| 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 | Feb 2026 |
| 4 | Aegis Fluids Management, LLC | Plano, TX 75093 | Oil & Gas Operator | Feb 2026 |
| 5 | Aim Consultants Inc. | Rockville, MD 20852 | Oil & Gas Operator | Mar 2008 |
| 6 | Akg Operating Company | Austin, TX 78701 | Oil & Gas Operator | Feb 2026 |
| 7 | Alamo Operating Company, L. C. | San Antonio, TX 78278 | Oil & Gas Operator | Aug 2023 |
| 8 | Alcorn Prod Co. | Victoria, TX 77902 | Oil & Gas Operator | Mar 1997 |
| 9 | Alexander Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 10 | All Am, Inc. | Houston, TX 77057 | Oil & Gas Operator | Feb 2016 |
| 11 | Allegiant Resources, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Feb 2026 |
| 12 | American Delta Corporation | Portland, TX 78374 | Oil & Gas Operator | Jun 2013 |
| 13 | American Royalty | Caldwell, TX 77836 | Oil & Gas Operator | Oct 2005 |
| 14 | Amoco Production Company | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 15 | Anadarko Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Feb 2006 |
| 16 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 17 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Feb 2026 |
| 18 | Anchor Operating Co. | Houston, TX 77055 | Oil & Gas Operator | Feb 2026 |
| 19 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Feb 2026 |
| 20 | Arabie, Inc. | Lake Charles, LA 70605 | Oil & Gas Operator | Apr 2025 |
| 21 | Arcturus Operating Company | Addison, TX 75001 | Oil & Gas Operator | Feb 2026 |
| 22 | Ares Energy, LTD. | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 23 | Argent Petroleum Corporation | Center, TX 75935 | Oil & Gas Operator | Feb 2026 |
| 24 | Arledge, Terry | Rockdale, TX 76567 | Oil & Gas Operator | Sep 2019 |
| 25 | Arrow Exploration Company | Plano, TX 75075 | Oil & Gas Operator | Dec 2004 |
| 26 | Arrowhead Operating Inc. | Argyle, TX 76226 | Oil & Gas Operator | Feb 2026 |
| 27 | Aruba Petroleum, LTD. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2003 |
| 28 | Asm Oil & Gas Company, Inc. | Dallas, TX 75367 | Oil & Gas Operator | May 2020 |
| 29 | Atasca Resources, Inc. | Houston, TX 77219 | Oil & Gas Operator | Feb 2026 |
| 30 | Atinum Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 31 | Atkinson Energy Corporation | Giddings, TX 78942 | Oil & Gas Operator | Jan 2010 |
| 32 | Atlas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 33 | Ausco Texas Exploration, LLC | Bastrop, TX 78602 | Oil & Gas Operator | Feb 2026 |
| 34 | Austin Minerals Inc. | Uvalde, TX 78801 | Oil & Gas Operator | Feb 2026 |
| 35 | Austin Ridge Energy Corporation | Houston, TX 77224 | Oil & Gas Operator | Feb 2026 |
| 36 | Austral Oil Company Incorporated | Sulphur, LA 70663 | Oil & Gas Operator | Mar 2008 |