| 1 | M K Oil Company | Gillette, WY 82717-3470 | Oil & Gas Operator | Apr 2025 |
| 2 | M-Tex Oil, LLC | Williston, ND 58803 | Oil Operator | Apr 2025 |
| 3 | Mach Petroleum, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | Nov 2014 |
| 4 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 5 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 6 | Makoil, Inc. | Lake Forest, CA 92630 | Oil & Gas Operator | Jul 2007 |
| 7 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | May 2025 |
| 8 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 9 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | May 2025 |
| 10 | McCarthy, Lawrence J. | Plains, MT 59859-9215 | Oil & Gas Operator | Nov 2011 |
| 11 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Apr 2025 |
| 12 | McMinn Operating Company, Inc. | Hempstead, TX 77445 | Oil & Gas Operator | Jul 2025 |
| 13 | McOil Montana One LLC | Vancouver, BC V6Z2W5 | Gas Operator | Jul 2024 |
| 14 | MCR, LLC | Shelby, MT 59474 | Oil & Gas Operator | Apr 2025 |
| 15 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 16 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 17 | Mercury Exploration Co | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 18 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 19 | Miami Oil Producers Inc | Reno, NV 89501 | Oil & Gas Operator | Dec 2012 |
| 20 | Midway Energy, LLC | Thermopolis, WY 82443 | Oil Operator | Apr 2025 |
| 21 | Miocene Oil & Gas, LTD. | Englewood, CO 80110 | Oil & Gas Operator | Jul 2025 |
| 22 | Misc Oil Co | Oilmont, MT 59466 | Oil Operator | Feb 2025 |
| 23 | Missouri Basin Well Service, Inc. | Belfield, ND 58622 | Oil & Gas Operator | Jan 2018 |
| 24 | Missouri River Royalty Corporation | Bismarck, ND 58504 | Oil & Gas Operator | May 2025 |
| 25 | Mogo Reagan, LLC | Cut Bank, MT 59427 | Oil & Gas Operator | May 2025 |
| 26 | Montalban Oil & Gas Operations, Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | May 2025 |
| 27 | Montana Energy Company, LLC | McAllen, TX 78501 | Oil & Gas Operator | Feb 2025 |
| 28 | Montana Heartland LLC | Bismarck, ND 58504 | Oil & Gas Operator | Apr 2025 |
| 29 | Montana Land & Exploration, Inc. | Calgary, AB T2P 3E7 | Oil & Gas Operator | Apr 2019 |
| 30 | Montana Land & Mineral Co. | Billings, MT 59105 | Gas Operator | Jan 2025 |
| 31 | Montana Oil Field Acquisition I, LLC | Rutherford, NJ 07070 | Oil Operator | Jun 2016 |
| 32 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 33 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 34 | Monte Grande Exploration, Inc. | Cut Bank, MT 59427 | Oil Operator | Oct 2000 |
| 35 | Morningstar Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2025 |
| 36 | Mountain Pacific General Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Jun 2022 |
| 37 | Mountain States Resources Inc | Cut Bank, MT 59427 | Oil & Gas Operator | Oct 2000 |
| 38 | Murex Petroleum Corporation | Humble, TX 77347 | Oil & Gas Operator | May 2025 |
| 39 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 40 | Mystique Resources Company | Aurora, CO 80016 | Oil & Gas Operator | Feb 2023 |