| 2001 | Concho Oilfield Serv & Oper Co. | Eden, TX 76837 | Oil & Gas Operator | Sep 2025 |
| 2002 | Concho Oilfield Service, Inc. | Albany, TX 76430 | Oil & Gas Operator | Apr 2013 |
| 2003 | Concho Petroleum | | Oil & Gas Operator | Dec 1994 |
| 2004 | Concho Resources Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2004 |
| 2005 | Concor Petroleum, Inc. | | Oil & Gas Operator | Feb 1983 |
| 2006 | Concord Energy, Inc. | Glen Rose, TX 76043 | Oil & Gas Operator | Sep 2025 |
| 2007 | Concord Operating Incorporated | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2008 |
| 2008 | Concord Resources, LLC | | Oil & Gas Operator | Nov 2000 |
| 2009 | Concorde Exploration, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Oct 1994 |
| 2010 | Concorde Resources Corporation | Eufaula, OK 74432 | Oil & Gas Operator | May 2025 |
| 2011 | Concordia Resources Inc. | | Oil & Gas Operator | Jul 2025 |
| 2012 | Condor Energy | | Oil Operator | Aug 1995 |
| 2013 | Condor Energy Inc | Great Bend, KS 67530 | Oil & Gas Operator | Oct 2021 |
| 2014 | Condor Energy Technology LLC | | Oil & Gas Operator | Jul 2018 |
| 2015 | Condor Exploration LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Sep 2009 |
| 2016 | Condor Oil Company Inc. | | Oil & Gas Operator | Dec 2000 |
| 2017 | Condor Oil Corp | Boulder, CO 80303 | Oil & Gas Operator | Dec 1994 |
| 2018 | Condor Operating Co. | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 2019 | Condor Operating Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2025 |
| 2020 | Condor Petroleum | | Oil & Gas Operator | Nov 1990 |
| 2021 | Condor Petroleum Corporation | | Oil & Gas Operator | Aug 2020 |
| 2022 | Condor Petroleum, Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2019 |
| 2023 | Condra, James M. Jr. | Sonora, TX 76950 | Oil & Gas Operator | May 1996 |
| 2024 | Condrin Oil 1985-A LTD | Tulsa, OK 74136 | Oil & Gas Operator | Nov 1998 |
| 2025 | Condry Oil Compa | | Oil Operator | May 1992 |
| 2026 | Cone & Petree Oil & Gas Exp. Inc | Lubbock, TX 79453 | Oil & Gas Operator | May 2024 |
| 2027 | Cone, Charles M. Services, Inc. | Dallas, TX 75372 | Oil & Gas Operator | Sep 2005 |
| 2028 | Cone, Ronald M. | Stafford, NY 14143 | Gas Operator | Dec 2024 |
| 2029 | Cone, S. E. Jr. | Lubbock, TX 79408 | Oil & Gas Operator | Feb 2002 |
| 2030 | Confed Oil Incorporated | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 2031 | Confederate Bay LLC | Okemah, OK 74859 | Oil & Gas Operator | Jun 2025 |
| 2032 | Confederate Spooling Inc | Okemah, OK 74859-2409 | Oil & Gas Operator | Apr 2020 |
| 2033 | Conklin Robert L Dba Conklin Oil LLC | Tulsa, OK 74153 | Oil Operator | May 2025 |
| 2034 | Conklin, Patrick J. | Rushville, NY 14544 | Gas Operator | Dec 2024 |
| 2035 | Conley Energy Co LLC | Marietta, OH 45750 | Oil & Gas Operator | Dec 2020 |
| 2036 | Conley Oil, Inc | Salyersville, KY 41465 | Oil & Gas Operator | Dec 2022 |
| 2037 | Conley P Smith Operating Co. | | Oil & Gas Operator | Jun 1995 |
| 2038 | Conley, Harry | Colony, KS 66015 | Oil Operator | Mar 2025 |
| 2039 | Conley, John | | Oil Operator | Aug 2000 |
| 2040 | Conn Energy Group, LLC | | Oil & Gas Operator | Apr 2024 |
| 2041 | Conn-Okla Producing Co Inc | | Oil & Gas Operator | Nov 1992 |
| 2042 | Connaway Oil & Gas Co. | Brookesmith, TX 76827 | Oil & Gas Operator | Feb 2016 |
| 2043 | Connell, Mark Allen | Claflin, KS 67525 | Oil Operator | Apr 2025 |
| 2044 | Conner Jelly | Seminole, OK 74868 | Oil & Gas Operator | Mar 1996 |
| 2045 | Conner Production Co LLC | Seminole, OK 74868 | Oil & Gas Operator | May 2025 |
| 2046 | Conner, E B Jr | | Oil & Gas Operator | Dec 2023 |
| 2047 | Conner, Eugene | Bartlesville, OK 74005 | Oil & Gas Operator | Jul 2020 |
| 2048 | Conner, Rick | Winfield, KS 67156 | Oil Operator | Aug 2019 |
| 2049 | Conner-Marrs Company | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2025 |
| 2050 | Connie J & Ronald L Yeany | Fairmount City, PA 16224-1903 | Gas Operator | Dec 2024 |
| 2051 | Connoil LLC | Grove City, OH 43123 | Oil & Gas Operator | Dec 2024 |
| 2052 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 2053 | Conoco Incorpora | | Oil & Gas Operator | Apr 1988 |
| 2054 | ConocoPhillips Alaska, Inc. | | Oil & Gas Operator | Jul 2025 |
| 2055 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Sep 2025 |
| 2056 | Conquest Energy, Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Sep 2025 |
| 2057 | Conquest Exploration | Houston, TX 77068 | Oil & Gas Operator | May 1991 |
| 2058 | Conquest Exploration Co. | | Oil & Gas Operator | Mar 1992 |
| 2059 | Conquest Oil Company | Big Spring, TX 79721 | Oil & Gas Operator | Aug 2024 |
| 2060 | Conquest Petroleum Inc | | Oil & Gas Operator | Nov 2014 |
| 2061 | Conquistador Petroleum,Inc. | Coleman, TX 76834 | Oil & Gas Operator | Sep 2025 |
| 2062 | Conrade Patsy | | Oil Operator | Jan 1986 |
| 2063 | Cons Asset MGMT SVCS E&P Op, LLC | Houston, TX 77002 | Oil Operator | Dec 2017 |
| 2064 | Considine, Barry | Burrton, KS 67020 | Gas Operator | Mar 2025 |
| 2065 | Consol Gas Company | Canonsburg, PA 15317 | Oil & Gas Operator | Dec 2021 |
| 2066 | Consolidated Energy Inv., Inc. | | Oil & Gas Operator | Oct 2013 |
| 2067 | Consolidated Energy Res., Inc. | | Oil Operator | Jun 1992 |
| 2068 | Consolidated Engy Reserve Inc | | Oil & Gas Operator | Jul 1991 |
| 2069 | Consolidated Exploration Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2015 |
| 2070 | Consolidated Gas & Energy Corp. | San Diego, CA 92130 | Oil Operator | Apr 2012 |
| 2071 | Consolidated Natural Res. Corp. | Kilgore, TX 75662 | Oil & Gas Operator | Jan 2016 |
| 2072 | Consolidated Oil | | Oil Operator | Jul 1996 |
| 2073 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 2074 | Consolidated Oil Well Services, Inc | Chanute, KS 66720 | Oil Operator | Jan 2008 |
| 2075 | Consolidated Peto Equity LTD | La Crescenta, CA 91214 | Oil & Gas Operator | Dec 1996 |
| 2076 | Consolidated Petro PTNRS I, LLC | Austin, TX 78759 | Oil & Gas Operator | Mar 2003 |
| 2077 | Consolidated Petrol Corp | Columbus, OH 43215 | Oil & Gas Operator | Dec 1995 |
| 2078 | Consolidated Production Inc. | Seminole, OK 74868 | Oil & Gas Operator | May 2025 |
| 2079 | Consolidated Properties | Tulsa, OK 74129 | Oil & Gas Operator | Jan 2017 |
| 2080 | Consolidated Res Of Amer | Cincinnati, OH 45208 | Oil & Gas Operator | Dec 1996 |
| 2081 | Consolidated Resources Corp | Shawnee, OK 74801 | Oil & Gas Operator | Sep 2014 |
| 2082 | Consolidated Resources Inc | | Oil & Gas Operator | May 2004 |
| 2083 | Consolidation Coal Company | Saint Clairsville, OH 43950-8742 | Oil & Gas Operator | Dec 2020 |
| 2084 | Consortium Energy LLC | Tallmadge, OH 44278 | Oil & Gas Operator | Dec 2024 |
| 2085 | Constitution Gas Transport Co., Inc. | Salt Lake City, UT 84124-1110 | Gas Operator | Jun 2012 |
| 2086 | Constitution Investment Co LLC | Marietta, OH 45750 | Oil & Gas Operator | Dec 2024 |
| 2087 | Constitution Petroleum | Salt Lake City, UT 84124-1110 | Oil & Gas Operator | Dec 2008 |
| 2088 | Consumers Energy Co | | Oil & Gas Operator | Apr 2010 |
| 2089 | Contango Midstream Company | Houston, TX 77002-3023 | Oil & Gas Operator | Jun 2025 |
| 2090 | Contango Operators, Inc. | Houston, TX 77098 | Oil & Gas Operator | Dec 2022 |
| 2091 | Contango Operators, LLC | | Oil & Gas Operator | Nov 2024 |
| 2092 | Contango Resources Company | | Oil & Gas Operator | Mar 2009 |
| 2093 | Contango Resources LLC | Andrews, TX 79714 | Oil & Gas Operator | Sep 2025 |
| 2094 | Contango Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 2095 | Contango Rocky Mountain Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2020 |
| 2096 | Continental Brok | | Oil Operator | Oct 1994 |
| 2097 | Continental Ener | | Oil & Gas Operator | Dec 1996 |
| 2098 | Continental Energy | Garden City, KS 67846-0918 | Oil & Gas Operator | Jul 2017 |
| 2099 | Continental Energy Operating LLC | Tulsa, OK 74114-1302 | Oil & Gas Operator | Jun 2025 |
| 2100 | Continental Expl | | Oil Operator | Sep 1991 |