| 401 | Robertson Resources, Inc. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Jul 2025 |
| 402 | Robertson, French M. Oil Co. | Abilene, TX 79608 | Oil & Gas Operator | Mar 1995 |
| 403 | Rocker A Operating Company | Post, TX 79356 | Oil & Gas Operator | Aug 2022 |
| 404 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 405 | Round Rock Resources, Inc. | College Sta, TX 77845 | Oil & Gas Operator | Sep 2012 |
| 406 | Rover Petroleum Operating, LLC | Plano, TX 75075 | Oil & Gas Operator | Jul 2025 |
| 407 | Royalty Land & Dev. Co., Inc. | Wolfforth, TX 79382 | Oil & Gas Operator | Jul 2025 |
| 408 | Rozzlle Operating Company, LLC | Blackwell, TX 79506 | Oil & Gas Operator | Jul 2025 |
| 409 | Rudman Partnership, The | Dallas, TX 75201 | Oil & Gas Operator | Dec 2014 |
| 410 | Rusk Co. Well Service Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |
| 411 | Russell, C. M. Oil Company | Lubbock, TX 79423 | Oil & Gas Operator | Jan 2008 |
| 412 | Russell, L. J. Oil Company | Snyder, TX 79549 | Oil & Gas Operator | Jul 2025 |
| 413 | Russell, Phillip | Colorado City, TX 79512 | Oil & Gas Operator | Jul 2025 |
| 414 | Ruwco Oil And Gas Corp. | Austin, TX 78701 | Oil & Gas Operator | Aug 2021 |
| 415 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 416 | S & M Royalty | Andrews, TX 79714 | Oil & Gas Operator | Jan 1997 |
| 417 | Saber Oil & Gas Ventures, LLC | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 418 | Sabine Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 419 | Sagebrush Oilandgas Company,LLC | Midland, TX 79701 | Oil & Gas Operator | Mar 2010 |
| 420 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 421 | Sammax Operating LLC | Snyder, TX 79549 | Oil Operator | Jul 2025 |
| 422 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 423 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 424 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 425 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Jul 2025 |
| 426 | Satanta Oil Company | Midland, TX 79704 | Oil & Gas Operator | Jul 2025 |
| 427 | Schlachter Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Jul 2025 |
| 428 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 429 | Schlachter, David A., Estate Of | Dallas, TX 75225 | Oil & Gas Operator | Jan 2000 |
| 430 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 431 | SDX Resources, Inc. | Midland, TX 79705 | Oil & Gas Operator | Jul 2025 |
| 432 | Seaboard Operating Co. | Midland, TX 79710 | Oil & Gas Operator | Jul 2025 |
| 433 | Seal Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2006 |
| 434 | Seely Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2025 |
| 435 | Sha-Jam Operating Corp. | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 436 | Sharp Image Energy, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Jul 2025 |
| 437 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 438 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Jul 2025 |
| 439 | Shifflett Operating Company | Snyder, TX 79550 | Oil & Gas Operator | Jul 2025 |
| 440 | Simmons, L.B. Energy, Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 2000 |
| 441 | Sinclair Oil & Gas Company | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Jul 2025 |
| 442 | Slagel, H. P. Prod. Co. | Snyder, TX 79550 | Oil & Gas Operator | Dec 2006 |
| 443 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Jul 2025 |
| 444 | Smith Vacuum Service | Snyder, TX 79550 | Oil & Gas Operator | Jul 2025 |
| 445 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | Jul 2025 |
| 446 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Jul 2025 |
| 447 | Spalding Energy, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2025 |
| 448 | Special JHR Corp | Bridgeville, PA 15017 | Oil & Gas Operator | Jul 2025 |
| 449 | Springfield Oil Services, Inc. | Mamaroneck, NY 10543 | Oil & Gas Operator | Jul 2025 |
| 450 | SSC, Inc. | Lubbock, TX 79408 | Oil & Gas Operator | Jul 2025 |
| 451 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jul 2025 |
| 452 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 453 | Sterlynn Oil & Gas, Inc. | Harper, TX 78631 | Oil Operator | Jul 2025 |
| 454 | Stonegate Operators, Inc. | Addison, TX 75001 | Oil Operator | Jul 2025 |
| 455 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Jul 2025 |
| 456 | Strawn Petroleum Operating, LLC | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 457 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 458 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jul 2025 |
| 459 | SWJN Oil Company | Kilgore, TX 75663 | Oil Operator | Jul 2025 |
| 460 | Talley Resources, Inc. | Houma, LA 70360 | Oil & Gas Operator | Apr 1993 |
| 461 | Tandem Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 462 | Taylor Oil & Gas Serv | Snyder, TX 79549 | Oil Operator | Jul 2025 |
| 463 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2025 |
| 464 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Jul 2025 |
| 465 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Jul 2025 |
| 466 | Texas Secondary Oil Corporation | Devine, TX 78016 | Oil & Gas Operator | Jul 2025 |
| 467 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 468 | Three J'S Petroleum, Inc. | Lubbock, TX 79423 | Oil & Gas Operator | Jul 2025 |
| 469 | Three R Oil Company | Post, TX 79356 | Oil & Gas Operator | Jul 2025 |
| 470 | Three Span Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jul 2025 |
| 471 | Three Summits Operating LLC | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2025 |
| 472 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 473 | TLH Production LLC | Abilene, TX 79602 | Oil & Gas Operator | Jul 2025 |
| 474 | TNCH, LLC | Colorado City, TX 79512 | Oil Operator | Jul 2025 |
| 475 | Townsend, R. F. Trustee | Dallas, TX 75201 | Oil & Gas Operator | Dec 1994 |
| 476 | Tradition Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 477 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 478 | Trail Ridge Energy PRTNS II LLC | Grapevine, TX 76051 | Oil & Gas Operator | Jun 2017 |
| 479 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Jul 2025 |
| 480 | Triag Energy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2014 |
| 481 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 482 | Tsar Energy, LLC | Dallas, TX 75205 | Oil & Gas Operator | Jul 2025 |
| 483 | Tucker Drilling Company, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Jul 1996 |
| 484 | Tyl Oil | Canon City, CO 81212 | Gas Operator | May 1994 |
| 485 | Unified Oil & Gas Corp. | Snyder, TX 79550 | Oil Operator | Jul 2025 |
| 486 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 487 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 488 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 489 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 490 | Unitex Oil & Gas, L.L.C. | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 491 | Uptex Operating Inc. | Dallas, TX 75201 | Oil & Gas Operator | May 2011 |
| 492 | Uptex Operating, L.P. | Dallas, TX 75201 | Oil & Gas Operator | May 2010 |
| 493 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 494 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Jul 2025 |
| 495 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2021 |
| 496 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 497 | Vantage Point Operating Co | Houston, TX 77057 | Oil & Gas Operator | Dec 2014 |
| 498 | Verado Energy, Inc. | Allen, TX 75013 | Oil & Gas Operator | Jul 2025 |
| 499 | Vess Oil Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 500 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |