| 1 | C. H. C. Gerard | | Oil & Gas Operator | Jan 2025 |
| 2 | C. H. Cuatro | | Gas Operator | Sep 1996 |
| 3 | C6 Operating, L.L.C. | Keatchie, LA 71046 | Oil & Gas Operator | Feb 2026 |
| 4 | Camterra Resources, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Feb 2026 |
| 5 | Capital Gas, Inc. | | Gas Operator | Jan 1998 |
| 6 | Cargas Operating Company | | Oil & Gas Operator | Dec 2024 |
| 7 | Caruthers Producing Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2019 |
| 8 | Caspen Oil, Inc. | Denver, CO 80226 | Oil & Gas Operator | Jul 1993 |
| 9 | Cavalry Resources LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2010 |
| 10 | Ceka Gas, Div Of GTC | | Oil & Gas Operator | May 1988 |
| 11 | Centerpoint Energy FLD Ser Inc | | Oil Operator | Feb 2011 |
| 12 | Charles Spencer | | Gas Operator | Jul 2011 |
| 13 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Feb 2026 |
| 14 | Cisco Petroleum, Inc. | | Oil & Gas Operator | Oct 2010 |
| 15 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 16 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 17 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 18 | Clements-B & MCK - Luffey | | Gas Operator | Apr 1979 |
| 19 | Coho Louisiana Production Co | | Gas Operator | Dec 1998 |
| 20 | Commonwealth Energy, Inc. | Weston, WV 26452-0000 | Oil & Gas Operator | Dec 2021 |
| 21 | Comstock Oil & Gas--La, LLC | | Oil & Gas Operator | Dec 2024 |
| 22 | Continental U.S. Management Corp | Dallas, TX 75240 | Oil & Gas Operator | Oct 2016 |
| 23 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 24 | Crescent Drilling Company, Inc. | | Gas Operator | Dec 2024 |
| 25 | Criswell E. White | | Gas Operator | Jun 2015 |
| 26 | Custer K. Primos | | Oil & Gas Operator | Oct 2002 |
| 27 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Feb 2026 |