| 1 | M E III Corporation | | Oil & Gas Operator | Apr 2022 |
| 2 | Machii-Ross Petroleum Co | | Oil & Gas Operator | Apr 2014 |
| 3 | Magpie Operating, Inc | | Oil & Gas Operator | Sep 2025 |
| 4 | Mallon Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 5 | Maralex Resources Inc | Ignacio, CO 81137 | Oil & Gas Operator | Sep 2025 |
| 6 | Markus Production, Inc | | Oil & Gas Operator | Mar 2021 |
| 7 | Markwest Resources Inc | Englewood, CO 801125004 | Oil & Gas Operator | Jun 2003 |
| 8 | Matrix Energy LLC | | Oil & Gas Operator | Apr 2013 |
| 9 | Matrix Oil Corporation | | Oil & Gas Operator | Sep 2025 |
| 10 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Oct 2025 |
| 11 | McCartney Engineering LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Oct 2025 |
| 12 | McClane Energy Inc | | Oil & Gas Operator | Aug 2017 |
| 13 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Oct 2025 |
| 14 | McElvain Energy Inc | Denver, CO 80265 | Oil & Gas Operator | Nov 2019 |
| 15 | McLane Trust* Dixie | | Gas Operator | Sep 2025 |
| 16 | McWhinney Holding Company LLLP | | Oil & Gas Operator | Mar 2021 |
| 17 | MDS Energy Development LLC | | Oil & Gas Operator | Oct 2025 |
| 18 | Mendell Finisterre II LLC | | Oil & Gas Operator | Jun 2017 |
| 19 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 20 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Oct 2025 |
| 21 | Mescko Operating & Prod | Seville, OH 44273 | Oil & Gas Operator | Oct 2025 |
| 22 | Messer LLC | | Gas Operator | Oct 2025 |
| 23 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 24 | Monago Operating Inc | | Oil & Gas Operator | Apr 2007 |
| 25 | Monahan* Rex Family Trust | | Oil & Gas Operator | May 2007 |
| 26 | Monument Gas Marketing Inc | | Oil & Gas Operator | Sep 2025 |
| 27 | Monument Global Resources Inc | Dallas, TX 75243 | Oil & Gas Operator | Jan 2025 |
| 28 | Morningstar Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 29 | Mountain Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Apr 2013 |
| 30 | Mull Drilling Company | Wichita, KS 67206 | Oil & Gas Operator | Sep 2025 |
| 31 | Murchison Oil & Gas Inc | Plano, TX 75024 | Oil & Gas Operator | Aug 2020 |
| 32 | Murfin Drilling Company, Inc. | Wichita, KS 67202 | Oil & Gas Operator | Oct 2025 |
| 33 | Mustang Resources LLC | Houston, TX 77046 | Oil & Gas Operator | Sep 2025 |
| 34 | Mystique Resources Company | Aurora, CO 80016 | Oil & Gas Operator | Feb 2023 |