| 1 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 2 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | 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 | Majestic Resources, Inc. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Nov 2007 |
| 6 | Mandarin Oil & Gas Company | Austin, TX 78714 | Oil & Gas Operator | Oct 2025 |
| 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 | Maverick Energy & Dev. Corp. | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 11 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 12 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 13 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 14 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 15 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Oct 2025 |
| 16 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 17 | Medders Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 18 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 19 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 20 | Merrimac Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 21 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 22 | Midway Drilling Co. | Richmond, TX 77469 | Oil & Gas Operator | Oct 2025 |
| 23 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 24 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 25 | Miner, R. C. Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 2002 |
| 26 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 27 | ML Resources, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Mar 2008 |
| 28 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 29 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Oct 2025 |
| 30 | Mogul Energy International, Inc. | Houston, TX 77042 | Oil & Gas Operator | Oct 2017 |
| 31 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 32 | Moose Oil & Gas Co. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 33 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 34 | Mse Operating Corp. | Beaverton, OR 97008 | Oil & Gas Operator | Oct 2025 |
| 35 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 36 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 37 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2025 |
| 38 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |