| 501 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 502 | Texsun Operating Company Limited | Abilene, TX 79601 | Oil & Gas Operator | Mar 1996 |
| 503 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 504 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | Sep 2026 |
| 505 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 506 | Titan Energy, Inc. | Austin, TX 78703 | Oil & Gas Operator | Sep 2026 |
| 507 | TKP Petroleum, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Sep 2026 |
| 508 | Tonk Creek Oil Company | Aspermont, TX 79502 | Oil & Gas Operator | Sep 2026 |
| 509 | Tri-Tex Exploration LTD | Abilene, TX 79608 | Oil Operator | Apr 2019 |
| 510 | Triangle Three Resources L.L.C. | Dallas, TX 75248 | Oil & Gas Operator | Sep 2026 |
| 511 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | Sep 2026 |
| 512 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Sep 2026 |
| 513 | Tritex Production Co. | Iowa Park, TX 76367 | Oil & Gas Operator | Jan 2013 |
| 514 | TS & T Drilling, Inc. | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2016 |
| 515 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 516 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 517 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 518 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | Sep 2026 |
| 519 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Sep 2026 |
| 520 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 521 | Van Operating, LTD. | Albany, TX 76430 | Oil & Gas Operator | Sep 2026 |
| 522 | Vanguard Production Company | Lubbock, TX 79410 | Oil & Gas Operator | Sep 2026 |
| 523 | Vertox LLC | Southlake, TX 76092 | Oil Operator | May 2025 |
| 524 | VX Operating, LLC | Abilene, TX 79605 | Oil & Gas Operator | Sep 2026 |
| 525 | W.H.D., Inc. | Euless, TX 76039 | Oil & Gas Operator | Aug 1998 |
| 526 | Waco Petro, LP | Sulphur SPGS, TX 75483 | Oil Operator | Sep 2015 |
| 527 | Waggoner, W. T., Estate | Vernon, TX 76385 | Oil & Gas Operator | Feb 2018 |
| 528 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Sep 2026 |
| 529 | Walter Exploration Company | Dallas, TX 75206 | Oil & Gas Operator | Sep 2026 |
| 530 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 531 | Walton Producing Company | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2005 |
| 532 | Walton Producing Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 2026 |
| 533 | Walton, W. W. | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 1994 |
| 534 | Wells Oilfield Services, Inc. | Graham, TX 76450 | Oil & Gas Operator | Sep 2026 |
| 535 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 536 | West Inland Energy, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Jan 2026 |
| 537 | Western Reserves Oil Co Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2020 |
| 538 | Westico Energy Co. | Abilene, TX 79605 | Oil & Gas Operator | Nov 2004 |
| 539 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 540 | Westwood Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2013 |
| 541 | Wheat, Buck Resources, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Dec 2009 |
| 542 | Whitemound Oil Company | FT Stockton, TX 79735 | Oil & Gas Operator | Jan 2017 |
| 543 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 544 | Wilco Properties, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Jan 2004 |
| 545 | Wilcox Oil Company | Rule, TX 79547 | Oil & Gas Operator | Aug 2008 |
| 546 | Wilcox Petroleum Operating LLC. | Rule, TX 79547 | Oil & Gas Operator | Sep 2026 |
| 547 | Williams Oil Company | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 548 | Williams, A. Oil | Wichita Falls, TX 76308 | Oil Operator | Sep 2026 |
| 549 | Willow Creek Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2009 |
| 550 | Wingrove Well Service, Inc. | Lueders, TX 79533 | Oil & Gas Operator | Nov 2023 |
| 551 | Winn Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 552 | WJH Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 553 | Wolfson, I. J. | Wichita Falls, TX 76301 | Oil & Gas Operator | Apr 2002 |
| 554 | Woodbine Petroleum, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Aug 2003 |
| 555 | WTG Exploration | Midland, TX 79705 | Oil & Gas Operator | Sep 2026 |
| 556 | WTG Exploration Inc | Midland, TX 79705 | Oil & Gas Operator | Dec 2023 |
| 557 | X-L Energy Company | El Paso, TX 79902 | Oil & Gas Operator | Sep 2026 |
| 558 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 559 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 560 | Yates, Harvey E. Company | Roswell, NM 88201 | Oil & Gas Operator | Dec 2002 |
| 561 | Young, Marshall R., Oil Co. | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2011 |
| 562 | Yucca Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 563 | Zenergy, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2026 |