| 1 | C & M Operating Company | Graham, TX 76450 | Oil & Gas Operator | Jun 2025 |
| 2 | C. H. C. Gerard | | Oil & Gas Operator | Jan 2025 |
| 3 | C. L. Morris | | Oil Operator | Feb 2004 |
| 4 | C. L. Morris, Inc. | | Oil & Gas Operator | Feb 2004 |
| 5 | C.B.C. Producing Co. | | Oil & Gas Operator | Jul 1989 |
| 6 | C6 Operating, L.L.C. | Keatchie, LA 71046 | Oil & Gas Operator | Oct 2025 |
| 7 | Caddo Resources Inc | | Oil & Gas Operator | Dec 1986 |
| 8 | Calais Oil & Gas, L.L.C. | | Oil Operator | Dec 2024 |
| 9 | Camterra Resources, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Oct 2025 |
| 10 | Canstar Oil & Gas, Inc. | | Oil & Gas Operator | Dec 1994 |
| 11 | Carder Oil Company | | Oil & Gas Operator | Dec 2024 |
| 12 | Carr Petroleum, Inc. | | Oil Operator | Apr 1987 |
| 13 | Carraway Co. | | Oil Operator | Apr 2006 |
| 14 | Celt Oil, Inc. | | Oil & Gas Operator | Jun 1986 |
| 15 | Centerpoint Energy FLD Ser Inc | | Oil Operator | Feb 2011 |
| 16 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Oct 2025 |
| 17 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 18 | Christopher Oil & Gas Inc | Fulshear, TX 77441 | Oil & Gas Operator | Apr 2015 |
| 19 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 20 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 21 | Cits BK & Trust Of Springhill | | Oil & Gas Operator | Jun 1990 |
| 22 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 23 | CNC Oil Co., Inc. | | Oil Operator | Aug 1991 |
| 24 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 25 | Comstock Oil & Gas--La, LLC | | Oil & Gas Operator | Dec 2024 |
| 26 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 27 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 28 | Cornerstone Natural Gas Co. | | Oil Operator | Oct 1999 |
| 29 | Coronado Energy E&P Company, LLC | Houston, TX 77252 | Oil & Gas Operator | Dec 2010 |
| 30 | Crystal Oil And Land Company | | Oil & Gas Operator | May 1992 |
| 31 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 32 | CSC Energy Corp. | | Oil & Gas Operator | Dec 2009 |
| 33 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Oct 2025 |