| 1 | M & S Exploration | El Campo, TX 77437 | Oil & Gas Operator | May 2024 |
| 2 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 3 | M.J.O.G., Inc. | Fort Smith, AR 72903 | Oil Operator | Mar 2015 |
| 4 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2024 |
| 5 | Magnum Oilfield Services LLC | Bakersfield, CA 93309 | Oil Operator | May 2024 |
| 6 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 7 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2024 |
| 8 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 9 | Marino, Charles B. | Tomball, TX 77377 | Oil & Gas Operator | May 2024 |
| 10 | Mark L Shidler, Inc. | Houston, TX 77055 | Oil & Gas Operator | Jan 2024 |
| 11 | Maroon Energy LLC | Spring, TX 77379 | Oil & Gas Operator | May 2024 |
| 12 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2024 |
| 13 | Marshall Petroleum, Inc. | Houston, TX 77040 | Oil & Gas Operator | Aug 2003 |
| 14 | Marwell Petroleum LTD Partnrship | Houston, TX 77056 | Oil & Gas Operator | May 2024 |
| 15 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | May 2024 |
| 16 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Feb 2024 |
| 17 | Mayfield Energy, LLC | Austin, TX 78732 | Oil & Gas Operator | May 2024 |
| 18 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 19 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 20 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | May 2024 |
| 21 | McLelland Engineering & MGMT. | Houston, TX 77042 | Oil & Gas Operator | Mar 1999 |
| 22 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 23 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 24 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 25 | Merlon Texas, Inc. | Houston, TX 77056 | Oil Operator | Jun 2013 |
| 26 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Mar 2024 |
| 27 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 28 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 29 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2024 |
| 30 | Middleton Oil Company | Houston, TX 77006 | Oil & Gas Operator | May 2024 |
| 31 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 32 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2024 |
| 33 | Minexprod LLC | Katy, TX 77494 | Oil Operator | May 2024 |
| 34 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 35 | MJ Oil, Inc. | Houston, TX 77265 | Oil & Gas Operator | May 2024 |
| 36 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 37 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2024 |
| 38 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | May 2024 |
| 39 | Moses, Tom | Beaumont, TX 77702 | Oil Operator | May 2024 |
| 40 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 41 | Murphy Oil USA Inc | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |