| 1 | M & C Operating, LLC | Poteet, TX 78065 | Oil Operator | Oct 2025 |
| 2 | M IV Ops., Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 1998 |
| 3 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 4 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 5 | Magnum Oilfield Services LLC | Bakersfield, CA 93309 | Oil Operator | Oct 2025 |
| 6 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 7 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 8 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 9 | Market Street Energy, Inc. | Flatonia, TX 78941 | Oil & Gas Operator | Oct 2025 |
| 10 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2025 |
| 11 | Marshfield Oil & Gas, LLC | Houston, TX 77070 | Oil & Gas Operator | Oct 2025 |
| 12 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 13 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 14 | Matrix Producing Company | Luling, TX 78648 | Oil & Gas Operator | Feb 2005 |
| 15 | MBC Operating Co., Inc. | Garland, TX 75042 | Oil & Gas Operator | Aug 1993 |
| 16 | McA Petroleum Corporation | Flatonia, TX 78941 | Oil & Gas Operator | Oct 2025 |
| 17 | McCutchin Petroleum Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 18 | Meb, LLC | Austin, TX 78737 | Oil Operator | Oct 2025 |
| 19 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | Oct 2025 |
| 20 | Metco Oil Corporation | Seguin, TX 78155 | Oil Operator | Apr 2016 |
| 21 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 22 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 23 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 24 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 25 | Midway Drilling Co. | Richmond, TX 77469 | Oil & Gas Operator | Oct 2025 |
| 26 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 27 | Mina Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2012 |
| 28 | Miranda Energy Corporation | Midland, TX 79705 | Oil & Gas Operator | Jun 2016 |
| 29 | More Texas Oil | Von Ormy, TX 78073 | Oil & Gas Operator | Oct 2025 |
| 30 | Morris, W. Dale Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Oct 2025 |
| 31 | Morrow Resources, Inc. | San Angelo, TX 76904 | Oil & Gas Operator | Oct 2004 |
| 32 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 33 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 34 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 35 | Murphy Expl. & Prod. Co. - USA | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |