| 1 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 2 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 3 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 4 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 5 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 6 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 7 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 8 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 9 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 10 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | Oct 2025 |
| 11 | Matrix Petroleum, LLC | Houston, TX 77077 | Oil & Gas Operator | Oct 2025 |
| 12 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Aug 2025 |
| 13 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 14 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | Oct 2025 |
| 15 | McCarter, A. Nelson | Houston, TX 77063 | Oil & Gas Operator | Aug 2003 |
| 16 | McCauley, F. R. | Houston, TX 77002 | Oil & Gas Operator | Apr 2000 |
| 17 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 18 | Mego Resources, LLC | Taft, TX 78390 | Oil & Gas Operator | Oct 2025 |
| 19 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 20 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 21 | Meridian Resource & Expl LLC,The | Houston, TX 77094 | Oil & Gas Operator | Nov 2012 |
| 22 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 23 | Merrimac Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 24 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | Oct 2025 |
| 25 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 26 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 27 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 28 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 29 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Oct 2025 |
| 30 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 31 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 32 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 33 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 34 | MLF, Inc. | Houston, TX 77096 | Gas Operator | Nov 2009 |
| 35 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 36 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 37 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Oct 2025 |
| 38 | Moose Oil & Gas Co. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 39 | Moose Operating Co., Inc. | Houston, TX 77006 | Oil & Gas Operator | Oct 2025 |
| 40 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 41 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 42 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 43 | Mosley Oil &Gas Inc | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 44 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 45 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 46 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 47 | Munson, Charles C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2002 |
| 48 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2025 |