| 1 | Magnum Engineering Company | Corpus Christ, TX 78401 | Oil & Gas Operator | Sep 2026 |
| 2 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 3 | Magnum Producing, LP | Corpus Christ, TX 78401 | Oil & Gas Operator | Sep 2026 |
| 4 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 5 | Marino, Charles B. | Tomball, TX 77377 | Oil & Gas Operator | Sep 2026 |
| 6 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Jun 2026 |
| 7 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 8 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Sep 2026 |
| 9 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 10 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 11 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 12 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Sep 2026 |
| 13 | McGuffin, Joe Jr. | Christoval, TX 76935 | Oil & Gas Operator | Sep 2026 |
| 14 | Mego Resources, LLC | Taft, TX 78390 | Oil & Gas Operator | May 2026 |
| 15 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 16 | Merrico Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2008 |
| 17 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 18 | MGM Well Service, Inc. | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Oct 2004 |
| 19 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2026 |
| 20 | Mid-Continent Energy, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2020 |
| 21 | Midcon Offshore, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 22 | Midland Res. Oper. Co., Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 1998 |
| 23 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 24 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2026 |
| 25 | Miltex Oil Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2026 |
| 26 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Sep 2026 |
| 27 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 28 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 29 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 30 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Sep 2026 |
| 31 | Mohican Operating, L.L.C. | Corpus Christ, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 32 | Monterey Resources LLC | Fort Worth, TX 76185 | Oil & Gas Operator | Oct 2019 |
| 33 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 34 | Morgan Enterprises, Inc. | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 35 | Mowata Oil Company | Victoria, TX 77903 | Oil & Gas Operator | Oct 1996 |
| 36 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 37 | Mueller Exploration, Inc. | Humble, TX 77346 | Oil & Gas Operator | Sep 2026 |
| 38 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Dec 2019 |
| 39 | Musselman, Owen & King Oper.,Inc | Houston, TX 77002 | Oil & Gas Operator | Feb 1998 |
| 40 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |