| 1 | Mako Operating Company, LLC | Andover, KS 67002 | Gas Operator | May 2002 |
| 2 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Jul 2025 |
| 3 | Marden Producing | | Gas Operator | Aug 1990 |
| 4 | Marden Producing Company | Edmond, OK 73083 | Gas Operator | Jun 2025 |
| 5 | Marexco | | Oil & Gas Operator | Nov 1994 |
| 6 | Marexco, Inc. | Castle Rock, CO 80104 | Oil & Gas Operator | Jun 2025 |
| 7 | McCoy Petroleum | | Oil & Gas Operator | Aug 1996 |
| 8 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Aug 2025 |
| 9 | McKelvy A D Oil | | Gas Operator | Feb 1995 |
| 10 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 11 | Merit Energy Company, LLC | Dallas, TX 75009 | Oil & Gas Operator | Jun 2025 |
| 12 | Mid Continent Resources, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2025 |
| 13 | Mid-Continent Energy Corp. | Wichita, KS 67208 | Oil & Gas Operator | Jun 2025 |
| 14 | Mid-Continent Energy, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2020 |
| 15 | Mobil Oil Corpor | | Oil & Gas Operator | Dec 1996 |
| 16 | Murfin Drilling Company Inc | Wichita, KS 67202 | Oil & Gas Operator | Aug 2025 |
| 17 | Mustang Drilling | | Oil & Gas Operator | Nov 1996 |