| 601 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 602 | CMS Oil And Gas Company | Jackson, MI 49201 | Oil & Gas Operator | Oct 2002 |
| 603 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 604 | CNS Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Nov 2010 |
| 605 | Co Energy | Benbrook, TX 76126 | Oil & Gas Operator | Sep 2025 |
| 606 | Co-Co Oil, Inc. | Lubbock, TX 79407 | Oil & Gas Operator | Aug 2003 |
| 607 | Coal Creek Energy, LLC | Overland Park, KS 66221 | Oil Operator | Dec 2019 |
| 608 | Coalinga Corporation | Houston, TX 77002 | Oil & Gas Operator | May 1999 |
| 609 | Coastal Bend Petroleum Corp. | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Dec 2002 |
| 610 | Coastal Expanse Oil & Gas | Austin, TX 78704 | Oil & Gas Operator | Sep 2025 |
| 611 | Coastal Investments Inc. | El Campo, TX 77437 | Oil & Gas Operator | Sep 2025 |
| 612 | Coastal Management Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 613 | Coastal New Mexico MGMT LLC | Carlsbad, NM 88220 | Oil & Gas Operator | Sep 2025 |
| 614 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 615 | Coastal Plains Energy Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 2025 |
| 616 | Coastal Plains Exploration, LLC | Port Lavaca, TX 77979 | Oil & Gas Operator | Sep 2025 |
| 617 | Coastal Production Company, Inc. | El Campo, TX 77437 | Oil & Gas Operator | Aug 1995 |
| 618 | Coastal Shoreline Corp. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Aug 2003 |
| 619 | Coastland Operations, LLC | Dallas, TX 75287 | Oil & Gas Operator | Sep 2025 |
| 620 | Coastline Exploration, Inc. | Stafford, TX 77477 | Oil & Gas Operator | Sep 2025 |
| 621 | Coastline Operating, L.L.C. | Houston, TX 77027 | Oil & Gas Operator | Dec 2006 |
| 622 | Coates Energy Interests, LTD. | San Antonio, TX 78217 | Oil & Gas Operator | Aug 1997 |
| 623 | Coates Energy Trust | San Antonio, TX 78209 | Oil & Gas Operator | Aug 2008 |
| 624 | Cobalt Energy LLC | Wichita, KS 67202 | Oil & Gas Operator | Apr 2025 |
| 625 | Cobalt Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Feb 2025 |
| 626 | Cobbs Brothers Oil & Gas | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Jun 2009 |
| 627 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2025 |
| 628 | Cobra Operating Company | Houston, TX 77002 | Oil & Gas Operator | Sep 2003 |
| 629 | Cochise Energy Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 630 | Cockburn Oil Corporation | Lubbock, TX 79493 | Oil & Gas Operator | Jul 2005 |
| 631 | Cockrell Production Co., Inc. | Irving, TX 75014 | Oil & Gas Operator | Sep 2025 |
| 632 | Coda Energy, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 1998 |
| 633 | Cody Company | Amarillo, TX 79121 | Oil & Gas Operator | Mar 2020 |
| 634 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 635 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Jul 2025 |
| 636 | Cody Resources, Inc. | Midland, TX 79705 | Oil & Gas Operator | Sep 2002 |
| 637 | Coenergy Operating Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 638 | Coert Holdings 1 LLC | Greenwich, CT 06830 | Oil & Gas Operator | Dec 2021 |
| 639 | Cofer & Crawford | Pampa, TX 79066 | Oil & Gas Operator | Sep 2025 |
| 640 | COG Operating LLC | Midland, TX 79701 | Oil & Gas Operator | Sep 2025 |
| 641 | COG Production LLC | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 642 | Coho Resources Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 2002 |
| 643 | Cohort Energy Company | Centennial, CO 80112 | Oil & Gas Operator | Feb 2007 |
| 644 | Coker, Jonathan C., Inc. | Austin, TX 78746 | Oil Operator | Mar 2011 |
| 645 | Coker, Nel Rey Daws | Throckmorton, TX 76483 | Oil & Gas Operator | Mar 2008 |
| 646 | Coker, Tom | Seymour, TX 76380 | Oil & Gas Operator | Sep 2006 |
| 647 | Cokinos, Inc. | Beaumont, TX 77701 | Oil & Gas Operator | Aug 2003 |
| 648 | Colby Production Resources, LLC | Granbury, TX 76048 | Oil Operator | Sep 2025 |
| 649 | Cole, Frank W Engineering | Dallas, TX 75254 | Oil & Gas Operator | Mar 2006 |
| 650 | Cole, John Otis | Big Spring, TX 79721 | Oil & Gas Operator | Jan 1999 |
| 651 | Coleman & Johnson Oil Company | Brownwood, TX 76801 | Oil & Gas Operator | Sep 2025 |
| 652 | Coleman County Project | Coleman, TX 76834 | Oil & Gas Operator | Oct 2012 |
| 653 | Coleman Oil & Gas Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Sep 2025 |
| 654 | Coleman Oil & Gas Inc | Farmington, NM 87499 | Oil & Gas Operator | Jan 2023 |
| 655 | Colemanite, Inc. | Abilene, TX 79606 | Oil & Gas Operator | Sep 2025 |
| 656 | Coleville Petroleum Company | McAllen, TX 78503 | Oil & Gas Operator | Mar 1996 |
| 657 | Coley, H. B. | Corsicana, TX 75110 | Oil & Gas Operator | Oct 2000 |
| 658 | Coley, Thomas | Graham, TX 76450 | Oil & Gas Operator | Sep 2025 |
| 659 | Colgate Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2024 |
| 660 | Collier Oil Field Services Inc | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2025 |
| 661 | Collier, Scott Inc. | Holliday, TX 76366 | Oil Operator | May 2003 |
| 662 | Collier, W. D. Ranch | Post, TX 79356 | Oil & Gas Operator | Jan 2012 |
| 663 | Collins & Ware, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2003 |
| 664 | Collins Resources, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Mar 2011 |
| 665 | Colo Construction Co., Inc. | Abilene, TX 79602 | Oil Operator | Apr 2004 |
| 666 | Colo Exploration Company, Inc. | Benbrook, TX 76126 | Oil & Gas Operator | Sep 2025 |
| 667 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 668 | Colorado Bluebonnet Energy Corp. | Englewood, CO 80112 | Oil & Gas Operator | Feb 2001 |
| 669 | Colorado-Swanson Landing Oil & Gas, LLC | Kilgore, TX 75663 | Oil Operator | Sep 2025 |
| 670 | Colotex Operating, LLC | Aurora, CO 80015 | Oil & Gas Operator | Sep 2025 |
| 671 | Colt Oil & Gas Co. | Abilene, TX 79601 | Oil Operator | Apr 2004 |
| 672 | Colt Oil Company | Andrews, TX 79714 | Oil & Gas Operator | Feb 1996 |
| 673 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 674 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 675 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 676 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 677 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 678 | Columbus Energy, LLC | Houston, TX 77046 | Oil & Gas Operator | Sep 2025 |
| 679 | Comac Well Service, Inc. | Borger, TX 79008 | Oil & Gas Operator | Mar 2008 |
| 680 | Comal Operating LLC | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2025 |
| 681 | Comanche Operating Co. | Oklahoma City, OK 73120 | Oil & Gas Operator | Aug 2002 |
| 682 | Comanche Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2006 |
| 683 | Comanche Well Service Corp. | Plano, TX 75093 | Oil & Gas Operator | Sep 2025 |
| 684 | Combined Resources Corporation | Edmond, OK 73083 | Oil & Gas Operator | Sep 2025 |
| 685 | Comco Of Louisiana, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2000 |
| 686 | Comet Oil & Gas, Inc. | Conroe, TX 77305 | Oil & Gas Operator | Sep 2025 |
| 687 | Comet Production | Conroe, TX 77305 | Oil Operator | Sep 2025 |
| 688 | Cometra Oil And Gas, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 689 | Common Resources L.L.C. | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 690 | Commonwealth Resources, LLC | Fort Collins, CO 80524 | Oil Operator | Dec 2008 |
| 691 | Commonwealth Royalty, LLC | Balmorhea, TX 79718 | Oil Operator | Sep 2025 |
| 692 | Compass Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2025 |
| 693 | Compass Operating, L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Sep 2025 |
| 694 | Compostella Oil Company | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 695 | Comstock Energy, LLC | Wichita Falls, TX 76301 | Oil & Gas Operator | Sep 2025 |
| 696 | Comstock Oil & Gas, Inc. | Frisco, TX 75034 | Oil & Gas Operator | Dec 2012 |
| 697 | Comstock Oil & Gas, LLC | Frisco, TX 75034 | Oil & Gas Operator | Sep 2025 |
| 698 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 699 | Comyn Natural Gas, Inc. | Fort Worth, TX 76163 | Oil & Gas Operator | Sep 2025 |
| 700 | Con-Lin Oil Co. | Graham, TX 76450 | Oil & Gas Operator | Nov 2017 |