| 1 | M & M Oil Co., LLC | Oil City, LA 71061 | Oil & Gas Operator | Mar 2025 |
| 2 | M & S Production, Inc. | | Oil Operator | Jul 1994 |
| 3 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 4 | Malone-Killen Oil Expl. Co. | | Oil Operator | Apr 1992 |
| 5 | Mandalay Trading Services Inc. | | Oil Operator | Jul 1999 |
| 6 | Mann Production Co., Inc. | | Oil Operator | Nov 1995 |
| 7 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 8 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Jan 2025 |
| 9 | Mark Seifer | | Oil & Gas Operator | Dec 2024 |
| 10 | Marshall Exploration, Inc. | | Oil & Gas Operator | Jun 1992 |
| 11 | Martin Oil & Gas Co. | | Oil Operator | Jul 1981 |
| 12 | Martin Production Company | | Oil & Gas Operator | Dec 2024 |
| 13 | Marvin L. Muslow | | Oil Operator | Jun 1995 |
| 14 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 15 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 16 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 17 | McConathy Production Co.,Inc. | | Oil & Gas Operator | Jun 1990 |
| 18 | McEn 1996 Partnership | | Oil & Gas Operator | Sep 1999 |
| 19 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 20 | McKenzie Management Inc. | | Oil & Gas Operator | Aug 1989 |
| 21 | McMullan Oil Company | San Antonio, TX 78212 | Oil & Gas Operator | Jun 2023 |
| 22 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 23 | Menoah Petroleum Inc | | Oil & Gas Operator | Dec 2024 |
| 24 | Mid-South Trading, Inc. | | Oil & Gas Operator | Jan 2025 |
| 25 | Midroc Operating Company | | Oil & Gas Operator | Apr 2013 |
| 26 | Mineral Ventures, Inc. | | Oil & Gas Operator | Dec 2024 |
| 27 | Mobil E&P North America Inc. | | Oil & Gas Operator | Jan 1994 |
| 28 | Mobil Oil E & P Southeast Inc | | Oil & Gas Operator | Sep 2013 |
| 29 | Monterey Resources LLC | Dallas, TX 75230 | Oil & Gas Operator | Oct 2019 |
| 30 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 31 | Moransco Energy Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 32 | MRD Operating LLC | | Oil & Gas Operator | Dec 2016 |