| 601 | Threshold Exploration, Inc. | College Sta, TX 77842 | Oil & Gas Operator | Oct 2015 |
| 602 | Tipperary Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 603 | Torch Operating LLC | Fort Worth, TX 76135 | Oil & Gas Operator | Oct 2020 |
| 604 | Tower Resources Inc | Conroe, TX 77304 | Oil & Gas Operator | Feb 2026 |
| 605 | Trace Energy Management Inc | Weatherford, TX 76086 | Oil & Gas Operator | Feb 2026 |
| 606 | Tracer Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Nov 1998 |
| 607 | Tracer Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 608 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 609 | Transcontinental Shale L.L.C. | Austin, TX 78717 | Oil & Gas Operator | Feb 2016 |
| 610 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Feb 2026 |
| 611 | Tres Azores Oil & Gas, Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Aug 2003 |
| 612 | Tresami, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 613 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 614 | Trey Resources Inc. | Midland, TX 79710 | Oil & Gas Operator | Nov 2025 |
| 615 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 616 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 617 | Tripower Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2020 |
| 618 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Feb 2026 |
| 619 | Trumter Petroleum Corporation | Fort Worth, TX 76185 | Oil & Gas Operator | Aug 1998 |
| 620 | Trust Oil Co. | Pine, CO 80470 | Oil & Gas Operator | Feb 2026 |
| 621 | United Energy Partners, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 622 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 623 | Upco | Mineral Wells, TX 76068 | Gas Operator | Sep 2001 |
| 624 | Upda Operators, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Dec 2009 |
| 625 | Upham Oil & Gas Company | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 626 | Upham, Chester R., Jr. | Mineral Wells, TX 76067 | Oil & Gas Operator | Aug 2001 |
| 627 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2026 |
| 628 | Vantage Fort Worth Energy LLC | Pittsburgh, PA 15222 | Oil & Gas Operator | Feb 2026 |
| 629 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Feb 2026 |
| 630 | Viejo Services, LLC | Boyd, TX 76023 | Oil & Gas Operator | Feb 2026 |
| 631 | Vortt Exploration Company, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2019 |
| 632 | Voth Operating, Inc. | Muenster, TX 76252 | Oil & Gas Operator | Oct 2005 |
| 633 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 634 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 635 | Waskom, Reagan Operating Company | Boerne, TX 78006 | Gas Operator | Mar 2005 |
| 636 | Watusi Energy LLC | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 637 | WB Mullin Operating LLC | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 638 | WBR, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 1995 |
| 639 | Wehunt Oil Company, Inc. | Dallas, TX 75376 | Oil & Gas Operator | Nov 2002 |
| 640 | Wells Oilfield Services, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 641 | Wes-Mor Drilling, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 642 | West Inland Energy, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Feb 2026 |
| 643 | Western Chief Oil & Gas Company | Graham, TX 76450 | Oil & Gas Operator | Jul 2009 |
| 644 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 645 | Western Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 646 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 647 | Westico Energy Co. | Abilene, TX 79605 | Oil & Gas Operator | Nov 2004 |
| 648 | Westridge Oil & Gas Properties | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 649 | Wharton Oil Co. | Vernon, TX 76384 | Oil & Gas Operator | Dec 2000 |
| 650 | Wheat, Buck Resources, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Dec 2009 |
| 651 | White Knight Production LLC | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2024 |
| 652 | Whitehead Prod. Co., Inc. | Humble, TX 77338 | Oil & Gas Operator | Dec 2025 |
| 653 | Wichita Falls Oil Expl. Co. | Holliday, TX 76366 | Oil & Gas Operator | Feb 2026 |
| 654 | Williams Petroleum Company, Inc. | Burkburnett, TX 76354 | Oil & Gas Operator | Feb 2026 |
| 655 | Willis Operating Co. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 656 | Willowbend Investments, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 657 | Wilson, Olan Max | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 658 | Wilson, W.W. Jr. Properties | Abilene, TX 79605 | Oil & Gas Operator | Jul 1995 |
| 659 | Wise Exploration | Perrin, TX 76486 | Oil & Gas Operator | Feb 2026 |
| 660 | Wise Production Company | Bowie, TX 76230 | Oil & Gas Operator | Feb 2026 |
| 661 | Wise Well Service | Bowie, TX 76230 | Oil & Gas Operator | Jul 2017 |
| 662 | World Producers, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1994 |
| 663 | WX Company LLC | Graham, TX 76450 | Oil & Gas Operator | Apr 2017 |
| 664 | Xplore Operating, LLC | Arlington, TX 76001 | Oil & Gas Operator | Feb 2026 |
| 665 | Xstar Resources LLC | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 666 | Yellow Rose Oil & Gas Oper. Inc. | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 667 | Young, Clint Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |