| 1 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 2 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 3 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2024 |
| 4 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 5 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | May 2024 |
| 6 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Mar 2024 |
| 7 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2024 |
| 8 | Marwell Petroleum LTD Partnrship | Houston, TX 77056 | Oil & Gas Operator | May 2024 |
| 9 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 10 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 11 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | May 2024 |
| 12 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2024 |
| 13 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | May 2024 |
| 14 | Mestena Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 2015 |
| 15 | Mestena Operating, LTD. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jun 2009 |
| 16 | Mestena, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Nov 2001 |
| 17 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 18 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 19 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | May 2024 |
| 20 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 21 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2024 |
| 22 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | May 2024 |
| 23 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 24 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 25 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 26 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |