| 1 | A.D.A. Oil Co | Iowa Park, TX 76367 | Oil Operator | Aug 2003 |
| 2 | Acacia Operating, LLC | | Oil & Gas Operator | Jul 2025 |
| 3 | Ace Energy LLC | Leawood, KS 66211 | Oil & Gas Operator | Sep 2025 |
| 4 | Achilles Oil, LLC | | Oil & Gas Operator | Aug 2025 |
| 5 | Ad Astra Resources LLC | Wichita, KS 67203 | Oil & Gas Operator | Sep 2025 |
| 6 | Ada Oil Exploration Corp | | Oil & Gas Operator | Jan 1986 |
| 7 | Adams Resources Expl. Corp. | Houston, TX 77001 | Oil & Gas Operator | Apr 2020 |
| 8 | Adco Producing Co. | | Oil & Gas Operator | Mar 1989 |
| 9 | Ainsworth, Otis | | Oil & Gas Operator | Jun 1987 |
| 10 | Alamosa Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2025 |
| 11 | Albert E. Smith Oil | | Oil Operator | Aug 2025 |
| 12 | Aldridge Operating Co., LLC | | Oil & Gas Operator | Aug 2019 |
| 13 | Alex Oil Co. | | Oil Operator | Jun 1996 |
| 14 | Allen Operating Company, LLC | | Oil & Gas Operator | Dec 2022 |
| 15 | Allstar Oil And Gas Inc. | | Oil & Gas Operator | Nov 1992 |
| 16 | Alpine Gas Operator, LLC | | Oil & Gas Operator | Jun 2024 |
| 17 | Alpine Well Service, Inc. | | Oil & Gas Operator | Dec 2023 |
| 18 | Amax Petroluem Corp. | | Oil & Gas Operator | Nov 1983 |
| 19 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 20 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 21 | American Quasar Petroleum Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2014 |
| 22 | American Southwest Corp. | | Oil & Gas Operator | Dec 1989 |
| 23 | Amoco Production Company | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 24 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Sep 2025 |
| 25 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 26 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 27 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Nov 2025 |
| 28 | Aria Operating LLC | | Oil Operator | Aug 2025 |
| 29 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |
| 30 | Austin Production Company, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Mar 2015 |
| 31 | Australis TMS Inc. | | Oil & Gas Operator | Aug 2025 |
| 32 | Avad Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Nov 2025 |
| 33 | Aviara Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2002 |