| 1 | M & M Royalty LTD | North Canton, OH 44720 | Oil & Gas Operator | Dec 2016 |
| 2 | M4 Energy, LLC | | Oil & Gas Operator | Dec 2025 |
| 3 | Madison Mark T | Marienville, PA 16239-6029 | Oil & Gas Operator | Dec 2012 |
| 4 | Madtick Dev Corp | | Oil & Gas Operator | Dec 2024 |
| 5 | Maney McNeal Oil & Gas | | Oil & Gas Operator | Dec 1999 |
| 6 | Manufacturers Light & Heat Co | | Gas Operator | Dec 1986 |
| 7 | Manx Inc | | Oil Operator | Dec 2020 |
| 8 | Maple Grove Enterprises Inc | | Oil & Gas Operator | Dec 2025 |
| 9 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | May 2026 |
| 10 | Marco Drilling Inc | Monroeville, PA 15146-0278 | Oil & Gas Operator | Dec 2025 |
| 11 | Mark & Troy Johnson | Sugar Grove, PA 16350-5938 | Oil Operator | Dec 2025 |
| 12 | Mark A & Michael J Midlik | Warren, PA 16365-2029 | Oil & Gas Operator | Dec 2015 |
| 13 | Mark Resources Corp | Pittsburgh, PA 15276 | Oil & Gas Operator | Dec 1993 |
| 14 | Marvin Sanders Oil | Sugar Grove, PA 16350-5612 | Oil & Gas Operator | Dec 2016 |
| 15 | Mat Oil & Gas Exploration Inc | Indiana, PA 15701-8931 | Gas Operator | Dec 1993 |
| 16 | Maxson Gas Corp | | Oil & Gas Operator | Dec 2025 |
| 17 | Maxson Lawrence C | Shinglehouse, PA 16748 | Oil & Gas Operator | Dec 2016 |
| 18 | Maxwell Bros | Clarion, PA 16214-7446 | Oil & Gas Operator | Dec 2025 |
| 19 | Mays Coal Co | | Gas Operator | Dec 2003 |
| 20 | Mays Gas & Coal Co | Clarion, PA 16214-0447 | Oil & Gas Operator | Dec 2025 |
| 21 | MBS Resources Inc | Wilcox, PA 15870-1810 | Oil & Gas Operator | Dec 2025 |
| 22 | McCall Carl E | Fairmount City, PA 16224 | Oil & Gas Operator | Dec 2025 |
| 23 | McCluskey J Sterling | New York, NY 10128-1008 | Gas Operator | Dec 1989 |
| 24 | McComb Oil Inc | Stoneboro, PA 16153-3017 | Oil & Gas Operator | Dec 2025 |
| 25 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Apr 2026 |
| 26 | McKenna Oil Co | Kane, PA 16735-9711 | Oil & Gas Operator | Dec 2004 |
| 27 | MDS Energy Dev LLC | Kittanning, PA 16201-4403 | Oil & Gas Operator | Apr 2026 |
| 28 | MDS Energy LTD | Kittanning, PA 16201-4403 | Gas Operator | Feb 2015 |
| 29 | Mead Oil LLC | Sheffield, PA 16347-1022 | Oil & Gas Operator | Dec 2025 |
| 30 | Medina Res Dev Co LLC | | Oil & Gas Operator | Apr 2026 |
| 31 | Meridian Exploration Corp. | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2021 |
| 32 | Meridian Oil & Gas Enterprises Inc | Blairsville, PA 15717-0337 | Oil & Gas Operator | Dec 2003 |
| 33 | Mervin Troyer | Union City, PA 16438-8510 | Gas Operator | Dec 2008 |
| 34 | Mid Amer Natural Resources Inc | | Gas Operator | Dec 1994 |
| 35 | Mid East Oil Co | Indiana, PA 15701-5378 | Gas Operator | Dec 2006 |
| 36 | Mid-Penn Energy Corporation | Harrisburg, PA 17101-1002 | Gas Operator | Dec 2021 |
| 37 | Mieka LLC | Flower Mound, TX 75028-7446 | Oil & Gas Operator | Dec 2014 |
| 38 | Millennium Oil & Gas Inc | Dexter, KS 67038 | Oil & Gas Operator | Dec 2025 |
| 39 | Minard Run Oil Co | Bradford, PA 16701 | Oil & Gas Operator | Dec 2025 |
| 40 | Minteer & Baker Gas Enterprise | Kittanning, PA 16201-5022 | Gas Operator | Dec 2025 |
| 41 | Missing Moon Oil Inc | Knox, PA 16232-4507 | Oil & Gas Operator | Dec 2025 |
| 42 | Mitch Well Energy Inc | Waterford, PA 16441-8143 | Oil & Gas Operator | Dec 2012 |
| 43 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 44 | Mob Corp | Waynesburg, PA 15370-2036 | Gas Operator | Dec 2007 |
| 45 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Apr 2026 |
| 46 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 47 | Mount Chestnut Dev LLC | Butler, PA 16002-3940 | Gas Operator | Dec 2017 |
| 48 | MSL Oil & Gas Corp | Bradford, PA 16701-0151 | Oil & Gas Operator | Dec 2025 |
| 49 | MT Savage Refractories | Pittsburgh, PA 15206-0171 | Gas Operator | Dec 2021 |
| 50 | MTN Energy | Aleppo, PA 15310 | Oil & Gas Operator | Apr 2026 |
| 51 | MTN V Oil & Gas Inc | | Oil & Gas Operator | Apr 2026 |
| 52 | Murphy Prod Inc | Vanderbilt, PA 15486-1001 | Oil & Gas Operator | Dec 2025 |
| 53 | Mutual Oil & Gas Co | Akron, OH 44311 | Oil & Gas Operator | Dec 2000 |