| 1 | Abo Petroleum Corp | Artesia, NM 88210 | Oil & Gas Operator | Jul 1988 |
| 2 | Adak Energy Corporation | Salt Lake City, UT 84106 | Gas Operator | Apr 1992 |
| 3 | Adams & Dizdar | | Gas Operator | Jun 1981 |
| 4 | Adams, Frank B | Corpus Christi, TX 78476 | Oil & Gas Operator | Feb 1988 |
| 5 | Advantage Resources Inc | Broomfield, CO 80020 | Oil & Gas Operator | Sep 2025 |
| 6 | Afe Management Limited | Concord, Ontario, L4K 4G4 | Oil & Gas Operator | Sep 1987 |
| 7 | Alberta Gas Company | Vernal, UT 84078 | Oil & Gas Operator | Nov 2021 |
| 8 | Albritton Resources Inc | Dallas, TX 75206 | Oil & Gas Operator | Feb 2001 |
| 9 | Alco Oil & Gas | Lafayette, LA 70130 | Oil & Gas Operator | Dec 1970 |
| 10 | Alta Energy Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1995 |
| 11 | Altamont Energy Operating LLC | Greenwood VIlliage, CO 80111 | Oil & Gas Operator | Sep 2024 |
| 12 | Altex Oil Corp | Breckenridge, CO 80424-1057 | Oil & Gas Operator | Dec 1999 |
| 13 | Amax Petroleum Corporation | Houston, TX 77042 | Oil & Gas Operator | Dec 2012 |
| 14 | Ambra Oil & Gas Company | Rangely, CO 81648 | Oil & Gas Operator | Jul 2006 |
| 15 | American Helium Operating, LLC | Katy, TX 77494 | Oil & Gas Operator | Nov 2025 |
| 16 | American Quasar Petroleum | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 1985 |
| 17 | Amoco Production Company | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 18 | Amoco Rocmount Company | Denver, CO 80201 | Oil & Gas Operator | Jan 1998 |
| 19 | Amtech Energy Inc | Plymouth, IL 62367-1016 | Oil & Gas Operator | Dec 2021 |
| 20 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Feb 2026 |
| 21 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Nov 2025 |
| 22 | Anr Limited Inc/Coastal | Houston, TX 770460995 | Oil & Gas Operator | Dec 1987 |
| 23 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 24 | Anschutz Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2016 |
| 25 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 26 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Feb 2026 |
| 27 | Apc Operating Partnership | Tulsa, OK 74136 | Oil & Gas Operator | Oct 1996 |
| 28 | Appaloosa Operating Company LLC | The Woodlands, TX 77387 | Oil & Gas Operator | Apr 2019 |
| 29 | Arb Energy Utah, LLC | Katy, TX 77494 | Oil & Gas Operator | Oct 2025 |
| 30 | Arch Oil And Gas Company | Midland, TX 79702 | Oil & Gas Operator | Feb 1994 |
| 31 | Arco Oil & Gas Company | Plano, TX 75086 | Oil & Gas Operator | Mar 2006 |
| 32 | Asamera Oil Us Inc | Denver, CO 80201 | Oil & Gas Operator | Jul 1985 |
| 33 | Ashley Valley Operating Company LLC | Orem, UT 84097 | Oil & Gas Operator | Oct 2025 |
| 34 | Augustus Energy Partners LLC | Billings, MT 59102 | Oil & Gas Operator | Oct 2013 |
| 35 | Avad Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 36 | Aviara Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2002 |
| 37 | Axia Energy II LLC | HGHLNDS Ranch, CO 80129 | Oil & Gas Operator | Jan 2020 |
| 38 | Axia Energy LLC | Hghlands Ranch, CO 80129-2258 | Oil & Gas Operator | Apr 2015 |
| 39 | Aztec Oil Co | | Oil & Gas Operator | Dec 1977 |