| 1901 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 1902 | Mobil Oil E & P Southeast Inc | | Oil & Gas Operator | Sep 2013 |
| 1903 | Mobil Oil E&P Se Inc - Pel-Tex | | Oil & Gas Operator | Dec 2005 |
| 1904 | Mobil Oil Expl & Prod S E | | Oil & Gas Operator | Dec 1979 |
| 1905 | Mobil Oil Exploration & Producing Southeast, Inc. | | Oil & Gas Operator | Dec 2025 |
| 1906 | Mobil Oil Exploration & Production North America Inc. | | Oil & Gas Operator | Dec 1996 |
| 1907 | Mobil Petro Vac, Inc. | Duncan, OK 73533 | Oil & Gas Operator | Feb 2026 |
| 1908 | Mobil Producing Texas & New Mexico | Denver City, TX 79323 | Oil & Gas Operator | Jun 2005 |
| 1909 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 1910 | Mobile Gulf, Inc. | | Oil & Gas Operator | Aug 1985 |
| 1911 | Mobile Petrovac, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 1912 | Mobile Production Systems, Inc. | Austin, TX 78711 | Oil & Gas Operator | Feb 1995 |
| 1913 | Mobley & Davis | | Oil & Gas Operator | Oct 1986 |
| 1914 | Mobley & McCain | | Oil & Gas Operator | Nov 1979 |
| 1915 | Mobley & McCain, Et Al | | Oil & Gas Operator | Jul 1986 |
| 1916 | Mobley Oil Company, Inc. | | Oil & Gas Operator | Feb 1990 |
| 1917 | Mobley Valve Service, Inc. | | Oil & Gas Operator | Nov 2006 |
| 1918 | Mobpar, Inc. | Houston, TX 77219 | Oil & Gas Operator | Feb 2026 |
| 1919 | Mobreal Oil Inc | Wilmington, DE 19808 | Oil & Gas Operator | Dec 1989 |
| 1920 | Mockingbird Oil, Inc. (I) | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 1921 | Moco Oil Inc | | Oil Operator | May 1984 |
| 1922 | Moco Operating Company | | Oil & Gas Operator | Mar 2002 |
| 1923 | Mode Oil & Gasdev LTD12/21/Ofb 9-98 | | Oil & Gas Operator | May 2013 |
| 1924 | Modena Operating LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 1925 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Feb 2026 |
| 1926 | Modus Inc. | | Oil & Gas Operator | Dec 2025 |
| 1927 | Moenning, Vernie | Electra, TX 76360 | Oil & Gas Operator | Aug 2025 |
| 1928 | Moff Oil Company | Pratt, KS 67124 | Gas Operator | Apr 1988 |
| 1929 | Moffitt W G Trust | Fort Gibson, OK 74434-4258 | Gas Operator | Nov 2019 |
| 1930 | Mog Energy LLC | Tyler, TX 75701 | Oil Operator | Feb 2026 |
| 1931 | Mogo Operating, LLC | Norman, OK 73069 | Oil & Gas Operator | Nov 2025 |
| 1932 | Mogo Reagan, LLC | Cut Bank, MT 59427 | Oil & Gas Operator | Dec 2025 |
| 1933 | Mogul Energy Corp | Los Angeles, CA 90024 | Oil & Gas Operator | Jan 2001 |
| 1934 | Mogul Energy International, Inc. | Houston, TX 77042 | Oil & Gas Operator | Oct 2017 |
| 1935 | Mogul Operating LLC | St Petersburg, FL 33706 | Oil Operator | Feb 2026 |
| 1936 | Mogul Resources, LLC | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 1937 | Mohawk Operating LLC | Oklahoma City, OK 73173-8907 | Gas Operator | Feb 2004 |
| 1938 | Mohawk Petroleum | | Oil & Gas Operator | Jan 1995 |
| 1939 | Mohican Exploration, LLC | Graham, TX 76450 | Oil & Gas Operator | Oct 2024 |
| 1940 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 1941 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 1942 | Mohr Hans | Carmichaels, PA 15320-2627 | Gas Operator | Dec 2014 |
| 1943 | Mohr, Steve | Maize, KS 67101 | Oil Operator | Aug 2022 |
| 1944 | Mojac Energy Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 1997 |
| 1945 | Mojave Operating Company | Midland, TX 79702 | Oil & Gas Operator | Nov 2002 |
| 1946 | Mojave Resources, LLC | New Braunfels, TX 78132 | Oil Operator | Feb 2026 |
| 1947 | Mojo Exploration & Production, LLC | Rockdale, TX 76567 | Oil Operator | Feb 2026 |
| 1948 | Mokan Capital, LLC | Spicewood, TX 78669 | Oil Operator | Feb 2026 |
| 1949 | Molder, Tom | Imperial, TX 79743 | Oil & Gas Operator | Feb 2026 |
| 1950 | Mole Hole Prod. | Bridgeport, TX 76426 | Oil Operator | Feb 2026 |
| 1951 | Mole Operating Co., Inc. | | Oil & Gas Operator | Oct 1983 |
| 1952 | Moleco, LLC | West Hills, CA 91308 | Oil Operator | Feb 2026 |
| 1953 | Moleo Gas Corp. | San Angelo, TX 76902 | Oil & Gas Operator | Apr 2018 |
| 1954 | Molitor Oil, Inc. | Wichita, KS 67205 | Oil & Gas Operator | Sep 2025 |
| 1955 | Mollenkopf Mark | Anadarko, OK 73005 | Oil Operator | Jul 2025 |
| 1956 | Moller, Herbert T. | Wichita Falls, TX 76301 | Oil & Gas Operator | Aug 2003 |
| 1957 | Mollett Oil Productions, LLC | Thelma, KY 41260 | Oil Operator | Dec 2020 |
| 1958 | Molly Oil & Gas, LLC | Dallas, TX 75209 | Oil & Gas Operator | Feb 2026 |
| 1959 | Molopo Energy Texas, LLC | Canada, 00100 | Oil & Gas Operator | Jan 2015 |
| 1960 | Molsdorf Ag LLC | McAllen, TX 78503 | Oil Operator | Sep 2013 |
| 1961 | Molz Oil Company Inc | Kiowa, KS 67070 | Oil & Gas Operator | Dec 2025 |
| 1962 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Feb 2026 |
| 1963 | Momentum Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2004 |
| 1964 | Momentum Oil & Gas, LLC | The Woodlands, TX 77382 | Oil & Gas Operator | May 2015 |
| 1965 | Momentum Oil Company | Albany, TX 76430 | Oil & Gas Operator | May 2003 |
| 1966 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 1967 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | Feb 2026 |
| 1968 | Moms Oil & Gas LLC | Nowata, OK 74048 | Oil & Gas Operator | Mar 2023 |
| 1969 | Mon Corp. | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 1970 | Mon-Oil Inc | | Oil & Gas Operator | Apr 1996 |
| 1971 | Monadnock Resources Op Co, LLC | Dallas, TX 75209 | Oil & Gas Operator | Jan 2021 |
| 1972 | Monadnock Resources, LLC | Addison, TX 75001 | Oil & Gas Operator | May 2020 |
| 1973 | Monago Operating Inc | | Oil & Gas Operator | Apr 2007 |
| 1974 | Monahan | | Oil Operator | Dec 2009 |
| 1975 | Monahan Rex | Sterling, CO 80751 | Oil & Gas Operator | Jun 2002 |
| 1976 | Monahan* Rex Family Trust | | Oil & Gas Operator | May 2007 |
| 1977 | Monarch Energy C | | Oil Operator | Nov 1987 |
| 1978 | Monarch Energy Company LLC | Eufaula, OK 74432 | Oil & Gas Operator | Dec 2025 |
| 1979 | Monarch Energy LLC | Paola, KS 66071 | Oil Operator | Sep 2025 |
| 1980 | Monarch Operating Company | Graham, TX 76450 | Oil & Gas Operator | Jun 2006 |
| 1981 | Monarch Petroleum Corporation | FT Worth, TX 76102 | Oil & Gas Operator | Dec 2019 |
| 1982 | Moncrief Oil | Casper, WY 82602 | Oil & Gas Operator | Feb 1986 |
| 1983 | Moncrief R W Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1994 |
| 1984 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 1985 | Moncrief, C. B. | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2021 |
| 1986 | Monday Creek Resources LTD | Logan, OH 43138 | Oil Operator | Dec 2024 |
| 1987 | Mondiale Energy, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Feb 2026 |
| 1988 | Mondo Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 1989 | Monex | | Oil Operator | Apr 1988 |
| 1990 | Monexco | Edmond, OK 73034-3776 | Oil & Gas Operator | Mar 2008 |
| 1991 | Monexco LLC | Dallas, TX 75204-2634 | Oil & Gas Operator | Nov 2025 |
| 1992 | Monexco Operating Company | Dallas, TX 75204-2634 | Oil & Gas Operator | Nov 2025 |
| 1993 | Monexco, Inc. | | Oil Operator | Dec 2003 |
| 1994 | Monfort, Roy C. | Iola, KS 66749 | Oil & Gas Operator | Sep 1989 |
| 1995 | Monge Oil Corp. | | Oil & Gas Operator | Dec 2021 |
| 1996 | Mongoose Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 1997 | Mongrue Oil Company, Inc. | | Oil & Gas Operator | Oct 1999 |
| 1998 | Mongrue, Roland, Inc | | Oil & Gas Operator | Mar 1979 |
| 1999 | Monitor O&G, L.L.C. | Frisco, TX 75034 | Oil & Gas Operator | Jan 2016 |
| 2000 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Dec 2025 |