| 401 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 402 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 403 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 404 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2025 |
| 405 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 406 | Santa Fe Energy Oper. Part., LP | Houston, TX 77057 | Oil & Gas Operator | Dec 1994 |
| 407 | Santa Fe Energy Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 408 | Santa Fe Snyder Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2000 |
| 409 | Sapient Energy Corp | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2002 |
| 410 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 411 | SDX Resources, Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2025 |
| 412 | Sei Operating, LLC | Mandeville, LA 70471 | Oil & Gas Operator | Mar 2025 |
| 413 | Shell Frontier Oil & Gas Inc. | Houston, TX 77001 | Oil & Gas Operator | Feb 1997 |
| 414 | Shell Trading Us Company | Houston, TX 77210 | Oil & Gas Operator | Dec 2024 |
| 415 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 416 | Shoshone Oil Company | Dallas, TX 75244 | Oil & Gas Operator | May 1994 |
| 417 | Siana Oil & Gas | Conroe, TX 77305 | Oil & Gas Operator | Mar 2025 |
| 418 | Simmons, L.B. Energy, Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 2000 |
| 419 | Simpson Oil Company | Odessa, TX 79760 | Oil & Gas Operator | Oct 2004 |
| 420 | Sixess Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 421 | Slape Oil Company, Inc. | Houston, TX 77064 | Oil & Gas Operator | Jun 2011 |
| 422 | Slate Holdings, Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Mar 2025 |
| 423 | Sloan Petroleum Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2025 |
| 424 | Smith & Marrs Inc. | Lubbock, TX 79424 | Oil & Gas Operator | Apr 2021 |
| 425 | Smith Operating & Management Co. | Shreveport, LA 71161 | Oil & Gas Operator | Feb 2005 |
| 426 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 427 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Mar 2025 |
| 428 | Snow Oil & Gas Inc. | Andrews, TX 79714 | Oil & Gas Operator | Mar 2025 |
| 429 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | Mar 2025 |
| 430 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Mar 2025 |
| 431 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 432 | SSC, Inc. | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2025 |
| 433 | St. Clair Energy Corporation | Tulsa, OK 74153 | Oil & Gas Operator | Mar 2008 |
| 434 | Staghorn Resources, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2015 |
| 435 | Stanolind Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Apr 2021 |
| 436 | Stanolind Permian LLC | Midland, TX 79705 | Oil & Gas Operator | Mar 2025 |
| 437 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2025 |
| 438 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 439 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 440 | Steward Energy II, LLC | Frisco, TX 75034 | Oil & Gas Operator | Mar 2025 |
| 441 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Mar 2025 |
| 442 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Mar 2025 |
| 443 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Mar 2025 |
| 444 | Sunlight Exploration, Inc. | Canyon, TX 79015 | Oil & Gas Operator | Mar 2025 |
| 445 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 446 | Synergex Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Dec 2024 |
| 447 | Tacor Resources Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2025 |
| 448 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 449 | Tamer Oil & Gas | Seminole, TX 79360 | Oil & Gas Operator | Mar 2025 |
| 450 | Taurus Exploration U.S.A., Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 1998 |
| 451 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Mar 2025 |
| 452 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | Mar 2025 |
| 453 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 454 | Texakoma Operating, L.P. | Plano, TX 75024 | Oil & Gas Operator | Jan 2025 |
| 455 | Texland Petroleum Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2003 |
| 456 | Texland Petroleum, L.P. | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2025 |
| 457 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 458 | Tgo Operating, LLC | Midland, TX 79705 | Oil & Gas Operator | Dec 2008 |
| 459 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 460 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 461 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | Mar 2025 |
| 462 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 463 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 464 | Tiburon Oil & Gas, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2000 |
| 465 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 466 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 467 | TMBR/Sharp Drilling, Inc. | Midland, TX 79703 | Oil & Gas Operator | Feb 2004 |
| 468 | Total E&P USA, Inc. | Houston, TX 77210 | Oil & Gas Operator | Nov 2011 |
| 469 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 470 | Trace Operating, LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Mar 2025 |
| 471 | Trinity Bay Oil & Gas, Inc. | Lubbock, TX 79416 | Oil & Gas Operator | Mar 2025 |
| 472 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 473 | Triple "S" Resources Inc | Sapulpa, OK 74066 | Oil & Gas Operator | Jun 1995 |
| 474 | Txla Energy, Inc. | Houston, TX 77018 | Oil & Gas Operator | Mar 2025 |
| 475 | U. S. Operating, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Mar 2025 |
| 476 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 477 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 478 | Union Royalty, Inc. | Midland, TX 79706 | Oil & Gas Operator | Jul 2014 |
| 479 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 480 | United Energy Trading LLC | Tulsa, OK 74133 | Gas Operator | Feb 2015 |
| 481 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 482 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Dec 2024 |
| 483 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 484 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 485 | Valla Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Aug 2003 |
| 486 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2021 |
| 487 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 488 | Vanguard Production Company | Lubbock, TX 79410 | Oil & Gas Operator | Mar 2025 |
| 489 | Verdugo-Pablo Energy, LLC | Amarillo, TX 79105 | Oil & Gas Operator | Nov 2024 |
| 490 | Vision Minerals, LLC | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 491 | Vista Resources, Inc. (A) | Midland, TX 79701 | Oil & Gas Operator | Feb 2000 |
| 492 | Vogel, A. J., Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1994 |
| 493 | Voskamp Exploration, Inc. | Midland, TX 79708 | Oil & Gas Operator | Sep 2010 |
| 494 | Wacker Oil Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 495 | Walkabout Operating, LLC | Lubbock, TX 79424 | Oil & Gas Operator | Mar 2025 |
| 496 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Mar 2025 |
| 497 | Walsh Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2022 |
| 498 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 499 | Warren American Oil Co | Tulsa, OK 74147 | Oil & Gas Operator | Jan 2025 |
| 500 | Warren American Oil Company LLC | Tulsa, OK 74147 | Oil & Gas Operator | Mar 2025 |