| 5801 | Cisco Operating LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 5802 | Cisco Petroleum, Inc. | | Oil & Gas Operator | Oct 2010 |
| 5803 | Cisco Production Company, LLC | Victoria, TX 77902 | Oil & Gas Operator | May 2012 |
| 5804 | Citadel Exploration Inc. | | Oil Operator | Sep 2025 |
| 5805 | Citadel Oil LLC | Edmond, OK 73083 | Oil Operator | Jun 2025 |
| 5806 | Citadel Prod Company Inc | Denver, CO 80201 | Oil Operator | Sep 1996 |
| 5807 | Citation Energy | | Oil & Gas Operator | Jul 1993 |
| 5808 | Citation Energy Company | Marietta, OH 45750 | Oil & Gas Operator | Dec 2024 |
| 5809 | Citation Oil & G | | Oil & Gas Operator | Dec 1996 |
| 5810 | Citation Oil & Gas Corp | Houston, TX 77269 | Oil & Gas Operator | Dec 2025 |
| 5811 | Cities Serv Oil & Gas Corp | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 1964 |
| 5812 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 5813 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 5814 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 5815 | Cities Services Company | | Oil & Gas Operator | Mar 2008 |
| 5816 | Citizen Energy II LLC | Tulsa, OK 74103-3729 | Oil & Gas Operator | Apr 2025 |
| 5817 | Citizen Energy III LLC | Devner, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 5818 | Citizen Energy Ventures LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2025 |
| 5819 | Citmoco Services, Inc. | | Oil Operator | Jan 1971 |
| 5820 | Citori Oil Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Nov 2004 |
| 5821 | Citori Oil Company, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2014 |
| 5822 | Citronelle Operating Co., LLC | | Oil & Gas Operator | Sep 1997 |
| 5823 | Citrus Energy Corporation | Castle Rock, CO 80104 | Oil & Gas Operator | Mar 2020 |
| 5824 | Cits BK & Trust Of Springhill | | Oil & Gas Operator | Jun 1990 |
| 5825 | City & County Of Denver | | Oil & Gas Operator | Sep 2023 |
| 5826 | City Of Akron | Akron, OH 44308 | Oil & Gas Operator | Dec 2024 |
| 5827 | City Of Baker | Baker, MT 59313 | Oil & Gas Operator | Sep 2025 |
| 5828 | City Of Brady | Brady, TX 76825 | Gas Operator | Feb 1998 |
| 5829 | City Of Chanute | Chanute, KS 66720 | Oil Operator | Feb 1994 |
| 5830 | City Of Cuyahoga Falls | Cuyahoga Falls, OH 44221 | Oil & Gas Operator | Dec 2024 |
| 5831 | City Of Dumas | Dumas, TX 79029 | Gas Operator | Dec 2025 |
| 5832 | City Of Dunkirk Waste Water Treatment Plant | Dunkirk, NY 14048 | Gas Operator | Dec 2024 |
| 5833 | City Of Garden City, Kansas | Garden City, KS 67846 | Gas Operator | Jun 2025 |
| 5834 | City Of Hermosa Beach | | Oil & Gas Operator | Dec 2005 |
| 5835 | City Of Hugoton, Kansas | Hugoton, KS 67951 | Gas Operator | Jun 2025 |
| 5836 | City Of Huntington Beach (Fire Dept.) | | Oil & Gas Operator | Aug 2025 |
| 5837 | City Of McLean | McLean, TX 79057 | Gas Operator | Dec 2025 |
| 5838 | City Of Newport Beach | | Oil & Gas Operator | Oct 2025 |
| 5839 | City Of Santa Fe Springs | | Oil Operator | Dec 2007 |
| 5840 | City Of Satanta | Satanta, KS 67870 | Gas Operator | Jun 2025 |
| 5841 | City Of Sunray Utilities | Sunray, TX 79086 | Oil & Gas Operator | Dec 2025 |
| 5842 | City Of White Deer | White Deer, TX 79097 | Gas Operator | May 2017 |
| 5843 | City Oil Corp. Oper. For | | Oil & Gas Operator | Dec 1989 |
| 5844 | Civego, Inc. | | Oil & Gas Operator | Jul 1994 |
| 5845 | Civic Energy Corporation | Colony, OK 73021 | Oil & Gas Operator | Oct 2025 |
| 5846 | Civiletto, George & Wendy | Fredonia, NY 14063 | Gas Operator | Dec 2024 |
| 5847 | Civitas North LLC | | Oil & Gas Operator | Sep 2025 |
| 5848 | Civitas Permian Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2025 |
| 5849 | Civron Petroleum Res., LLC | San Antonio, TX 78229 | Oil & Gas Operator | Dec 2025 |
| 5850 | CJ Oil Inc | Madison, KS 66860 | Oil Operator | Jun 2025 |
| 5851 | CJ Tejas Energy, LLC | Pearland, TX 77581 | Oil Operator | Dec 2025 |
| 5852 | CJR Operating LLC | Wister, OK 74966 | Gas Operator | Oct 2025 |
| 5853 | CJRW Oil & Gas | MC Camey, TX 79752 | Oil Operator | Dec 2025 |
| 5854 | CK Oil | | Oil Operator | May 2025 |
| 5855 | CK Oil & Gas LLC | Herington, KS 67449 | Oil & Gas Operator | Mar 2025 |
| 5856 | CK Operating Company, LLC | Wichita Falls, TX 76308 | Oil Operator | Dec 2025 |
| 5857 | CK Resources | Cleveland, OK 74020-0772 | Oil Operator | Aug 2013 |
| 5858 | CK5 Services LLC | Zephyr, TX 76890 | Oil & Gas Operator | Sep 2025 |
| 5859 | CKB Corporation | Borger, TX 79008 | Oil & Gas Operator | Aug 1997 |
| 5860 | CKT Energy LLC | Dallas, TX 75379 | Oil & Gas Operator | Sep 2020 |
| 5861 | CL&F Operating LLC | Spring, TX 77389 | Oil & Gas Operator | Dec 2022 |
| 5862 | Cla-Mar Oil Company, LLC | Hays, KS 67601 | Oil Operator | Dec 2019 |
| 5863 | Claassen Oil And Gas Inc | Estes Park, CO 80517 | Oil & Gas Operator | Sep 2025 |
| 5864 | Claborn Julia | Okmulgee, OK 74447-9781 | Oil & Gas Operator | Mar 2022 |
| 5865 | Claco Oil Co | Artesia, NM 88210 | Oil & Gas Operator | Dec 2014 |
| 5866 | Claiborne-McDonald Inc | Chickasha, OK 73018 | Oil Operator | Jul 2007 |
| 5867 | Claibourn, Darrel R. | Neodesha, KS 66757 | Oil Operator | Oct 2011 |
| 5868 | Clair Oil, Inc. | Russell, KS 67665 | Oil Operator | Nov 2019 |
| 5869 | Clamp Operating | San Antonio, TX 78264 | Oil & Gas Operator | Apr 2002 |
| 5870 | Clamp Operating Incorporated | San Antonio, TX 78264 | Oil & Gas Operator | Mar 2011 |
| 5871 | Clapp Carl O | Cedar Vale, KS 67024 | Oil Operator | Aug 2013 |
| 5872 | Clapp Oil LLC | | Oil Operator | Jun 2025 |
| 5873 | Clarco Gas Co., Inc. | Westmont, IL 60559 | Oil Operator | Dec 2011 |
| 5874 | Claremont Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2017 |
| 5875 | Claremont Energy | | Gas Operator | Dec 1993 |
| 5876 | Claremont Exploration Inc | Tulsa, OK 74103-4107 | Oil & Gas Operator | Jun 1997 |
| 5877 | Clarence F. Routon, Jr. | | Oil Operator | Apr 1990 |
| 5878 | Clarence K Tussel Jr LTD | Jefferson, OH 44047 | Oil & Gas Operator | Dec 2024 |
| 5879 | Clarence R. Barnett Inc. | | Oil & Gas Operator | Jul 2025 |
| 5880 | Clarita Operating LLC | Ada, OK 74821 | Oil Operator | Jun 2022 |
| 5881 | Clark And Clark | Princeton, NJ 08540-1930 | Oil & Gas Operator | Jul 2013 |
| 5882 | Clark B & Cahoj | | Oil Operator | Apr 1995 |
| 5883 | Clark Blake | | Gas Operator | Sep 2023 |
| 5884 | Clark Energy, LLC | Chanute, KS 66720 | Oil & Gas Operator | Jun 2022 |
| 5885 | Clark Exploratio | | Oil & Gas Operator | Jun 1991 |
| 5886 | Clark Exploration Company | Highlands Ranch, CO 80126-7645 | Oil & Gas Operator | Nov 2024 |
| 5887 | Clark Krista | Ada, OK 74820-8595 | Oil Operator | Sep 2001 |
| 5888 | Clark Oil & Gas Inc | | Oil & Gas Operator | Dec 1990 |
| 5889 | Clark Oil Co. | Dallas, TX 75360 | Oil & Gas Operator | Dec 2025 |
| 5890 | Clark Oil Producing Company | | Oil & Gas Operator | Oct 1979 |
| 5891 | Clark Oil, LLC | Wellsville, KS 66092 | Oil Operator | Apr 2022 |
| 5892 | Clark Operating | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 5893 | Clark Operating Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2025 |
| 5894 | Clark Operating Services Inc | Okmulgee, OK 74447 | Oil & Gas Operator | May 2013 |
| 5895 | Clark Well Service | Depew, OK 74028-0296 | Oil & Gas Operator | Aug 2013 |
| 5896 | Clark, B. C. | Cross Plains, TX 76443 | Oil Operator | Dec 2007 |
| 5897 | Clark, Daniel J. | Auburn, NY 13021 | Gas Operator | Dec 2024 |
| 5898 | Clark, Daryl | Phillipsburg, KS 67661 | Oil Operator | Nov 2024 |
| 5899 | Clark, Donald E. | | Gas Operator | Dec 2003 |
| 5900 | Clark, Donald-Roger Young | | Oil & Gas Operator | Jan 1988 |