| 1 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 2 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2025 |
| 3 | Magnum Petroleum, Inc. | Palm Desert, CA 92260 | Oil & Gas Operator | Nov 2013 |
| 4 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 5 | Manti Exploration Operating LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Feb 2015 |
| 6 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Apr 2025 |
| 7 | Mantle Oil & Gas, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Apr 2025 |
| 8 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |
| 9 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Apr 2025 |
| 10 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 11 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | Apr 2025 |
| 12 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2025 |
| 13 | Maverick Energy Group, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 14 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 2025 |
| 15 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 16 | May Investments, Inc. | New Boston, TX 75570 | Oil & Gas Operator | Aug 2003 |
| 17 | Mayo Oil Co. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2019 |
| 18 | Mazco Energy LLC | San Antonio, TX 78266 | Oil & Gas Operator | Apr 2025 |
| 19 | McA Petroleum Corporation | Flatonia, TX 78941 | Oil & Gas Operator | Apr 2025 |
| 20 | McCombs Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2006 |
| 21 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Apr 2025 |
| 22 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Apr 2025 |
| 23 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 24 | McMinn Operating Company, Inc. | Hempstead, TX 77445 | Oil & Gas Operator | Apr 2025 |
| 25 | Megaenergy Operating, Inc. | Edmond, OK 73034 | Oil & Gas Operator | Jul 2015 |
| 26 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 27 | Mescalero Energy, Inc. | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 28 | Metco Oil Corporation | Seguin, TX 78155 | Oil Operator | Apr 2016 |
| 29 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 30 | Mid Texas Natural Gas | Kyle, TX 78640 | Oil & Gas Operator | May 2019 |
| 31 | Midas Resources, Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2025 |
| 32 | Miesch Exploration Corporation | Dallas, TX 75229 | Oil & Gas Operator | Nov 2002 |
| 33 | Mina Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2012 |
| 34 | Mineral Development, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 1996 |
| 35 | Mineral Resources, Incorporated | Lewisville, TX 75029 | Oil & Gas Operator | Apr 2025 |
| 36 | Mobile Production Systems, Inc. | Austin, TX 78711 | Oil & Gas Operator | Feb 1995 |
| 37 | Moody Oil Co. | Pearsall, TX 78061 | Oil & Gas Operator | Apr 2025 |
| 38 | Mosaic Texas LLC | Dallas, TX 75205 | Oil & Gas Operator | Apr 2025 |
| 39 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 40 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Apr 2025 |