| 1 | Madtick Dev Corp | Punxsutawney, PA 15767-1179 | Oil & Gas Operator | Dec 2024 |
| 2 | Maple Grove Enterprises Inc | Rimersburg, PA 16248-6415 | Oil & Gas Operator | Dec 2024 |
| 3 | Marco Drilling Inc | Monroeville, PA 15146-0278 | Oil & Gas Operator | Dec 2024 |
| 4 | Mays Coal Co | Clarion, PA 16214-0447 | Gas Operator | Dec 2003 |
| 5 | Mays Gas & Coal Co | Clarion, PA 16214-0447 | Oil & Gas Operator | Dec 2024 |
| 6 | MCQ Natural Gas Co Inc | Leechburg, PA 15656-0594 | Gas Operator | Dec 2012 |
| 7 | MDS Energy Dev LLC | Kittanning, PA 16201-4403 | Oil & Gas Operator | Jan 2025 |
| 8 | MDS Energy LTD | Kittanning, PA 16201-4403 | Gas Operator | Feb 2015 |
| 9 | Mid East Oil Co | Indiana, PA 15701-5378 | Gas Operator | Dec 2006 |
| 10 | Minteer & Baker Gas Enterprise | Worthington, PA 16262-0739 | Gas Operator | Dec 2024 |
| 11 | Mount Chestnut Dev LLC | Butler, PA 16002-3940 | Gas Operator | Dec 2017 |
| 12 | MT Savage Refractories | Pittsburgh, PA 15206-0171 | Gas Operator | Dec 2021 |
| 13 | MTN V Oil & Gas Inc | Indiana, PA 15701-8914 | Oil & Gas Operator | Dec 2024 |
| 14 | Murphy Prod Inc | Vanderbilt, PA 15486-1001 | Oil & Gas Operator | Dec 2024 |