| 1 | M A S Operators | Kilgore, TX 75663 | Oil & Gas Operator | Jul 1999 |
| 2 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2024 |
| 3 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2024 |
| 4 | Mako Exploration Management, LLC | Shreveport, LA 71105 | Oil & Gas Operator | Dec 2024 |
| 5 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 6 | Mar-Bec Energy Company, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | May 2001 |
| 7 | Mark Oil, Inc. | Chanute, KS 66720 | Oil Operator | May 2024 |
| 8 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 9 | Martin Cannon Interests, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 10 | Martin Oil LLC | Madison, KS 66860 | Oil Operator | Aug 2024 |
| 11 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2024 |
| 12 | Mass Energy, Inc | Houston, TX 77056 | Oil & Gas Operator | Mar 2008 |
| 13 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 14 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 15 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | Dec 2024 |
| 16 | McBride Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 17 | McBride, Jerrel L Enterprise Inc | Kilgore, TX 75663 | Oil & Gas Operator | Jun 1999 |
| 18 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 19 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 20 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 21 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 22 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 23 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 24 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 25 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 26 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 27 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Dec 2024 |
| 28 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 29 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 30 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 31 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 32 | Miltuck Operating, Inc. | Elysian Field, TX 75642 | Oil & Gas Operator | Dec 1996 |
| 33 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 34 | Mondo Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 35 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 36 | Munoco Co. | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2021 |
| 37 | Munson, David M. Inc. | Dallas, TX 75251 | Oil & Gas Operator | Dec 2024 |
| 38 | Muras Energy, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Oct 2024 |
| 39 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Jul 2024 |
| 40 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |
| 41 | Mustang Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2006 |