| 1 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | Oil & Gas Operator | Dec 2024 |
| 2 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2024 |
| 3 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 4 | Majestic Petroleum Corporation | Dallas, TX 75230 | Oil & Gas Operator | Oct 1996 |
| 5 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Oct 2024 |
| 6 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 7 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 8 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 2024 |
| 9 | Martin Gas Sales, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | May 1993 |
| 10 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2024 |
| 11 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2024 |
| 12 | Maverick Energy Group, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 13 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | Dec 2024 |
| 14 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Dec 2024 |
| 15 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Dec 2024 |
| 16 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 17 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 18 | Melton, Joe, DRLG. Co., Inc. | Midland, TX 79704 | Oil & Gas Operator | Dec 2004 |
| 19 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 20 | Merzbacher, George F. Jr. | Robstown, TX 78380 | Oil & Gas Operator | May 1994 |
| 21 | Mestena Operating, LTD. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jun 2009 |
| 22 | Metis Energy LLC | Friendswood, TX 77546 | Oil & Gas Operator | Dec 2024 |
| 23 | Mextex Operating Company | Austin, TX 78734 | Oil & Gas Operator | Dec 2024 |
| 24 | Midwestern Exploration Co. | Edmond, OK 73013 | Oil & Gas Operator | Aug 2024 |
| 25 | Millennium Petro-Physics, Inc. | Corpus Chrsti, TX 78480 | Oil & Gas Operator | Dec 2024 |
| 26 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Dec 2024 |
| 27 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2024 |
| 28 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | Dec 2024 |
| 29 | Moran-Lavaca, L.L.C. | Shreveport, LA 71134 | Oil Operator | Feb 2018 |
| 30 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 31 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2024 |
| 32 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 33 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Dec 2024 |
| 34 | Munoz Farms Operating Co., LLC | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Dec 2024 |
| 35 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |