| 1 | M & C Operating, LLC | Poteet, TX 78065 | Oil Operator | Oct 2025 |
| 2 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 3 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 4 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 5 | Magnum Oilfield Services LLC | Bakersfield, CA 93309 | Oil Operator | Oct 2025 |
| 6 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 7 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Oct 2025 |
| 8 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 9 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 10 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 11 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 12 | Maverick Energy Group, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 13 | Mazco Energy LLC | San Antonio, TX 78266 | Oil & Gas Operator | Oct 2025 |
| 14 | McA Petroleum Corporation | Flatonia, TX 78941 | Oil & Gas Operator | Oct 2025 |
| 15 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 16 | McOsker Bros., Inc. | San Antonio, TX 78264 | Oil & Gas Operator | Aug 2003 |
| 17 | Mello-Dy Resources, LLC | Devine, TX 78016 | Oil Operator | Oct 2025 |
| 18 | Mercury Exploration Co | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 19 | Merzbacher, George F. Jr. | Robstown, TX 78380 | Oil & Gas Operator | May 1994 |
| 20 | Mesa Energy, Inc. | Austin, TX 78755 | Oil & Gas Operator | Dec 2013 |
| 21 | Mescalero Energy, Inc. | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 22 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 23 | Mims, William S. | Pleasanton, TX 78064 | Oil Operator | Jun 2009 |
| 24 | Mineral Resources, Incorporated | Lewisville, TX 75029 | Oil & Gas Operator | Oct 2025 |
| 25 | Miranda Energy Corporation | Midland, TX 79705 | Oil & Gas Operator | Jun 2016 |
| 26 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 27 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 28 | Mobile Production Systems, Inc. | Austin, TX 78711 | Oil & Gas Operator | Feb 1995 |
| 29 | Momentum Oil & Gas, LLC | The Woodlands, TX 77382 | Oil & Gas Operator | May 2015 |
| 30 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | Oct 2025 |
| 31 | More Texas Oil | Von Ormy, TX 78073 | Oil & Gas Operator | Oct 2025 |
| 32 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 33 | Moxy Oil Company | Seguin, TX 78155 | Oil & Gas Operator | Aug 2003 |
| 34 | MPG Petroleum | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2003 |
| 35 | MPG Petroleum, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 36 | MSSK Consulting LLC | San Antonio, TX 78253 | Oil Operator | Oct 2025 |
| 37 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 38 | Murphy Expl. & Prod. Co. - USA | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 39 | Murphy Exploration & Production | Houston, TX 77024 | Oil Operator | Jan 2025 |