| 401 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 402 | Southwest Petroleum | San Antonio, TX 78253 | Oil & Gas Operator | Dec 2025 |
| 403 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 2025 |
| 404 | Sproul, C. R. Inc. | Eldorado, TX 76936 | Oil & Gas Operator | Aug 2000 |
| 405 | SS Operating LLC | Water Valley, TX 76958 | Oil Operator | Dec 2025 |
| 406 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 407 | Staley Operating Co. | Midland, TX 79702 | Oil & Gas Operator | Jan 2022 |
| 408 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Dec 2025 |
| 409 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 410 | Strand Energy, Inc. (I) | Houston, TX 77002 | Oil & Gas Operator | Sep 1996 |
| 411 | Stringer Oil & Gas Co., Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Oct 1996 |
| 412 | Subsurface Energy Corp. | Coleman, TX 76834 | Oil & Gas Operator | Dec 2025 |
| 413 | Sun River Operating, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Dec 2025 |
| 414 | Sunburst, Inc. | Wheat Ridge, CO 80033 | Oil & Gas Operator | Oct 2025 |
| 415 | Surge Solutions, Inc. | Bandera, TX 78003 | Oil & Gas Operator | Dec 2025 |
| 416 | Swartz Oil Company | San Angelo, TX 76906 | Oil & Gas Operator | Dec 2025 |
| 417 | Swartz, Guy A. | San Angelo, TX 76904 | Oil & Gas Operator | Aug 1993 |
| 418 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Dec 2025 |
| 419 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 420 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | Dec 2025 |
| 421 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 422 | Taubert & Steed | Wichita Falls, TX 76301 | Oil & Gas Operator | Aug 2001 |
| 423 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Dec 2025 |
| 424 | TCS Petroleum Co., LLC | Abilene, TX 79608 | Oil & Gas Operator | Dec 2025 |
| 425 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Dec 2025 |
| 426 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 427 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Dec 2025 |
| 428 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | Dec 2025 |
| 429 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 2025 |
| 430 | Thomas Oil And Gas Inc. | San Angelo, TX 76906 | Oil & Gas Operator | May 2019 |
| 431 | Thorp Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 432 | THP Operating LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Dec 2025 |
| 433 | Tiki Oil & Gas, LLC | Cisco, TX 76437 | Oil Operator | Dec 2025 |
| 434 | Tipperary Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 435 | TKP Petroleum, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Dec 2025 |
| 436 | Toc Energy Resources, LLC | Fort Worth, TX 76101 | Oil & Gas Operator | Dec 2025 |
| 437 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 438 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Dec 2025 |
| 439 | Trend Exploration I LLC | Midland, TX 79701 | Oil & Gas Operator | May 2011 |
| 440 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 441 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | Dec 2025 |
| 442 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 443 | Twin Oaks Construction Company | Irving, TX 75063 | Oil & Gas Operator | Dec 2025 |
| 444 | TX Lone Star Operating Co, LLC | Sulphur SPGS, TX 75483 | Oil & Gas Operator | Dec 2025 |
| 445 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | Dec 2025 |
| 446 | Txu Gas Company | Dallas, TX 75201 | Oil & Gas Operator | Sep 2004 |
| 447 | Txu Lone Star Pipeline | Dallas, TX 75201 | Oil & Gas Operator | Oct 2003 |
| 448 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 449 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 450 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Dec 2025 |
| 451 | Upstream Properties, LLC | Southlake, TX 76092 | Oil & Gas Operator | Dec 2025 |
| 452 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 453 | Vaca Operating Company LLC | Pacific PLSDS, CA 90272 | Oil & Gas Operator | Aug 2017 |
| 454 | Valley Resources, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Aug 2003 |
| 455 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 456 | Vanguard Permian, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 457 | Vaquero Operating | FT Stockton, TX 79735 | Oil & Gas Operator | Dec 2025 |
| 458 | Vaughn Petroleum, Inc. | Dallas, TX 75219 | Oil & Gas Operator | May 2004 |
| 459 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Dec 2025 |
| 460 | Vista Resources, Inc. (A) | Midland, TX 79701 | Oil & Gas Operator | Feb 2000 |
| 461 | W.O.G., Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 462 | Walbet | Monahans, TX 79756 | Oil & Gas Operator | Dec 1993 |
| 463 | Walbet, Inc. | Monahans, TX 79756 | Oil & Gas Operator | Dec 2025 |
| 464 | Walsh Resources, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Dec 2025 |
| 465 | Watco Energy, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Apr 1996 |
| 466 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 467 | West Bay Exploration Company | Muenster, TX 76252 | Oil & Gas Operator | Sep 2025 |
| 468 | Western Pride Resources, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Jan 2011 |
| 469 | Western Reserves Oil Co Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2020 |
| 470 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 471 | Wetwick DRLG. & Prod. | Carlsbad, TX 76934 | Oil Operator | Dec 2025 |
| 472 | WG Oil, LLC | Wichita Falls, TX 76308 | Oil Operator | Dec 2025 |
| 473 | Whitehawk Production Company | Midland, TX 79710 | Oil & Gas Operator | Dec 2025 |
| 474 | Wilbanks, Bruce A. | Midland, TX 79701 | Oil & Gas Operator | Aug 1996 |
| 475 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 476 | Wilshire Oil Co. Of Texas | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2004 |
| 477 | Wilson, WM. B. Exploration Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 1996 |
| 478 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 479 | Yuma E & P Company, Inc. | Houston, TX 77027 | Oil & Gas Operator | Dec 2025 |
| 480 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | Dec 2025 |