| 1 | M & R Exploration Company | Houston, TX 77074 | Oil & Gas Operator | Aug 2003 |
| 2 | Maggert Energy Corp. | Spring, TX 77387 | Gas Operator | Jun 1998 |
| 3 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 4 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 5 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 6 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 7 | Manley, John D. III, Oper., Inc | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Feb 2016 |
| 8 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 9 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 10 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 11 | Martin Oil & Gas | Freer, TX 78357 | Oil & Gas Operator | Aug 2025 |
| 12 | Martin Oil & Gas Inc. | Freer, TX 78357 | Oil & Gas Operator | Dec 2025 |
| 13 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Dec 2025 |
| 14 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 15 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 16 | Mayo Oil Co. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2019 |
| 17 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | Dec 2025 |
| 18 | McCombs Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2006 |
| 19 | McDonnold Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 20 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 21 | McGuffin, Joe Jr. | Christoval, TX 76935 | Oil & Gas Operator | Dec 2025 |
| 22 | McLelland Engineering & MGMT. | Houston, TX 77042 | Oil & Gas Operator | Mar 1999 |
| 23 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 24 | McRae, Nathan Rathburn | Hebbronville, TX 78361 | Oil & Gas Operator | Apr 1994 |
| 25 | Medallion Oil Company | Houston, TX 77251 | Oil & Gas Operator | Jan 2012 |
| 26 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 27 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 28 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 29 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 30 | Merritt Operating, Inc. | Mineola, TX 75773 | Oil & Gas Operator | Dec 2025 |
| 31 | Mesa Operating LTD Partnership | Amarillo, TX 79189 | Oil & Gas Operator | May 1994 |
| 32 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 33 | Metco Oil Corporation | Seguin, TX 78155 | Oil Operator | Apr 2016 |
| 34 | MGM Oil & Gas Company | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 35 | Michael Petr. & Hurd Ent., LTD. | Houston, TX 77056 | Oil & Gas Operator | Oct 1993 |
| 36 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 37 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 38 | Middleton Oil Company | Houston, TX 77006 | Oil & Gas Operator | Dec 2025 |
| 39 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 40 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 41 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 42 | Minuja Oil And Gas LLC | Corpus Christi, TX 78401 | Oil & Gas Operator | Sep 1996 |
| 43 | Mir-Tex Energy Corp. | Mirando City, TX 78369 | Oil & Gas Operator | Aug 2003 |
| 44 | Miramar Petroleum, Inc. | Corpus Chrsti, TX 78463 | Oil & Gas Operator | Sep 2017 |
| 45 | Mirando Crude Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Jul 1994 |
| 46 | Mirando Resource, L.L.C. | Freer, TX 78357 | Oil & Gas Operator | Dec 2025 |
| 47 | Mitsui E&P USA LLC | Houston, TX 77056 | Oil & Gas Operator | Dec 2025 |
| 48 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 49 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 50 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 51 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 52 | Monitor O&G, L.L.C. | Frisco, TX 75034 | Oil & Gas Operator | Jan 2016 |
| 53 | Morgan Enterprises, Inc. | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 54 | Morsey Oil & Gas Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 55 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 56 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 57 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 58 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 59 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |
| 60 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |