| 1 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Jun 2025 |
| 2 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 3 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jun 2025 |
| 4 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Apr 2025 |
| 5 | Marshall R. Young Operating, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2025 |
| 6 | Maverick Expl. & Drilling Co. | Richland, TX 76681 | Oil & Gas Operator | Aug 2003 |
| 7 | Maverick Oil Co. | Richland, TX 76681 | Oil Operator | Jun 2025 |
| 8 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Jun 2025 |
| 9 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 10 | McBrayer Oil Corporation | Rockport, TX 78381 | Oil & Gas Operator | Nov 1994 |
| 11 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 12 | Means Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Feb 2013 |
| 13 | Means Oil Company, LLC | Corsicana, TX 75110 | Oil & Gas Operator | Jun 2025 |
| 14 | Means, Frank L. | Corsicana, TX 75110 | Oil & Gas Operator | Jan 2001 |
| 15 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 16 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 17 | Micro Operating, Inc. | Bryan, TX 77807 | Oil & Gas Operator | Jun 2025 |
| 18 | Midcoast G & P (East Texas) L.P. | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 19 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 20 | Miller Oil Company | Corsicana, TX 75110 | Oil & Gas Operator | Dec 2015 |
| 21 | Miller Production Co. | Tyler, TX 75701 | Oil & Gas Operator | Jun 2025 |
| 22 | Miller, B. H. Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Sep 2002 |
| 23 | Miller, C. R. Oil Co. | Olney, TX 76374 | Oil & Gas Operator | Jun 2025 |
| 24 | Miller, Cecil G. | Corsicana, TX 75110 | Oil & Gas Operator | Jan 2023 |
| 25 | Miller, Cecil G. Estate Of | Corsicana, TX 75110 | Oil Operator | Jun 2025 |
| 26 | Miller, Mike | Corsicana, TX 75110 | Oil & Gas Operator | Jun 2025 |
| 27 | Miller, Mike / Miller Prod. Co. | Corsicana, TX 75110 | Oil & Gas Operator | Jun 2025 |
| 28 | Mixon, Robert N. | Lometa, TX 76853 | Oil & Gas Operator | Jun 2025 |
| 29 | MLB Operating Services, LLC | Tenn Colony, TX 75861 | Oil & Gas Operator | Jun 2025 |
| 30 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Jun 2025 |
| 31 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Jun 2025 |
| 32 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 33 | Mosaic Texas LLC | Dallas, TX 75205 | Oil & Gas Operator | Jun 2025 |
| 34 | Mud Creek Operating, LLC | Tyler, TX 75702 | Oil & Gas Operator | Jun 2025 |
| 35 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2025 |
| 36 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Feb 2025 |
| 37 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |