| 1 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Jun 2025 |
| 2 | M2S Oil LLC | | Oil Operator | Jun 2025 |
| 3 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 4 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 5 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 6 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 7 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Aug 2025 |
| 8 | McAdams Roux & Associates | Denver, CO 80202 | Oil & Gas Operator | Dec 1999 |
| 9 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 10 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 11 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 12 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 13 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 14 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 15 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 16 | Meritage Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 17 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Aug 2025 |
| 18 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2025 |
| 19 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 20 | Mineral Resources & Engineering | Aladdin, WY 82710 | Oil Operator | Jul 1991 |
| 21 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2025 |
| 22 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 23 | Mosbacher Production Co. | Houston, TX 77001 | Oil & Gas Operator | Aug 1984 |
| 24 | MRD Operating LLC (Delaware) | Houston, TX 77010 | Oil & Gas Operator | Jul 2015 |
| 25 | Mustang Resources LLC | Houston, TX 77256 | Oil & Gas Operator | Aug 2025 |
| 26 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |
| 27 | Mystique Developments | Denver, CO 80202 | Oil & Gas Operator | Dec 1997 |