| 1 | M & J Production Company | Austwell, TX 77950 | Oil & Gas Operator | Jun 2020 |
| 2 | M-Five Oil Company | Seguin, TX 78155 | Oil & Gas Operator | Apr 2002 |
| 3 | Main Street Royalty, Inc. | Lockhart, TX 78644 | Oil & Gas Operator | Aug 1999 |
| 4 | Manning, Jack | Odessa, TX 79760 | Oil & Gas Operator | Dec 2003 |
| 5 | Marjo Oil Company | Lockhart, TX 78644 | Oil & Gas Operator | Oct 1999 |
| 6 | Marymac Oil Company | Lockhart, TX 78644 | Oil & Gas Operator | Sep 2001 |
| 7 | Matrix Producing Company | Luling, TX 78648 | Oil & Gas Operator | Feb 2005 |
| 8 | Maverick Energy Group, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2026 |
| 9 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 10 | McMinn Operating Company, Inc. | Hempstead, TX 77445 | Oil & Gas Operator | Feb 2026 |
| 11 | Meb, LLC | Austin, TX 78737 | Oil Operator | Feb 2026 |
| 12 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 13 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 14 | Merkin LLC | Austin, TX 78737 | Oil Operator | Feb 2026 |
| 15 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 16 | MGR Resources | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 17 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Feb 2026 |
| 18 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 19 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 20 | Mobile Production Systems, Inc. | Austin, TX 78711 | Oil & Gas Operator | Feb 1995 |
| 21 | Mockingbird Oil, Inc. (I) | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 22 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | Feb 2026 |
| 23 | Multipay Energy, Inc. | Austin, TX 78749 | Oil Operator | Feb 2026 |
| 24 | Muroz International Group Inc | Houston, TX 77056 | Oil Operator | Feb 2026 |