| 1 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2024 |
| 2 | Manziel Management Corporation | Tyler, TX 75711 | Oil Operator | Feb 2014 |
| 3 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Oct 2024 |
| 4 | Martin Foree Operating II, LLC | Royse City, TX 75189 | Oil & Gas Operator | Dec 2024 |
| 5 | Martin Foree Operating, LLC | Royse City, TX 75189 | Oil & Gas Operator | Dec 2024 |
| 6 | MCZ, Inc. | Houston, TX 77026 | Oil & Gas Operator | Sep 1990 |
| 7 | Means Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Feb 2013 |
| 8 | Means, Frank L. | Corsicana, TX 75110 | Oil & Gas Operator | Jan 2001 |
| 9 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 10 | Midcoast G & P (East Texas) L.P. | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 11 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 12 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 13 | Miller, B. H. Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Sep 2002 |
| 14 | Milton Oil & Gas Company | Charleston, WV 25322 | Gas Operator | Nov 1997 |
| 15 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 16 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 17 | ML Resources, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Mar 2008 |
| 18 | MM China Star Oil Co., LLC | Woodway, TX 76712 | Oil & Gas Operator | Dec 2024 |
| 19 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2024 |
| 20 | Moncrief, C. B. | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2021 |
| 21 | Montex Drilling Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2024 |
| 22 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Jul 2024 |
| 23 | Mustang Drilling, LTD. | Henderson, TX 75653 | Oil & Gas Operator | May 2008 |