| 501 | Sabre Oil And Gas Corp. | Houston, TX 77063 | Oil & Gas Operator | May 2025 |
| 502 | Salida Exploration, LLC | Abilene, TX 79603 | Oil & Gas Operator | May 2025 |
| 503 | Sanders Energy LLC | Aledo, TX 76008 | Oil & Gas Operator | May 2025 |
| 504 | Sandstone Services, LLC | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 505 | Schiff, H. G. & Co. | Dallas, TX 75206 | Oil & Gas Operator | Jul 1993 |
| 506 | Schkade Bros. Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Oct 2021 |
| 507 | Schkade, Carl E. | Albany, TX 76430 | Oil & Gas Operator | Sep 2009 |
| 508 | Scope Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2003 |
| 509 | Scott Operating, Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 510 | Scranton Exploration | Eastland, TX 76448 | Oil & Gas Operator | May 2025 |
| 511 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 512 | Seco Petroleum Corp | Houston, TX 77290 | Oil & Gas Operator | Jan 1997 |
| 513 | Sedona Oil & Gas Corporation | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 514 | Sequoia Energy Resources | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 515 | Sequoia Fossil Fuels, Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 516 | Sequoia Natural Gas, Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 517 | Seven Wells Oil & Gas Expl. | Abilene, TX 79601 | Oil & Gas Operator | Jun 2014 |
| 518 | Shack, Bill | Albany, TX 76430 | Oil & Gas Operator | Apr 2006 |
| 519 | Shadawn Corporation | Wichita Falls, TX 76310 | Oil & Gas Operator | Mar 2005 |
| 520 | Shahan, Donald Allan | Abilene, TX 79602 | Oil Operator | May 2025 |
| 521 | Sheets Exploration Co., Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2016 |
| 522 | Sheets, P. A. | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 1994 |
| 523 | Sherman, L. B. | Early, TX 76803 | Oil & Gas Operator | Jun 1998 |
| 524 | Shoshone Oil Company | Dallas, TX 75244 | Oil & Gas Operator | May 1994 |
| 525 | Simple Operating LLC | Cross Plains, TX 76443 | Oil Operator | May 2025 |
| 526 | Simpson Oil & Land Co. | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 527 | Sims, John S. | Lawn, TX 79530 | Oil & Gas Operator | Aug 2003 |
| 528 | Singleton Investments, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2012 |
| 529 | Smalley, Bill | Albany, TX 76430 | Oil & Gas Operator | Jul 2001 |
| 530 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 531 | Smith, Joe T., Inc. | Hawley, TX 79525 | Oil & Gas Operator | May 2025 |
| 532 | Snyder Drilling Corp. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 533 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 534 | Southlake Exploration, Inc. | Southlake, TX 76092 | Oil & Gas Operator | May 2025 |
| 535 | Southwest Gas Systems, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 536 | Spartan Oil Corporation | Abilene, TX 79601 | Oil & Gas Operator | Aug 2003 |
| 537 | Special Energy Corporation | Stillwater, OK 74076 | Oil & Gas Operator | May 2025 |
| 538 | Spence Energy Company | Dallas, TX 75360 | Oil & Gas Operator | May 2025 |
| 539 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 540 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 541 | St. Johns Operating #1 L.P. | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 542 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | May 2025 |
| 543 | Startex Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 544 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2025 |
| 545 | Stovall Operating Co. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 546 | Stovall, Howard | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 547 | Stryker Energy Corp. | Mesquite, TX 75180 | Oil & Gas Operator | May 2025 |
| 548 | Sun-Key Oil Co., Inc. | Dublin, TX 76446 | Oil & Gas Operator | May 2025 |
| 549 | Sunray Energy, Inc. | Round Rock, TX 78683 | Oil & Gas Operator | Nov 2018 |
| 550 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 551 | Susanna Corporation | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 552 | Sweet Texas T Energy LLC | Clyde, TX 79510 | Oil Operator | May 2025 |
| 553 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 554 | T & M Oil Company | Midlothian, TX 76065 | Oil & Gas Operator | May 2025 |
| 555 | T & T Oil Co. | San Antonio, TX 78205 | Oil & Gas Operator | Dec 2002 |
| 556 | Tam2 Squared Energy Services,LLC | Cisco, TX 76437 | Oil Operator | May 2025 |
| 557 | Targo Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 558 | TCS Petroleum Co., LLC | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 559 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 560 | Teaco | Snyder, TX 79550 | Oil & Gas Operator | Jan 1998 |
| 561 | Teal Exploration, LLC | Abilene, TX 79602 | Oil Operator | May 2025 |
| 562 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 563 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | May 2025 |
| 564 | Tema Oil And Gas, LLC | Houston, TX 77040 | Oil & Gas Operator | Apr 2000 |
| 565 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 566 | Texas Pharchem Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2019 |
| 567 | Texas Sands Resources, LLC | Abilene, TX 79603 | Oil Operator | May 2025 |
| 568 | Texas United Geoproduction, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 569 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 570 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 571 | Thomas, T. N. Oil Company | Aiken, SC 29801 | Oil & Gas Operator | May 2025 |
| 572 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | May 2025 |
| 573 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | May 2025 |
| 574 | Three Span Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 575 | THT Covenant Holdings, LLC | Wichita Falls, TX 76307 | Oil Operator | May 2025 |
| 576 | Thunderbolt Oil & Gas, Inc. | Abilene, TX 79605 | Oil & Gas Operator | Feb 2004 |
| 577 | Tiza Energy, Inc. | Austin, TX 78715 | Oil & Gas Operator | May 2025 |
| 578 | TK Operating | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 579 | Tollett Oil | Graham, TX 76450 | Oil Operator | May 2025 |
| 580 | Tom-Tom Operating, LLC | Dallas, TX 75209 | Oil Operator | May 2025 |
| 581 | Trace Energy Management Inc | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 582 | Tracker Mineral | Clyde, TX 79510 | Oil & Gas Operator | May 2025 |
| 583 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 584 | Tri-Tex Exploration LTD | Abilene, TX 79608 | Oil Operator | Apr 2019 |
| 585 | Trinity Minerals&Operating Corp. | Abilene, TX 79605 | Oil & Gas Operator | Dec 1995 |
| 586 | Triple "G" Oil Company | Clyde, TX 79510 | Oil & Gas Operator | Apr 1999 |
| 587 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | May 2025 |
| 588 | Tristar Oil & Gas | Freer, TX 78357 | Oil & Gas Operator | May 2025 |
| 589 | TSW Oil & Gas, LLC | Abilene, TX 79602 | Oil & Gas Operator | Jan 2016 |
| 590 | Tuckco Petroleum Corporation | Andrews, TX 79714 | Oil & Gas Operator | May 2025 |
| 591 | Turner, Greg | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 592 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 593 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 594 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 595 | Van Operating, LTD. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 596 | Vanco Oil & Gas Corp. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 597 | Vanguard Production Company | Lubbock, TX 79410 | Oil & Gas Operator | May 2025 |
| 598 | Vantage Fort Worth Energy LLC | Pittsburgh, PA 15222 | Oil & Gas Operator | Oct 2017 |
| 599 | Viathon Hydrocarbons, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2020 |
| 600 | Vin Fisher Operating, Inc. | Andrews, TX 79714 | Oil & Gas Operator | May 2025 |