| 1 | A & T Oil Company | Midland, TX 79707 | Oil & Gas Operator | Sep 2008 |
| 2 | A & T Production Company | Wheat Ridge, CO 80034-1048 | Oil & Gas Operator | Jun 2009 |
| 3 | A J Acid Inc | Blackwell, OK 74631-0758 | Oil & Gas Operator | Dec 2012 |
| 4 | A R W Exploration Corp | Stillwater, OK 74076 | Oil & Gas Operator | May 2013 |
| 5 | Aaron Oil Company Inc | Shawnee, OK 74801-2321 | Oil Operator | Oct 2022 |
| 6 | Abarr Trust (The) | Oklahoma City, OK 73179 | Oil & Gas Operator | Jul 2025 |
| 7 | ABC Oil Co. | Wichita Falls, TX 76301 | Oil & Gas Operator | Oct 2023 |
| 8 | Abercrombie, A. L., Inc | Wichita, KS 67202 | Oil & Gas Operator | Jun 2025 |
| 9 | Ablaze Drilling Company | Garland, TX 75044-2912 | Oil & Gas Operator | Aug 2013 |
| 10 | Advent Oil & Operating Inc | Gulfport, MS 39506-7115 | Oil & Gas Operator | Nov 2014 |
| 11 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 12 | Aguila Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Jul 2025 |
| 13 | Alamo Resources Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 14 | Allen Michael | Broken Arrow, OK 74014-2239 | Oil & Gas Operator | Apr 2025 |
| 15 | Altex Resources, Inc. | Carney, OK 74832 | Oil & Gas Operator | Mar 2015 |
| 16 | Altman Energy, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Oct 2025 |
| 17 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 18 | American Domestic MGMT Inc | Tulsa, OK 74155 | Oil & Gas Operator | Apr 2015 |
| 19 | American Trading & Prod Corp | Houston, TX 77040-6471 | Oil & Gas Operator | Nov 2014 |
| 20 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 21 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jul 2025 |
| 22 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 23 | Anstine & Musgrove Inc | Ponca City, OK 74602 | Oil & Gas Operator | Jun 2025 |
| 24 | Anstine-Musgrove Oil Company | Ponca City, OK 74602-0391 | Oil & Gas Operator | Jan 2013 |
| 25 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 26 | Apc Operating Partnership LP | Tulsa, OK 74136-4224 | Oil & Gas Operator | Jun 2015 |
| 27 | Apogee Oil & Gas LLC | Edmond, OK 73034 | Oil Operator | May 2025 |
| 28 | Arrow Oil & Gas, LLC | Norman, OK 73070 | Oil & Gas Operator | Oct 2025 |
| 29 | Aspen Operating Company LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Oct 2025 |
| 30 | Avalanche Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Oct 2025 |