| 1 | M G U Development Co | | Oil & Gas Operator | Jun 1987 |
| 2 | M G U Development Co And Mask Thomas B And Ma020 | | Oil & Gas Operator | Jun 1987 |
| 3 | M K M LTD | | Oil & Gas Operator | Jun 1998 |
| 4 | M L Energy LLC | | Oil Operator | Oct 2025 |
| 5 | M R Ventures LLC | Dallas, TX 75367 | Oil & Gas Operator | Sep 2025 |
| 6 | Mack Oil Corp | | Oil & Gas Operator | Nov 1998 |
| 7 | Mack Oil Corp And Delta Oil Co Inc Great Lakes Nia | | Oil & Gas Operator | Feb 1986 |
| 8 | Mack Oil Corp And Neyer Oil Inc | | Oil & Gas Operator | May 1988 |
| 9 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 10 | Majoil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 1996 |
| 11 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 12 | Mask Thomas B | | Oil & Gas Operator | Jul 1991 |
| 13 | Mask Thomas B And Markel Ray D | | Oil & Gas Operator | Jul 1991 |
| 14 | Mask Thomas B And Markel Ray D And Wood K P | | Oil & Gas Operator | Aug 1986 |
| 15 | Mask Thomas B And Patrick Petroleum Corp | | Oil & Gas Operator | Jun 1992 |
| 16 | Maskeny Edward D | | Oil & Gas Operator | Jun 1998 |
| 17 | Matrex LLC | | Gas Operator | May 2006 |
| 18 | Matrix Exploration And Development LLC | | Oil & Gas Operator | Oct 2008 |
| 19 | Maverick Exploration And Production Inc | | Oil & Gas Operator | Nov 2025 |
| 20 | Mayfield Energy, LLC | Austin, TX 78732 | Oil & Gas Operator | Dec 2025 |
| 21 | McClure Oil Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 22 | McConnell And Scully Inc | | Oil & Gas Operator | Nov 2025 |
| 23 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Sep 2025 |
| 24 | Mercury Exploration Co. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 25 | Meridian Production Services LLC | | Oil & Gas Operator | Aug 2025 |
| 26 | Meridian Resources (USA) Inc. | | Oil & Gas Operator | Aug 2024 |
| 27 | Meridian Resources LLC | Evansville, IN 47715 | Oil Operator | Jul 2024 |
| 28 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 29 | Michigan Gas Utilities Co | | Oil & Gas Operator | Mar 2011 |
| 30 | Michigan Geosearch Inc | Lansing, MI 48917 | Oil & Gas Operator | Oct 2025 |
| 31 | Michigan Oil Company | FT Worth, TX 76117 | Oil & Gas Operator | Feb 1998 |
| 32 | Michigan Petroleum Exploration Inc | | Oil & Gas Operator | Oct 2005 |
| 33 | Michigan Production Co LLC | | Oil & Gas Operator | Oct 2002 |
| 34 | Mid Atlantic Oil Co | Hillsdale, MI 49242 | Oil & Gas Operator | Dec 1999 |
| 35 | Mid Michigan Gas Storage Co | | Oil & Gas Operator | Mar 2022 |
| 36 | Midstate Employment Services LLC | | Oil Operator | Apr 2024 |
| 37 | Midway Terrel Operating Co | | Oil & Gas Operator | Dec 1999 |
| 38 | Miller Brothers | | Oil & Gas Operator | Nov 2000 |
| 39 | Miller Brothers And Federal Oil Co | | Oil Operator | May 1984 |
| 40 | Miller Brothers And Total Petroleum And Wiser Oil | | Oil & Gas Operator | Sep 1991 |
| 41 | Miller Energy Company II LLC | | Oil & Gas Operator | Oct 2025 |
| 42 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 43 | Miller Raymond V | | Oil Operator | Jul 2007 |
| 44 | Mills Glen A | | Gas Operator | Dec 1985 |
| 45 | Miracle Petroleum LLC | | Oil & Gas Operator | Oct 2018 |
| 46 | Missaukee Oil And Gas Company LLC | | Oil & Gas Operator | Sep 2025 |
| 47 | Monroe James | | Oil & Gas Operator | Oct 1997 |
| 48 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 49 | Moskowitz Charles J | | Oil Operator | Feb 2014 |
| 50 | Moskowitz Oil & Gas LLC | | Oil Operator | Oct 2025 |
| 51 | Mosthaf Edwin C And Mosthaf Levina M | | Oil Operator | Jul 2020 |
| 52 | Muskegon Development Co And Miller Energy Inc An | | Gas Operator | Dec 1997 |
| 53 | Muskegon Development Company | MT Pleasant, MI 48858 | Oil & Gas Operator | Dec 2025 |
| 54 | Muskegon Operating Company LLC | | Oil & Gas Operator | Oct 2025 |
| 55 | Mutch Harry L | | Oil & Gas Operator | Oct 1991 |
| 56 | Mutch J O | | Gas Operator | Mar 1990 |
| 57 | Mutch Oil And Gas Development Inc | | Oil & Gas Operator | Dec 2004 |
| 58 | Muzyl Oil Corp | | Oil & Gas Operator | Oct 2025 |
| 59 | My Investments Too LLC | | Oil Operator | Oct 2025 |