| 1 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2025 |
| 2 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Mar 2025 |
| 3 | Manziel Management Corporation | Tyler, TX 75711 | Oil Operator | Feb 2014 |
| 4 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 5 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 6 | Marconi Exploration, Inc. | Houston, TX 77056 | Oil & Gas Operator | Aug 1997 |
| 7 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 8 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 9 | McBee Operating Company, L.L.C. | Dallas, TX 75209 | Oil & Gas Operator | Mar 2025 |
| 10 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 11 | McCutchin, Gene | Dallas, TX 75380 | Oil & Gas Operator | Aug 2003 |
| 12 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Mar 2025 |
| 13 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 14 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Mar 2025 |
| 15 | Means Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Feb 2013 |
| 16 | Means Oil Company, LLC | Corsicana, TX 75110 | Oil & Gas Operator | Mar 2025 |
| 17 | Means, Frank L. | Corsicana, TX 75110 | Oil & Gas Operator | Jan 2001 |
| 18 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Dec 2024 |
| 19 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 20 | Midcoast G & P (East Texas) L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 21 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Mar 2025 |
| 22 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 23 | Miller, B. H. Oil Co. | Corsicana, TX 75110 | Oil & Gas Operator | Sep 2002 |
| 24 | Miller, R. A. Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2003 |
| 25 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Mar 2025 |
| 26 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 27 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 28 | Mitsui E&P USA LLC | Houston, TX 77056 | Oil & Gas Operator | Mar 2025 |
| 29 | ML Resources, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Mar 2008 |
| 30 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Mar 2025 |
| 31 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2025 |
| 32 | Montex Exploration Company | Houston, TX 77057 | Oil & Gas Operator | Mar 2011 |
| 33 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 34 | Mosaic Texas LLC | Dallas, TX 75205 | Oil & Gas Operator | Mar 2025 |
| 35 | Mustang Drilling, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Aug 2024 |