| 1 | C & D Resources, Inc. | | Oil & Gas Operator | Nov 2001 |
| 2 | C & VC, Inc. | | Oil & Gas Operator | Sep 1991 |
| 3 | C.F. Braun & Company | | Oil & Gas Operator | Dec 1986 |
| 4 | Caddo Management, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 5 | Cajun Minerals, Inc. | | Oil & Gas Operator | Mar 1997 |
| 6 | Cajun Operating, Inc. | | Oil & Gas Operator | Jun 2011 |
| 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 | Camex, Inc. | | Oil & Gas Operator | Jun 1992 |
| 10 | Cankton Oil Company | | Oil Operator | May 1985 |
| 11 | Capturepoint LLC | Allen, TX 75013 | Oil & Gas Operator | Oct 2025 |
| 12 | Cardinal Expl And Prod | | Oil & Gas Operator | May 2019 |
| 13 | Carl Oil & Gas Co. | Bakersfield, CA 93309 | Oil & Gas Operator | Dec 1995 |
| 14 | Celeron Oil & Gas Company | | Oil & Gas Operator | Dec 1987 |
| 15 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 16 | Chaparral Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2009 |
| 17 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Oct 2025 |
| 18 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 19 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 20 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 21 | Cliffs Drilling Company | | Oil & Gas Operator | Dec 1984 |
| 22 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 23 | Colorado Oil Co., Inc. | | Oil & Gas Operator | Dec 1977 |
| 24 | Concord Operating Incorporated | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2008 |
| 25 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 26 | Cougar Exploration, Inc. | | Oil & Gas Operator | Jun 1988 |
| 27 | Cox Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 28 | Credo Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | Jan 2013 |
| 29 | Crosstex Lig, LLC | | Oil Operator | Mar 2014 |
| 30 | CX Operating, Inc. | | Oil & Gas Operator | Oct 2023 |
| 31 | Cypress Gas Pipeline Company | | Oil Operator | Dec 1998 |
| 32 | Cypress Gas Pipeline, LLC | | Oil Operator | Sep 2019 |
| 33 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Oct 2025 |