| 1 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 2 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 3 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 4 | Mamerow Energy Corp | Ganado, TX 77962 | Oil & Gas Operator | Oct 2025 |
| 5 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Oct 2025 |
| 6 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 7 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Jun 2025 |
| 8 | Marmaton Oil Company | Houston, TX 77002 | Oil & Gas Operator | Jul 1998 |
| 9 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 10 | Martin, William C. | Houston, TX 77071 | Oil & Gas Operator | Oct 2025 |
| 11 | Martino, Joseph C. | Pasadena, TX 77504 | Oil & Gas Operator | Oct 2025 |
| 12 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 13 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 14 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 15 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 16 | MBX Operating LLC | Houston, TX 77007 | Oil & Gas Operator | Oct 2025 |
| 17 | McCarter, A. Nelson | Houston, TX 77063 | Oil & Gas Operator | Aug 2003 |
| 18 | McCarter, W. B. Jr. | Houston, TX 77063 | Oil & Gas Operator | Feb 2002 |
| 19 | McCombs Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2006 |
| 20 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Jul 2025 |
| 21 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 22 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Oct 2025 |
| 23 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 24 | Meridian Resource & Expl Co, The | Houston, TX 77077 | Oil & Gas Operator | Dec 2000 |
| 25 | Meridian Resource & Expl LLC,The | Houston, TX 77094 | Oil & Gas Operator | Nov 2012 |
| 26 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 27 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | Oct 2025 |
| 28 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 29 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 30 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 31 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Oct 2025 |
| 32 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 33 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 34 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 35 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 36 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Oct 2025 |
| 37 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2025 |
| 38 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 39 | MSR Exploration, Inc. | Winters, TX 79567 | Oil & Gas Operator | Mar 2000 |
| 40 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 41 | Murex Petroleum Corporation | Humble, TX 77347 | Oil & Gas Operator | Aug 2025 |
| 42 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2025 |
| 43 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |