| 1 | A. J. Hodges, Ind. Inc Et Al | | Oil & Gas Operator | Jan 1979 |
| 2 | A. Michael Hyde Oil & Gas Co. | | Oil & Gas Operator | Jan 1989 |
| 3 | A.J. Hodges Industries, Inc. | | Oil & Gas Operator | Sep 1987 |
| 4 | Aethon Energy Operating LLC | Dallas, TX 75251 | Oil & Gas Operator | Oct 2025 |
| 5 | Ainsworth Prod Co. | | Oil Operator | Aug 1986 |
| 6 | Aix Energy Inc | | Oil & Gas Operator | Jul 2016 |
| 7 | Akin Beene Resources LLC | | Oil & Gas Operator | May 2016 |
| 8 | Alpine Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 9 | Amax Petroleum Corporation | Houston, TX 77042 | Oil & Gas Operator | Dec 2012 |
| 10 | Ambrit Energy Corporation | Garland, TX 75044 | Oil & Gas Operator | Jun 2003 |
| 11 | American Petrofina Co Of Texas | | Oil & Gas Operator | Jun 1985 |
| 12 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 13 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 14 | Aracca Petroleum Corporation | | Oil Operator | Dec 1987 |
| 15 | Arapahoe SPV LLC | | Oil & Gas Operator | Feb 2023 |
| 16 | Arco O & G Co-Div Atl Rich Co | | Oil & Gas Operator | Feb 1994 |
| 17 | Arena Resources LLC | Longview, TX 75608 | Oil & Gas Operator | Jul 2025 |
| 18 | Arkla Energy Resources | Shreveport, LA 71151 | Oil & Gas Operator | Mar 2015 |
| 19 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |
| 20 | Arxana Oil & Gas Company, LLC | | Oil & Gas Operator | Jun 1998 |
| 21 | Ashton Oil & Gas, Inc. | | Oil Operator | Jun 1990 |
| 22 | Associated Natural Gas, Inc. | | Oil Operator | Apr 1996 |
| 23 | Atlanta Exploration Co. | | Oil & Gas Operator | Oct 2001 |
| 24 | Austral Oil Company Incorporated | Sulphur, LA 70663 | Oil & Gas Operator | Mar 2008 |