| 18001 | M. D. & G. Partnership | | Oil & Gas Operator | Dec 1996 |
| 18002 | M. E. Fitzgerald | | Oil & Gas Operator | May 1993 |
| 18003 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2025 |
| 18004 | M. F. McCain, Inc. | | Oil & Gas Operator | Jul 1987 |
| 18005 | M. Grace, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Dec 2025 |
| 18006 | M. H. Thomson | | Gas Operator | Dec 2014 |
| 18007 | M. H. Whittier Energy LLC | | Oil & Gas Operator | Sep 1996 |
| 18008 | M. H.Marr | | Oil & Gas Operator | Mar 1998 |
| 18009 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 18010 | M. J. McCaffery Oil Co. | Allegany, NY 14706 | Oil Operator | Dec 2017 |
| 18011 | M. J. T. Enterprises | | Oil Operator | Sep 2025 |
| 18012 | M. K. Fuhrman LLC | | Oil Operator | Sep 2025 |
| 18013 | M. K. Production | Caldwell, TX 77836 | Oil & Gas Operator | Mar 2008 |
| 18014 | M. L. Mayfield | | Oil & Gas Operator | Oct 1990 |
| 18015 | M. L. Mayfield Co. | | Oil & Gas Operator | Aug 1991 |
| 18016 | M. M. & M. Resources, Inc. | Wetumka, OK 74883 | Oil & Gas Operator | Apr 2020 |
| 18017 | M. M. Miller & Sons, LTD. | Alice, TX 78333 | Oil & Gas Operator | Jan 2023 |
| 18018 | M. P. O'Meara Oil Co. | | Oil & Gas Operator | Apr 1991 |
| 18019 | M. P. S. Prod. Co. | Houston, TX 77225 | Oil & Gas Operator | Dec 1996 |
| 18020 | M. Parker Production Co. | | Oil Operator | Dec 2024 |
| 18021 | M. S. Delone | | Oil Operator | Nov 1990 |
| 18022 | M. S. Productions, Inc. | Pittsburg, KS 66762 | Oil & Gas Operator | Nov 2019 |
| 18023 | M. T. R. Production | | Oil Operator | Mar 2006 |
| 18024 | M. W. Maxwell | | Oil & Gas Operator | Apr 1990 |
| 18025 | M.A. Yost Operations, Inc | Russell, KS 67665 | Oil Operator | Sep 2025 |
| 18026 | M.A.E. Resources, Inc. | Parker, KS 66072 | Oil Operator | Sep 2011 |
| 18027 | M.A.R.S. Energy | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 18028 | M.B. Properties, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Oct 1995 |
| 18029 | M.B.J. Operating | Argyle, TX 76226 | Oil & Gas Operator | Jun 2022 |
| 18030 | M.C.E. Trust Group, A General Partnership | Cherryvale, KS 67335 | Oil & Gas Operator | Sep 2009 |
| 18031 | M.D. Skroopka Operating, LLC | Oakland, CA 94611 | Oil & Gas Operator | Dec 2025 |
| 18032 | M.J. Bernos, Jr./PKR Oil, Inc. | | Gas Operator | Aug 1990 |
| 18033 | M.J.O.G., Inc. | Fort Smith, AR 72903 | Oil Operator | Mar 2015 |
| 18034 | M.O.K.A.T. | Bartlesville, OK 74003 | Oil Operator | Jun 2001 |
| 18035 | M.R.M. Operating, Inc. | Midland, TX 79707 | Oil & Gas Operator | Aug 2003 |
| 18036 | M.T.M. Petroleum | | Oil & Gas Operator | Oct 1995 |
| 18037 | M2 Louisiana Gas Service, LLC | | Oil Operator | Apr 2010 |
| 18038 | M2 Squared Operating, LLC | Rockwall, TX 75032 | Oil Operator | Dec 2025 |
| 18039 | M2S Oil LLC | | Oil Operator | Oct 2025 |
| 18040 | M3 Helium Corp | | Gas Operator | Sep 2025 |
| 18041 | M3V Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Dec 2025 |
| 18042 | M4 Energy, LLC | Watsontown, PA 17777-1133 | Oil & Gas Operator | Dec 2024 |
| 18043 | M5 Standing Energy, LLC | Decatur, TX 76234 | Oil & Gas Operator | Dec 2025 |
| 18044 | M5oexit, LLC | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 18045 | M7 Resources LLC | Santa Fe, NM 87505 | Oil Operator | Oct 2025 |
| 18046 | Ma-Si, Inc. | | Oil & Gas Operator | May 1998 |
| 18047 | Mac 5 Operating, LLC | Pampa, TX 79065 | Oil & Gas Operator | Feb 2021 |
| 18048 | Mac Engineering & Operating Co | | Oil & Gas Operator | May 2005 |
| 18049 | Mac Oil Field Service Inc | Millersburg, OH 44654 | Oil & Gas Operator | Dec 2024 |
| 18050 | Mac Operating | Graham, TX 76450 | Oil & Gas Operator | Jun 2023 |
| 18051 | Mace, T. A. | Oklahoma City, OK 73127 | Oil & Gas Operator | Feb 2008 |
| 18052 | Macfarlan Oil And Gas, LLC | Ellenboro, WV 26346-0058 | Oil & Gas Operator | Dec 2021 |
| 18053 | Mach Petroleum, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | Nov 2014 |
| 18054 | Macha Enterprises, Inc. | Wichita Falls, TX 76309 | Oil Operator | Dec 2025 |
| 18055 | Machii-Ross Petroleum Co | | Oil & Gas Operator | Apr 2014 |
| 18056 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2025 |
| 18057 | Macina, P.T. | Shamrock, TX 79079 | Gas Operator | Dec 2025 |
| 18058 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Nov 2025 |
| 18059 | Mack Energy Comp | | Oil & Gas Operator | Nov 1994 |
| 18060 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | Nov 2025 |
| 18061 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 18062 | Mack Oil Corp | | Oil & Gas Operator | Nov 1998 |
| 18063 | Mack Oil Corp And Delta Oil Co Inc Great Lakes Nia | | Oil & Gas Operator | Feb 1986 |
| 18064 | Mack Oil Corp And Neyer Oil Inc | | Oil & Gas Operator | May 1988 |
| 18065 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Nov 2025 |
| 18066 | Mackenco Inc | Columbus, OH 43235 | Oil & Gas Operator | Dec 2020 |
| 18067 | Mackey Consulting & Leasing LLC | Cleveland, OK 74020 | Oil & Gas Operator | Oct 2025 |
| 18068 | Mackinaw Two, LLC | | Oil & Gas Operator | May 2020 |
| 18069 | Maclane Gas Company L.P. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Mar 1994 |
| 18070 | Macmart Inc | Wynnewood, OK 73098 | Oil & Gas Operator | Jan 2016 |
| 18071 | Macnichols, Jennifer | Akron, NY 14001 | Gas Operator | Dec 2024 |
| 18072 | Maco Incorporate | | Oil Operator | Jun 1984 |
| 18073 | Macpherson Oil Company LLC | | Oil & Gas Operator | Oct 2025 |
| 18074 | Macpherson Operating Company L.P. | | Oil & Gas Operator | Nov 2025 |
| 18075 | Macro Oil Company | Bartlesville, OK 74006 | Oil Operator | Aug 1999 |
| 18076 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 18077 | Mad Dog Oil Co. | | Oil Operator | Mar 2016 |
| 18078 | Mad Operators LLC | | Oil & Gas Operator | Sep 2025 |
| 18079 | Madco Energy Corp | Logan, OH 43138 | Oil & Gas Operator | Dec 1987 |
| 18080 | Madden Ventures | Mundelein, IL 60060 | Oil & Gas Operator | Dec 2008 |
| 18081 | Maddox Energy Corp | Dallas, TX BAD ADDR | Oil & Gas Operator | Jul 1995 |
| 18082 | Maddox Oil & Gas | | Gas Operator | Jun 1982 |
| 18083 | Maddox Oil & Gas, Inc. | | Oil Operator | Apr 1983 |
| 18084 | Maddox Operating | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 18085 | Maddux Oil & Gas | Strawn, TX 76475 | Oil & Gas Operator | Dec 2025 |
| 18086 | Maddux, Elizabeth H. | San Antonio, TX 78217 | Oil & Gas Operator | Nov 1995 |
| 18087 | Madera, R. F. | Palm Desert, CA 92210 | Oil & Gas Operator | Sep 2000 |
| 18088 | Madison And Wright LLC | The Colony, TX 75056 | Oil & Gas Operator | Dec 2025 |
| 18089 | Madison Brothers Investment, LLC | Brownsville, KY 42210 | Oil & Gas Operator | Dec 2023 |
| 18090 | Madison Mark T | Marienville, PA 16239-6029 | Oil & Gas Operator | Dec 2012 |
| 18091 | Madison Oil Co.-Halbouty, M. T. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1998 |
| 18092 | Madison Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1998 |
| 18093 | Madtick Dev Corp | Punxsutawney, PA 15767-0140 | Oil & Gas Operator | Dec 2024 |
| 18094 | Maersk Energy Inc. | Houston, TX 77042 | Oil & Gas Operator | Oct 1994 |
| 18095 | Maertins Production, LLC | Queen City, TX 75572 | Oil Operator | Dec 2025 |
| 18096 | Magaw & Zimmer | Perry, OK 73077-1055 | Oil & Gas Operator | Aug 2013 |
| 18097 | Magellan E&P Holdings, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jun 2021 |
| 18098 | Magellan Exploration Co LTD | Bethany, OK 73008-0909 | Oil & Gas Operator | Jun 2014 |
| 18099 | Maggard Joe | Mannford, OK 74044 | Oil & Gas Operator | May 2023 |
| 18100 | Maggard Oil Co Inc | Manford, OK 74044 | Oil & Gas Operator | Sep 1997 |