| 401 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 402 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 403 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 404 | Signal Oil And Gas Company | Colleyville, TX 76034 | Oil & Gas Operator | Apr 2026 |
| 405 | Signal Petroleum | | Oil & Gas Operator | Jul 1980 |
| 406 | Slam Resources, Inc. | | Oil & Gas Operator | Apr 1994 |
| 407 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2026 |
| 408 | Sola Oil Company, Inc. | | Oil & Gas Operator | Aug 1991 |
| 409 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Apr 2026 |
| 410 | Sooner Corp | | Oil & Gas Operator | Oct 1990 |
| 411 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Apr 2026 |
| 412 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 413 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 414 | Southern Oil Of Louisiana LLC | Madisonville, LA 70447 | Oil & Gas Operator | Apr 2026 |
| 415 | Southwest Gas Producing Co Inc | | Oil & Gas Operator | Nov 1994 |
| 416 | Spectrum Opco LLC | | Oil & Gas Operator | Nov 2024 |
| 417 | Statoil Exploration (Us) Inc. | | Oil & Gas Operator | Jul 1997 |
| 418 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 419 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 420 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Apr 2026 |
| 421 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 422 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 423 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 424 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |
| 425 | Talos Energy Offshore LLC | | Oil & Gas Operator | Jan 2025 |
| 426 | Tana Exploration Company LLC | Dallas, TX 75219 | Oil & Gas Operator | Aug 2021 |
| 427 | Tchefuncte Natural Resources, L.L.C. | | Oil & Gas Operator | Aug 2011 |
| 428 | Tenneco Inc. | | Oil & Gas Operator | Jun 1989 |
| 429 | Tennessee Gas Pipeline Company | | Oil & Gas Operator | Dec 2011 |
| 430 | Tennessee Gas Pipeline Company, LLC | | Oil Operator | Dec 2024 |
| 431 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 432 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Apr 2026 |
| 433 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 434 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 435 | Texas Crude Exploration Inc | Fort Worth, TX 76116 | Oil & Gas Operator | Aug 1992 |
| 436 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Apr 2026 |
| 437 | Texoil Company | | Oil & Gas Operator | Dec 2000 |
| 438 | The Harvest Group, LLC | | Oil & Gas Operator | May 2011 |
| 439 | The Meridian Res. & Exp. LLC | | Oil & Gas Operator | Sep 2010 |
| 440 | The WM G Helis Company, L.L.C. | | Oil & Gas Operator | Nov 2003 |
| 441 | Tiger Oil Company | Dallas, TX 75221 | Oil & Gas Operator | May 2007 |
| 442 | Time Energy, L.L.C. | | Oil & Gas Operator | Nov 2020 |
| 443 | Tipco | Shreveport, LA 71104-3047 | Oil & Gas Operator | May 1988 |
| 444 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 445 | Trafalgar House Oil & Gas Inc | Houston, TX 77002-7346 | Oil & Gas Operator | Jan 1992 |
| 446 | Transco Exploration Company | | Oil & Gas Operator | Jul 1989 |
| 447 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 448 | U S Exploraton Liq Trust | | Oil & Gas Operator | Oct 1994 |
| 449 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 450 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 451 | Ultramar Production Company | | Oil & Gas Operator | Dec 1991 |
| 452 | Union Expl. Partners, LTD. | | Oil & Gas Operator | Aug 1990 |
| 453 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 454 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 455 | Union Texas Petroleum Corp | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 456 | United Gas Pipe Line Co. | | Oil Operator | Aug 1993 |
| 457 | Unocal Exploration Corporation | Houston, TX 77001 | Oil & Gas Operator | May 1992 |
| 458 | Upstream Exploration LLC | Metairie, LA 70002 | Oil & Gas Operator | Jan 2020 |
| 459 | V. Monta Currie, Jr. | | Oil Operator | Jun 2007 |
| 460 | Vamos Oil & Gas, LLC | Miami, FL 33129 | Oil & Gas Operator | Apr 2026 |
| 461 | Vantage Point Operating Co. | Houston, TX 77057 | Oil & Gas Operator | Dec 2014 |
| 462 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Dec 2025 |
| 463 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2026 |
| 464 | Virgin Offshore U.S.A., Inc. | | Oil & Gas Operator | Oct 2012 |
| 465 | Virtex Petroleum Company, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Jan 2008 |
| 466 | W&T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2026 |
| 467 | W. B. Jayred | | Oil & Gas Operator | Aug 1982 |
| 468 | W. B. McCarter, Jr., Inc. | | Oil & Gas Operator | Dec 1995 |
| 469 | W. L. Estis | | Oil & Gas Operator | Dec 1999 |
| 470 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 471 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 472 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 473 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | Apr 2026 |
| 474 | WCC Energy Group LLC | | Oil & Gas Operator | Dec 2024 |
| 475 | West Delta Oil Co. | | Oil & Gas Operator | Jul 2000 |
| 476 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Apr 2026 |
| 477 | Whitetail Operators LLC | | Oil Operator | Nov 2021 |
| 478 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 479 | Whitney Oil & Gas, LLC | | Oil & Gas Operator | Jan 2025 |
| 480 | Windfohr Oil Company | | Oil & Gas Operator | May 1980 |
| 481 | Wintershall Corporation | | Oil & Gas Operator | Oct 1989 |
| 482 | Workover One, Inc. | | Oil & Gas Operator | Jul 1989 |
| 483 | Xplor Energy Operating Co. | Houston, TX 77079 | Oil & Gas Operator | Jan 2012 |
| 484 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 485 | Yuma E & P Company, Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2026 |
| 486 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 487 | Zgen, Inc. | | Oil & Gas Operator | Jul 1990 |