| 1 | Caerus Southern Rockies LLC | Denver, CO 80202 | Gas Operator | Nov 2017 |
| 2 | Calpine Natural Gas Company L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 3 | Calpine Natural Gas L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2006 |
| 4 | Carbon Energy Corporation (USA) | Denver, CO 80290 | Oil & Gas Operator | Jul 2004 |
| 5 | Catamount Energy Partners LLC | Denver, CO 80202 | Gas Operator | Aug 2025 |
| 6 | Central Resources Inc | Denver, CO 80203 | Oil & Gas Operator | Dec 2019 |
| 7 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Oct 2025 |
| 8 | Chaparral Oil & Gas Co | Aztec, NM 87410 | Gas Operator | Jul 2025 |
| 9 | Charger Resources, LLC | Hurst, TX 76054 | Oil & Gas Operator | Aug 2015 |
| 10 | Chateau Oil And Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Feb 2017 |
| 11 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 12 | Chevron Midcontinent, L.P. | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 13 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 14 | Chuza Oil Company | Farmington, NM 87402 | Oil Operator | Dec 2017 |
| 15 | Clifford C. Or Mary A. Terry | Dadeville, AL 36853 | Oil Operator | Feb 2003 |
| 16 | Coleman Oil & Gas Inc | Farmington, NM 87499 | Oil & Gas Operator | Jan 2023 |
| 17 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 18 | Condor Oil Corp | Boulder, CO 80303 | Oil & Gas Operator | Dec 1994 |
| 19 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 20 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 21 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 22 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 23 | Coronado Energy E&P Company, LLC | Houston, TX 77252 | Oil & Gas Operator | Dec 2010 |
| 24 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 25 | Cross Creek Corporation | Duncan, OK 73534 | Oil & Gas Operator | Mar 1999 |
| 26 | Cross Timbers Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 27 | Curtis J Little | Farmington, NM 87499 | Oil & Gas Operator | Aug 2005 |