| 19901 | Monitor O&G, L.L.C. | Frisco, TX 75034 | Oil & Gas Operator | Jan 2016 |
| 19902 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Feb 2025 |
| 19903 | Monroe County Water Authority | Rochester, NY 14612 | Gas Operator | Dec 2023 |
| 19904 | Monroe Gas Associates-1 | | Gas Operator | Mar 2000 |
| 19905 | Monroe Gas Associates-2 | | Gas Operator | Mar 2000 |
| 19906 | Monroe Gas Joint Venture | | Gas Operator | Sep 2011 |
| 19907 | Monroe James | | Oil & Gas Operator | Oct 1997 |
| 19908 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Jan 2025 |
| 19909 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 19910 | Monroe Well Ser-Amsterdam | | Oil Operator | Dec 1988 |
| 19911 | Monroe Well Ser-La Petr Assoc | | Oil Operator | Dec 1988 |
| 19912 | Monroe Well Ser-La Petro II | | Oil Operator | Dec 1988 |
| 19913 | Monroe Well Ser-New American85 | | Oil Operator | Dec 1988 |
| 19914 | Monroe Well Ser-Ocean Petr '84 | | Oil & Gas Operator | Dec 1988 |
| 19915 | Monroe Well Ser-Ocean Yacht II | | Oil Operator | May 1989 |
| 19916 | Monroe Well Ser-Oceanyacht1985 | | Oil Operator | Dec 1988 |
| 19917 | Monroe Well Ser-Riverside 1985 | | Oil Operator | Dec 1988 |
| 19918 | Monroe Well Serv-New American | | Oil Operator | Dec 1988 |
| 19919 | Monroe Well Serv-Northern La | | Oil Operator | Dec 1988 |
| 19920 | Monroe Well Serv-Omega 1985 | | Oil Operator | Dec 1988 |
| 19921 | Monroe Well Service | | Oil & Gas Operator | Apr 1998 |
| 19922 | Monroe Well Service-Ajk | | Oil Operator | Dec 1988 |
| 19923 | Monroe Well Service-Apk | | Oil Operator | Dec 1988 |
| 19924 | Monroe Well Service-Beaver1985 | | Oil Operator | Nov 1991 |
| 19925 | Monroe Well Service-Broadway | | Oil Operator | Dec 1988 |
| 19926 | Monroe Well Service-BWK | | Oil Operator | Dec 1988 |
| 19927 | Monroe Well Service-Columbus | | Oil Operator | Dec 1988 |
| 19928 | Monroe Well Service-Das | | Oil Operator | Mar 1989 |
| 19929 | Monroe Well Service-Derrick | | Oil Operator | Dec 1988 |
| 19930 | Monroe Well Service-East End | | Oil Operator | Dec 1988 |
| 19931 | Monroe Well Service-Empire | | Oil Operator | Dec 1988 |
| 19932 | Monroe Well Service-Energy | | Oil Operator | Dec 1988 |
| 19933 | Monroe Well Service-Energy 84 | | Oil Operator | Aug 1989 |
| 19934 | Monroe Well Service-Ged | | Oil Operator | Dec 1988 |
| 19935 | Monroe Well Service-Gotham | | Oil Operator | Apr 1992 |
| 19936 | Monroe Well Service-Gramercy | | Oil Operator | May 1992 |
| 19937 | Monroe Well Service-HGC | | Oil Operator | Dec 1988 |
| 19938 | Monroe Well Service-Lebo | | Oil Operator | Jun 1989 |
| 19939 | Monroe Well Service-Lexington | | Oil Operator | Feb 1989 |
| 19940 | Monroe Well Service-Newtown | | Oil Operator | Aug 1990 |
| 19941 | Monroe Well Service-Ocean | | Oil Operator | Feb 1989 |
| 19942 | Monroe Well Service-Oceanyacht | | Oil Operator | Jan 1989 |
| 19943 | Monroe Well Service-Oil City | | Oil Operator | Aug 1992 |
| 19944 | Monroe Well Service-Omega | | Oil Operator | Aug 1992 |
| 19945 | Monroe Well Service-Par | | Oil Operator | Jan 1990 |
| 19946 | Monroe Well Service-Petrol | | Oil Operator | Sep 1992 |
| 19947 | Monroe Well Service-Petrovest | | Oil Operator | Dec 1988 |
| 19948 | Monroe Well Service-PRG | | Oil Operator | Nov 1990 |
| 19949 | Monroe Well Service-Redstone | | Oil Operator | Jul 1989 |
| 19950 | Monroe Well Service-RVS | | Oil Operator | Dec 1990 |
| 19951 | Monroe Well Service-Shemen | | Oil Operator | Dec 1988 |
| 19952 | Monroe Well Service-Shemen1984 | | Oil Operator | Jan 1989 |
| 19953 | Monroe Well Service-Shemen1985 | | Oil Operator | Nov 1990 |
| 19954 | Monroe Well Service-Sla | | Oil Operator | Mar 1989 |
| 19955 | Monroe Well Service-SPD | | Oil Operator | Dec 1988 |
| 19956 | Monroe Well Service-SPD 1985 | | Oil Operator | Dec 1988 |
| 19957 | Monroe Well Service-TBR | | Oil Operator | Aug 1991 |
| 19958 | Monroe Well Service-TG I | | Oil Operator | Oct 1990 |
| 19959 | Monroe Well Service-TG II | | Oil Operator | Oct 1990 |
| 19960 | Monroe Well Service-TG III | | Oil Operator | Jul 1992 |
| 19961 | Monroe Well Service-TG VI | | Oil Operator | Aug 1989 |
| 19962 | Monroe Well Service-Tpa 1985 | | Oil Operator | Dec 1990 |
| 19963 | Monroe Well Service-Vista | | Oil Operator | Nov 1990 |
| 19964 | Monroe Well Service-West End | | Oil Operator | Dec 1988 |
| 19965 | Monroe Well Service-York | | Oil Operator | Dec 1988 |
| 19966 | Monroe, Cameron | Westfield, NY 14787 | Gas Operator | Dec 2023 |
| 19967 | Monsanto | Englewood, CO 80111 | Oil & Gas Operator | Apr 1986 |
| 19968 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 19969 | Monsanto Oil Com | | Oil Operator | Nov 1996 |
| 19970 | Monsanto Oil Company | | Oil & Gas Operator | Apr 1986 |
| 19971 | Mont-Land Co. | Graham, TX 76450 | Oil & Gas Operator | Mar 2008 |
| 19972 | Montalban Oil & Gas Operations, Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Feb 2025 |
| 19973 | Montana Energy Company, LLC | McAllen, TX 78501 | Oil & Gas Operator | Dec 2024 |
| 19974 | Montana Heartland LLC | Bismarck, ND 58504 | Oil & Gas Operator | Feb 2025 |
| 19975 | Montana Land & Exploration, Inc. | Calgary, AB T2P 3E7 | Oil & Gas Operator | Apr 2019 |
| 19976 | Montana Land & Mineral Co. | Billings, MT 59105 | Gas Operator | Jan 2025 |
| 19977 | Montana Oil Field Acquisition I, LLC | Rutherford, NJ 07070 | Oil Operator | Jun 2016 |
| 19978 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 19979 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 19980 | Montani Energy, LLC | Smithville, WV 26178 | Gas Operator | Dec 2021 |
| 19981 | Montare Operating, LTD. | Flower Mound, TX 75022 | Oil & Gas Operator | Apr 2025 |
| 19982 | Montclair Energy LLC | Edmond, OK 73034-7291 | Oil & Gas Operator | Jan 2025 |
| 19983 | Montclair Production Company | Austin, TX 78755 | Oil & Gas Operator | Apr 2025 |
| 19984 | Montco Oil & Gas, Inc. | Pampa, TX 79066 | Oil & Gas Operator | May 1999 |
| 19985 | Monte Grande Exploration, Inc. | Cut Bank, MT 59427 | Oil Operator | Oct 2000 |
| 19986 | Montego Resources Inc | Oklahoma City, OK 73172-0192 | Oil & Gas Operator | Mar 2015 |
| 19987 | Monterey Pipeline Co. | | Oil Operator | Aug 1993 |
| 19988 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2025 |
| 19989 | Monterey Resources Inc. | | Oil & Gas Operator | Dec 1997 |
| 19990 | Monterey Resources LLC | Dallas, TX 75230 | Oil & Gas Operator | Oct 2019 |
| 19991 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2025 |
| 19992 | Montex Exploration | Sugarland, TX 77478 | Oil Operator | Apr 2003 |
| 19993 | Montex Exploration Company | Houston, TX 77057 | Oil & Gas Operator | Mar 2011 |
| 19994 | Montgomery Count | | Oil Operator | Dec 1992 |
| 19995 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | Jan 2025 |
| 19996 | Montgomery Jake E | Henryetta, OK 74437 | Oil & Gas Operator | Jan 2025 |
| 19997 | Montgomery Oil & Gas Expl Inc | Tulsa, OK 74170-1884 | Oil & Gas Operator | Mar 2005 |
| 19998 | Montgomery Oil Co | | Oil Operator | Dec 2018 |
| 19999 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 20000 | Montgomery Production & Operating LLC | Herington, KS 67449 | Oil & Gas Operator | Dec 2024 |