| 1 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2025 |
| 2 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Mar 2025 |
| 3 | Masters Rat Hole Service, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Nov 1998 |
| 4 | Mayco Oil | Nocona, TX 76255 | Oil & Gas Operator | Mar 2025 |
| 5 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Mar 2025 |
| 6 | Mayo, Paul R. | Quinlan, TX 75474 | Oil & Gas Operator | May 1999 |
| 7 | McCown Engineering | Wichita Falls, TX 76310 | Oil & Gas Operator | Mar 2025 |
| 8 | McMahon-Bullington Drilling Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 1996 |
| 9 | McMahon-Bullington LP | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2009 |
| 10 | Medders Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 11 | Mehaffey Investments, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Mar 2025 |
| 12 | Menasco, J. | Wichita Falls, TX 76310 | Oil & Gas Operator | Dec 2019 |
| 13 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 14 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2025 |
| 15 | Mid-Tex Energy Inc. | Costa Mesa, CA 92626 | Oil & Gas Operator | Jan 1999 |
| 16 | Middle Bay Oil Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 17 | Midland Oil And Gas, Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2025 |
| 18 | Midwestern Energy | Mankato, MN 56003 | Oil & Gas Operator | Mar 2025 |
| 19 | MM China Star Oil Co., LLC | Woodway, TX 76712 | Oil & Gas Operator | Mar 2025 |
| 20 | Monument Resources, Inc. | Castle Rock, CO 80104 | Oil & Gas Operator | Jun 2012 |
| 21 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Mar 2025 |