| 5601 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 5602 | Cimarron Engineering, LLC | Kingsville, TX 78364 | Oil & Gas Operator | Aug 2026 |
| 5603 | Cimarron Management Corp | | Oil & Gas Operator | Jul 2020 |
| 5604 | Cimarron Oil & Gas Inc | Perry, OK 73077-1318 | Oil & Gas Operator | Sep 2000 |
| 5605 | Cimarron Operating Company | Oklahoma City, OK 73112-3967 | Oil & Gas Operator | May 2011 |
| 5606 | Cimarron Petroleum Corporation | Houston, TX 77057-2696 | Oil & Gas Operator | Mar 2026 |
| 5607 | Cimarron Production Co Inc | Oklahoma City, OK 73142-3017 | Oil & Gas Operator | Apr 2026 |
| 5608 | Cimarron Properties, Inc. | San Angelo, TX 76904 | Oil & Gas Operator | Nov 1997 |
| 5609 | Cimarron River Operating Co | Mannford, OK 74044 | Oil & Gas Operator | Apr 2026 |
| 5610 | Cimarron Valley Energy Inc | Stillwater, OK 74076 | Oil Operator | Apr 2015 |
| 5611 | Cimic Energy, LLC | | Oil Operator | Jan 2025 |
| 5612 | Ciminello, Angeline | Fredonia, NY 14063 | Gas Operator | Dec 2025 |
| 5613 | Cinab, Inc. | FT. Scott, KS 66701 | Oil Operator | Jan 1998 |
| 5614 | Cinco Exploratio | | Oil & Gas Operator | Jan 1988 |
| 5615 | Cinco General Partnership | Albuquerque, NM 87103 | Oil & Gas Operator | Oct 1999 |
| 5616 | Cinco Natural Resources Corp | La Grange, TX 78945 | Oil & Gas Operator | Aug 2026 |
| 5617 | Cinco Oil & Gas, LLC | Irving, TX 75039 | Oil & Gas Operator | Jan 2026 |
| 5618 | Cincris Energy C | | Oil & Gas Operator | Jun 1991 |
| 5619 | Cinder Production Company | | Oil & Gas Operator | Apr 2014 |
| 5620 | Cinnabar Energy, LTD. | Fort Worth, TX 76107 | Oil & Gas Operator | May 2018 |
| 5621 | Cinnabar Operating, LLC | Fort Worth, TX 76121 | Oil & Gas Operator | Aug 2026 |
| 5622 | Cinnamon Creek Oil & Gas Inc | | Oil Operator | May 2026 |
| 5623 | Cinron Energy, LLC | Arp, TX 75750 | Oil & Gas Operator | Aug 2026 |
| 5624 | Cippele Resources Co. | Longview, TX 75608 | Oil & Gas Operator | May 1994 |
| 5625 | Circle "M" Energy Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Aug 2003 |
| 5626 | Circle 9 Resources LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | May 2026 |
| 5627 | Circle B Oil & Gas | Bowie, TX 76230 | Oil & Gas Operator | Dec 2021 |
| 5628 | Circle C Oilfield Supply Inc | Wetumka, OK 74883-0068 | Oil & Gas Operator | Apr 2017 |
| 5629 | Circle C Operations | Winnsboro, TX 75494 | Oil Operator | Aug 2026 |
| 5630 | Circle D Oil & Gas, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Aug 2026 |
| 5631 | Circle E Oil - E | | Oil Operator | May 1990 |
| 5632 | Circle H Oil Company | Big Spring, TX 79721 | Oil & Gas Operator | Apr 2020 |
| 5633 | Circle K Enterprises | | Oil & Gas Operator | Aug 2023 |
| 5634 | Circle K Oil & Gas Inc | Sand Springs, OK 74063 | Oil & Gas Operator | Apr 2026 |
| 5635 | Circle Ridge Production, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2026 |
| 5636 | Circle T Oil | | Oil Operator | Nov 2024 |
| 5637 | Circle W Oil & Gas Company | Pampa, TX 79066 | Oil & Gas Operator | Aug 2026 |
| 5638 | Circle-S Energy, LLC | McKinney, TX 75071 | Oil & Gas Operator | Aug 2026 |
| 5639 | Circleville Gas Co | Westerville, OH 43081 | Oil & Gas Operator | Dec 2004 |
| 5640 | Ciri Production Company | | Gas Operator | Mar 1994 |
| 5641 | Ciris Energy Inc | Centennial, CO 80112 | Gas Operator | Dec 2016 |
| 5642 | Cirque Resources LP | Denver, CO 80202 | Oil & Gas Operator | Aug 2016 |
| 5643 | Cirrus Exploration Company | Prosper, TX 75078 | Oil & Gas Operator | Aug 2026 |
| 5644 | Cirrus Production Company | Enid, OK 73702 | Oil & Gas Operator | Apr 2026 |
| 5645 | Cisco Operating LLC | Plano, TX 75024 | Oil & Gas Operator | May 2026 |
| 5646 | Cisco Petroleum, Inc. | | Oil & Gas Operator | Oct 2010 |
| 5647 | Cisco Production Company, LLC | Victoria, TX 77902 | Oil & Gas Operator | May 2012 |
| 5648 | Citadel Exploration Inc. | | Oil Operator | Dec 2025 |
| 5649 | Citadel Oil LLC | Edmond, OK 73083 | Oil Operator | Apr 2026 |
| 5650 | Citadel Prod Company Inc | Denver, CO 80201 | Oil Operator | Sep 1996 |
| 5651 | Citation Energy | | Oil & Gas Operator | Jul 1993 |
| 5652 | Citation Energy Company | Marietta, OH 45750 | Oil & Gas Operator | Dec 2025 |
| 5653 | Citation Oil & G | | Oil & Gas Operator | Dec 1996 |
| 5654 | Citation Oil & Gas Corp | Houston, TX 77269 | Oil & Gas Operator | Aug 2026 |
| 5655 | Cities Serv Oil & Gas Corp | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 1964 |
| 5656 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 5657 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 5658 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 5659 | Cities Services Company | | Oil & Gas Operator | Mar 2008 |
| 5660 | Citizen Energy II LLC | Tulsa, OK 74103-3729 | Oil & Gas Operator | Apr 2025 |
| 5661 | Citizen Energy III LLC | Devner, CO 80202 | Oil & Gas Operator | Apr 2026 |
| 5662 | Citizen Energy Ventures LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 5663 | Citmoco Services, Inc. | | Oil Operator | Jan 1971 |
| 5664 | Citori Oil Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Nov 2004 |
| 5665 | Citori Oil Company, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2014 |
| 5666 | Citronelle Operating Co., LLC | | Oil & Gas Operator | Sep 1997 |
| 5667 | Citrus Energy Corporation | Castle Rock, CO 80104 | Oil & Gas Operator | Dec 2025 |
| 5668 | Cits BK & Trust Of Springhill | | Oil & Gas Operator | Jun 1990 |
| 5669 | City & County Of Denver | | Oil & Gas Operator | Sep 2023 |
| 5670 | City Of Akron | Akron, OH 44308 | Oil & Gas Operator | Dec 2025 |
| 5671 | City Of Baker | Baker, MT 59313 | Oil & Gas Operator | May 2026 |
| 5672 | City Of Brady | Brady, TX 76825 | Gas Operator | Feb 1998 |
| 5673 | City Of Chanute | Chanute, KS 66720 | Oil Operator | Feb 1994 |
| 5674 | City Of Dumas | Dumas, TX 79029 | Gas Operator | Aug 2026 |
| 5675 | City Of Garden City, Kansas | Garden City, KS 67846 | Gas Operator | Apr 2026 |
| 5676 | City Of Hermosa Beach | | Oil & Gas Operator | Dec 2005 |
| 5677 | City Of Hugoton, Kansas | Hugoton, KS 67951 | Gas Operator | Apr 2026 |
| 5678 | City Of Huntington Beach (Fire Dept.) | | Oil & Gas Operator | Dec 2025 |
| 5679 | City Of McLean | McLean, TX 79057 | Gas Operator | Aug 2025 |
| 5680 | City Of Newport Beach | | Oil & Gas Operator | Jun 2026 |
| 5681 | City Of Santa Fe Springs | | Oil Operator | Dec 2007 |
| 5682 | City Of Satanta | Satanta, KS 67870 | Gas Operator | Apr 2026 |
| 5683 | City Of Sunray Utilities | Sunray, TX 79086 | Oil & Gas Operator | Aug 2026 |
| 5684 | City Of White Deer | White Deer, TX 79097 | Gas Operator | May 2017 |
| 5685 | City Oil Corp. Oper. For | | Oil & Gas Operator | Dec 1989 |
| 5686 | Civego, Inc. | | Oil & Gas Operator | Jul 1994 |
| 5687 | Civic Energy Corporation | Colony, OK 73021 | Oil & Gas Operator | May 2026 |
| 5688 | Civiletto, George & Wendy | Fredonia, NY 14063 | Gas Operator | Dec 2025 |
| 5689 | Civitas North LLC | | Oil & Gas Operator | May 2026 |
| 5690 | Civitas Permian Operating, LLC | Midland, TX 79707 | Oil & Gas Operator | Aug 2026 |
| 5691 | Civron Petroleum Res., LLC | San Antonio, TX 78229 | Oil & Gas Operator | Aug 2026 |
| 5692 | CJ Oil Inc | Madison, KS 66860 | Oil Operator | Apr 2026 |
| 5693 | CJR Operating LLC | Wister, OK 74966 | Gas Operator | Apr 2026 |
| 5694 | CJRW Oil & Gas | MC Camey, TX 79752 | Oil Operator | Aug 2026 |
| 5695 | CJT Oil Company LLC | Decatur, TX 76234 | Oil Operator | Aug 2026 |
| 5696 | CK Oil | | Oil Operator | Mar 2026 |
| 5697 | CK Oil & Gas LLC | Herington, KS 67449 | Oil & Gas Operator | Dec 2023 |
| 5698 | CK Operating Company, LLC | Wichita Falls, TX 76308 | Oil Operator | Dec 2025 |
| 5699 | CK Resources | Cleveland, OK 74020-0772 | Oil Operator | Aug 2013 |
| 5700 | CK5 Services LLC | Zephyr, TX 76890 | Oil & Gas Operator | Sep 2025 |