| 1 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Oct 2025 |
| 2 | Abraxas Production Corporation | San Antonio, TX 78270 | Oil & Gas Operator | Sep 1999 |
| 3 | Acock Engineering & Assoc., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2002 |
| 4 | Acock Operating Limited | San Antonio, TX 78270 | Oil & Gas Operator | Oct 2025 |
| 5 | Acock/Anaqua Operating Co., LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 6 | Ageron Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 7 | Alamo Operating Company, L. C. | San Antonio, TX 78278 | Oil & Gas Operator | Aug 2023 |
| 8 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 9 | American Cometra, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2008 |
| 10 | American Shoreline, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 11 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 12 | Ampak Oil Company | Plano, TX 75074 | Oil & Gas Operator | Oct 2025 |
| 13 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 14 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 15 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jul 2025 |
| 16 | Apex Resources Inc | Allison Park, PA 15101-3838 | Oil & Gas Operator | Dec 1993 |
| 17 | Arpel, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2014 |
| 18 | Ashby, Andrew M. | Golden, CO 80401 | Oil & Gas Operator | Jul 1998 |
| 19 | Asher Resources | Boerne, TX 78006 | Oil & Gas Operator | May 2015 |
| 20 | Aurora Resources Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 21 | Av-Tech Resources Corporation | Kerrville, TX 78028 | Oil & Gas Operator | Jul 2022 |