| 1 | A N R Pipeline Co | | Oil & Gas Operator | Jan 2025 |
| 2 | A. L. Coon | | Oil Operator | May 1979 |
| 3 | A. W. Sour, Jr. | | Oil Operator | Mar 2003 |
| 4 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Dec 2025 |
| 5 | Addie, James & John Thornton | | Oil & Gas Operator | Dec 2024 |
| 6 | Ainsworth Rig Service, LLC | | Oil Operator | Nov 2024 |
| 7 | Alameda Oil Company | | Oil Operator | Mar 1998 |
| 8 | Alpine Well Service, Inc. | | Oil & Gas Operator | Dec 2023 |
| 9 | American Casing Crews, Inc. | | Oil Operator | Dec 1979 |
| 10 | Apollo Petroleum Corporation | | Oil & Gas Operator | Dec 2012 |
| 11 | Aracca Petroleum Company | | Oil Operator | May 1984 |
| 12 | Aracca Petroleum Corporation | | Oil Operator | Dec 1987 |
| 13 | Arbor Petroleum Corporation | Oklahoma City, OK 73102-4003 | Oil & Gas Operator | Mar 2011 |
| 14 | Array Operating, LLC | | Oil & Gas Operator | Mar 2017 |
| 15 | Atkins Production | | Oil Operator | Dec 2008 |
| 16 | Atlanta Exploration Co. | | Oil & Gas Operator | Oct 2001 |
| 17 | Australis TMS Inc. | | Oil & Gas Operator | Sep 2025 |
| 18 | Axis Onshore, LLC | | Oil & Gas Operator | Apr 2008 |
| 19 | Axis Onshore, LP | | Oil & Gas Operator | Dec 2010 |