| 1 | M & B Oil Company | Holliday, TX 76366 | Oil & Gas Operator | Nov 2025 |
| 2 | M & M Drilling And Development | | Gas Operator | Dec 1988 |
| 3 | M & M Investments | | Oil & Gas Operator | May 1990 |
| 4 | M & M Oil Co., LLC | Oil City, LA 71061 | Oil & Gas Operator | Feb 2026 |
| 5 | M & M Oil Company | Monahans, TX 79756 | Oil & Gas Operator | Sep 2025 |
| 6 | M & M Production | | Oil & Gas Operator | Jun 2010 |
| 7 | M & R Exploration Company | Houston, TX 77074 | Oil & Gas Operator | Aug 2003 |
| 8 | M & S Production, Inc. | | Oil Operator | Jul 1994 |
| 9 | M & T Petroleum Management Inc | | Oil Operator | May 1984 |
| 10 | M & Z Engineering, Inc. | | Oil & Gas Operator | May 1998 |
| 11 | M G Gulff | | Oil Operator | May 1988 |
| 12 | M L Mayfield Petroleum Corp. | | Oil & Gas Operator | Aug 1991 |
| 13 | M P O'Meara, Jr. Inc. | | Oil & Gas Operator | Sep 2000 |
| 14 | M V Production Co | | Oil & Gas Operator | Jun 1990 |
| 15 | M V Ventures, G. P. | | Oil & Gas Operator | Dec 2000 |
| 16 | M-P Petroleum, Inc. | McPherson, KS 67460 | Oil & Gas Operator | Jan 2013 |
| 17 | M-X Oil & Gas, Inc. | | Oil & Gas Operator | Jun 1993 |
| 18 | M. A. Robison | | Oil & Gas Operator | Oct 1998 |
| 19 | M. B. And D. I. Dupree | | Oil Operator | Nov 1992 |
| 20 | M. E. Fitzgerald | | Oil & Gas Operator | May 1993 |
| 21 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Feb 2026 |
| 22 | M. F. McCain, Inc. | | Oil & Gas Operator | Jul 1987 |
| 23 | M. H. Thomson | | Gas Operator | Dec 2014 |
| 24 | M. H.Marr | | Oil & Gas Operator | Mar 1998 |
| 25 | M. L. Mayfield | | Oil & Gas Operator | Oct 1990 |
| 26 | M. L. Mayfield Co. | | Oil & Gas Operator | Aug 1991 |
| 27 | M. P. O'Meara Oil Co. | | Oil & Gas Operator | Apr 1991 |
| 28 | M. P. S. Prod. Co. | Houston, TX 77225 | Oil & Gas Operator | Dec 1996 |
| 29 | M. Parker Production Co. | | Oil Operator | Dec 2024 |
| 30 | M. S. Delone | | Oil Operator | Nov 1990 |
| 31 | M. T. R. Production | | Oil Operator | Mar 2006 |
| 32 | M. W. Maxwell | | Oil & Gas Operator | Apr 1990 |
| 33 | M.J. Bernos, Jr./PKR Oil, Inc. | | Gas Operator | Aug 1990 |
| 34 | M2 Louisiana Gas Service, LLC | | Oil Operator | Apr 2010 |
| 35 | Ma-Si, Inc. | | Oil & Gas Operator | May 1998 |
| 36 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Feb 2026 |
| 37 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Dec 2025 |
| 38 | Maddox Energy Corp | Dallas, TX BAD ADDR | Oil & Gas Operator | Jul 1995 |
| 39 | Maddox Oil & Gas | | Gas Operator | Jun 1982 |
| 40 | Maddox Oil & Gas, Inc. | | Oil Operator | Apr 1983 |
| 41 | Magic Circle Energy | Oklahoma City, OK 73185 | Oil & Gas Operator | Dec 1983 |
| 42 | Magna Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 43 | Magnolia Production Company LLC | | Oil & Gas Operator | Nov 2024 |
| 44 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 45 | Magnum Gas Pipeline, L.L.C. | | Oil Operator | Dec 2024 |
| 46 | Magnum Hunter Resources Corporation | | Oil & Gas Operator | Nov 2019 |
| 47 | Magnum Minerals, Inc. | | Oil & Gas Operator | May 1998 |
| 48 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 49 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 50 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 51 | Majestic Energy Corporation | Shreveport, LA 71164 | Oil & Gas Operator | May 2013 |
| 52 | Mako Exploration Management, LLC | Shreveport, LA 71105 | Oil & Gas Operator | Feb 2026 |
| 53 | Mallard Drilling Corp. | | Oil & Gas Operator | Jan 1993 |
| 54 | Mallard DRLG & Central Oil Co | | Gas Operator | Mar 1978 |
| 55 | Mallard Operating LLC | | Oil & Gas Operator | Nov 2024 |
| 56 | Mallard Petroleum, Inc. | | Oil & Gas Operator | Apr 1986 |
| 57 | Malmac | | Gas Operator | Mar 1991 |
| 58 | Malmac Energy Corp. | | Oil & Gas Operator | Jul 1987 |
| 59 | Malone Oil & Gas Exploration, Inc. | | Oil Operator | Dec 2018 |
| 60 | Malone-Killen Oil Expl. Co. | | Oil Operator | Apr 1992 |
| 61 | Mammoth Service Group, LLC | | Oil & Gas Operator | Nov 2025 |
| 62 | Mandalay Oil & Gas, L.L.C. | | Oil & Gas Operator | May 2008 |
| 63 | Mandalay Trading Services Inc. | | Oil Operator | Jul 1999 |
| 64 | Mandina & Murphy Oil Company | | Oil Operator | Nov 1990 |
| 65 | Mann Production Co., Inc. | | Oil Operator | Nov 1995 |
| 66 | Manna Minerals, Inc. | | Oil & Gas Operator | Apr 1989 |
| 67 | Mannon L. Walters, Inc. | | Oil & Gas Operator | Jun 2024 |
| 68 | Manolo Energy, Inc. | | Oil Operator | Sep 1996 |
| 69 | Manorado Oil Company | | Oil Operator | Feb 1999 |
| 70 | Manti Exploration Operating LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Feb 2015 |
| 71 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Feb 2026 |
| 72 | Mantle Oil & Gas, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Feb 2026 |
| 73 | Manursing Island Prod. Corp. | | Oil & Gas Operator | Sep 2002 |
| 74 | Map Associates, L.P. | | Oil & Gas Operator | Mar 1995 |
| 75 | Map Drilling Company | | Oil & Gas Operator | Apr 2012 |
| 76 | Map Oil Co. | | Oil Operator | Jan 1978 |
| 77 | Mapco Oil & Gas Company | Tulsa, OK 74101-2115 | Oil & Gas Operator | Jan 1985 |
| 78 | Mapco Production Co | Billings, MT 59102 | Oil & Gas Operator | Apr 1994 |
| 79 | Maple Gulf Coast Props. Corp. | | Oil & Gas Operator | Jun 1989 |
| 80 | Mar-Bec Energy Company, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | May 2001 |
| 81 | Mar-Low Corporation | | Oil & Gas Operator | Mar 1992 |
| 82 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 83 | Marathon Corporation | | Oil Operator | Dec 1994 |
| 84 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Dec 2025 |
| 85 | Marathon Oil Company/Fina | | Oil & Gas Operator | Jan 2005 |
| 86 | Marben Corporation | | Oil Operator | Jul 1995 |
| 87 | Marine Cont. & Supply Inc. | | Oil & Gas Operator | Nov 1985 |
| 88 | Marine Properties, Inc. | | Oil & Gas Operator | Feb 1995 |
| 89 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 90 | Marion Corporation | | Oil & Gas Operator | Jan 2001 |
| 91 | Maritech Resources, LLC | | Oil & Gas Operator | May 2011 |
| 92 | Marjo, Inc. | | Oil & Gas Operator | Sep 1991 |
| 93 | Mark F Preddy & Associates,Inc | | Oil & Gas Operator | Dec 1987 |
| 94 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Dec 2025 |
| 95 | Mark Producing Inc | Houston, TX 77057 | Oil & Gas Operator | Dec 1987 |
| 96 | Mark Seifer | | Oil & Gas Operator | Dec 2024 |
| 97 | Mark V Petroleum Company | | Oil & Gas Operator | Feb 2020 |
| 98 | Markham Enterprises Inc | | Oil & Gas Operator | May 1981 |
| 99 | Marks Operating LLC | | Oil & Gas Operator | Jul 2016 |
| 100 | Marlan Anderson | | Oil Operator | Jan 2025 |