| 1 | Madtick Dev Corp | | Oil & Gas Operator | Dec 2024 |
| 2 | Maple Grove Enterprises Inc | | Oil & Gas Operator | Dec 2025 |
| 3 | Marco Drilling Inc | Monroeville, PA 15146-0278 | Oil & Gas Operator | Dec 2025 |
| 4 | Mays Coal Co | | Gas Operator | Dec 2003 |
| 5 | Mays Gas & Coal Co | Clarion, PA 16214-0447 | Oil & Gas Operator | Dec 2025 |
| 6 | MDS Energy Dev LLC | Kittanning, PA 16201-4403 | Oil & Gas Operator | May 2026 |
| 7 | MDS Energy LTD | Kittanning, PA 16201-4403 | Gas Operator | Feb 2015 |
| 8 | Mid East Oil Co | Indiana, PA 15701-5378 | Gas Operator | Dec 2006 |
| 9 | Minteer & Baker Gas Enterprise | Kittanning, PA 16201-5022 | Gas Operator | Dec 2025 |
| 10 | Mount Chestnut Dev LLC | Butler, PA 16002-3940 | Gas Operator | Dec 2017 |
| 11 | MTN V Oil & Gas Inc | | Oil & Gas Operator | May 2026 |
| 12 | Murphy Prod Inc | Vanderbilt, PA 15486-1001 | Oil & Gas Operator | Dec 2025 |