| 501 | Texu Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Jan 2007 |
| 502 | Thomas, M.A. Oil Associates | Nocona, TX 76255 | Oil & Gas Operator | Oct 2025 |
| 503 | Three P Operating Company | Newcastle, TX 76372 | Oil & Gas Operator | Nov 2007 |
| 504 | Tomar Petroleum Inc | Dallas, TX 75225 | Oil & Gas Operator | Mar 2001 |
| 505 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Oct 2025 |
| 506 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 507 | Triangle Three Resources L.L.C. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2024 |
| 508 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 509 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 510 | Trio Production Company, LLC | Stephens, AR 71764 | Oil Operator | Jan 2025 |
| 511 | Triple G Well Service, Inc. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2025 |
| 512 | TS Oil, LLC | Fort Worth, TX 76114 | Oil & Gas Operator | Oct 2025 |
| 513 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 514 | Txon Partners, LLC | Houston, TX 77057 | Oil & Gas Operator | Jun 2017 |
| 515 | U. S. Energy Development Corporation | Fort Worth, TX 76164 | Oil & Gas Operator | Oct 2025 |
| 516 | Ulatex Oil & Gas Inc. | Nocona, TX 76255 | Oil & Gas Operator | Dec 1998 |
| 517 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | Oct 2025 |
| 518 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 519 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2025 |
| 520 | United Energy Partners, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 521 | United Texas Petroleum Inc. | McKinney, TX 75070 | Oil & Gas Operator | Oct 2025 |
| 522 | Us Energy Holdings, LLC | Richardson, TX 75080 | Oil & Gas Operator | Oct 2025 |
| 523 | V & H Oil, L.P. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2025 |
| 524 | Valley Petroleum Company | Abilene, TX 79608 | Oil & Gas Operator | Oct 2025 |
| 525 | Van Oil Co Inc | Fort Worth, TX 76116 | Oil Operator | Dec 1997 |
| 526 | Vantage Fort Worth Energy LLC | Pittsburgh, PA 15222 | Oil & Gas Operator | Oct 2017 |
| 527 | Ventex Operating Corp. | Addison, TX 75001 | Oil & Gas Operator | Oct 2025 |
| 528 | Veteran Exploration & Prod, LLC | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 529 | Viejo Services, LLC | Boyd, TX 76023 | Oil & Gas Operator | Oct 2025 |
| 530 | Vincus Investment Company | Dallas, TX 75225 | Oil & Gas Operator | Apr 2004 |
| 531 | Vortt Exploration Company, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2019 |
| 532 | Voth Operating, Inc. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2005 |
| 533 | W&W Oil And Gas, Inc. | Muenster, TX 76252 | Oil Operator | Oct 2025 |
| 534 | W.E.S. Operating Company, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Nov 2011 |
| 535 | Waggoner-Baldridge Oper. Co, Inc | Dallas, TX 75206 | Oil & Gas Operator | Jan 1998 |
| 536 | Wako Oil Co. LLC | Graham, TX 76450 | Oil Operator | Oct 2025 |
| 537 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Oct 2025 |
| 538 | Walter Exploration Company | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 539 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 540 | Walter H. Husfeld Oil Co LLC | Bowie, TX 76230 | Oil & Gas Operator | Oct 2025 |
| 541 | Warnock Operating Company, LLC | Graham, TX 76450 | Oil & Gas Operator | Jul 2013 |
| 542 | Watkins Production Company | Dallas, TX 75229 | Oil & Gas Operator | Feb 2008 |
| 543 | Watson Energy Investments, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 544 | WBH Energy Partners LLC | Austin, TX 78703 | Oil & Gas Operator | Oct 2025 |
| 545 | West Bay Exploration Company | Muenster, TX 76252 | Oil & Gas Operator | Jul 2025 |
| 546 | Westbrook Oil & Gas Co. Inc. | Gainesville, TX 76240 | Oil & Gas Operator | Oct 2025 |
| 547 | Western Chief Oil & Gas Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2009 |
| 548 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 549 | Westside Energy Op. Co., LP | Oklahoma City, OK 73142 | Oil & Gas Operator | Jun 2008 |
| 550 | WFW Production Company, Inc. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2025 |
| 551 | White Knight Production LLC | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2024 |
| 552 | Whitehead Prod. Co., Inc. | Humble, TX 77338 | Oil & Gas Operator | Jun 2025 |
| 553 | Wichita Operating Company, Inc. | Spring, TX 77393 | Oil & Gas Operator | May 2009 |
| 554 | Willowbend Investments, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 555 | Wills Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Jun 1995 |
| 556 | Winchester Exploration, Inc. | Arlington, TX 76013 | Oil & Gas Operator | Aug 2003 |
| 557 | Window Operating Co., The | Coleman, TX 76834 | Oil & Gas Operator | Oct 2025 |
| 558 | Wineland Oil - LLC | Hays, KS 67601 | Oil Operator | May 2025 |
| 559 | Winfield Operating Company | Dallas, TX 75214 | Oil & Gas Operator | Oct 2025 |
| 560 | Wise Exploration | Perrin, TX 76486 | Oil & Gas Operator | Oct 2025 |
| 561 | Wise Production Company | Bowie, TX 76230 | Oil & Gas Operator | Oct 2025 |
| 562 | Wise Supply Company | Bowie, TX 76230 | Oil & Gas Operator | Oct 2025 |
| 563 | Wise Well Service | Bowie, TX 76230 | Oil & Gas Operator | Jul 2017 |
| 564 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 565 | WJR Production LLC | Fort Worth, TX 76177 | Oil Operator | Oct 2025 |
| 566 | Wolsey Oil Inc. | Bowie, TX 76230 | Oil & Gas Operator | Oct 2013 |
| 567 | Wolsey Well Service, Inc. | Windthorst, TX 76389 | Oil & Gas Operator | Jul 2006 |
| 568 | Wolsey Well Service, L.P. | Bowie, TX 76230 | Oil & Gas Operator | Jun 2014 |
| 569 | Woodbine Petroleum, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Aug 2003 |
| 570 | Wooley Petroleum | Alvord, TX 76225 | Oil & Gas Operator | Oct 1994 |
| 571 | Wortham Operating, LLC | Holliday, TX 76366 | Oil & Gas Operator | Apr 2023 |
| 572 | WT Fitts Operating | Bowie, TX 76230 | Oil & Gas Operator | Oct 2025 |
| 573 | WTG Exploration | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 574 | Wynn-Crosby Operating, LTD. | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 575 | Wynne Petroleum Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Nov 1997 |
| 576 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 577 | Xyz Oil, Inc. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2025 |