| 1 | C12 Energy: North Dakota LLC | | Oil Operator | Apr 2017 |
| 2 | Calvert Drilling Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 1992 |
| 3 | Calvert Exploration Co | | Oil & Gas Operator | Apr 1993 |
| 4 | Camwest II LP | McKinney, TX 75070 | Oil & Gas Operator | Jul 2007 |
| 5 | Cardinal & Great Plains & Kaufman | | Oil Operator | Apr 1985 |
| 6 | Cardinal Drilling Co. | | Oil Operator | Jan 2007 |
| 7 | Cardinal Petroleum Co. | | Oil & Gas Operator | May 2004 |
| 8 | Carlson Oil Inc. | | Oil & Gas Operator | Oct 2008 |
| 9 | Caroline Hunt Trust Estate | | Oil & Gas Operator | Feb 1987 |
| 10 | Cenex | | Oil & Gas Operator | Dec 1996 |
| 11 | Chaco Energy Company | Denver, CO 80201 | Oil & Gas Operator | Sep 2024 |
| 12 | Challenger Point Energy, LLC | | Oil & Gas Operator | Sep 2024 |
| 13 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 14 | Chandler & Associates, Inc. | Denver, CO 80202 | Oil & Gas Operator | May 1997 |
| 15 | Chandler Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2009 |
| 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 | Nov 2024 |
| 18 | Charger Resources, LLC | Hurst, TX 76054 | Oil & Gas Operator | Aug 2015 |
| 19 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jul 2024 |
| 20 | Christmann Energy Corp. | | Oil & Gas Operator | Feb 1991 |
| 21 | Cirque Resources LP | Denver, CO 80202 | Oil & Gas Operator | Aug 2016 |
| 22 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Nov 2024 |
| 23 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 24 | Cline Production Company | Billings, MT 59104 | Oil & Gas Operator | Aug 2024 |
| 25 | Clinton Oil Co | Wichita, KS 67202 | Oil & Gas Operator | Apr 1980 |
| 26 | Clyde G. Kissinger | | Oil Operator | Jun 1964 |
| 27 | Clyde W. Jones | | Oil Operator | Sep 2003 |
| 28 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 29 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Nov 2024 |
| 30 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 31 | Columbus Production Inc | | Oil & Gas Operator | Mar 2005 |
| 32 | Condor Petroleum, Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2019 |
| 33 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 34 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Nov 2024 |
| 35 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 36 | Continental Oil Co. | Durango, CO 81301 | Oil & Gas Operator | Dec 1983 |
| 37 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2024 |
| 38 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | Nov 2024 |
| 39 | Corinthian Exploration (USA) Corp | | Oil & Gas Operator | Apr 2016 |
| 40 | Cornerstone Natural Resources LLC | Denver, CO 80234 | Oil & Gas Operator | Sep 2024 |
| 41 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 42 | Crescent Point Energy Us Corp | Denver, CO 80202 | Oil & Gas Operator | Apr 2024 |
| 43 | Crystal Exploration & Production Company | Shreveport, LA 71120 | Oil & Gas Operator | Feb 1995 |