| 2801 | Mammoth Service Group, LLC | | Oil & Gas Operator | Jun 2025 |
| 2802 | Mandalay Oil & Gas, L.L.C. | | Oil & Gas Operator | May 2008 |
| 2803 | Mandalay Trading Services Inc. | | Oil Operator | Jul 1999 |
| 2804 | Mandina & Murphy Oil Company | | Oil Operator | Nov 1990 |
| 2805 | Mann Production Co., Inc. | | Oil Operator | Nov 1995 |
| 2806 | Manna Minerals, Inc. | | Oil & Gas Operator | Apr 1989 |
| 2807 | Mannon L. Walters, Inc. | | Oil & Gas Operator | Jun 2024 |
| 2808 | Manolo Energy, Inc. | | Oil Operator | Sep 1996 |
| 2809 | Manorado Oil Company | | Oil Operator | Feb 1999 |
| 2810 | Manti Exploration Operating LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Feb 2015 |
| 2811 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Sep 2025 |
| 2812 | Mantle Oil & Gas, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Sep 2025 |
| 2813 | Manursing Island Prod. Corp. | | Oil & Gas Operator | Sep 2002 |
| 2814 | Map Associates, L.P. | | Oil & Gas Operator | Mar 1995 |
| 2815 | Map Drilling Company | | Oil & Gas Operator | Apr 2012 |
| 2816 | Map Oil Co. | | Oil Operator | Jan 1978 |
| 2817 | Mapco Oil & Gas Company | Tulsa, OK 74101-2115 | Oil & Gas Operator | Jan 1985 |
| 2818 | Mapco Production Co | Billings, MT 59102 | Oil & Gas Operator | Apr 1994 |
| 2819 | Maple Gulf Coast Props. Corp. | | Oil & Gas Operator | Jun 1989 |
| 2820 | Mar-Bec Energy Company, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | May 2001 |
| 2821 | Mar-Low Corporation | | Oil & Gas Operator | Mar 1992 |
| 2822 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 2823 | Marathon Corporation | | Oil Operator | Dec 1994 |
| 2824 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Jul 2025 |
| 2825 | Marathon Oil Company/Fina | | Oil & Gas Operator | Jan 2005 |
| 2826 | Marben Corporation | | Oil Operator | Jul 1995 |
| 2827 | Marine Cont. & Supply Inc. | | Oil & Gas Operator | Nov 1985 |
| 2828 | Marine Properties, Inc. | | Oil & Gas Operator | Feb 1995 |
| 2829 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 2830 | Marion Corporation | | Oil & Gas Operator | Jan 2001 |
| 2831 | Maritech Resources, LLC | | Oil & Gas Operator | May 2011 |
| 2832 | Marjo, Inc. | | Oil & Gas Operator | Sep 1991 |
| 2833 | Mark F Preddy & Associates,Inc | | Oil & Gas Operator | Dec 1987 |
| 2834 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Jul 2025 |
| 2835 | Mark Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Dec 1987 |
| 2836 | Mark Seifer | | Oil & Gas Operator | Dec 2024 |
| 2837 | Mark V Petroleum Company | | Oil & Gas Operator | Feb 2020 |
| 2838 | Marks Operating LLC | | Oil & Gas Operator | Jul 2016 |
| 2839 | Marlan Anderson | | Oil Operator | Jan 2025 |
| 2840 | Marlin And Davis | | Oil Operator | Sep 1987 |
| 2841 | Marlin Coastal, L.L.C. | | Oil & Gas Operator | Apr 2008 |
| 2842 | Marlin Energy Offshore, L.L.C. | | Oil & Gas Operator | Jun 2006 |
| 2843 | Marlin Expl.,Inc&Exchg O&G Co | | Oil & Gas Operator | Jun 1987 |
| 2844 | Marlin Exploration, Inc. | | Oil & Gas Operator | Oct 2006 |
| 2845 | Marlin Exploration, LLC | | Oil & Gas Operator | Jul 2025 |
| 2846 | Marlin Resources, L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jan 2025 |
| 2847 | Marline Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 1989 |
| 2848 | Marline Petroleum Corporation | | Oil & Gas Operator | Dec 1985 |
| 2849 | Marmaton Oil Company | Houston, TX 77002 | Oil & Gas Operator | Jul 1998 |
| 2850 | Maroski, Inc. | | Oil Operator | Jan 1989 |
| 2851 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Sep 2025 |
| 2852 | Marquis Resources, LLC | | Oil & Gas Operator | Jul 2021 |
| 2853 | Marr Company | | Oil & Gas Operator | Mar 1989 |
| 2854 | Marsh Engineering, Inc. | | Oil & Gas Operator | Dec 1990 |
| 2855 | Marshall & McCain | | Oil & Gas Operator | Oct 1988 |
| 2856 | Marshall Exploration, Inc. | | Oil & Gas Operator | Jun 1992 |
| 2857 | Marshall Petroleum, Inc. | Houston, TX 77040 | Oil & Gas Operator | Aug 2003 |
| 2858 | Marshall Prod. & Energy Inc. | | Oil & Gas Operator | Jan 1992 |
| 2859 | Marshland Exploration Company | | Oil & Gas Operator | May 2006 |
| 2860 | Martin Energy LLC | | Oil & Gas Operator | Apr 2023 |
| 2861 | Martin Exploration Co. | | Oil & Gas Operator | Apr 1986 |
| 2862 | Martin Oil & Gas Co. | | Oil Operator | Jul 1981 |
| 2863 | Martin Oil Co. | Aspermont, TX 79502 | Oil & Gas Operator | Jul 2023 |
| 2864 | Martin Production Company | | Oil & Gas Operator | Dec 2024 |
| 2865 | Martin-Marks Operating Co. LLC | | Oil & Gas Operator | Dec 2010 |
| 2866 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 2867 | Marvin L. Muslow | | Oil Operator | Jun 1995 |
| 2868 | Mass Resources, Inc. | | Oil Operator | Jan 2025 |
| 2869 | Master Well Works, Inc. | | Oil Operator | Dec 2024 |
| 2870 | Masters Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2008 |
| 2871 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 2872 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Sep 2025 |
| 2873 | Matrix Oil & Gas, Inc. | | Oil & Gas Operator | Jul 2001 |
| 2874 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Jul 2025 |
| 2875 | Matthews Operating Co., Inc. | | Gas Operator | Aug 2001 |
| 2876 | Matthews-Bunn Operating Co. | | Oil & Gas Operator | Apr 1981 |
| 2877 | Matzinger & Bell Inc-Carl O&G | | Oil & Gas Operator | Dec 1981 |
| 2878 | Matzinger & Bell, Inc. | | Oil & Gas Operator | Dec 1982 |
| 2879 | Matzinger Petroleum Co. | | Oil & Gas Operator | Jan 1991 |
| 2880 | Maurine B. Pyle | | Oil & Gas Operator | Mar 1993 |
| 2881 | Maverick Oil Co. | Richland, TX 76681 | Oil Operator | Sep 2025 |
| 2882 | Maverick Oil Corp. | | Oil Operator | May 1997 |
| 2883 | Maverick Producers, Inc. | | Oil Operator | May 2012 |
| 2884 | Maxim Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Jul 2025 |
| 2885 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2025 |
| 2886 | Maxum Energy Corp | Plano, TX 75025 | Oil & Gas Operator | Jan 2003 |
| 2887 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 2888 | Maxwell Oil & Gas Corp. | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2001 |
| 2889 | May Oil & Gas, L.L.C. | | Oil & Gas Operator | Dec 2013 |
| 2890 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 2891 | Maybrier Brothers | | Oil Operator | Apr 2006 |
| 2892 | Maybrier Production, L.L.C. | | Oil Operator | Oct 2022 |
| 2893 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 2894 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 2895 | MBM Partnership | | Gas Operator | Nov 1991 |
| 2896 | Mbo, LLC | | Oil Operator | Jan 2025 |
| 2897 | McAlester Fuel Co | Houston, TX 77042 | Oil & Gas Operator | Jan 2010 |
| 2898 | McBrayer Oil Corporation | Rockport, TX 78381 | Oil & Gas Operator | Nov 1994 |
| 2899 | McCarter-Greenbrier-Macdonald | | Oil Operator | Sep 1981 |
| 2900 | McClinton & 4-M Invest Inc | | Oil & Gas Operator | Aug 1992 |