| 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 | Mantle Oil & Gas, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Oct 2025 |
| 5 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Jun 2025 |
| 6 | Marlin Energy Southwest GP, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Oct 2025 |
| 7 | Marmaton Oil Company | Houston, TX 77002 | Oil & Gas Operator | Jul 1998 |
| 8 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 9 | Masters Oil & Gas, LLC | Houston, TX 77079 | Oil & Gas Operator | Oct 2025 |
| 10 | Masters Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2008 |
| 11 | McCarter, A. Nelson | Houston, TX 77063 | Oil & Gas Operator | Aug 2003 |
| 12 | McCarter, W. B. Jr. | Houston, TX 77063 | Oil & Gas Operator | Feb 2002 |
| 13 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 14 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Oct 2025 |
| 15 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 16 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 17 | Meridian Resource & Expl Co, The | Houston, TX 77077 | Oil & Gas Operator | Dec 2000 |
| 18 | Meridian Resource & Expl LLC,The | Houston, TX 77094 | Oil & Gas Operator | Nov 2012 |
| 19 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 20 | Mid Continent Resources, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2025 |
| 21 | Midcon Offshore, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 22 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 23 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 24 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 25 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 26 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 27 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |