| 501 | Snyder Drilling Corp. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 502 | So Operating Company | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 503 | Southeastern Resources Corp. | Mansfield, TX 76063 | Oil & Gas Operator | Feb 2004 |
| 504 | Southwest Gas Systems, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 505 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 506 | Square One Energy, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Oct 2015 |
| 507 | Squyres Oil Co., Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Nov 2024 |
| 508 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 509 | SSC, Inc. | Lubbock, TX 79408 | Oil & Gas Operator | May 2025 |
| 510 | St. Johns Operating #1 L.P. | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 511 | Stacha, Eddy A. | Rice, TX 75155 | Oil & Gas Operator | May 2025 |
| 512 | Star One Energy, Inc. | Fort Worth, TX 76163 | Oil & Gas Operator | May 2012 |
| 513 | Stasney, H. R. & Sons, LTD. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 514 | STB Energy Inc. | Tulsa, OK 74105 | Oil & Gas Operator | Jul 2008 |
| 515 | Stellex | De Leon, TX 76444 | Oil & Gas Operator | May 2025 |
| 516 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2025 |
| 517 | Stephenson Oil & Gas, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Sep 1999 |
| 518 | Sterling Oil And Gas | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 519 | Stewart Family Holdings LLC | Weatherford, TX 76087 | Oil & Gas Operator | May 2025 |
| 520 | Stewart, James G. | Graham, TX 76450 | Oil & Gas Operator | Sep 2019 |
| 521 | Stober Oil And Gas Services, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 522 | Stovall, Howard | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 523 | Stowe Energy, Inc. | Vernon, TX 76384 | Oil & Gas Operator | Mar 2003 |
| 524 | Stream Energy, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2025 |
| 525 | Subsurface Energy Corp. | Coleman, TX 76834 | Oil & Gas Operator | May 2025 |
| 526 | Sun-Key Oil Co., Inc. | Dublin, TX 76446 | Oil & Gas Operator | May 2025 |
| 527 | Sunbelt Salvage | Eastland, TX 76448 | Oil & Gas Operator | Sep 1998 |
| 528 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 529 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 530 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 531 | T-Square Petroleum Co. | Rising Star, TX 76471 | Oil & Gas Operator | May 2025 |
| 532 | T. L. J. Incorporated | Big Lake, TX 76932 | Oil & Gas Operator | Dec 1998 |
| 533 | T.L.S. Oil Co. | Hawley, TX 79525 | Oil & Gas Operator | May 2025 |
| 534 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 535 | Tandem Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 536 | Targo Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 537 | Taylor Oil & Gas Serv | Snyder, TX 79549 | Oil Operator | May 2025 |
| 538 | TCF Energy, Inc. | Midland, TX 79704 | Oil & Gas Operator | Dec 2004 |
| 539 | Teaco | Snyder, TX 79550 | Oil & Gas Operator | Jan 1998 |
| 540 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 541 | Terrick Resources | Midland, TX 79708 | Oil & Gas Operator | Jul 2005 |
| 542 | Tex-Am Petroleum Corp. | Eastland, TX 76448 | Oil & Gas Operator | May 2025 |
| 543 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 544 | Texas State Oil Co. | Irving, TX 75062 | Oil & Gas Operator | Mar 2017 |
| 545 | Texas United Geoproduction, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 546 | Texdon Operating | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2005 |
| 547 | Texokan Operating, Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |
| 548 | Texxol Operating Company, Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | May 2025 |
| 549 | Thrifty Well Service | Rice, TX 75155 | Oil & Gas Operator | Jun 2009 |
| 550 | THT Covenant Holdings, LLC | Wichita Falls, TX 76307 | Oil Operator | May 2025 |
| 551 | Tidwell Production Company | Sonora, TX 76950 | Oil & Gas Operator | May 2025 |
| 552 | TK Drilling Corp. | Tulsa, OK 74133 | Oil & Gas Operator | Feb 2025 |
| 553 | TK Operating | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 554 | Todd, J R Oil & Investments, Inc | Dallas, TX 75206 | Oil & Gas Operator | Jun 2002 |
| 555 | Toklan Oil And Gas Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2025 |
| 556 | Torch Operating LLC | Fort Worth, TX 76135 | Oil & Gas Operator | Oct 2020 |
| 557 | Trace Energy Management Inc | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 558 | Tracer Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 559 | Transcontinental Shale L.L.C. | Austin, TX 78717 | Oil & Gas Operator | Feb 2016 |
| 560 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 561 | Tri Sportsmen Energy, Inc. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 562 | Triple Singleton, Inc. | Santa Fe, TX 77510 | Oil & Gas Operator | Dec 2020 |
| 563 | Trumter Petroleum Corporation | Fort Worth, TX 76185 | Oil & Gas Operator | Aug 1998 |
| 564 | Tuckco Petroleum Corporation | Andrews, TX 79714 | Oil & Gas Operator | May 2025 |
| 565 | Turning Point Oil, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Jan 2021 |
| 566 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 567 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 568 | United Operating, LLC *** | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 569 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 570 | Valley Petroleum Company | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 571 | Van Operating, LTD. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 572 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2021 |
| 573 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 574 | Verado Energy, Inc. | Allen, TX 75013 | Oil & Gas Operator | May 2025 |
| 575 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 576 | Vortt Exploration Company, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2019 |
| 577 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 578 | Watson Oil & Gas Co. | Gorman, TX 76454 | Oil & Gas Operator | Jan 2002 |
| 579 | Watson Oil & Gas, Inc. | Spicewood, TX 78669 | Oil & Gas Operator | May 2025 |
| 580 | Weakland Investments, Inc. | Denver, CO 80215 | Oil & Gas Operator | May 2025 |
| 581 | Wehunt Oil Company, Inc. | Dallas, TX 75376 | Oil & Gas Operator | Nov 2002 |
| 582 | Wejco, Inc. | Rising Star, TX 76471 | Oil & Gas Operator | May 2025 |
| 583 | Welcome Well Serv. & Boykin Bros | Abilene, TX 79604 | Oil & Gas Operator | Apr 1995 |
| 584 | Wells Oilfield Services, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 585 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 586 | West Texas Royalties, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 587 | Western Chief Oil & Gas Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2009 |
| 588 | Western Gulf Oil & Gas Inc. | Dallas, TX 75360 | Oil & Gas Operator | Jul 2000 |
| 589 | Western Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 590 | Wheat, Buck Resources, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Dec 2009 |
| 591 | Whiteside, Robert | Comanche, TX 76442 | Oil & Gas Operator | May 1998 |
| 592 | Whitt, W. J. | Albany, TX 76430 | Oil & Gas Operator | Nov 1996 |
| 593 | Whittington, James C., Inc. | Dallas, TX 75214 | Oil & Gas Operator | Jan 2017 |
| 594 | Wilbanks, Bruce A. | Midland, TX 79701 | Oil & Gas Operator | Aug 1996 |
| 595 | Wilbrook Exploration, Inc. | Lingleville, TX 76461 | Oil & Gas Operator | Aug 2003 |
| 596 | Wilchar, DR. R. B. | Fort Worth, TX 76185 | Oil & Gas Operator | Jan 2007 |
| 597 | Wilson Well Service Inc. | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 598 | Wilson, Jerry L. | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 599 | Wilson, Olan Max | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 600 | Wilson, WM. B. Exploration Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 1996 |