| 1 | Abel Production Company | San Angelo, TX 76904 | Oil & Gas Operator | Sep 2000 |
| 2 | Aberdeen Petroleum (USA) Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 1994 |
| 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 | Adcock, Carol | Ozona, TX 76943 | Oil & Gas Operator | Oct 2025 |
| 6 | Adcock, Leroy | Ozona, TX 76943 | Oil & Gas Operator | Jun 2009 |
| 7 | Alegre Energy, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Oct 2025 |
| 8 | Allegro Operating, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 9 | Allison Lease Services LLC | Boerne, TX 78006 | Oil & Gas Operator | Oct 2025 |
| 10 | Alta Energy Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1995 |
| 11 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 12 | American Cometra, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2008 |
| 13 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 14 | Amerind Oil Company, LTD. | Midland, TX 79701 | Oil & Gas Operator | Nov 2004 |
| 15 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 16 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 17 | Anderson, James K. Inc. | Abilene, TX 79608 | Oil & Gas Operator | Oct 2025 |
| 18 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 19 | Apex Royalties, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 1997 |
| 20 | Approach Operating LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Sep 2020 |
| 21 | Arch Oil & Gas, LLC | Dallas, TX 75254 | Oil & Gas Operator | Oct 2025 |
| 22 | Arco Oil & Gas Company | Plano, TX 75086 | Oil & Gas Operator | Mar 2006 |
| 23 | Ardent Energy LLC | Edmond, OK 73083 | Oil & Gas Operator | Oct 2025 |
| 24 | Aries Operating LP | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 25 | Aries Operating, LLC | Houston, TX 77010 | Oil & Gas Operator | Feb 2010 |
| 26 | Arrington,David H. Oil & Gas,Inc | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 27 | Atlas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 28 | Atropos Exploration Company | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |