| 2801 | Masters Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2008 |
| 2802 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 2803 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2024 |
| 2804 | Matrix Oil & Gas, Inc. | | Oil & Gas Operator | Jul 2001 |
| 2805 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Feb 2024 |
| 2806 | Matthews Operating Co., Inc. | | Gas Operator | Aug 2001 |
| 2807 | Matzinger & Bell Inc-Carl O&G | | Oil & Gas Operator | Dec 1981 |
| 2808 | Matzinger & Bell, Inc. | | Oil & Gas Operator | Dec 1982 |
| 2809 | Matzinger Petroleum Co. | | Oil & Gas Operator | Jan 1991 |
| 2810 | Maurine B. Pyle | | Oil & Gas Operator | Mar 1993 |
| 2811 | Maverick Oil Co. | Richland, TX 76681 | Oil Operator | Apr 2024 |
| 2812 | Maverick Oil Corp. | | Oil Operator | May 1997 |
| 2813 | Maverick Producers, Inc. | | Oil Operator | May 2012 |
| 2814 | Maxim Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Dec 2023 |
| 2815 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2024 |
| 2816 | Maxum Energy Corp | Plano, TX 75025 | Oil & Gas Operator | Jan 2003 |
| 2817 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 2818 | Maxwell Oil & Gas Corp. | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2001 |
| 2819 | May Oil & Gas, L.L.C. | | Oil & Gas Operator | Dec 2013 |
| 2820 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 2821 | Maybrier Brothers | | Oil Operator | Apr 2006 |
| 2822 | Maybrier Production, L.L.C. | | Oil Operator | Oct 2022 |
| 2823 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 2824 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 2825 | MBM Partnership | | Gas Operator | Nov 1991 |
| 2826 | Mbo, LLC | | Oil Operator | Jan 2024 |
| 2827 | McAlester Fuel Co | Houston, TX 77042 | Oil & Gas Operator | Jan 2010 |
| 2828 | McBrayer Oil Corporation | Rockport, TX 78381 | Oil & Gas Operator | Nov 1994 |
| 2829 | McCarter-Greenbrier-Macdonald | | Oil Operator | Sep 1981 |
| 2830 | McClinton & 4-M Invest Inc | | Oil & Gas Operator | Sep 1992 |
| 2831 | McClinton & Mosing | | Oil & Gas Operator | Oct 1977 |
| 2832 | McConathy & Associates | | Oil & Gas Operator | Dec 1983 |
| 2833 | McConathy Production Co.,Inc. | | Oil & Gas Operator | Jun 1990 |
| 2834 | McCord Exploration Co. | | Oil & Gas Operator | Dec 1990 |
| 2835 | McCord Oil Co. And T. Walker | | Oil & Gas Operator | Dec 1985 |
| 2836 | McCord-Dale Exploration | | Oil & Gas Operator | May 1986 |
| 2837 | McCord-Goodrich Oil Company | | Oil & Gas Operator | Oct 1991 |
| 2838 | McCormick Operating Company | | Oil & Gas Operator | Mar 1984 |
| 2839 | McCormick Operating PRTNSHP | | Oil & Gas Operator | Sep 1985 |
| 2840 | McCormick Production Co, Inc. | Oil City, LA 71061 | Oil & Gas Operator | Apr 2024 |
| 2841 | McCormick-Bintliff | | Oil & Gas Operator | Feb 1984 |
| 2842 | McCormick-Bintliff-Pettit | | Oil & Gas Operator | Feb 1984 |
| 2843 | McCormick-Ciroco, Inc. | | Oil & Gas Operator | Jan 1984 |
| 2844 | McCormick-Terra-Bintliff | | Oil & Gas Operator | Dec 1979 |
| 2845 | McCormick-WHB | | Gas Operator | Jan 1984 |
| 2846 | McCulloch Oil Corp.-Ids | | Oil & Gas Operator | Dec 1981 |
| 2847 | McCurdy Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2024 |
| 2848 | McDaniel Petroleum Company, Inc. | | Oil Operator | Jun 2020 |
| 2849 | McDowell And Cook, Inc. | | Oil Operator | Feb 1987 |
| 2850 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 2851 | McGoldrick & Watson | | Oil & Gas Operator | Jul 1987 |
| 2852 | McGoldrick & Watson - Alagood | | Oil Operator | Oct 1995 |
| 2853 | McGoldrick & Watson DRLG., Co. | | Oil & Gas Operator | Jul 1987 |
| 2854 | McGoldrick & Watson, Et Al | | Oil Operator | Jul 1987 |
| 2855 | McGoldrick & Watson-Walker | | Oil Operator | Jul 1987 |
| 2856 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 2857 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 2858 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Apr 2024 |
| 2859 | McGowen Resources Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2003 |
| 2860 | McIlhenny-Powell Operating Co | | Gas Operator | Aug 1983 |
| 2861 | McIntyre Oil Company | | Oil & Gas Operator | Jan 1992 |
| 2862 | McKenzie Management Inc. | | Oil & Gas Operator | Aug 1989 |
| 2863 | McKenzie Petroleum Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 2864 | McKenzie Production Company | Houston, TX 77063 | Oil & Gas Operator | May 1995 |
| 2865 | McLain J. Forman | | Oil & Gas Operator | Mar 1988 |
| 2866 | McLaurin Oil Co. | | Oil Operator | Jan 2024 |
| 2867 | McLeod Gas Gath & Proc Co. L.L.C. | | Oil Operator | Jul 2012 |
| 2868 | McMoran Exploration Company | | Oil & Gas Operator | May 1985 |
| 2869 | McMoran Oil & Gas LLC | New Orleans, LA 70160 | Oil & Gas Operator | Oct 2021 |
| 2870 | McMoran Production Co. | | Oil & Gas Operator | May 1985 |
| 2871 | McMoran-Transco | | Oil & Gas Operator | Aug 1979 |
| 2872 | McMullan Oil Company | San Antonio, TX 78212 | Oil & Gas Operator | May 2023 |
| 2873 | McOr Oil & Gas Corp | Houston, TX 77002 | Oil & Gas Operator | Oct 2013 |
| 2874 | McOr Oil Development, Inc. | | Oil & Gas Operator | Feb 1990 |
| 2875 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 2876 | McRae Exploration, Inc. | | Oil & Gas Operator | Mar 1984 |
| 2877 | McRae Exploration, Inc. & Epm | | Oil & Gas Operator | Mar 1978 |
| 2878 | McRae Exploration, Inc. & Herd | | Oil & Gas Operator | Mar 1984 |
| 2879 | McRae Exploration,Inc & Bec | | Oil & Gas Operator | Feb 1984 |
| 2880 | McRae Oil Corporation | | Oil & Gas Operator | Mar 1984 |
| 2881 | MCZ Oil Co, Inc. | | Oil Operator | Feb 1994 |
| 2882 | MCZ, Inc. | Houston, TX 77026 | Oil & Gas Operator | Sep 1990 |
| 2883 | Meason Operating Company | Natchez, MS 39121 | Oil & Gas Operator | Dec 2011 |
| 2884 | Mec-Goodrich Oil Co. | | Oil & Gas Operator | Feb 1985 |
| 2885 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 2886 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 2887 | Medders Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Apr 2024 |
| 2888 | Mega Drilling Company | | Oil Operator | Feb 1984 |
| 2889 | Melren Oil & Gas Expl., Inc. | | Gas Operator | Dec 1989 |
| 2890 | Memaca Petroleum Corporation | | Oil & Gas Operator | Jan 1990 |
| 2891 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 2892 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2024 |
| 2893 | Meng Oper. & Expl. Co. | | Oil & Gas Operator | Dec 1989 |
| 2894 | Menoah Petroleum Inc | | Oil & Gas Operator | Dec 2023 |
| 2895 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 2896 | Meridian Oil Offshore Inc. | | Oil & Gas Operator | Aug 1996 |
| 2897 | Meridian Resources (USA) Inc. | | Oil & Gas Operator | Jul 2023 |
| 2898 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2024 |
| 2899 | Merl Wiggins Et Al | | Oil & Gas Operator | Sep 1996 |
| 2900 | Merrico Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2008 |