| 1 | Abaco Operating, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 2 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Oct 2025 |
| 3 | Abraxas Production Corporation | San Antonio, TX 78270 | Oil & Gas Operator | Sep 1999 |
| 4 | Acock Engineering & Assoc., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2002 |
| 5 | Acock Operating Limited | San Antonio, TX 78270 | Oil & Gas Operator | Oct 2025 |
| 6 | Acock/Anaqua Operating Co., LC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2004 |
| 7 | Acock/Anaqua Operating Co., LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 8 | Alamo Operating Company, L. C. | San Antonio, TX 78278 | Oil & Gas Operator | Aug 2023 |
| 9 | Alcorn Prod Co. | Victoria, TX 77902 | Oil & Gas Operator | Mar 1997 |
| 10 | Alegre Energy, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Oct 2025 |
| 11 | Alltex Exploration, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 12 | Alpha Omega Petroleum, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Mar 1996 |
| 13 | Altman Energy, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Oct 2025 |
| 14 | Alyndson Oil & Gas Inc. | Alice, TX 78333 | Oil & Gas Operator | Jun 2000 |
| 15 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 16 | Amend Energy Company | Houston, TX 77227 | Oil & Gas Operator | Apr 2002 |
| 17 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 18 | Americo Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2012 |
| 19 | Ammo Energy, LLC | Oklahoma City, OK 73160 | Oil & Gas Operator | Feb 2009 |
| 20 | Ampak Oil Company | Plano, TX 75074 | Oil & Gas Operator | Oct 2025 |
| 21 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 22 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 23 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 24 | Ascent Energy, Inc | McKinney, TX 75069 | Oil & Gas Operator | Nov 2008 |
| 25 | Ascent Operating, LP | Plano, TX 75093 | Oil & Gas Operator | Aug 2008 |
| 26 | Atinum Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 27 | Aurora Resources Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |