| 1 | A. Michael Hyde Oil & Gas Co. | | Oil & Gas Operator | Jan 1989 |
| 2 | Abco Petroleum Corp. | | Oil & Gas Operator | Feb 1999 |
| 3 | Acadian Land & Expl., Inc. | | Oil & Gas Operator | May 1992 |
| 4 | Aethon Energy Operating LLC | Dallas, TX 75251 | Oil & Gas Operator | Oct 2025 |
| 5 | Agate Petroleum, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2015 |
| 6 | Akin Beene Resources LLC | | Oil & Gas Operator | May 2016 |
| 7 | Alice-Sidney Oil Co | El Dorado, AR 71730 | Oil & Gas Operator | Feb 1995 |
| 8 | Alice-Sidney Oil Co LTD PRTSHP | | Oil & Gas Operator | Mar 2020 |
| 9 | Altair Corporation | | Oil & Gas Operator | Jul 1998 |
| 10 | American Trading & Prod Corp | Houston, TX 77040-6471 | Oil & Gas Operator | Nov 2014 |
| 11 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 12 | Amplify Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 13 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 14 | Arapahoe SPV LLC | | Oil & Gas Operator | Feb 2023 |
| 15 | Arco O & G Co-Div Atl Rich Co | | Oil & Gas Operator | Feb 1994 |
| 16 | Arkla Energy Resources | Shreveport, LA 71151 | Oil & Gas Operator | Mar 2015 |
| 17 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |
| 18 | Art Machin & Associates, Inc. | | Oil & Gas Operator | Jul 1997 |
| 19 | Arxana Oil & Gas Company, LLC | | Oil & Gas Operator | Jun 1998 |
| 20 | Associated Natural Gas, Inc. | | Oil Operator | Apr 1996 |