| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | M. H. Thomson | Gas Operator | Dec 2014 | |
| 2 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Nov 2025 |
| 3 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Nov 2025 |
| 4 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 5 | McCarter | Gas Operator | Nov 1996 | |
| 6 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 7 | McLain J. Forman | Oil & Gas Operator | Mar 1988 | |
| 8 | Melren Oil & Gas Expl., Inc. | Gas Operator | Nov 1989 | |
| 9 | Mid Louisiana Gas Company | Oil & Gas Operator | Oct 2002 | |
| 10 | Midroc Operating Company | Oil & Gas Operator | Apr 2013 | |
| 11 | Midway Production Co. | Gas Operator | May 1990 | |
| 12 | Midway Testing Company Inc | Gas Operator | Mar 1984 | |
| 13 | Mineral Ventures, Inc. | Oil & Gas Operator | Dec 2024 | |
| 14 | Mississippi River Transm. Corp | Oil & Gas Operator | Sep 2002 | |
| 15 | Mitchell Energy & Goodrich Oil | Oil & Gas Operator | Feb 1985 | |
| 16 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 17 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 18 | MLGW | Gas Operator | Sep 1984 | |
| 19 | Mobil Oil E & P Southeast Inc | Oil & Gas Operator | Sep 2013 | |
| 20 | MRD Operating LLC | Oil & Gas Operator | Dec 2016 | |
| 21 | Mrs. Clara B. Guthrie | Gas Operator | Jun 1996 | |
| 22 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |