| 1 | C And D Explorations LLC | | Oil Operator | Mar 2026 |
| 2 | C M F Oil LLC | | Oil Operator | Mar 2026 |
| 3 | C M S Gas Transmission Co | | Oil & Gas Operator | Dec 2020 |
| 4 | C M S Oil And Gas Co And Miller Brothers | | Oil & Gas Operator | Apr 1992 |
| 5 | Cain Glen | | Oil Operator | Dec 2016 |
| 6 | Ceja Corporation | Tulsa, OK 74172 | Oil & Gas Operator | Feb 2026 |
| 7 | Center Dean Dba Center Operating Co | | Oil & Gas Operator | Jul 2003 |
| 8 | Center Junction Corp | | Oil Operator | Mar 2009 |
| 9 | Century Oil Company Inc | | Oil Operator | Dec 2025 |
| 10 | Chandler Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2009 |
| 11 | Cherokee Resources Inc | | Oil & Gas Operator | Mar 1996 |
| 12 | Christian Oil Co | | Oil & Gas Operator | Feb 2026 |
| 13 | Cimarex Energy Co | Midland, TX 79706 | Oil & Gas Operator | May 2026 |
| 14 | Clarkston Oil Co | | Oil Operator | Dec 2025 |
| 15 | Clarkston Oil Corp | | Oil Operator | Dec 2025 |
| 16 | Claybanks Oil Co LLC | | Oil Operator | Jun 2019 |
| 17 | CMS Oil And Gas Company | Jackson, MI 49201 | Oil & Gas Operator | Oct 2002 |
| 18 | CNG Development Co | | Oil & Gas Operator | Dec 2008 |
| 19 | Coastal Oil & Gas Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 20 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2026 |
| 21 | Collin C W Jr | | Oil Operator | Oct 2015 |
| 22 | Collin Oil Operations LLC | | Oil Operator | Dec 2025 |
| 23 | Collins C R And Collins F Dba Collins Brothers Oil | | Oil & Gas Operator | Jul 2008 |
| 24 | Columbus III Production LC | | Oil Operator | Oct 2003 |
| 25 | Columbus Oil And Gas LLC | | Oil Operator | Oct 2020 |
| 26 | Comerica Properties Corp | | Oil Operator | May 1985 |
| 27 | Conoco Inc | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 28 | Consumers Energy Co | | Oil & Gas Operator | Apr 2010 |
| 29 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | May 2026 |
| 30 | Core Antrim Company LLC | | Gas Operator | Feb 2026 |
| 31 | Core Energy LLC | | Oil & Gas Operator | Feb 2026 |
| 32 | Country Boy Oil Co Inc | | Oil Operator | Nov 2017 |
| 33 | Countrymark Energy Resources L L C | MT Vernon, IN 47620 | Oil & Gas Operator | Dec 2024 |
| 34 | Cowen Michael T | | Oil & Gas Operator | Dec 2009 |
| 35 | Cozart Producers | | Oil Operator | Dec 2025 |
| 36 | Crawford Arthur E Dba The Lazy Oil Co | | Oil Operator | Dec 2024 |
| 37 | Creco Operating LLC | | Oil & Gas Operator | Nov 2015 |
| 38 | Cronus Exploration Co LLC | | Oil & Gas Operator | Feb 2026 |
| 39 | Crystal Exploration Co | | Oil & Gas Operator | Dec 2009 |