| 401 | Taylor Energy Corporation | Amarillo, TX 79114 | Oil & Gas Operator | Feb 1999 |
| 402 | Taylor, Gordon Oil Company | Sunray, TX 79086 | Oil & Gas Operator | Apr 1996 |
| 403 | TB Petroleum, LLC | Petrolia, TX 76377 | Oil & Gas Operator | Apr 2026 |
| 404 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Apr 2026 |
| 405 | Tecolote Energy Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jan 2024 |
| 406 | Templar Operating LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2026 |
| 407 | Tenison Oil Company | Abilene, TX 79605 | Oil & Gas Operator | Jan 2026 |
| 408 | Tess Oil Company | Borger, TX 79008 | Oil & Gas Operator | Mar 2008 |
| 409 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Apr 2026 |
| 410 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Apr 2026 |
| 411 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Apr 2026 |
| 412 | Texas Crude Operator, Inc. | Houston, TX 77098 | Oil & Gas Operator | Aug 2017 |
| 413 | Thompson, Joe L., Inc. | Oklahoma City, OK 73132 | Oil & Gas Operator | Oct 2005 |
| 414 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 415 | Tilley Oil & Gas, Inc. | Oklahoma City, OK 73172 | Oil & Gas Operator | Apr 2026 |
| 416 | Trail Ridge Energy Partners, LLC | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2026 |
| 417 | Transpetco I | Shreveport, LA 71101 | Oil & Gas Operator | May 2009 |
| 418 | Travelers Oil Company | Amarillo, TX 79102 | Oil & Gas Operator | Apr 2026 |
| 419 | Trek Exploration, Inc. | Pampa, TX 79065 | Oil & Gas Operator | Apr 2026 |
| 420 | Tri-Ex Petroleum, L.P. | Amarillo, TX 79101 | Oil & Gas Operator | Jan 2013 |
| 421 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 422 | Unbridled Resources, LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 423 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 424 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 425 | United Oil & Shale LLC | Woodward, OK 73801 | Oil & Gas Operator | Apr 2026 |
| 426 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 427 | Untamed Resources, LLC | Spearman, TX 79081 | Gas Operator | Apr 2026 |
| 428 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Apr 2026 |
| 429 | Us Petro LP | Amarillo, TX 79106 | Oil & Gas Operator | Apr 2020 |
| 430 | Vantage Point Operating Co. | Houston, TX 77057 | Oil & Gas Operator | Dec 2014 |
| 431 | Venus Exploration, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 432 | Venus Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2002 |
| 433 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Apr 2026 |
| 434 | Virtex Operating Company, Inc. | Corpus Christ, TX 78401 | Oil & Gas Operator | Oct 2023 |
| 435 | Virtex Petroleum Company, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Jan 2008 |
| 436 | Vistatex Energy LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 437 | VRK Oil And Gas, Inc. | Arlington, TX 76016 | Oil & Gas Operator | Mar 2014 |
| 438 | VT VIstatex Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Apr 2026 |
| 439 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2026 |
| 440 | Washita Oil And Gas, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 441 | Washita Production Company | Tulsa, OK 74136 | Oil & Gas Operator | May 2006 |
| 442 | Weinkauf Petroleum, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 443 | Weldon Corporation | Houston, TX 77056 | Oil Operator | Feb 2020 |
| 444 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Apr 2026 |
| 445 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 446 | Westport Oil And Gas Company Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2002 |
| 447 | White Stride LLC | Piedmont, OK 73078 | Oil & Gas Operator | Apr 2026 |
| 448 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 449 | Wilbanks Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 450 | Wildhorse Oil & Gas Corporation | Ardmore, OK 73402 | Oil & Gas Operator | May 2019 |
| 451 | Wildhorse Operating Company | Ardmore, OK 73402 | Oil & Gas Operator | Apr 2026 |
| 452 | Wilham Investments, Inc. | Pampa, TX 79065 | Oil & Gas Operator | Jan 2020 |
| 453 | Will Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jan 2026 |
| 454 | Winright Resources Operating,LLC | Houston, TX 77007 | Oil & Gas Operator | Apr 2026 |
| 455 | Woolley, Gary W. | Spearman, TX 79081 | Gas Operator | Apr 2026 |
| 456 | Wright Trucking, Inc. | Weatherford, OK 73096 | Oil & Gas Operator | Feb 2019 |
| 457 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 458 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 459 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |