| 401 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 402 | Tall City Operations LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2016 |
| 403 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 404 | Tawa Operating Co., Inc. | Mertzon, TX 76941 | Oil & Gas Operator | May 2019 |
| 405 | Tejas Jack Sales, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Jul 2025 |
| 406 | Tejas Permian Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 407 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jul 2025 |
| 408 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Jul 2025 |
| 409 | Thomas Oil And Gas Inc. | San Angelo, TX 76906 | Oil & Gas Operator | May 2019 |
| 410 | THP Operating LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Jul 2025 |
| 411 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 412 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 413 | Tiburon Oil & Gas, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2000 |
| 414 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 415 | Toc Energy Resources, LLC | Fort Worth, TX 76101 | Oil & Gas Operator | Jul 2025 |
| 416 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 417 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 418 | Tpet, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Mar 2008 |
| 419 | Tracker Resource Dev III, LLC | Englewood, CO 80112 | Oil & Gas Operator | Jul 2021 |
| 420 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Jul 2025 |
| 421 | Trend Exploration I LLC | Midland, TX 79701 | Oil & Gas Operator | May 2011 |
| 422 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 423 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | Jul 2025 |
| 424 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Jul 2025 |
| 425 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 426 | Triple Crown Resources, LLC | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 427 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 428 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 429 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2025 |
| 430 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 431 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 432 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2025 |
| 433 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 434 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 435 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 436 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 437 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Jul 2025 |
| 438 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Jul 2025 |
| 439 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |
| 440 | Vision Energy LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 441 | Vital Energy, Inc. | Tulsa, OK 74120 | Oil & Gas Operator | Jul 2025 |
| 442 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 443 | West Inland Energy, Inc. | N Richlnd HLS, TX 76182 | Oil & Gas Operator | May 2025 |
| 444 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Jul 2025 |
| 445 | Western Energy Management, Inc. | Austin, TX 78716 | Oil & Gas Operator | Aug 1997 |
| 446 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | May 2025 |
| 447 | Wild Cat Operating Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 448 | Winchester Energy Operating Co. | Austin, TX 78746 | Oil & Gas Operator | Jul 2025 |
| 449 | Woodbine Production Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |
| 450 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | Jul 2025 |