| 1 | C & M Operating Company | Graham, TX 76450 | Oil & Gas Operator | Jun 2025 |
| 2 | C. D. Pierce | | Oil Operator | Mar 1991 |
| 3 | C.F. Braun & Company | | Oil & Gas Operator | Dec 1986 |
| 4 | Cabot Petroleum Corporation | Englewood, CO 80111-2529 | Oil & Gas Operator | Dec 2004 |
| 5 | Caddo Management, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 6 | Cajun Minerals, Inc. | | Oil & Gas Operator | Mar 1997 |
| 7 | Callon Offshore Production, Inc. | Natchez, MS 39121 | Oil & Gas Operator | Dec 2005 |
| 8 | Callon Petroleum Company | Natchez, MS 39120 | Oil & Gas Operator | Jan 2000 |
| 9 | Callon Petroleum Operating Co | Houston, TX 77042 | Oil & Gas Operator | Jul 2024 |
| 10 | Calyx Exploration & Production | | Oil & Gas Operator | Jul 1991 |
| 11 | Campbell Energy Corp. | | Oil & Gas Operator | May 1992 |
| 12 | Cardinal Oil & Gas, Inc. | | Oil & Gas Operator | Jun 1995 |
| 13 | Carl Oil & Gas Co. | Bakersfield, CA 93309 | Oil & Gas Operator | Dec 1995 |
| 14 | Caskids Operating Company | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 15 | Celeron Oil & Gas Company | | Oil & Gas Operator | Dec 1987 |
| 16 | Cenergy Exploration Company | Dallas, TX 75231 | Oil & Gas Operator | Sep 2000 |
| 17 | Centura Inc | | Oil & Gas Operator | Feb 1985 |
| 18 | Chaparral Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2009 |
| 19 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Oct 2025 |
| 20 | Charing Cross Properties | | Oil Operator | Aug 1995 |
| 21 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 22 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 23 | Coalinga Corporation | Houston, TX 77002 | Oil & Gas Operator | May 1999 |
| 24 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2025 |
| 25 | Columbia Gas Dev. Corp. | | Oil & Gas Operator | Apr 1996 |
| 26 | Comstock Oil & Gas -- La, Inc. | | Oil & Gas Operator | Mar 2005 |
| 27 | Condor Petroleum Corporation | | Oil & Gas Operator | Aug 2020 |
| 28 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 29 | Cox Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 30 | Creek Operating Company, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Sep 1998 |
| 31 | Cygnus Producing Corporation | | Oil & Gas Operator | Feb 1990 |
| 32 | Cypress Oil Company, Inc. | | Oil & Gas Operator | Aug 2003 |
| 33 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Oct 2025 |