| 1 | M IV Ops., Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 1998 |
| 2 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 3 | Maggert Energy Corp. | Spring, TX 77387 | Gas Operator | Jun 1998 |
| 4 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 5 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 6 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 7 | Manley, John D. III, Oper., Inc | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Feb 2016 |
| 8 | Manti Exploration Operating LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Feb 2015 |
| 9 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Oct 2025 |
| 10 | Mantle Oil & Gas, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Oct 2025 |
| 11 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 12 | Marco Polo Exploration, Inc. | Rosenberg, TX 77471 | Oil & Gas Operator | Dec 1993 |
| 13 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 14 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 15 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 16 | Marshall Energy, Inc. | Dallas, TX 75243 | Oil & Gas Operator | May 1997 |
| 17 | Martin Oil & Gas | Freer, TX 78357 | Oil & Gas Operator | May 2025 |
| 18 | Martin Oil & Gas Inc. | Freer, TX 78357 | Oil & Gas Operator | Oct 2025 |
| 19 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 20 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 21 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 22 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Oct 2025 |
| 23 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 24 | Mayo Oil Co. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2019 |
| 25 | McAnear Oil & Gas | Freer, TX 78357 | Oil & Gas Operator | Dec 2002 |
| 26 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 27 | McCutchin, Jerry | Dallas, TX 75380 | Oil & Gas Operator | Mar 2008 |
| 28 | McDonald & Johnson Resources,LLC | Cypress, TX 77429 | Oil & Gas Operator | Dec 2010 |
| 29 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 30 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Oct 2025 |
| 31 | McGuffin, Joe Jr. | Christoval, TX 76935 | Oil & Gas Operator | Oct 2025 |
| 32 | McGuffin, Joe S. Inc. | Mathis, TX 78368 | Gas Operator | Oct 2025 |
| 33 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 34 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 35 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 36 | McRae, Nathan Rathburn | Hebbronville, TX 78361 | Oil & Gas Operator | Apr 1994 |
| 37 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 38 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 39 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 40 | MHM Pipeline Co., Inc. | Dallas, TX 75252 | Oil & Gas Operator | Oct 2025 |
| 41 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 42 | Micro Operating, Inc. | Bryan, TX 77807 | Oil & Gas Operator | Oct 2025 |
| 43 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 44 | Midway Drilling Co. | Richmond, TX 77469 | Oil & Gas Operator | Oct 2025 |
| 45 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 46 | Miller, M. M. & Sons | Alice, TX 78333 | Oil & Gas Operator | Apr 2007 |
| 47 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 48 | Miramar Petroleum, Inc. | Corpus Chrsti, TX 78463 | Oil & Gas Operator | Sep 2017 |
| 49 | Mirando Crude Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Jul 1994 |
| 50 | Mirando Resource, L.L.C. | Freer, TX 78357 | Oil & Gas Operator | Oct 2025 |
| 51 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 52 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 53 | Mo-Jon, Inc. | Edroy, TX 78352 | Oil & Gas Operator | May 1999 |
| 54 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 55 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 56 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Oct 2025 |
| 57 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 58 | Morsey Oil & Gas Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 59 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 60 | MPG Petroleum | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2003 |
| 61 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 62 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 63 | Munson, Charles C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2002 |
| 64 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |
| 65 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |