| 1 | C C Co | Holladay, UT 84124 | Oil & Gas Operator | Jan 2020 |
| 2 | Cargas Operating Company | | Oil & Gas Operator | Jun 2024 |
| 3 | Caruthers Producing Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2019 |
| 4 | Ceka Gas, Div Of GTC | | Oil & Gas Operator | May 1988 |
| 5 | Centerpoint Energy FLD Ser Inc | | Oil Operator | Feb 2011 |
| 6 | Chanse Energy Corporation | Shreveport, LA 71165-1572 | Oil & Gas Operator | Sep 2021 |
| 7 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Nov 2024 |
| 8 | Ciera Resources, Inc. | | Gas Operator | Nov 1998 |
| 9 | Cisco Petroleum, Inc. | | Oil & Gas Operator | Oct 2010 |
| 10 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 11 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 12 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 13 | Clements Energy, Inc. | | Oil & Gas Operator | Oct 1987 |
| 14 | Clements-B & MCK - Luffey | | Gas Operator | Apr 1979 |
| 15 | Coho Louisiana Production Co | | Gas Operator | Dec 1998 |
| 16 | Commonwealth Energy, Inc. | Weston, WV 26452-0000 | Oil & Gas Operator | Dec 2021 |
| 17 | Contour Energy E & P, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 18 | Contour Energy E & P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2003 |
| 19 | Coronado Energy E&P Company, LLC | Houston, TX 77252 | Oil & Gas Operator | Dec 2010 |
| 20 | Crescent Drilling Company, Inc. | | Gas Operator | Jun 2024 |
| 21 | Criswell E. White | | Gas Operator | Jun 2015 |
| 22 | Cross Timbers Operating Co | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2024 |
| 23 | Cti Associates | | Gas Operator | Jan 1990 |
| 24 | Custer K. Primos | | Oil & Gas Operator | Oct 2002 |
| 25 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Nov 2024 |