| 1901 | Comanche Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2006 |
| 1902 | Comanche Resources Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Mar 2026 |
| 1903 | Comanche Well Service Corp. | Plano, TX 75093 | Oil & Gas Operator | Jun 2026 |
| 1904 | Combest A L | Purcell, OK 73080-6829 | Oil & Gas Operator | Aug 2021 |
| 1905 | Combined Oil & Gas | Denver, CO 80202 | Oil & Gas Operator | Feb 1990 |
| 1906 | Combined Resources Corporation | Edmond, OK 73083 | Oil & Gas Operator | Jun 2026 |
| 1907 | Combs Production LLC | Depew, OK 74028 | Oil & Gas Operator | Feb 2026 |
| 1908 | Combs, Steven H | Corydon, KY 42406 | Oil Operator | Dec 2023 |
| 1909 | Comco Of Louisiana, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2000 |
| 1910 | Comdisco Exploration Inc | | Oil Operator | Dec 1990 |
| 1911 | Comdisco Resources Inc | | Oil Operator | Aug 2004 |
| 1912 | Comerica Properties Corp | | Oil Operator | May 1985 |
| 1913 | Comet Energy Services LLC | Traverse City, MI 49686 | Oil & Gas Operator | Oct 2011 |
| 1914 | Comet Oil & Gas, Inc. | Conroe, TX 77305 | Oil & Gas Operator | Jun 2026 |
| 1915 | Comet Oil Company | Velma, OK 73091 | Oil & Gas Operator | May 2005 |
| 1916 | Comet Production | Conroe, TX 77305 | Oil Operator | Jun 2026 |
| 1917 | Comet-Haines Oil Company | Sulphur, OK 73086-0546 | Oil & Gas Operator | Mar 2013 |
| 1918 | Cometra Oil And Gas, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 1919 | Command Energy Operating LLC | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2026 |
| 1920 | Commander Oil Company LTD. | | Oil & Gas Operator | Dec 2021 |
| 1921 | Commerce Energy Co | Cleveland, OH 44115 | Oil & Gas Operator | Dec 1987 |
| 1922 | Commerce Energy, Inc. | | Oil & Gas Operator | Dec 1999 |
| 1923 | Commerce Oil & Gas Co | Rocky River, OH 44116 | Oil & Gas Operator | Dec 1996 |
| 1924 | Commercial Oil - | | Oil Operator | Apr 1994 |
| 1925 | Commercial Oil Company, Inc. | Wichita, KS 67204 | Oil Operator | Jun 2001 |
| 1926 | Commodore Energy Co | Rolling Hills, CA 90274-5265 | Oil & Gas Operator | Dec 2007 |
| 1927 | Common Energy Inc | Douglas, WY 82633 | Oil & Gas Operator | Aug 1995 |
| 1928 | Common Resources L.L.C. | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 1929 | Commonwealth Energy, Inc. | Weston, WV 26452-0000 | Oil & Gas Operator | Dec 2021 |
| 1930 | Commonwealth Pet | | Oil & Gas Operator | Nov 1995 |
| 1931 | Commonwealth Resources, LLC | Fort Collins, CO 80524 | Oil Operator | Dec 2008 |
| 1932 | Commonwealth Royalty, LLC | Balmorhea, TX 79718 | Oil Operator | Jun 2026 |
| 1933 | Compadre Drilling & Expl Corp | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2015 |
| 1934 | Compadres, Inc. | | Oil & Gas Operator | Dec 1988 |
| 1935 | Compass Drilling Inc | Enid, OK 73702-5467 | Oil & Gas Operator | Sep 2014 |
| 1936 | Compass Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2026 |
| 1937 | Compass Exploration LLC | Hill City, KS 67642 | Oil Operator | Feb 2026 |
| 1938 | Compass Global Resources LLC | | Oil & Gas Operator | Dec 2015 |
| 1939 | Compass Operating, L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jun 2026 |
| 1940 | Compass Resources | Enid, OK 73702 | Oil & Gas Operator | Dec 2007 |
| 1941 | Complete Energy Services LLC | Gainesville, TX 76240 | Oil Operator | Aug 2022 |
| 1942 | Compostella Oil Company | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 1943 | Compressor Syste | | Oil Operator | May 1991 |
| 1944 | Compro Services Inc | Williamstown, WV 26187 | Oil & Gas Operator | Dec 1985 |
| 1945 | Comstock Energy, LLC | Wichita Falls, TX 76301 | Oil & Gas Operator | Jun 2026 |
| 1946 | Comstock Offshore, LLC | | Oil & Gas Operator | Nov 2004 |
| 1947 | Comstock Oil & Gas -- La, Inc. | | Oil & Gas Operator | Mar 2005 |
| 1948 | Comstock Oil & Gas, Inc. | Frisco, TX 75034 | Oil & Gas Operator | Dec 2012 |
| 1949 | Comstock Oil & Gas, LLC | Frisco, TX 75034 | Oil & Gas Operator | Jun 2026 |
| 1950 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 1951 | Comstock Oil & Gas--La, LLC | | Oil & Gas Operator | Dec 2024 |
| 1952 | Comyn Natural Gas, Inc. | Fort Worth, TX 76163 | Oil & Gas Operator | Jun 2026 |
| 1953 | Con-Lin Oil Co. | Graham, TX 76450 | Oil & Gas Operator | Nov 2017 |
| 1954 | Conch Oil, Inc. | Wichita, KS 67202 | Oil Operator | Jun 2002 |
| 1955 | Concho Exploration | Midland, TX 79701 | Oil & Gas Operator | Feb 2004 |
| 1956 | Concho Exploration Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2015 |
| 1957 | Concho Oil & Gas Corp. | Midland, TX 79701 | Oil & Gas Operator | May 2003 |
| 1958 | Concho Oilfield Serv & Oper Co. | Eden, TX 76837 | Oil & Gas Operator | Jun 2026 |
| 1959 | Concho Oilfield Service, Inc. | Albany, TX 76430 | Oil & Gas Operator | Apr 2013 |
| 1960 | Concho Petroleum | | Oil & Gas Operator | Dec 1994 |
| 1961 | Concho Resources Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2004 |
| 1962 | Concor Petroleum, Inc. | | Oil & Gas Operator | Feb 1983 |
| 1963 | Concord Energy, Inc. | Glen Rose, TX 76043 | Oil & Gas Operator | Jun 2026 |
| 1964 | Concord Operating Incorporated | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2008 |
| 1965 | Concord Resources, LLC | | Oil & Gas Operator | Nov 2000 |
| 1966 | Concorde Exploration, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Oct 1994 |
| 1967 | Concorde Resources Corporation | Eufaula, OK 74432 | Oil & Gas Operator | Jan 2026 |
| 1968 | Concordia Resources Inc. | | Oil & Gas Operator | Dec 2025 |
| 1969 | Condor Energy | | Oil Operator | Aug 1995 |
| 1970 | Condor Energy, Inc. | Great Bend, KS 67530 | Oil & Gas Operator | Nov 2019 |
| 1971 | Condor Exploration LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Sep 2009 |
| 1972 | Condor Oil Company Inc. | | Oil & Gas Operator | Dec 2000 |
| 1973 | Condor Oil Corp | Boulder, CO 80303 | Oil & Gas Operator | Dec 1994 |
| 1974 | Condor Operating Co. | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 1975 | Condor Operating Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Jun 2026 |
| 1976 | Condor Petroleum | | Oil & Gas Operator | Nov 1990 |
| 1977 | Condor Petroleum Corporation | | Oil & Gas Operator | Aug 2020 |
| 1978 | Condor Petroleum, Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2019 |
| 1979 | Condra, James M. Jr. | Sonora, TX 76950 | Oil & Gas Operator | May 1996 |
| 1980 | Condrin Oil 1985-A LTD | Tulsa, OK 74136 | Oil & Gas Operator | Nov 1998 |
| 1981 | Condry Oil Compa | | Oil Operator | May 1992 |
| 1982 | Cone & Petree Oil & Gas Exp. Inc | Lubbock, TX 79453 | Oil & Gas Operator | May 2024 |
| 1983 | Cone, Charles M. Services, Inc. | Dallas, TX 75372 | Oil & Gas Operator | Sep 2005 |
| 1984 | Cone, Ronald M. | Stafford, NY 14143 | Gas Operator | Dec 2024 |
| 1985 | Cone, S. E. Jr. | Lubbock, TX 79408 | Oil & Gas Operator | Feb 2002 |
| 1986 | Confed Oil Incorporated | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 1987 | Confederate Bay LLC | Okemah, OK 74859 | Oil & Gas Operator | Mar 2026 |
| 1988 | Confederate Spooling Inc | Okemah, OK 74859-2409 | Oil & Gas Operator | Apr 2020 |
| 1989 | Conklin Robert L Dba Conklin Oil LLC | Tulsa, OK 74153 | Oil Operator | Feb 2026 |
| 1990 | Conklin, Patrick J. | Rushville, NY 14544 | Gas Operator | Dec 2024 |
| 1991 | Conley Energy Co LLC | Marietta, OH 45750 | Oil & Gas Operator | Dec 2020 |
| 1992 | Conley Oil, Inc | Salyersville, KY 41465 | Oil & Gas Operator | Dec 2022 |
| 1993 | Conley P Smith Operating Co. | | Oil & Gas Operator | Jun 1995 |
| 1994 | Conley, Harry | Colony, KS 66015 | Oil Operator | Nov 2025 |
| 1995 | Conley, John | | Oil Operator | Aug 2000 |
| 1996 | Conn Energy Group, LLC | | Oil & Gas Operator | Apr 2024 |
| 1997 | Conn-Okla Producing Co Inc | | Oil & Gas Operator | Nov 1992 |
| 1998 | Connaway Oil & Gas Co. | Brookesmith, TX 76827 | Oil & Gas Operator | Feb 2016 |
| 1999 | Connell, Mark Allen | Claflin, KS 67525 | Oil Operator | Feb 2026 |
| 2000 | Conner Jelly | Seminole, OK 74868 | Oil & Gas Operator | Mar 1996 |