| 1 | M E G G , Inc. | Borger, TX 79008 | Oil & Gas Operator | Sep 2003 |
| 2 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Jul 2025 |
| 3 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 4 | Magnum Hunter Production, Inc. | Irving, TX 75014 | Oil & Gas Operator | Dec 2019 |
| 5 | Makar Production Company | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 6 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 7 | Marexco, Inc. | Castle Rock, CO 80104 | Oil & Gas Operator | Jun 2025 |
| 8 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 9 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Oct 2025 |
| 10 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 11 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Jun 2025 |
| 12 | McKinney Operating Company | Canadian, TX 79014 | Gas Operator | May 2002 |
| 13 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 14 | McNic Oil & Gas Midcontinent,Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 1999 |
| 15 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 16 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 17 | Megg, L.P. | Borger, TX 79008 | Oil & Gas Operator | Oct 2025 |
| 18 | Merex Resources, Inc. | Amarillo, TX 79159 | Oil & Gas Operator | Sep 2019 |
| 19 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Oct 2025 |
| 20 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jun 2025 |
| 21 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 22 | Midstates Petroleum Company LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 23 | Mineral Development, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 1996 |
| 24 | Mitchell Ehrlich Oil & Gas, LLC | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 25 | MMGL TXPH, LLC | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 26 | Mon Corp. | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 27 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 28 | MRR Oil Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jun 2002 |