| 1 | A & A Tank Truck Company | Norman, OK 73070-8969 | Oil & Gas Operator | Jul 2025 |
| 2 | Abarr Trust (The) | Oklahoma City, OK 73179 | Oil & Gas Operator | Jul 2025 |
| 3 | Adams Res & Energy Co | Houston, TX 77001-0844 | Oil & Gas Operator | Mar 2015 |
| 4 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 5 | Aguila Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Jul 2025 |
| 6 | Aleco Production Company | | Oil & Gas Operator | Nov 1997 |
| 7 | Alexander Energy Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 8 | Alliance Resources Corporation | Dallas, TX 75367 | Oil & Gas Operator | Nov 2024 |
| 9 | Alpar Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jul 2011 |
| 10 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 11 | American Cometra, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2008 |
| 12 | Amplify Oklahoma Operating LLC | Houston, TX 77002-4800 | Oil & Gas Operator | Jun 2025 |
| 13 | An-Son Corporation | Oklahoma City, OK 73124 | Oil & Gas Operator | Jan 2006 |
| 14 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 15 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 16 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jul 2025 |
| 17 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 18 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 19 | Antares Energy Company | Houston, TX 77010 | Oil & Gas Operator | Oct 2025 |
| 20 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 21 | Apache PHN North America, Inc. | | Oil & Gas Operator | Mar 2005 |
| 22 | Apc Operating Partnership LP | Tulsa, OK 74136-4224 | Oil & Gas Operator | Jun 2015 |
| 23 | Apco Oil Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jun 1993 |
| 24 | Arapaho Petroleum Inc | Englewood, CO 80155 | Oil & Gas Operator | Nov 1998 |
| 25 | Arnett Saltwater Disposal LLC | Shattuck, OK 73858-0848 | Oil Operator | Dec 2021 |
| 26 | Arrow Oil & Gas, LLC | Norman, OK 73070 | Oil & Gas Operator | Oct 2025 |
| 27 | Arrowhead Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Jun 2025 |
| 28 | Arvine Pipe & Supply Co Inc | Norman, OK 73069-8224 | Oil & Gas Operator | Jul 2015 |
| 29 | Aspen Energy Group, Inc. | Santa Ynez, CA 93460 | Oil & Gas Operator | Mar 2015 |
| 30 | Atchley Resources, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 31 | Athena Energy, Inc. | Gallatin, TN 37066 | Oil & Gas Operator | Oct 2025 |
| 32 | Atlantic Richfield Company | Plano, TX 75074 | Oil & Gas Operator | Dec 2016 |
| 33 | Atteberry Engineering | Edmond, OK 73013-6624 | Oil & Gas Operator | Mar 2008 |
| 34 | Axem Resources Inc | Denver, CO 80202-4617 | Oil & Gas Operator | Jul 2013 |
| 35 | Axis Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | Oct 2025 |