| 601 | Trey Services, Inc. | Midland, TX 79711 | Oil & Gas Operator | Dec 1996 |
| 602 | Triesco, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 1996 |
| 603 | Trigo Oil And Gas, LLC | Amarillo, TX 79101 | Oil & Gas Operator | Mar 2022 |
| 604 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 605 | Triple Crown Resources, LLC | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 606 | Tripledee Drilling Co Inc | Ardmore, OK 73402-1888 | Oil & Gas Operator | Dec 2015 |
| 607 | Tripp & Sons, LLC | Odessa, TX 79768 | Oil & Gas Operator | Feb 2026 |
| 608 | TRP Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 609 | True Oil Company LLC | Midland, TX 79701 | Oil & Gas Operator | Mar 2016 |
| 610 | TS Oil, LLC | Fort Worth, TX 76114 | Oil & Gas Operator | Feb 2026 |
| 611 | TSF Operating | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 612 | TX Heat Of The Permian Basin Inc | Odessa, TX 79768 | Oil & Gas Operator | Dec 2021 |
| 613 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2026 |
| 614 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | Feb 2026 |
| 615 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 616 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 617 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 618 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 619 | United Company | Lubbock, TX 79408 | Oil & Gas Operator | Jun 1995 |
| 620 | United Oil & Shale LLC | Woodward, OK 73801 | Oil & Gas Operator | Feb 2026 |
| 621 | Upland Production Company | Edmond, OK 73083 | Oil & Gas Operator | Feb 2026 |
| 622 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 623 | Valla Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Aug 2003 |
| 624 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 625 | Vanguard Permian, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 626 | Vencer Energy, LLC | Abilene, TX 79602 | Oil & Gas Operator | Dec 2023 |
| 627 | Venus Exploration, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 628 | Venus Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2002 |
| 629 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Feb 2026 |
| 630 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 631 | Vital Energy, Inc. | Tulsa, OK 74120 | Oil & Gas Operator | Feb 2026 |
| 632 | Walker, Kent | Midland, TX 79704 | Oil & Gas Operator | Jun 2004 |
| 633 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Feb 2026 |
| 634 | Walton Properties LTD. | Midland, TX 79702 | Oil & Gas Operator | Feb 2004 |
| 635 | Warren, Earl T. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2026 |
| 636 | WCWB Energy, LLC | Midland, TX 79701 | Oil Operator | Sep 2015 |
| 637 | Westar Energy, Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 638 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 639 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 640 | WG Oil, LLC | Wichita Falls, TX 76308 | Oil Operator | Feb 2026 |
| 641 | WGR, Inc. | Houston, TX 77046 | Gas Operator | Jul 2007 |
| 642 | White'S Industrial Engine'S | Houston, TX 77070 | Oil & Gas Operator | Feb 2026 |
| 643 | Whiteman Industries Inc | Oklahoma City, OK 73101 | Oil & Gas Operator | May 2025 |
| 644 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 645 | Wildhorse Oil & Gas Corporation | Ardmore, OK 73402 | Oil & Gas Operator | May 2019 |
| 646 | Wildhorse Operating Company | Ardmore, OK 73402 | Oil & Gas Operator | Feb 2026 |
| 647 | Williams, Clayton Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Feb 2026 |
| 648 | Wilshire Oil Co. Of Texas | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2004 |
| 649 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 650 | Windsor Permian LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2012 |
| 651 | Winn Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 652 | Wiseman, B. W., Jr. | Midland, TX 79702 | Oil & Gas Operator | Dec 2002 |
| 653 | WTG Exploration | Midland, TX 79705 | Oil & Gas Operator | Feb 2026 |
| 654 | Xeric Oil & Gas Company | Midland, TX 79702 | Oil & Gas Operator | Jul 1997 |
| 655 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 656 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 657 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 658 | Yates Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | Feb 2026 |
| 659 | Yegen E C | Casper, WY 82604 | Oil & Gas Operator | Mar 2015 |
| 660 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | Feb 2026 |
| 661 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |