| 501 | Sinclair Exploration Company | Abilene, TX 79604 | Oil & Gas Operator | Nov 1998 |
| 502 | Smalley, Bill | Albany, TX 76430 | Oil & Gas Operator | Jul 2001 |
| 503 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 504 | Smith, Donnie D. | Coleman, TX 76834 | Gas Operator | Oct 2017 |
| 505 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 506 | Southern Exploration, Inc. | Fort Worth, TX 76137 | Oil & Gas Operator | Aug 2023 |
| 507 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 508 | Southwest Gas Systems, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 509 | Spartan Oil Corporation | Abilene, TX 79601 | Oil & Gas Operator | Aug 2003 |
| 510 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 511 | SRV Oil Co | Coleman, TX 76834 | Oil Operator | May 2025 |
| 512 | St. Johns Operating #1 L.P. | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 513 | Standard Oil Tools, Inc. | College Sta, TX 77845 | Oil & Gas Operator | May 2025 |
| 514 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | May 2025 |
| 515 | Stasney, H. R. & Sons, LTD. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 516 | Stearns Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Oct 1993 |
| 517 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2025 |
| 518 | Stewardship Resources | Roanoke, TX 76262 | Oil & Gas Operator | Jun 2022 |
| 519 | Stivers Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 1995 |
| 520 | Stonegate Operators, Inc. | Addison, TX 75001 | Oil Operator | May 2025 |
| 521 | Strawn Partners Operating, LLC | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 522 | Stubblefield Energy Company | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 523 | Sub Surface Operations | Brownwood, TX 76804 | Oil & Gas Operator | May 2025 |
| 524 | Subsurface Energy Corp. | Coleman, TX 76834 | Oil & Gas Operator | May 2025 |
| 525 | Subsurface Exploration | Coleman, TX 76834 | Oil & Gas Operator | Apr 2006 |
| 526 | Subsurface Production, Inc. | Coleman, TX 76834 | Oil & Gas Operator | May 2025 |
| 527 | Sun-Key Oil Co., Inc. | Dublin, TX 76446 | Oil & Gas Operator | May 2025 |
| 528 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 529 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 530 | Tam2 Squared Operating, LLC | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 531 | Tanglewood Oil & Gas Co. | Gouldbusk, TX 76845 | Oil & Gas Operator | May 2025 |
| 532 | Tankersley, D. C. | Abilene, TX 79601 | Oil & Gas Operator | Sep 2002 |
| 533 | Targo Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 534 | Tarpon Oil Company | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2017 |
| 535 | Taylor, Frank Well Service | Cross Plains, TX 76443 | Oil & Gas Operator | Aug 2003 |
| 536 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | May 2025 |
| 537 | TCS Petroleum Co., LLC | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 538 | Teague Operating Co. | Mabank, TX 75147 | Oil & Gas Operator | Jul 1995 |
| 539 | Tejas Jack Sales, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | May 2025 |
| 540 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | May 2025 |
| 541 | Tema Oil And Gas, LLC | Houston, TX 77040 | Oil & Gas Operator | Apr 2000 |
| 542 | Tempo Resources GP, LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Apr 2013 |
| 543 | Texas International Resource LLC | Allen, TX 75013 | Oil Operator | May 2025 |
| 544 | Texas Pharchem Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2019 |
| 545 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 546 | Thomas, T. N. Oil Company | Aiken, SC 29801 | Oil & Gas Operator | May 2025 |
| 547 | Three P Operating Co.,GP, L.L.C. | Newcastle, TX 76372 | Oil & Gas Operator | May 2025 |
| 548 | Threeway Drilling Company | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 549 | THT Covenant Holdings, LLC | Wichita Falls, TX 76307 | Oil Operator | May 2025 |
| 550 | Tidwell Production Company | Sonora, TX 76950 | Oil & Gas Operator | May 2025 |
| 551 | TK Operating | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 552 | TLH Production LLC | Abilene, TX 79602 | Oil & Gas Operator | May 2025 |
| 553 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 554 | TPC Exploration, LLC | May, TX 76857 | Oil & Gas Operator | May 2025 |
| 555 | Tracker Mineral | Clyde, TX 79510 | Oil & Gas Operator | May 2025 |
| 556 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 557 | Transcontinental Shale L.L.C. | Austin, TX 78717 | Oil & Gas Operator | Feb 2016 |
| 558 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 559 | Triple D Oil & Gas Co., Inc. | Brownwood, TX 76801 | Oil & Gas Operator | May 2025 |
| 560 | Tritex Resources, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2009 |
| 561 | Trump Energy | Austin, TX 78734 | Oil & Gas Operator | Mar 2008 |
| 562 | Trust Oil Co. | Pine, CO 80470 | Oil & Gas Operator | May 2025 |
| 563 | Trustar Operating Company Inc. | Austin, TX 78750 | Oil Operator | May 2025 |
| 564 | TSW Oil & Gas, LLC | Abilene, TX 79602 | Oil & Gas Operator | Jan 2016 |
| 565 | TT Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 566 | Turner, Greg | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 567 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 568 | Tyco Operating Co. | Archer City, TX 76351 | Oil & Gas Operator | May 2025 |
| 569 | Unoso Operating Company L.L.C. | Georgetown, TX 78633 | Oil & Gas Operator | May 2025 |
| 570 | Upda Operators, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Dec 2009 |
| 571 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 572 | Valera Oil Company | Kingsland, TX 78639 | Oil & Gas Operator | Apr 2000 |
| 573 | Valley Petroleum Company | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 574 | Vega Energy Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2015 |
| 575 | Viathon Hydrocarbons, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2020 |
| 576 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 577 | W.W.R. Holding, LLC | Coleman, TX 76834 | Oil & Gas Operator | Mar 2008 |
| 578 | Wagman Petroleum, Inc. | Dallas, TX 75202 | Oil & Gas Operator | May 2025 |
| 579 | Wagman, Brent A. | Dallas, TX 75202 | Oil & Gas Operator | May 2025 |
| 580 | Walker Oil & Gas | Early, TX 76802 | Oil & Gas Operator | Dec 2002 |
| 581 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | May 2025 |
| 582 | Ward Trust | Spring, TX 77383 | Oil & Gas Operator | May 2013 |
| 583 | Warren, Earl T. | San Angelo, TX 76906 | Oil & Gas Operator | May 2025 |
| 584 | Watson, B. G. Oil Field Salv Inc | Coleman, TX 76834 | Oil & Gas Operator | Mar 2000 |
| 585 | WCT Leasing Co. | Austin, TX 78734 | Oil & Gas Operator | Apr 2019 |
| 586 | Weldon Corporation | Houston, TX 77056 | Oil Operator | Feb 2020 |
| 587 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 588 | Western Sky Oil & Gas | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 589 | Weststar Operating Company | Santa Anna, TX 76878 | Oil & Gas Operator | Mar 2015 |
| 590 | Westwood Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2013 |
| 591 | White, Oscar | Tuscola, TX 79562 | Oil & Gas Operator | May 2025 |
| 592 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 593 | Whitt Oil & Gas, Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 594 | Whitt, W. J. | Albany, TX 76430 | Oil & Gas Operator | Nov 1996 |
| 595 | Wilson, Dewey | Coleman, TX 76834 | Oil & Gas Operator | Nov 2007 |
| 596 | Winco Oil Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 597 | Windham Resources | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 598 | Windham Resources, Inc. | Tuscola, TX 79562 | Oil & Gas Operator | Feb 2004 |
| 599 | Window Operating Co., The | Coleman, TX 76834 | Oil & Gas Operator | May 2025 |
| 600 | WJH Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |