| 501 | Christie Oil Co., Inc | Breckenridge, TX 76424 | Oil & Gas Operator | Nov 1996 |
| 502 | Christie, C. B., Jr. | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 2014 |
| 503 | Christopher Oil & Gas Inc | Fulshear, TX 77441 | Oil & Gas Operator | Apr 2015 |
| 504 | Chroma Operating, Inc. | Washington, DC 20036 | Oil & Gas Operator | Jun 2016 |
| 505 | Chumley, George Estate Of | Alice, TX 78333 | Oil & Gas Operator | Feb 2026 |
| 506 | Church Ranch, LLC | Lubbock, TX 79423 | Oil Operator | Feb 2026 |
| 507 | Chuza Operating | Midland, TX 79710 | Oil & Gas Operator | Sep 2006 |
| 508 | Cibolo Energy Operating, Inc. | Bulverde, TX 78163 | Oil & Gas Operator | Feb 2026 |
| 509 | Cibolo Production, LLC | Boerne, TX 78006 | Oil Operator | Jan 2020 |
| 510 | Cico Oil & Gas Company | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 511 | Ciervo Resources Asset Holding, LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 512 | Cig Exploration Inc | Houston, TX 77046 | Oil & Gas Operator | Nov 1999 |
| 513 | Cimarex Energy Co | Midland, TX 79706 | Oil & Gas Operator | Feb 2026 |
| 514 | Cimarex Energy Co. Of Colorado | Midland, TX 79706 | Oil & Gas Operator | Feb 2026 |
| 515 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 516 | Cimarron Engineering, LLC | Kingsville, TX 78364 | Oil & Gas Operator | Feb 2026 |
| 517 | Cimarron Properties, Inc. | San Angelo, TX 76904 | Oil & Gas Operator | Nov 1997 |
| 518 | Cinco Natural Resources Corp | La Grange, TX 78945 | Oil & Gas Operator | Feb 2026 |
| 519 | Cinco Oil & Gas, LLC | Irving, TX 75039 | Oil & Gas Operator | Feb 2026 |
| 520 | Cinnabar Energy, LTD. | Fort Worth, TX 76107 | Oil & Gas Operator | May 2018 |
| 521 | Cinnabar Operating, LLC | Fort Worth, TX 76121 | Oil & Gas Operator | Feb 2026 |
| 522 | Cinron Energy, LLC | Arp, TX 75750 | Oil & Gas Operator | Feb 2026 |
| 523 | Cippele Resources Co. | Longview, TX 75608 | Oil & Gas Operator | May 1994 |
| 524 | Circle "M" Energy Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Aug 2003 |
| 525 | Circle B Oil & Gas | Bowie, TX 76230 | Oil & Gas Operator | Dec 2021 |
| 526 | Circle C Operations | Winnsboro, TX 75494 | Oil Operator | Feb 2026 |
| 527 | Circle D Oil & Gas, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Feb 2026 |
| 528 | Circle H Oil Company | Big Spring, TX 79721 | Oil & Gas Operator | Apr 2020 |
| 529 | Circle M Royalty Co., Inc. | Weatherford, TX 76087 | Oil & Gas Operator | May 2007 |
| 530 | Circle Ridge Production, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 531 | Circle S Production, Inc. | FT McKavett, TX 76841 | Oil & Gas Operator | May 2000 |
| 532 | Circle W Oil & Gas Company | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 533 | Circle W Operating, Inc. | Mertzon, TX 76941 | Oil & Gas Operator | Feb 2026 |
| 534 | Circle-S Energy, LLC | McKinney, TX 75071 | Oil & Gas Operator | Feb 2026 |
| 535 | Cirrus Exploration Company | Prosper, TX 75078 | Oil & Gas Operator | Feb 2026 |
| 536 | Cirrus Production Company | Enid, OK 73702 | Oil & Gas Operator | Nov 2025 |
| 537 | Cisco Operating LLC | Plano, TX 75024 | Oil & Gas Operator | Dec 2025 |
| 538 | Cisco Production Company, LLC | Victoria, TX 77902 | Oil & Gas Operator | May 2012 |
| 539 | Citation Oil & Gas Corp | Houston, TX 77269 | Oil & Gas Operator | Feb 2026 |
| 540 | Citori Oil Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Nov 2004 |
| 541 | Citori Oil Company, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2014 |
| 542 | Citrus Energy Corporation | Castle Rock, CO 80104 | Oil & Gas Operator | Mar 2020 |
| 543 | City Of Brady | Brady, TX 76825 | Gas Operator | Feb 1998 |
| 544 | City Of Dumas | Dumas, TX 79029 | Gas Operator | Feb 2026 |
| 545 | City Of McLean | McLean, TX 79057 | Gas Operator | Aug 2025 |
| 546 | City Of Sunray Utilities | Sunray, TX 79086 | Oil & Gas Operator | Feb 2026 |
| 547 | City Of White Deer | White Deer, TX 79097 | Gas Operator | May 2017 |
| 548 | Civitas Permian Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2026 |
| 549 | Civron Petroleum Res., LLC | San Antonio, TX 78229 | Oil & Gas Operator | Feb 2026 |
| 550 | CJRW Oil & Gas | MC Camey, TX 79752 | Oil Operator | Feb 2026 |
| 551 | CK Operating Company, LLC | Wichita Falls, TX 76308 | Oil Operator | Feb 2026 |
| 552 | CK5 Services LLC | Zephyr, TX 76890 | Oil & Gas Operator | Sep 2025 |
| 553 | CKB Corporation | Borger, TX 79008 | Oil & Gas Operator | Aug 1997 |
| 554 | CL&F Operating LLC | Spring, TX 77389 | Oil & Gas Operator | Dec 2022 |
| 555 | Clamp Operating | San Antonio, TX 78264 | Oil & Gas Operator | Apr 2002 |
| 556 | Clamp Operating Incorporated | San Antonio, TX 78264 | Oil & Gas Operator | Mar 2011 |
| 557 | Clark Oil Co. | Dallas, TX 75360 | Oil & Gas Operator | Feb 2026 |
| 558 | Clark Operating | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 559 | Clark Operating Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 560 | Clark, B. C. | Cross Plains, TX 76443 | Oil Operator | Dec 2007 |
| 561 | Clark, G. A., Trustee | San Antonio, TX 78210 | Oil & Gas Operator | Nov 2017 |
| 562 | Clark, John M. | Midland, TX 79701 | Oil & Gas Operator | Dec 1993 |
| 563 | Clark, John M., Inc. | Midland, TX 79704 | Oil & Gas Operator | Feb 2026 |
| 564 | Clark, Richard E., Inc. | Longview, TX 75604 | Oil & Gas Operator | May 2001 |
| 565 | Claron Corporation | Houston, TX 77219 | Oil & Gas Operator | Feb 2026 |
| 566 | Classic Energy Incorporated | Tyler, TX 75701 | Oil & Gas Operator | Jul 2005 |
| 567 | Classic Oil & Gas, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jan 2004 |
| 568 | Classic Operating Co. LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 569 | Classic Petroleum Partners, Inc. | Whitehouse, TX 75791 | Oil & Gas Operator | Feb 2026 |
| 570 | Claude-Maggie Co. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 571 | Clausen, A. G. | Cross Plains, TX 76443 | Oil & Gas Operator | Feb 2026 |
| 572 | Clavo Oil, LLC | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 573 | Clay Exploration, Inc. | Spring, TX 77387 | Oil & Gas Operator | Jun 2019 |
| 574 | Clay Petroleum | Prosper, TX 75078 | Oil & Gas Operator | Feb 2023 |
| 575 | Clay, Charles E. | Jacksboro, TX 76458 | Oil & Gas Operator | Sep 2010 |
| 576 | Clay, Jerry H. | Tyler, TX 75702 | Oil & Gas Operator | Mar 2006 |
| 577 | Clayton Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | May 2004 |
| 578 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 579 | CLC Operations Inc | Midland, TX 79701 | Oil & Gas Operator | Mar 1997 |
| 580 | Cleantex Oilfield Services, LLC | Tyler, TX 75702 | Oil Operator | Feb 2026 |
| 581 | Clear Brooke Ranches, LLC | Fort Worth, TX 76179 | Oil & Gas Operator | Feb 2026 |
| 582 | Clear Fork Gas Company | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 583 | Clear Fork, Incorporated | Abilene, TX 79604 | Oil & Gas Operator | Feb 2026 |
| 584 | Clear Water Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 585 | Clearfork Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2011 |
| 586 | Clearfork Petroleum Inc. (A) | Lubbock, TX 79408 | Oil & Gas Operator | Feb 2026 |
| 587 | Clearfork Production, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2018 |
| 588 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 589 | Cleary Petroleum Corporation | Edmond, OK 73083 | Oil & Gas Operator | Jul 2019 |
| 590 | Clements Exploration Co | Oklahoma City, OK 73132-5922 | Oil & Gas Operator | Jan 2006 |
| 591 | Clements Operating Company, Inc. | Luling, TX 78648 | Oil & Gas Operator | Aug 2003 |
| 592 | Clemons, Tony W. | Minden, LA 71055 | Oil & Gas Operator | Dec 2016 |
| 593 | Cleo Oil, Inc. | Olney, TX 76374 | Oil & Gas Operator | May 1997 |
| 594 | Cleveland Oil & Gas | Wichita Falls, TX 76308 | Oil Operator | Feb 2026 |
| 595 | Cleveland Oil Company,L.L.C.,The | Midland, TX 79702 | Oil & Gas Operator | Sep 1999 |
| 596 | Cleveland Production Company | Summit, MS 39666 | Oil & Gas Operator | Jul 1999 |
| 597 | Click Corp | Monroe, LA 71207 | Oil & Gas Operator | Jan 2025 |
| 598 | Click Energy Company | Houston, TX 77269 | Oil & Gas Operator | Feb 2026 |
| 599 | Clide Oil Corp. | Iraan, TX 79744 | Oil & Gas Operator | Nov 2015 |
| 600 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |