| 1 | A & T Production Company | Wheat Ridge, CO 80034-1048 | Oil & Gas Operator | Jun 2009 |
| 2 | A H & L Operating Company Inc | Norman, OK 73070-4084 | Oil & Gas Operator | Apr 2015 |
| 3 | Abarr Trust (The) | Oklahoma City, OK 73179 | Oil & Gas Operator | Jul 2025 |
| 4 | Ablaze Drilling Company | Garland, TX 75044-2912 | Oil & Gas Operator | Aug 2013 |
| 5 | Access Petroleum Corporation | | Oil & Gas Operator | Mar 2015 |
| 6 | Ackley Earl H & Glenora Trust | Cushing, OK 74023-5230 | Oil & Gas Operator | Mar 2015 |
| 7 | Adams Res & Energy Co | Houston, TX 77001-0844 | Oil & Gas Operator | Mar 2015 |
| 8 | Adeco Energy Corporation | Norman, OK 73071 | Oil & Gas Operator | Apr 2014 |
| 9 | Aei Production Company | Edmond, OK 73083 | Oil & Gas Operator | Mar 2014 |
| 10 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 11 | Aggie Oil Company | Lakewood, CO 80226 | Oil & Gas Operator | May 2001 |
| 12 | Alexander Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 13 | Allenergy Operating Co Inc | Coffeyville, KS 67337-6653 | Oil & Gas Operator | Mar 2015 |
| 14 | Alpha Energy Texas Operating LLC | Golden, CO 80401-3275 | Oil & Gas Operator | May 2025 |
| 15 | Alpine Inc | Oklahoma City, OK 73134-2504 | Oil & Gas Operator | Feb 2024 |
| 16 | Alpine Oil & Gas Inc | Edmond, OK 73083-1264 | Oil & Gas Operator | Mar 2008 |
| 17 | Alta Energy Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1995 |
| 18 | Altex Energy Corporation | Oklahoma City, OK 73142-1920 | Oil & Gas Operator | Mar 2015 |
| 19 | Altex Resources, Inc. | Carney, OK 74832 | Oil & Gas Operator | Mar 2015 |
| 20 | Altman Energy, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Oct 2025 |
| 21 | Amerex Corporation | Edmond, OK 73013-1044 | Oil & Gas Operator | Apr 2020 |
| 22 | American Energy Recovery Inc | Oklahoma City, OK 73123-0549 | Oil & Gas Operator | Aug 2017 |
| 23 | American Natural Energy Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 24 | American Natural Resources LLC | Tulsa, OK 74145-1117 | Oil & Gas Operator | May 2020 |
| 25 | Ames Oil Corporation Of Texas | Austin, TX 78720 | Oil & Gas Operator | Mar 2015 |
| 26 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 27 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 28 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jul 2025 |
| 29 | Anchorage Oil & Gas Inc | Oklahoma City, OK 73128-1422 | Oil & Gas Operator | Oct 1999 |
| 30 | Andco Mud Inc | Edmond, OK 73034-3910 | Oil & Gas Operator | Mar 2006 |
| 31 | Anderson Robert C Estate | San Diego, CA 92109 | Oil & Gas Operator | Jul 1994 |
| 32 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 33 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 34 | Apache Energy Resources Corp | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 35 | Apexco, Inc. | Sand Springs, OK 74063 | Oil & Gas Operator | Mar 2025 |
| 36 | Appleton Oil Company | Chicago, IL 60657-4097 | Oil & Gas Operator | May 1993 |
| 37 | Aqua-Oil Inc | Enid, OK 73703-6511 | Oil & Gas Operator | May 2019 |
| 38 | Arbuckle Enterprises, Inc. | Edmond, OK 73083 | Oil & Gas Operator | Jun 2025 |
| 39 | Arcadia Refining Company | Tyler, TX 75701 | Oil & Gas Operator | Jan 1994 |
| 40 | Ardent Energy LLC | Edmond, OK 73083 | Oil & Gas Operator | Oct 2025 |
| 41 | Aries Operating LP | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 42 | Arnold Oil Properties, L.L.C. | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 43 | Arrow Oil & Gas, LLC | Norman, OK 73070 | Oil & Gas Operator | Oct 2025 |
| 44 | Arrowhead Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Jun 2025 |
| 45 | Ashley, Jim Company | Broken Arrow, OK 74012 | Oil Operator | Jun 2025 |
| 46 | Aspen Energy Group, Inc. | Santa Ynez, CA 93460 | Oil & Gas Operator | Mar 2015 |
| 47 | Aspen Operating Company LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Oct 2025 |
| 48 | Assiduous Energy LLC | Edmond, OK 73034 | Oil & Gas Operator | Jun 2025 |
| 49 | Astro Energy Corporation | Edmond, OK 73083-3607 | Oil & Gas Operator | Sep 2014 |
| 50 | Atchley Resources, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 51 | Athabasca Energy Corporation | Simonton, TX 77476 | Oil & Gas Operator | Dec 2017 |
| 52 | Athan Inc | Edmond, OK 73013-6628 | Oil & Gas Operator | Jul 2025 |
| 53 | Atlanko Oil & Gas Inc | Tulsa, OK 74135-7846 | Oil & Gas Operator | Jun 2025 |
| 54 | Atlas Oil Inc | Oklahoma City, OK 73154-0467 | Oil & Gas Operator | Aug 2008 |
| 55 | Avalanche Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Oct 2025 |
| 56 | Avalon Exploration Inc | Tulsa, OK 74119-5401 | Oil & Gas Operator | Dec 2019 |