| 1 | C & H Oil Company | Ratliff City, OK 73481-0130 | Oil & Gas Operator | Apr 2015 |
| 2 | Cabot Petroleum Corporation | Englewood, CO 80111-2529 | Oil & Gas Operator | Dec 2004 |
| 3 | Canvas Energy LLC | Oklahoma City, OK 73142-1839 | Oil & Gas Operator | May 2025 |
| 4 | Carl E Gungoll Exploration Inc | Oklahoma City, OK 73154-0466 | Oil & Gas Operator | Jan 2016 |
| 5 | Carlson Petroleum Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 6 | Charter Oak Production Co LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 7 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jul 2025 |
| 8 | Cheyenne Petroleum Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 9 | Choctaw Gas Company | Quinton, OK 74561 | Gas Operator | Apr 2025 |
| 10 | Cimarron Operating Company | Oklahoma City, OK 73112-3967 | Oil & Gas Operator | May 2011 |
| 11 | Cimarron Petroleum Corporation | Houston, TX 77057-2696 | Oil & Gas Operator | Apr 2025 |
| 12 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Jul 2025 |
| 13 | CJR Operating LLC | Wister, OK 74966 | Gas Operator | Apr 2025 |
| 14 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 15 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 16 | Concho Exploration Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2015 |
| 17 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 18 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 19 | Continental Gas Inc | Enid, OK 73702-5103 | Oil & Gas Operator | Apr 2012 |
| 20 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 21 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | Jul 2025 |
| 22 | Cordillera Energy Partners LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Mar 2020 |
| 23 | Cory, Kenneth W. | Bellaire, TX 77401 | Oil & Gas Operator | Mar 2012 |
| 24 | Cox Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 25 | Crest Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2025 |
| 26 | Cross Timbers Operating Co | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 27 | Crown Central Pet Corp | Bellaire, TX 77401 | Oil & Gas Operator | Dec 2016 |
| 28 | Cyanostar Energy, Inc | Tulsa, OK 74103-4122 | Oil & Gas Operator | Sep 2001 |