| 1 | Maggert Energy Corp. | Spring, TX 77387 | Gas Operator | Jun 1998 |
| 2 | Magna Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 3 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 4 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 5 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 6 | Marmaton Oil Company | Houston, TX 77002 | Oil & Gas Operator | Jul 1998 |
| 7 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 8 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 9 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 10 | McRae, Nathan Rathburn | Hebbronville, TX 78361 | Oil & Gas Operator | Apr 1994 |
| 11 | Medallion Oil Company | Houston, TX 77251 | Oil & Gas Operator | Jan 2012 |
| 12 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 13 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 14 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 15 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 16 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 17 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Oct 2025 |
| 18 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 19 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 20 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 21 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 22 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 23 | Mote Resources, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Dec 2004 |
| 24 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 25 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 26 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |