| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | M & B Oil Company | Holliday, TX 76366 | Oil & Gas Operator | Jul 2025 |
| 2 | M & J Operator | Oil & Gas Operator | Aug 2025 | |
| 3 | Magness Petroleum Company | Oil & Gas Operator | Dec 1994 | |
| 4 | Manley Energy Resources LLC | Oil Operator | Jan 2018 | |
| 5 | Marina Pacifica Oil Company | Oil & Gas Operator | Dec 1981 | |
| 6 | Marmac Resources Co. | Oil & Gas Operator | Mar 2015 | |
| 7 | Mary E. Wertalla | Oil Operator | Dec 1984 | |
| 8 | Matrix Oil Corporation | Oil & Gas Operator | Aug 2025 | |
| 9 | McBo Oil Co. | Oil & Gas Operator | Dec 1996 | |
| 10 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 11 | Medallion Calif Properties Co. | Oil & Gas Operator | Dec 2003 | |
| 12 | Mills Oil Co. | Oil Operator | Dec 1986 | |
| 13 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 14 | Mitchell-Grossu Oil Co. | Oil & Gas Operator | Sep 2023 | |
| 15 | Mitchwil Investments LLC | Oil & Gas Operator | Dec 2019 | |
| 16 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 17 | Monterey Resources Inc. | Oil & Gas Operator | Dec 1997 | |
| 18 | Morton And Dolley | Oil Operator | Dec 1991 |