| 401 | Roil Production Company | Houston, TX 77056 | Gas Operator | Sep 2005 |
| 402 | Rolling Hills Oil & Gas, Inc | Austin, TX 78731 | Oil & Gas Operator | Sep 2026 |
| 403 | Rumble Energy LLC | Skiatook, OK 74070 | Oil & Gas Operator | Sep 2026 |
| 404 | Russell Operating Company, LLC | Big Lake, TX 76932 | Oil Operator | Sep 2026 |
| 405 | Rust Oil Corp. | Fort Worth, TX 76121 | Oil & Gas Operator | Sep 2026 |
| 406 | Ruwco Oil And Gas Corp. | Austin, TX 78701 | Oil & Gas Operator | Aug 2021 |
| 407 | Rwa, LLC | Boyd, TX 76023 | Oil & Gas Operator | Sep 2026 |
| 408 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 409 | S2 Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2023 |
| 410 | Sable Permian Resources Land,LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2019 |
| 411 | Sable Permian Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2021 |
| 412 | Sabre Oil And Gas Corp. | Houston, TX 77063 | Oil & Gas Operator | Sep 2026 |
| 413 | Salt Creek Production, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Sep 2026 |
| 414 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2026 |
| 415 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 416 | Saxon Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Oct 2009 |
| 417 | Scout Energy Management LLC | Dallas, TX 75240 | Oil & Gas Operator | Sep 2026 |
| 418 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 419 | SDX Resources, Inc. | Midland, TX 79704 | Oil & Gas Operator | Sep 2026 |
| 420 | Sedona Oil & Gas Corporation | Dallas, TX 75231 | Oil & Gas Operator | Sep 2026 |
| 421 | Selous Energy, LLC | Fort Worth, TX 76109 | Oil & Gas Operator | Jul 2015 |
| 422 | Sem Operating Company LLC | Houston, TX 77042 | Oil & Gas Operator | Sep 2026 |
| 423 | Ser E&P, Inc. | McKinney, TX 75069 | Oil & Gas Operator | Sep 2026 |
| 424 | Sharp Image Energy, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Sep 2026 |
| 425 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 426 | Shifflett Operating Company | Snyder, TX 79550 | Oil & Gas Operator | Sep 2026 |
| 427 | Shoco Production LLC | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 428 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 429 | Silver Oil & Gas Inc. | San Angelo, TX 76906 | Oil & Gas Operator | Sep 2026 |
| 430 | Sinclair Energy Corporation | Fort Worth, TX 76177 | Oil & Gas Operator | Sep 2026 |
| 431 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 432 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 433 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Sep 2026 |
| 434 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 435 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 436 | Spence Energy Company | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 437 | Sproul, C. R. Inc. | Eldorado, TX 76936 | Oil & Gas Operator | Aug 2000 |
| 438 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 439 | Staley Operating Co. | Midland, TX 79702 | Oil & Gas Operator | Jan 2022 |
| 440 | Stanolind Operating Corp. | Midland, TX 79701 | Oil & Gas Operator | Apr 2008 |
| 441 | Startex Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 2026 |
| 442 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 443 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2026 |
| 444 | Stephens, Hayseed Oil Inc. | Weatherford, TX 76087 | Oil & Gas Operator | Mar 2008 |
| 445 | Summit Petroleum LLC | Midland, TX 79705 | Oil & Gas Operator | Sep 2026 |
| 446 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Sep 2026 |
| 447 | Sundown Oil Operating, LLC | Graham, TX 76450 | Oil Operator | Sep 2026 |
| 448 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Sep 2026 |
| 449 | Swartz Oil Company | San Angelo, TX 76906 | Oil & Gas Operator | Sep 2026 |
| 450 | Swartz, Guy A. | San Angelo, TX 76904 | Oil & Gas Operator | Aug 1993 |
| 451 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 452 | Synergex Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | May 2026 |
| 453 | T.O.I. | Midland, TX 79710 | Oil & Gas Operator | Mar 2001 |
| 454 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 455 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 456 | Targa Midstream Services LLC | Tulsa, OK 74103 | Oil Operator | Mar 2023 |
| 457 | Taurus Exploration U.S.A., Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 1998 |
| 458 | Taurus Minerals, Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 459 | Taurus Operating, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 460 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Sep 2026 |
| 461 | Tejas Permian Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 462 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Sep 2026 |
| 463 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Sep 2026 |
| 464 | Texas Crude Operator, Inc. | Houston, TX 77098 | Oil & Gas Operator | Aug 2017 |
| 465 | Texas Royalty Corp. | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 466 | Texzona Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Dec 1997 |
| 467 | Thomas Exploration & Devel., Inc | Jourdanton, TX 78026 | Oil & Gas Operator | Sep 2026 |
| 468 | Thomas Oil And Gas Inc. | San Angelo, TX 76906 | Oil & Gas Operator | May 2019 |
| 469 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 470 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | Sep 2026 |
| 471 | THP Operating LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Sep 2026 |
| 472 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 473 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Sep 2026 |
| 474 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 475 | Toc Energy Resources, LLC | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2026 |
| 476 | Tracer Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Sep 2026 |
| 477 | Tracker Mineral | Clyde, TX 79510 | Oil & Gas Operator | Sep 2026 |
| 478 | Tradition Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 479 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 480 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Sep 2026 |
| 481 | Triag Energy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2014 |
| 482 | Triple G Oil & Gas | Sonora, TX 76950 | Oil & Gas Operator | Oct 2022 |
| 483 | TS Oil, LLC | River Oaks, TX 76114 | Oil & Gas Operator | Sep 2026 |
| 484 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 485 | Tug Hill Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Dec 2021 |
| 486 | TXP, Incorporated | San Angelo, TX 76906 | Oil & Gas Operator | Sep 2026 |
| 487 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 488 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 489 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |
| 490 | United Energy Corporation | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2026 |
| 491 | Unitex Oil & Gas, L.L.C. | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 492 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 493 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 494 | Valla Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Aug 2003 |
| 495 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jan 2021 |
| 496 | Vanguard Permian, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 497 | Vecta Oil & Gas LTD | Dallas, TX 75235 | Oil & Gas Operator | Jun 2026 |
| 498 | Venado Petroleum Corporation | Dallas, TX 75231 | Oil & Gas Operator | May 2012 |
| 499 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | May 2026 |
| 500 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Sep 2026 |