| 1 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 2 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | 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 | Manhattan Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 6 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 7 | Marino, Charles B. | Tomball, TX 77377 | Oil & Gas Operator | Oct 2025 |
| 8 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 9 | Marmaton Oil Company | Houston, TX 77002 | Oil & Gas Operator | Jul 1998 |
| 10 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 11 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 12 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | Oct 2025 |
| 13 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 14 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 15 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 16 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 17 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 18 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 19 | Milam, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 20 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 21 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Oct 2025 |
| 22 | MLC Operating, LP | Houston, TX 77063 | Oil & Gas Operator | Oct 2025 |
| 23 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 24 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 25 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Oct 2025 |
| 26 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 27 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 28 | Murphy Expl. & Prod. Co. - USA | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 29 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 30 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |