| 401 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 402 | SMR Natural Gas Ventures Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Jan 1999 |
| 403 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | Jan 2026 |
| 404 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 405 | Sonat Exploration Company-MCR | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 406 | Southwest Energy LP | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 407 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2026 |
| 408 | Spring Resources, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2007 |
| 409 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 410 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 411 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Apr 2026 |
| 412 | STB Energy Inc. | Tulsa, OK 74105 | Oil & Gas Operator | Jul 2008 |
| 413 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 414 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Apr 2026 |
| 415 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Apr 2026 |
| 416 | Sunstone Energy Company | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2009 |
| 417 | Suoco Oil Corporation | Pampa, TX 79066 | Oil & Gas Operator | Apr 2026 |
| 418 | T-Y Development Corp | Perryton, TX 79070 | Oil & Gas Operator | Apr 2026 |
| 419 | Tabula Rasa Energy, LLC | Allen, TX 75013 | Oil & Gas Operator | Dec 2020 |
| 420 | Talus Inc | Graham, TX 76450-1210 | Oil & Gas Operator | Feb 2017 |
| 421 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Apr 2026 |
| 422 | Technical Energy Services, Inc. | Norman, OK 73070 | Oil & Gas Operator | Jan 2026 |
| 423 | Templar Operating LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2026 |
| 424 | Tempo Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2026 |
| 425 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | Apr 2026 |
| 426 | Texakoma Operating, L.P. | Plano, TX 75024 | Oil & Gas Operator | Mar 2025 |
| 427 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Apr 2026 |
| 428 | Texian Energy Corporation | Amarillo, TX 79120 | Oil & Gas Operator | Apr 1997 |
| 429 | The Cornell Corporation | Fort Worth, TX 76109 | Oil & Gas Operator | Sep 1993 |
| 430 | The Operating Co. | Pampa, TX 79065 | Oil & Gas Operator | Sep 2007 |
| 431 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 432 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 433 | Toklan Oil And Gas Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 434 | Trail Ridge Energy Partners, LLC | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2026 |
| 435 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Apr 2026 |
| 436 | Tri-Ex Petroleum, L.P. | Amarillo, TX 79101 | Oil & Gas Operator | Jan 2013 |
| 437 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 438 | Unbridled Resources, LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 439 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 440 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 441 | United Energy Operating, LLC | Edmond, OK 73083 | Oil & Gas Operator | Apr 2026 |
| 442 | United Oil & Shale LLC | Woodward, OK 73801 | Oil & Gas Operator | Apr 2026 |
| 443 | Universal Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2002 |
| 444 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 445 | Upland Exploration, LLC | Boerne, TX 78006 | Oil & Gas Operator | Jul 2024 |
| 446 | Upland Resources LLC | Canadian, TX 79014 | Oil & Gas Operator | Apr 2026 |
| 447 | Upland Resources, Inc. | Canadian, TX 79014 | Oil & Gas Operator | Dec 2009 |
| 448 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Apr 2026 |
| 449 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 450 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2026 |
| 451 | Vintage Petroleum, LLC | Houston, TX 77210 | Oil & Gas Operator | Dec 2019 |
| 452 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | Apr 2026 |
| 453 | VRK Oil And Gas, Inc. | Arlington, TX 76016 | Oil & Gas Operator | Mar 2014 |
| 454 | Wadi Petroleum Inc | Houston, TX 77014 | Oil & Gas Operator | May 2018 |
| 455 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2026 |
| 456 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Apr 2026 |
| 457 | Washita Oil And Gas, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 458 | Weinkauf Petroleum, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 459 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 460 | Western Petroleum Company Inc | Tulsa, OK 74170-2676 | Oil & Gas Operator | Apr 2020 |
| 461 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 462 | WG Operating, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | May 2012 |
| 463 | Wheeler Energy Co. | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 464 | Wheeler Energy, LLC | Tulsa, OK 74101 | Oil & Gas Operator | Apr 2026 |
| 465 | White Stride LLC | Piedmont, OK 73078 | Oil & Gas Operator | Apr 2026 |
| 466 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 467 | Whitlock, J.R. Operator | Amarillo, TX 79105 | Gas Operator | Jul 1997 |
| 468 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 469 | Wilbanks Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 470 | Wilbanks Reserve Corporation | Denver, CO 80203 | Oil & Gas Operator | Apr 2026 |
| 471 | Wildhorse Operating Company | Ardmore, OK 73402 | Oil & Gas Operator | Apr 2026 |
| 472 | Will Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jan 2026 |
| 473 | Williams, W. R. | Amarillo, TX 79105 | Oil & Gas Operator | Jun 2013 |
| 474 | Williams, W. R., Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Feb 2024 |
| 475 | Williford Energy Company | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2026 |
| 476 | Williford Petroleum, L.L.C. | Green CV SPGS, FL 32043 | Oil & Gas Operator | Apr 2026 |
| 477 | Wilshire Oil Co. Of Texas | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2004 |
| 478 | Winright Resources Operating,LLC | Houston, TX 77007 | Oil & Gas Operator | Apr 2026 |
| 479 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 480 | Wolf Creek Exploration Company | Amarillo, TX 79159 | Oil & Gas Operator | Aug 2000 |
| 481 | Wright Trucking, Inc. | Weatherford, OK 73096 | Oil & Gas Operator | Feb 2019 |
| 482 | Wynn-Crosby Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 483 | Wynn-Crosby Operating, LTD. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2026 |
| 484 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 485 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 486 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |