| 1 | C. E. Allen Co. Inc. | | Oil & Gas Operator | Jul 2025 |
| 2 | C. E. Braly | | Oil & Gas Operator | Dec 1991 |
| 3 | C. F. Sudduth | | Oil & Gas Operator | Dec 1988 |
| 4 | Cal Continental Capital Inc. | | Oil Operator | Dec 2006 |
| 5 | California E.D.I. Inc. | | Oil & Gas Operator | Jan 2018 |
| 6 | California Resources Long Beach Inc. | | Oil & Gas Operator | Aug 2025 |
| 7 | California Resources Production Corporation | | Oil & Gas Operator | Jul 2025 |
| 8 | California Southern Oil Co. | | Oil Operator | Dec 2000 |
| 9 | California/Nevada Developments LLC | | Oil Operator | Dec 2001 |
| 10 | Calresources LLC | | Oil & Gas Operator | Dec 1996 |
| 11 | Caltico Oil Corp. | | Oil Operator | Jul 2025 |
| 12 | Carl Weaver Properties | | Oil & Gas Operator | Dec 1987 |
| 13 | Carol Rhodabarger Heitz | | Oil & Gas Operator | Dec 1996 |
| 14 | Carson Dominguez Real Est Corp | | Oil & Gas Operator | Dec 1996 |
| 15 | Cascade Resources LLC | Edmond, OK 73083 | Oil & Gas Operator | Aug 2025 |
| 16 | Casex Company | | Oil & Gas Operator | Dec 2007 |
| 17 | Chaim Nathan & Edie Bato | | Oil & Gas Operator | Jul 2025 |
| 18 | Chalmers-Santa Fe LLC | | Oil & Gas Operator | Dec 2007 |
| 19 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 20 | City Of Hermosa Beach | | Oil & Gas Operator | Dec 2005 |
| 21 | City Of Santa Fe Springs | | Oil Operator | Dec 2007 |
| 22 | Clean Energy Systems Placerita Inc. | | Oil & Gas Operator | Jul 2025 |
| 23 | Coal Oil Inc. | | Oil & Gas Operator | Dec 1997 |
| 24 | Coast Supply Company LTD. | | Oil & Gas Operator | Dec 1991 |
| 25 | Cockriel Petroleum | | Oil & Gas Operator | Dec 1993 |
| 26 | Commander Oil Company LTD. | | Oil & Gas Operator | Dec 2021 |
| 27 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 28 | Cooper & Brain Inc. | | Oil & Gas Operator | Aug 2025 |
| 29 | Courtland City Lights Assoc. | | Oil Operator | Dec 2005 |
| 30 | Cree Oil LLC | | Oil & Gas Operator | Aug 2025 |
| 31 | CRG Properties LTD. | | Oil & Gas Operator | Dec 2013 |
| 32 | Crimson Resource Management Corp. | | Oil & Gas Operator | Jul 2025 |