| 2001 | Monroe Gas Associates-1 | | Gas Operator | Mar 2000 |
| 2002 | Monroe Gas Associates-2 | | Gas Operator | Mar 2000 |
| 2003 | Monroe Gas Joint Venture | | Gas Operator | Sep 2011 |
| 2004 | Monroe James | | Oil & Gas Operator | Oct 1997 |
| 2005 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Nov 2025 |
| 2006 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 2007 | Monroe Well Ser-Amsterdam | | Oil Operator | Dec 1988 |
| 2008 | Monroe Well Ser-La Petr Assoc | | Oil Operator | Dec 1988 |
| 2009 | Monroe Well Ser-La Petro II | | Oil Operator | Dec 1988 |
| 2010 | Monroe Well Ser-New American85 | | Oil Operator | Dec 1988 |
| 2011 | Monroe Well Ser-Ocean Petr '84 | | Oil & Gas Operator | Dec 1988 |
| 2012 | Monroe Well Ser-Ocean Yacht II | | Oil Operator | May 1989 |
| 2013 | Monroe Well Ser-Oceanyacht1985 | | Oil Operator | Dec 1988 |
| 2014 | Monroe Well Ser-Riverside 1985 | | Oil Operator | Dec 1988 |
| 2015 | Monroe Well Serv-New American | | Oil Operator | Dec 1988 |
| 2016 | Monroe Well Serv-Northern La | | Oil Operator | Dec 1988 |
| 2017 | Monroe Well Serv-Omega 1985 | | Oil Operator | Dec 1988 |
| 2018 | Monroe Well Service | | Oil & Gas Operator | Apr 1998 |
| 2019 | Monroe Well Service-Ajk | | Oil Operator | Dec 1988 |
| 2020 | Monroe Well Service-Apk | | Oil Operator | Dec 1988 |
| 2021 | Monroe Well Service-Beaver1985 | | Oil Operator | Nov 1991 |
| 2022 | Monroe Well Service-Broadway | | Oil Operator | Dec 1988 |
| 2023 | Monroe Well Service-BWK | | Oil Operator | Dec 1988 |
| 2024 | Monroe Well Service-Columbus | | Oil Operator | Dec 1988 |
| 2025 | Monroe Well Service-Das | | Oil Operator | Mar 1989 |
| 2026 | Monroe Well Service-Derrick | | Oil Operator | Dec 1988 |
| 2027 | Monroe Well Service-East End | | Oil Operator | Dec 1988 |
| 2028 | Monroe Well Service-Empire | | Oil Operator | Dec 1988 |
| 2029 | Monroe Well Service-Energy | | Oil Operator | Dec 1988 |
| 2030 | Monroe Well Service-Energy 84 | | Oil Operator | Aug 1989 |
| 2031 | Monroe Well Service-Ged | | Oil Operator | Dec 1988 |
| 2032 | Monroe Well Service-Gotham | | Oil Operator | Apr 1992 |
| 2033 | Monroe Well Service-Gramercy | | Oil Operator | May 1992 |
| 2034 | Monroe Well Service-HGC | | Oil Operator | Dec 1988 |
| 2035 | Monroe Well Service-Lebo | | Oil Operator | Jun 1989 |
| 2036 | Monroe Well Service-Lexington | | Oil Operator | Feb 1989 |
| 2037 | Monroe Well Service-Newtown | | Oil Operator | Aug 1990 |
| 2038 | Monroe Well Service-Ocean | | Oil Operator | Feb 1989 |
| 2039 | Monroe Well Service-Oceanyacht | | Oil Operator | Jan 1989 |
| 2040 | Monroe Well Service-Oil City | | Oil Operator | Aug 1992 |
| 2041 | Monroe Well Service-Omega | | Oil Operator | Aug 1992 |
| 2042 | Monroe Well Service-Par | | Oil Operator | Jan 1990 |
| 2043 | Monroe Well Service-Petrol | | Oil Operator | Sep 1992 |
| 2044 | Monroe Well Service-Petrovest | | Oil Operator | Dec 1988 |
| 2045 | Monroe Well Service-PRG | | Oil Operator | Nov 1990 |
| 2046 | Monroe Well Service-Redstone | | Oil Operator | Jul 1989 |
| 2047 | Monroe Well Service-RVS | | Oil Operator | Dec 1990 |
| 2048 | Monroe Well Service-Shemen | | Oil Operator | Dec 1988 |
| 2049 | Monroe Well Service-Shemen1984 | | Oil Operator | Jan 1989 |
| 2050 | Monroe Well Service-Shemen1985 | | Oil Operator | Nov 1990 |
| 2051 | Monroe Well Service-Sla | | Oil Operator | Mar 1989 |
| 2052 | Monroe Well Service-SPD | | Oil Operator | Dec 1988 |
| 2053 | Monroe Well Service-SPD 1985 | | Oil Operator | Dec 1988 |
| 2054 | Monroe Well Service-TBR | | Oil Operator | Aug 1991 |
| 2055 | Monroe Well Service-TG I | | Oil Operator | Oct 1990 |
| 2056 | Monroe Well Service-TG II | | Oil Operator | Oct 1990 |
| 2057 | Monroe Well Service-TG III | | Oil Operator | Jul 1992 |
| 2058 | Monroe Well Service-TG VI | | Oil Operator | Aug 1989 |
| 2059 | Monroe Well Service-Tpa 1985 | | Oil Operator | Dec 1990 |
| 2060 | Monroe Well Service-Vista | | Oil Operator | Nov 1990 |
| 2061 | Monroe Well Service-West End | | Oil Operator | Dec 1988 |
| 2062 | Monroe Well Service-York | | Oil Operator | Dec 1988 |
| 2063 | Monroe, Cameron | Westfield, NY 14787 | Gas Operator | Dec 2024 |
| 2064 | Monroe,Eugene R. | Midland, TX 79702 | Oil & Gas Operator | Jul 1999 |
| 2065 | Monsanto | Englewood, CO 80111 | Oil & Gas Operator | Apr 1986 |
| 2066 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 2067 | Monsanto Oil Com | | Oil Operator | Nov 1996 |
| 2068 | Monsanto Oil Company | | Oil & Gas Operator | Apr 1986 |
| 2069 | Mont Rouge Inc | | Gas Operator | Feb 2020 |
| 2070 | Mont-Land Co. | Graham, TX 76450 | Oil & Gas Operator | Mar 2008 |
| 2071 | Montalban Oil & Gas Operations, Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Dec 2025 |
| 2072 | Montana Energy Company, LLC | McAllen, TX 78504 | Oil & Gas Operator | Nov 2025 |
| 2073 | Montana Heartland LLC | Bismarck, ND 58504 | Oil & Gas Operator | Nov 2025 |
| 2074 | Montana Land & Exploration, Inc. | Calgary, AB T2P 3E7 | Oil & Gas Operator | Apr 2019 |
| 2075 | Montana Land & Mineral Co. | Billings, MT 59105 | Gas Operator | Sep 2025 |
| 2076 | Montana Oil Field Acquisition I, LLC | Rutherford, NJ 07070 | Oil Operator | Jun 2016 |
| 2077 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 2078 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 2079 | Montare Operating, LTD. | Flower Mound, TX 75022 | Oil & Gas Operator | Feb 2026 |
| 2080 | Montclair Energy LLC | Edmond, OK 73034-7291 | Oil & Gas Operator | Dec 2025 |
| 2081 | Montclair Production Company | Austin, TX 78755 | Oil & Gas Operator | Feb 2026 |
| 2082 | Montco Oil & Gas, Inc. | Pampa, TX 79066 | Oil & Gas Operator | May 1999 |
| 2083 | Monte Carlo Exploration Inc. | | Oil & Gas Operator | Oct 1984 |
| 2084 | Monte Grande Exploration, Inc. | Cut Bank, MT 59427 | Oil Operator | Oct 2000 |
| 2085 | Montego Resources Inc | Oklahoma City, OK 73172-0192 | Oil & Gas Operator | Mar 2015 |
| 2086 | Monterey Pipeline Co. | | Oil Operator | Aug 1993 |
| 2087 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2025 |
| 2088 | Monterey Resources Inc. | | Oil & Gas Operator | Dec 1997 |
| 2089 | Monterey Resources LLC | Dallas, TX 75230 | Oil & Gas Operator | Oct 2019 |
| 2090 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 2091 | Montex Exploration | Sugarland, TX 77478 | Oil Operator | Apr 2003 |
| 2092 | Montex Exploration Company | Houston, TX 77057 | Oil & Gas Operator | Mar 2011 |
| 2093 | Montgomery Count | | Oil Operator | Dec 1992 |
| 2094 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | Dec 2025 |
| 2095 | Montgomery Jake E | Henryetta, OK 74437 | Oil & Gas Operator | Sep 2025 |
| 2096 | Montgomery Oil & Gas Expl Inc | Tulsa, OK 74170-1884 | Oil & Gas Operator | Mar 2005 |
| 2097 | Montgomery Oil Co | | Oil Operator | Dec 2018 |
| 2098 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 2099 | Montgomery Production & Operating LLC | Herington, KS 67449 | Oil & Gas Operator | Sep 2025 |
| 2100 | Montgomery Royalty | Moran, TX 76464 | Oil & Gas Operator | Feb 2026 |