| 3001 | McCord Oil Co. And T. Walker | | Oil & Gas Operator | Dec 1985 |
| 3002 | McCord-Dale Exploration | | Oil & Gas Operator | May 1986 |
| 3003 | McCord-Goodrich Oil Company | | Oil & Gas Operator | Oct 1991 |
| 3004 | McCormick Operating Company | | Oil & Gas Operator | Mar 1984 |
| 3005 | McCormick Operating PRTNSHP | | Oil & Gas Operator | Sep 1985 |
| 3006 | McCormick Production Co, Inc. | Oil City, LA 71061 | Oil & Gas Operator | Feb 2026 |
| 3007 | McCormick-Bintliff | | Oil & Gas Operator | Feb 1984 |
| 3008 | McCormick-Bintliff-Pettit | | Oil & Gas Operator | Feb 1984 |
| 3009 | McCormick-Ciroco, Inc. | | Oil & Gas Operator | Jan 1984 |
| 3010 | McCormick-Terra-Bintliff | | Oil & Gas Operator | Dec 1979 |
| 3011 | McCormick-WHB | | Gas Operator | Jan 1984 |
| 3012 | McCulloch Oil Corp.-Ids | | Oil & Gas Operator | Dec 1981 |
| 3013 | McCulloch Oil Corporation | | Oil & Gas Operator | Feb 1978 |
| 3014 | McCurdy Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2025 |
| 3015 | McDaniel Petroleum Company, Inc. | | Oil Operator | Jun 2020 |
| 3016 | McDonald Marketing & Operg. Co | | Gas Operator | May 1991 |
| 3017 | McDowell And Cook, Inc. | | Oil Operator | Jan 1987 |
| 3018 | McElroy Drilling Co., Inc. | | Gas Operator | Dec 1987 |
| 3019 | McEn 1996 Partnership | | Oil & Gas Operator | Sep 1999 |
| 3020 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 3021 | McGoldrick & Watson | | Oil & Gas Operator | Jul 1987 |
| 3022 | McGoldrick & Watson - Alagood | | Oil Operator | Oct 1995 |
| 3023 | McGoldrick & Watson DRLG., Co. | | Oil & Gas Operator | Jul 1987 |
| 3024 | McGoldrick & Watson, Et Al | | Oil Operator | Jul 1987 |
| 3025 | McGoldrick & Watson-Walker | | Oil Operator | Jul 1987 |
| 3026 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 3027 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 3028 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Feb 2026 |
| 3029 | McGowen Resources Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2003 |
| 3030 | McIlhenny-Powell Operating Co | | Gas Operator | Aug 1983 |
| 3031 | McIntyre Oil Company | | Oil & Gas Operator | Jan 1992 |
| 3032 | McKenzie Management Inc. | | Oil & Gas Operator | Aug 1989 |
| 3033 | McKenzie Petroleum Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 3034 | McKenzie Production Company | Houston, TX 77063 | Oil & Gas Operator | May 1995 |
| 3035 | McLain J. Forman | | Oil & Gas Operator | Mar 1988 |
| 3036 | McLaurin Oil Co. | | Oil Operator | Jan 2025 |
| 3037 | McLeod Gas Gath & Proc Co. L.L.C. | | Oil Operator | Jul 2012 |
| 3038 | McMoran Exploration Company | | Oil & Gas Operator | May 1985 |
| 3039 | McMoran Oil & Gas LLC | New Orleans, LA 70160 | Oil & Gas Operator | Oct 2021 |
| 3040 | McMoran Production Co. | | Oil & Gas Operator | May 1985 |
| 3041 | McMoran-Transco | | Oil & Gas Operator | Aug 1979 |
| 3042 | McMullan Oil Company | San Antonio, TX 78212 | Oil & Gas Operator | Jun 2023 |
| 3043 | McOr Oil & Gas Corp | Houston, TX 77002 | Oil & Gas Operator | Oct 2013 |
| 3044 | McOr Oil Development, Inc. | | Oil & Gas Operator | Feb 1990 |
| 3045 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 3046 | McRae Exploration, Inc. | | Oil & Gas Operator | Mar 1984 |
| 3047 | McRae Exploration, Inc. & Epm | | Oil & Gas Operator | Mar 1978 |
| 3048 | McRae Exploration, Inc. & Herd | | Oil & Gas Operator | Mar 1984 |
| 3049 | McRae Exploration,Inc & Bec | | Oil & Gas Operator | Feb 1984 |
| 3050 | McRae Oil Corporation | | Oil & Gas Operator | Mar 1984 |
| 3051 | MCZ Oil Co, Inc. | | Oil Operator | Feb 1994 |
| 3052 | MCZ, Inc. | Houston, TX 77026 | Oil & Gas Operator | Sep 1990 |
| 3053 | Meason Operating Company | Natchez, MS 39121 | Oil & Gas Operator | Dec 2011 |
| 3054 | Mec-Goodrich Oil Co. | | Oil & Gas Operator | Feb 1985 |
| 3055 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 3056 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 3057 | Medders Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 3058 | Mega Drilling Company | | Oil Operator | Feb 1984 |
| 3059 | Melren Oil & Gas Expl., Inc. | | Gas Operator | Nov 1989 |
| 3060 | Memaca Petroleum Corporation | | Oil & Gas Operator | Jan 1990 |
| 3061 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 3062 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 3063 | Meng Oper & Expl Co | | Oil & Gas Operator | Dec 1989 |
| 3064 | Menoah Petroleum Inc | | Oil & Gas Operator | Dec 2024 |
| 3065 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 3066 | Meridian Oil Offshore Inc. | | Oil & Gas Operator | Aug 1996 |
| 3067 | Meridian Resources (USA) Inc. | | Oil & Gas Operator | Aug 2024 |
| 3068 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Feb 2026 |
| 3069 | Merl Wiggins Et Al | | Oil & Gas Operator | Sep 1996 |
| 3070 | Merlin J Verret | | Gas Operator | Jun 1986 |
| 3071 | Merrico Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2008 |
| 3072 | Merritt Operating, Inc. | Mineola, TX 75773 | Oil & Gas Operator | Feb 2026 |
| 3073 | Mertz Energy LLC | Houston, TX 77098 | Oil & Gas Operator | Jan 2025 |
| 3074 | Mesa Gulf Coast LLC | | Oil & Gas Operator | Dec 2020 |
| 3075 | Mesa Operating LTD Partnership | Amarillo, TX 79189 | Oil & Gas Operator | May 1994 |
| 3076 | Mesa Petroleum Co. | | Oil & Gas Operator | Aug 1985 |
| 3077 | Mescalero Energy, Inc. | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 3078 | Metairie Energy Company, Inc. | | Oil & Gas Operator | Nov 2019 |
| 3079 | Metro Energy Group, Inc. | Bossier City, LA 71112 | Oil & Gas Operator | May 2013 |
| 3080 | Mettz,Carmody & Foster Oil Co | | Oil Operator | May 1990 |
| 3081 | Meyers-Lasher, Inc. | | Oil & Gas Operator | Mar 1999 |
| 3082 | MFP Petroleum LTD. Partnership | Oklahoma City, OK 73142 | Oil & Gas Operator | Nov 2017 |
| 3083 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 3084 | Mich-La Oil & Gas Exploration | | Oil & Gas Operator | Jan 1992 |
| 3085 | Michael D Brown | | Oil Operator | Jul 1993 |
| 3086 | Michael W Mills | | Oil Operator | Jul 2007 |
| 3087 | Michel T. Halbouty | | Oil & Gas Operator | Dec 1996 |
| 3088 | Michel T. Halbouty Energy Co. | | Oil & Gas Operator | Nov 1986 |
| 3089 | Michigan-Wisconsin Pipe Line Co | | Oil & Gas Operator | Dec 1983 |
| 3090 | Micron Minerals Company | | Oil & Gas Operator | Sep 1988 |
| 3091 | Mid Field Oil Co. | | Oil & Gas Operator | Mar 1989 |
| 3092 | Mid Louisiana Gas Company | | Oil & Gas Operator | Oct 2002 |
| 3093 | Mid South Oil & Gas Expl Inc | | Oil & Gas Operator | Jan 1992 |
| 3094 | Mid-America Resources Corporation | | Oil Operator | Jan 2019 |
| 3095 | Mid-America Resources, Inc. | | Oil & Gas Operator | Feb 2008 |
| 3096 | Mid-America/Hughes & Hughes | | Oil Operator | Jul 1984 |
| 3097 | Mid-Con Energy Operating, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | May 2020 |
| 3098 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 3099 | Mid-Continent Energy Operating | | Gas Operator | Aug 2007 |
| 3100 | Mid-Continent Energy, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2020 |