| 401 | Senkel, Wesley, Inc. | Graham, TX 76450 | Oil & Gas Operator | Apr 2007 |
| 402 | Serendipity Exploration, Inc. | Weatherford, TX 76087 | Gas Operator | May 1997 |
| 403 | Sha Stephens, Incorporated | Weatherford, TX 76087 | Oil & Gas Operator | Apr 2006 |
| 404 | Shamrock Minerals Corporation | Merkel, TX 79536 | Oil & Gas Operator | Nov 1998 |
| 405 | Sheets Exploration Co., Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2016 |
| 406 | Shell Western E&P | Houston, TX 77001 | Oil & Gas Operator | Mar 2025 |
| 407 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Mar 2025 |
| 408 | Siegfried R H Inc | Tulsa, OK 74104 | Oil & Gas Operator | Mar 2008 |
| 409 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Dec 2024 |
| 410 | Simpson Oil & Land Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 411 | Sitton, Ronnie Incorporated | Graford, TX 76449 | Oil & Gas Operator | Feb 2020 |
| 412 | Slate Holdings, Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Mar 2025 |
| 413 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Mar 2025 |
| 414 | Somerset Operating, LLC | Weatherford, TX 76086 | Gas Operator | Mar 2025 |
| 415 | Spartan Oil Corporation | Abilene, TX 79601 | Oil & Gas Operator | Aug 2003 |
| 416 | Special Energy Corporation | Stillwater, OK 74076 | Oil & Gas Operator | Mar 2025 |
| 417 | Spindletop Drilling Co. | Dallas, TX 75230 | Oil & Gas Operator | Mar 2025 |
| 418 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Mar 2025 |
| 419 | St. Johns Operating #1 L.P. | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 420 | Staghorn Resources, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2015 |
| 421 | Stamper Operating Co., Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Mar 2025 |
| 422 | Star Of Texas Energy SRVS, Inc. | Austin, TX 78702 | Oil & Gas Operator | Mar 2025 |
| 423 | Star Operating, Inc | Fort Worth, TX 76185 | Oil & Gas Operator | Mar 2025 |
| 424 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2025 |
| 425 | Stephens, Hayseed Oil Inc. | Weatherford, TX 76087 | Oil & Gas Operator | Mar 2008 |
| 426 | Stephenson Oil & Gas, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Sep 1999 |
| 427 | Sterling Oil And Gas | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2025 |
| 428 | Stovall, Howard | Cisco, TX 76437 | Oil & Gas Operator | Mar 2025 |
| 429 | Strata Operating, Inc. | Corpus Chrsti, TX 78466 | Oil & Gas Operator | Mar 2025 |
| 430 | Stratagas, Inc. | Rowlett, TX 75088 | Oil & Gas Operator | May 2006 |
| 431 | Stroud Energy, LTD. | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2006 |
| 432 | Sullivan, Hollis R. Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2009 |
| 433 | Sun-Key Oil Co., Inc. | Dublin, TX 76446 | Oil & Gas Operator | Mar 2025 |
| 434 | Sundance Consulting Corp. | Abilene, TX 79605 | Oil & Gas Operator | Mar 2025 |
| 435 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 436 | Swan PC, LP | Jacksboro, TX 76458 | Oil & Gas Operator | Mar 2025 |
| 437 | Swan Production Co. | Jacksboro, TX 76458 | Oil & Gas Operator | Nov 2009 |
| 438 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Mar 2025 |
| 439 | Talon Oil & Gas LLC | Dallas, TX 75243 | Oil & Gas Operator | Dec 2010 |
| 440 | Talon Production, Inc. | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2025 |
| 441 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 442 | Tanglewood Oil & Gas LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2017 |
| 443 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 444 | Tarpon Oil & Gas Co. | Fort Worth, TX 76147 | Oil & Gas Operator | Mar 2025 |
| 445 | Tarpon Oil Company | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2017 |
| 446 | Tatanka Operating, LLC | Whitesboro, TX 76273 | Oil & Gas Operator | Mar 2025 |
| 447 | Taylor, Ben J. Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2022 |
| 448 | Tejas Western Corp. | Granbury, TX 76048 | Oil & Gas Operator | Jul 2018 |
| 449 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Mar 2025 |
| 450 | Tempo Resources GP, LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Apr 2013 |
| 451 | Tep Barnett USA, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 452 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Mar 2025 |
| 453 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 454 | Texxol Operating Company, Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | Mar 2025 |
| 455 | Three J Operating Company, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Mar 2025 |
| 456 | Titan Energy, Inc. | Austin, TX 78703 | Oil & Gas Operator | Mar 2025 |
| 457 | Titan Operating, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2012 |
| 458 | Tower Resources Inc | Conroe, TX 77304 | Oil & Gas Operator | Mar 2025 |
| 459 | Trace Energy Management Inc | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2025 |
| 460 | Tree Operating, LLC | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 461 | Tren Energy LLC | El Paso, TX 79912 | Oil Operator | Mar 2025 |
| 462 | Tres Azores Oil & Gas, Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Aug 2003 |
| 463 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 464 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2025 |
| 465 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Mar 2025 |
| 466 | Trust Oil Co. | Pine, CO 80470 | Oil & Gas Operator | Mar 2025 |
| 467 | Tuckco Petroleum Corporation | Andrews, TX 79714 | Oil & Gas Operator | Mar 2025 |
| 468 | U.S. Sovereign Oil And Gas, Inc. | Dallas, TX 75355 | Oil & Gas Operator | Mar 2025 |
| 469 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | Mar 2025 |
| 470 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | Mar 2025 |
| 471 | United Operating, LLC *** | Midland, TX 79710 | Oil & Gas Operator | Mar 2025 |
| 472 | Upham Oil & Gas Company | Mineral Wells, TX 76068 | Oil & Gas Operator | Mar 2025 |
| 473 | Upham, Chester R., Jr. | Mineral Wells, TX 76067 | Oil & Gas Operator | Aug 2001 |
| 474 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 475 | Utility Ventures Company | Pasadena, TX 77504 | Oil & Gas Operator | Mar 2025 |
| 476 | Vaca Operating Company LLC | Pacific PLSDS, CA 90272 | Oil & Gas Operator | Aug 2017 |
| 477 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2025 |
| 478 | Vanco Oil & Gas Corp. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2025 |
| 479 | Vantage Fort Worth Energy LLC | Pittsburgh, PA 15222 | Oil & Gas Operator | Oct 2017 |
| 480 | Vargas Energy, LTD. | Fort Worth, TX 76109 | Gas Operator | Mar 2025 |
| 481 | Venado Operating Company LLC | Austin, TX 78738 | Oil & Gas Operator | Mar 2022 |
| 482 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Mar 2025 |
| 483 | Walsh, F H Jr. Operating Co. Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2019 |
| 484 | Watco Energy | Jacksboro, TX 76458 | Oil & Gas Operator | Mar 2025 |
| 485 | WCWB Energy, LLC | Midland, TX 79701 | Oil Operator | Sep 2015 |
| 486 | Wellington Securities, Inc. | Plano, TX 75093 | Gas Operator | Jul 2014 |
| 487 | Westerly Exploration, Inc. | Houston, TX 77256 | Oil & Gas Operator | Mar 2025 |
| 488 | Western Chief Oil & Gas Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2009 |
| 489 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 490 | Western Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 491 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 492 | Westoil LLC | Austin, TX 78747 | Oil & Gas Operator | Mar 2025 |
| 493 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 494 | Westridge Oil & Gas Properties | Mineral Wells, TX 76068 | Oil & Gas Operator | Mar 2025 |
| 495 | Wheat, Buck Resources, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Dec 2009 |
| 496 | White Heart, Inc. | Georgetown, TX 78628 | Gas Operator | Jun 1996 |
| 497 | White Knight Production LLC | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2024 |
| 498 | Whitehead Prod. Co., Inc. | Humble, TX 77338 | Oil & Gas Operator | Dec 2024 |
| 499 | Whittier Operating Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2007 |
| 500 | Williams Prod. Gulf Coast, L.P. | Benbrook, TX 76126 | Oil & Gas Operator | Jan 2012 |