| 401 | Crumpler Oil | | Oil & Gas Operator | Nov 2023 |
| 402 | Crystal Gas, L.L.C. | | Oil & Gas Operator | Apr 2000 |
| 403 | Crystal Oil & Land Company | | Oil & Gas Operator | Apr 2002 |
| 404 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 405 | CSC Energy Corp. | | Oil & Gas Operator | Dec 2009 |
| 406 | CSC, Inc. | | Oil Operator | Jan 2000 |
| 407 | CSL Exploration, LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2018 |
| 408 | CSV Holdings, Inc. | | Oil & Gas Operator | Dec 2014 |
| 409 | CSX Oil & Gas Corporation | Houston, TX 77210-4326 | Oil & Gas Operator | Mar 1993 |
| 410 | Cti Associates | | Gas Operator | Jan 1990 |
| 411 | Cuatro Petro Corp. | Richardson, TX 75080 | Oil & Gas Operator | Apr 2024 |
| 412 | Culoco, Inc. | Dallas, TX 75374 | Oil & Gas Operator | Dec 2023 |
| 413 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 414 | Curt Weaver Et Al | | Oil Operator | Mar 1982 |
| 415 | Curtis Beard & Huston P. Ganey | | Oil Operator | Mar 1987 |
| 416 | Curtis F. Adams | | Oil & Gas Operator | Nov 2023 |
| 417 | Custer K. Primos | | Oil & Gas Operator | Oct 2002 |
| 418 | CWJ Operating Co., Inc. | | Oil & Gas Operator | Sep 2001 |
| 419 | CX Operating, Inc. | | Oil & Gas Operator | Nov 2023 |
| 420 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 421 | Cygnus Producing Corporation | | Oil & Gas Operator | Feb 1990 |
| 422 | Cymri Corporation, The | Houston, TX 77057 | Oil & Gas Operator | Mar 2008 |
| 423 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 424 | Cypress Gas Pipeline Company | | Oil Operator | Dec 1998 |
| 425 | Cypress Gas Pipeline, LLC | | Oil Operator | Sep 2019 |
| 426 | Cypress Oil Company, Inc. | | Oil & Gas Operator | Aug 2003 |
| 427 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2024 |
| 428 | Cypress Partners, Inc. | Houston, TX 77068 | Oil & Gas Operator | May 1999 |
| 429 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Apr 2024 |
| 430 | Cypress Resources | | Oil & Gas Operator | Jul 2004 |
| 431 | Czar Resources Inc | Houston, TX 77060 | Oil & Gas Operator | Oct 1992 |