| 501 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 502 | Spartan Oil Corporation | Abilene, TX 79601 | Oil & Gas Operator | Aug 2003 |
| 503 | Spence Energy Company | Dallas, TX 75360 | Oil & Gas Operator | Apr 2025 |
| 504 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Apr 2025 |
| 505 | Sportsman Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Nov 1998 |
| 506 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 507 | Stagg Investment Group, Inc. | Midland, TX 79701 | Oil Operator | May 2013 |
| 508 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Apr 2025 |
| 509 | Startex Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 510 | Stearns Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Oct 1993 |
| 511 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2025 |
| 512 | Stephens, Hayseed Oil Inc. | Weatherford, TX 76087 | Oil & Gas Operator | Mar 2008 |
| 513 | Stetson Petroleum Corp. | Rollins, MT 59931 | Oil & Gas Operator | Apr 2025 |
| 514 | Stober Oil And Gas Services, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2025 |
| 515 | Stoneburner Exploration, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Oct 1997 |
| 516 | Strawn Operating Co., L.L.C. | El Paso, TX 79912 | Oil Operator | Apr 2025 |
| 517 | Stryker Energy Corp. | Mesquite, TX 75180 | Oil & Gas Operator | Apr 2025 |
| 518 | Stubblefield Energy Company | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 519 | Subsurface Production, Inc. | Coleman, TX 76834 | Oil & Gas Operator | Apr 2025 |
| 520 | Sunbelt Salvage | Eastland, TX 76448 | Oil & Gas Operator | Sep 1998 |
| 521 | Sundance Consulting Corp. | Abilene, TX 79605 | Oil & Gas Operator | Apr 2025 |
| 522 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 523 | Sunwest Oklahoma, Inc | Dallas, TX 75231 | Oil & Gas Operator | May 2023 |
| 524 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2025 |
| 525 | Susanna Corporation | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2025 |
| 526 | Sweet Texas T Energy LLC | Clyde, TX 79510 | Oil Operator | Apr 2025 |
| 527 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Apr 2025 |
| 528 | T & C Oil, Inc. | Lubbock, TX 79424 | Oil & Gas Operator | Apr 2024 |
| 529 | Tabco Exploration Inc. | New Orleans, LA 70131 | Oil & Gas Operator | Dec 1998 |
| 530 | Tahoe Exploration Inc. | Abilene, TX 79608 | Oil & Gas Operator | Mar 2016 |
| 531 | Talisman Resources, Inc. | Argyle, TX 76226 | Oil & Gas Operator | Mar 1995 |
| 532 | Talus Inc | Graham, TX 76450-1210 | Oil & Gas Operator | Feb 2017 |
| 533 | Targo Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 534 | Taylor, Ben J. Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2022 |
| 535 | TCS Petroleum Co., LLC | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 536 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 537 | Teal Exploration, LLC | Abilene, TX 79602 | Oil Operator | Apr 2025 |
| 538 | Tejas Petroleum Resources, LLC | Aubrey, TX 76227 | Oil & Gas Operator | Apr 2025 |
| 539 | Tetragon Investments, LLC | Abilene, TX 79604 | Oil Operator | Jul 2014 |
| 540 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 541 | Texas Operating & Consult., LLC | Abilene, TX 79608 | Oil & Gas Operator | Feb 2018 |
| 542 | Texas Pharchem Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2019 |
| 543 | Texas Sands Resources, LLC | Abilene, TX 79603 | Oil Operator | Apr 2025 |
| 544 | Texas United Geoproduction, Inc. | Abilene, TX 79606 | Oil & Gas Operator | Apr 2025 |
| 545 | Texland Petroleum Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2003 |
| 546 | Texland Petroleum, L.P. | Fort Worth, TX 76107 | Oil & Gas Operator | Apr 2025 |
| 547 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 548 | Texoma Oil Tools, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Apr 2025 |
| 549 | Texxon Resources, Inc. | Winter Park, FL 32792 | Oil & Gas Operator | Apr 2025 |
| 550 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 551 | Thornton Oil Co. | Abilene, TX 79603 | Oil & Gas Operator | Aug 2003 |
| 552 | Thornton, Michael D. | Breckenridge, TX 76424 | Oil & Gas Operator | Nov 1995 |
| 553 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 554 | Threshold Exploration, Inc. | College Sta, TX 77842 | Oil & Gas Operator | Oct 2015 |
| 555 | THT Covenant Holdings, LLC | Wichita Falls, TX 76307 | Oil Operator | Apr 2025 |
| 556 | Thunderbolt Oil & Gas, Inc. | Abilene, TX 79605 | Oil & Gas Operator | Feb 2004 |
| 557 | Tidwell Production Company | Sonora, TX 76950 | Oil & Gas Operator | Apr 2025 |
| 558 | TKP Petroleum, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Apr 2025 |
| 559 | TNC Energy, LLC | Lubbock, TX 79401 | Oil & Gas Operator | Nov 2016 |
| 560 | Tollett Oil | Graham, TX 76450 | Oil Operator | Apr 2025 |
| 561 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 562 | Tracker Mineral | Clyde, TX 79510 | Oil & Gas Operator | Apr 2025 |
| 563 | Trans Oil Marketing LLC | Abilene, TX 79608 | Oil Operator | Aug 2023 |
| 564 | Tri-Tex Exploration LTD | Abilene, TX 79608 | Oil Operator | Apr 2019 |
| 565 | Triple "G" Oil Company | Clyde, TX 79510 | Oil & Gas Operator | Apr 1999 |
| 566 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Apr 2025 |
| 567 | Trust Oil Co. | Pine, CO 80470 | Oil & Gas Operator | Apr 2025 |
| 568 | TSW Oil & Gas, LLC | Abilene, TX 79602 | Oil & Gas Operator | Jan 2016 |
| 569 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 570 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 571 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2025 |
| 572 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 573 | Valley Petroleum Company | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 574 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 575 | Ventex Operating Corp. | Addison, TX 75001 | Oil & Gas Operator | Apr 2025 |
| 576 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Apr 2025 |
| 577 | Viathon Hydrocarbons, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2020 |
| 578 | Victory Oil & Gas Inc | Gun Barrel Cy, TX 75156 | Oil & Gas Operator | Apr 2025 |
| 579 | Viejo Services, LLC | Boyd, TX 76023 | Oil & Gas Operator | Apr 2025 |
| 580 | Viking Ventures, LLC | Garland, TX 75044 | Oil & Gas Operator | Mar 2009 |
| 581 | Vista Exploration, LLC | Abilene, TX 79601 | Oil & Gas Operator | May 2017 |
| 582 | VX Operating, LLC | Abilene, TX 79605 | Oil & Gas Operator | Apr 2025 |
| 583 | W&S Energy LLC | Woodward, OK 73801 | Oil & Gas Operator | Sep 2022 |
| 584 | W.R. Guffey LLC | Dallas, TX 75206 | Oil & Gas Operator | Jul 2020 |
| 585 | W.W.R. Holding, LLC | Coleman, TX 76834 | Oil & Gas Operator | Mar 2008 |
| 586 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Apr 2025 |
| 587 | Walsh Resources, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Apr 2025 |
| 588 | Warren Producers, Inc. | Bowling Green, KY 42102 | Oil & Gas Operator | Dec 2017 |
| 589 | Watco Energy, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Apr 1996 |
| 590 | Waters Petroleum | Albany, TX 76430 | Oil & Gas Operator | Aug 2016 |
| 591 | Wayland Drilling & Explr., Inc. | Grapevine, TX 76099 | Oil & Gas Operator | Apr 2006 |
| 592 | Weaver Global Operating, LLC | Colleyville, TX 76034 | Oil Operator | Apr 2025 |
| 593 | Wellington Securities, Inc. | Plano, TX 75093 | Gas Operator | Jul 2014 |
| 594 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 595 | West Inland Energy, Inc. | N Richlnd HLS, TX 76182 | Oil & Gas Operator | Apr 2025 |
| 596 | West,Gordon T.Jr. & Rugeley,Stan | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2019 |
| 597 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 598 | Western Sky Oil & Gas | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 599 | Westico Energy Co. | Abilene, TX 79605 | Oil & Gas Operator | Nov 2004 |
| 600 | Westlake Energy Consultants Corp | Thousand Oaks, CA 91362 | Oil & Gas Operator | Aug 2003 |