| 1 | Calpine Natural Gas Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2002 |
| 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 | Cambrian Management LTD | McCaulley, TX 79534 | Oil & Gas Operator | Dec 2024 |
| 5 | Cashco Oil Company | Houston, TX 77024 | Oil & Gas Operator | Aug 2003 |
| 6 | Chartex Petroleum Company | Houston, TX 77070 | Oil & Gas Operator | Aug 2000 |
| 7 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2024 |
| 8 | Classic Oil & Gas, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jan 2004 |
| 9 | Clover Production Company | Sourlake, TX 77659 | Oil & Gas Operator | Dec 2024 |
| 10 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 11 | Coastal Investments Inc. | El Campo, TX 77437 | Oil & Gas Operator | Dec 2024 |
| 12 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 13 | Coastal Production Company, Inc. | El Campo, TX 77437 | Oil & Gas Operator | Aug 1995 |
| 14 | Cockrell Production Co., Inc. | Irving, TX 75014 | Oil & Gas Operator | Dec 2024 |
| 15 | Comstock Oil & Gas, Inc. | Frisco, TX 75034 | Oil & Gas Operator | Dec 2012 |
| 16 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 17 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2024 |
| 18 | Contour Expl And Prod, LLC | Dallas, TX 75204 | Oil & Gas Operator | Dec 2024 |
| 19 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | Dec 2024 |
| 20 | Crestmont Operating LLC | New York, NY 10151 | Oil Operator | Dec 2024 |
| 21 | Crossroads Energy L.P. | Houston, TX 77064 | Oil & Gas Operator | Jun 2011 |
| 22 | Crossroads Energy Partners, LLC | Houston, TX 77070 | Oil & Gas Operator | Mar 2018 |
| 23 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |