| 1 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Feb 2026 |
| 2 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 3 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Feb 2026 |
| 4 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Feb 2026 |
| 5 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2026 |
| 6 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Feb 2026 |
| 7 | Matador E & P Company Inc | | Oil & Gas Operator | May 2020 |
| 8 | May Petroleum Inc | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 9 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Jan 2026 |
| 10 | McOr Oil & Gas Corp | Houston, TX 77002 | Oil & Gas Operator | Oct 2013 |
| 11 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Feb 2026 |
| 12 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Feb 2026 |
| 13 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 14 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 15 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2026 |
| 16 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 17 | Metropolitan Resources Corp | Tulsa, OK 74169-1734 | Oil & Gas Operator | Mar 2015 |
| 18 | Mewbourne Marketing, Inc. | | Oil & Gas Operator | Mar 2013 |
| 19 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Apr 2026 |
| 20 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jan 2026 |
| 21 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 22 | Midway Operating Company, L.L.C. | Woodward, OK 73802 | Oil & Gas Operator | Apr 2026 |
| 23 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 24 | Milmac Operating Company | Lubbock, TX 79408-2976 | Oil & Gas Operator | Sep 2004 |
| 25 | Mito Resources LLC | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 26 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2026 |
| 27 | Moss Ted A Operating Company | Oklahoma City, OK 73126-0187 | Oil & Gas Operator | Jun 1997 |
| 28 | Moss William Properties Inc | Dallas, TX 75219 | Oil & Gas Operator | Apr 2014 |
| 29 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Jan 2026 |
| 30 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 31 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2026 |
| 32 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |