| 401 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 402 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 403 | Tiburon Oil & Gas, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2000 |
| 404 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 405 | Toc Energy Resources, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | May 2024 |
| 406 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 407 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 408 | Tpet, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Mar 2008 |
| 409 | Tracker Resource Dev III, LLC | Englewood, CO 80112 | Oil & Gas Operator | Jul 2021 |
| 410 | Trans Oil Marketing LLC | Abilene, TX 79602 | Oil Operator | Aug 2023 |
| 411 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2024 |
| 412 | Trend Exploration I LLC | Midland, TX 79701 | Oil & Gas Operator | May 2011 |
| 413 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 414 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | May 2024 |
| 415 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2024 |
| 416 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2024 |
| 417 | Triple Crown Resources, LLC | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 418 | Truth Resources LP | Conroe, TX 77304 | Oil Operator | Sep 2021 |
| 419 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 420 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 421 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | May 2024 |
| 422 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 423 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 424 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2024 |
| 425 | United Energy Trading LLC | Tulsa, OK 74133 | Gas Operator | Feb 2015 |
| 426 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 427 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2024 |
| 428 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2024 |
| 429 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 430 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | May 2024 |
| 431 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | May 2024 |
| 432 | Viola Prod., Inc. | Dallas, TX 75251 | Oil & Gas Operator | May 2024 |
| 433 | Vital Energy, Inc. | Tulsa, OK 74120 | Oil & Gas Operator | May 2024 |
| 434 | West Inland Energy, Inc. | Aledo, TX 76008 | Oil & Gas Operator | May 2024 |
| 435 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | May 2024 |
| 436 | Western Energy Management, Inc. | Austin, TX 78716 | Oil & Gas Operator | Aug 1997 |
| 437 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2024 |
| 438 | Wild Cat Operating Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 439 | Winchester Energy Operating Co. | Austin, TX 78746 | Oil & Gas Operator | May 2024 |
| 440 | Woodbine Production Corporation | Kilgore, TX 75663 | Oil & Gas Operator | May 2024 |
| 441 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | May 2024 |