| 1 | M H W, Inc. | Dallas, TX 75230 | Oil & Gas Operator | Jul 1996 |
| 2 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 3 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 4 | Marbil Oil, Inc. | Olney, TX 76374 | Oil & Gas Operator | Jun 2013 |
| 5 | Marjac Oil Company, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2025 |
| 6 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2025 |
| 7 | Marshall Pipe & Supply Co. | Nocona, TX 76255 | Oil & Gas Operator | Mar 2008 |
| 8 | Martin Petroleum Corp. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 9 | Mash Oilfield Services, LP | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 10 | Mayes Operating Co. | Stephenville, TX 76401 | Oil & Gas Operator | Oct 2019 |
| 11 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | Oct 2025 |
| 12 | McBride Production Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | May 1993 |
| 13 | McClymond, B. W. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2020 |
| 14 | McClymond, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2001 |
| 15 | McClymond, LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2009 |
| 16 | McCrea Exploration Company, Inc. | Carrollton, TX 75007 | Oil & Gas Operator | Nov 1995 |
| 17 | McCurdy Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2025 |
| 18 | McKee, Kenneth W. Oil Co. | Graham, TX 76450 | Oil & Gas Operator | Aug 2011 |
| 19 | McNallen & Griffin | Keller, TX 76244 | Oil & Gas Operator | Oct 2025 |
| 20 | McNallen Oil Co., Inc. | Keller, TX 76244 | Oil & Gas Operator | Oct 2025 |
| 21 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 22 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 23 | Mehaffey Investments, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Oct 2025 |
| 24 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 25 | Merrimac Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 26 | Mesquite Oil & Gas Production | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2025 |
| 27 | Micro Operating, Inc. | Bryan, TX 77807 | Oil & Gas Operator | Oct 2025 |
| 28 | Midville Energy, LLC. | Midland, TX 79705 | Oil & Gas Operator | Jul 2024 |
| 29 | Miller, Bob I. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 30 | Mingus Oil & Gas | Mingus, TX 76463 | Oil & Gas Operator | Oct 2025 |
| 31 | Misener Operating, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2010 |
| 32 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 33 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 34 | Mna Enterprises LTD. Co. | Hobbs, NM 88242 | Oil & Gas Operator | Jul 2025 |
| 35 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 36 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 37 | Mogul Resources, LLC | Cisco, TX 76437 | Oil & Gas Operator | Oct 2025 |
| 38 | Momentum Oil Company | Albany, TX 76430 | Oil & Gas Operator | May 2003 |
| 39 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Oct 2025 |
| 40 | Montgomery Royalty | Moran, TX 76464 | Oil & Gas Operator | Oct 2025 |
| 41 | Moore, Stephen Operating | Graham, TX 76450 | Oil & Gas Operator | Jun 2002 |
| 42 | Mormar Family Holdings, L.L.C. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2025 |
| 43 | Morton Valley Oil & Gas, Inc. | Dallas, TX 75222 | Oil & Gas Operator | Jun 2007 |
| 44 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |