| 1 | Aber Oil & Gas Co. | Tyler, TX 75702 | Oil & Gas Operator | Nov 2013 |
| 2 | Ac Exploration, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 3 | Aeon Operating, Inc. | Fate, TX 75132 | Oil & Gas Operator | Oct 2025 |
| 4 | Alegre Energy Operating, LP | San Antonio, TX 78216 | Oil & Gas Operator | Sep 2005 |
| 5 | Alegre Energy, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Oct 2025 |
| 6 | Alexander, Herbert R. Inc. | Houma, LA 70360 | Oil & Gas Operator | Jun 1998 |
| 7 | Allied Operating Texas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 8 | Allison/Hobbs Inc. | Alba, TX 75410 | Oil & Gas Operator | Oct 2025 |
| 9 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 10 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 11 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 12 | Andrews & Corkran, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Feb 2000 |
| 13 | Arcadia Expl. & Prod. Company | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2011 |
| 14 | Ark-La-Tex Energy, L.L.C. | Shreveport, LA 71101 | Oil & Gas Operator | Oct 2025 |
| 15 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |
| 16 | Aruba Petroleum, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Jun 2025 |
| 17 | Atlantis Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Oct 2025 |
| 18 | Atoka Operating, Inc. | Gainesville, TX 76241 | Oil & Gas Operator | Oct 2025 |