operating Company LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Jun 2025 |
| 30 | Athlon Energy Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2014 |
| 31 | Athlon Fe Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2015 |
| 32 | Athlon Holdings LP | Denver, CO 80202 | Oil & Gas Operator | Jan 2015 |
| 33 | Atlantic Oil Corporation | Denver, CO 80206 | Oil & Gas Operator | Dec 1982 |
| 34 | Atlas Energy Corporation (Del.) | Oklahoma City, OK 73112 | Oil & Gas Operator | Jun 2025 |
| 35 | Austral Oil Company Incorporated | Sulphur, LA 70663 | Oil & Gas Operator | Mar 2008 |
| 36 | Avra Oil Co | Dallas, TX 75248 | Oil & Gas Operator | Jun 2025 |