| 1 | Acco Oil & Gas Company | Houston, TX 77056 | Oil & Gas Operator | Sep 2001 |
| 2 | Acierto Resources Company, LLC | Houston, TX 77070 | Oil & Gas Operator | Oct 2025 |
| 3 | Acoma Oil Corporation | Saint Paul, MN 55102 | Oil & Gas Operator | Oct 2025 |
| 4 | Adams Resources Expl. Corp. | Houston, TX 77001 | Oil & Gas Operator | Apr 2020 |
| 5 | Alamo Operating Company, L. C. | San Antonio, TX 78278 | Oil & Gas Operator | Aug 2023 |
| 6 | Alaron Energy, Inc. | Irving, TX 75038 | Oil & Gas Operator | Oct 2025 |
| 7 | Allegro Investments, Inc. | Victoria, TX 77903 | Oil & Gas Operator | Nov 2020 |
| 8 | Alltex Exploration, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 9 | Alpine Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 10 | Altman Energy, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Oct 2025 |
| 11 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 12 | Ambrit Energy Corporation | Garland, TX 75044 | Oil & Gas Operator | Jun 2003 |
| 13 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 14 | American Energy Op. Corp.,The | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 15 | American Energy Sources, Inc. | Spring, TX 77388 | Oil & Gas Operator | Dec 2008 |
| 16 | Anadarko Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Feb 2006 |
| 17 | Anaqua Oil & Gas, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2008 |
| 18 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 19 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 20 | Arco Oil & Gas Company | Plano, TX 75086 | Oil & Gas Operator | Mar 2006 |
| 21 | Arrington Oil&Gas Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 22 | Arrington,David H. Oil & Gas,Inc | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 23 | Ashland Exploration Inc | Houston, TX 77218 | Oil & Gas Operator | Nov 2000 |
| 24 | Aspect Energy, LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 25 | Atapco | Houston, TX 77040 | Oil & Gas Operator | Feb 1999 |
| 26 | Atlas Oil & Gas Exploration, LLC | Cedar Park, TX 78613 | Oil & Gas Operator | Aug 2003 |
| 27 | Atlas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 28 | Atmic, Inc. | Houston, TX 77002 | Oil & Gas Operator | Jun 2008 |
| 29 | Aurora Resources Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |