| 1 | Adams Resources Expl. Corp. | Houston, TX 77001 | Oil & Gas Operator | Apr 2020 |
| 2 | Ads | Caldwell, TX 77836 | Oil & Gas Operator | Dec 2010 |
| 3 | Ads Oil & Gas, Inc. | Caldwell, TX 77836 | Oil & Gas Operator | Dec 2024 |
| 4 | Alcorn Prod Co. | Victoria, TX 77902 | Oil & Gas Operator | Mar 1997 |
| 5 | Alexander Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 6 | Allegiant Resources, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Dec 2024 |
| 7 | Amcon Resources, Inc. | Oklahoma City, OK 73101 | Gas Operator | Jun 2016 |
| 8 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 9 | Anadarko Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Feb 2006 |
| 10 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 11 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Sep 2024 |
| 12 | Anatexas Offshore, Inc. | Houston, TX 77024 | Oil & Gas Operator | Dec 2024 |
| 13 | Anchor Operating Co. | Houston, TX 77055 | Oil & Gas Operator | Dec 2024 |
| 14 | Aop Operating Corporation | Dallas, TX 75313 | Oil & Gas Operator | Aug 2003 |
| 15 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Dec 2024 |
| 16 | Arledge, Terry | Rockdale, TX 76567 | Oil & Gas Operator | Sep 2019 |
| 17 | Arm Energy Management LLC | Houston, TX 77070 | Oil & Gas Operator | Sep 2024 |
| 18 | Armor Energy LLC | Tulsa, OK 74146 | Oil & Gas Operator | Jun 2022 |
| 19 | Arrow Exploration Company | Plano, TX 75075 | Oil & Gas Operator | Dec 2004 |
| 20 | Atasca Resources Inc | Houston, TX 77219 | Oil & Gas Operator | Dec 2024 |
| 21 | Atkinson Energy Corporation | Giddings, TX 78942 | Oil & Gas Operator | Jan 2010 |
| 22 | Atlas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 23 | Austin Energy Operations, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Dec 2024 |
| 24 | Austin Minerals Inc. | Austin, TX 78720 | Oil & Gas Operator | Dec 2024 |