| 401 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Sep 2026 |
| 402 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 403 | Senora Resources, Inc. | Dime Box, TX 77853 | Oil & Gas Operator | Sep 2026 |
| 404 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 405 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 406 | Showhorn Holding Co., L.L.C. | Normangee, TX 77871 | Oil & Gas Operator | Sep 2026 |
| 407 | Shubuta Oil Corporation | Houston, TX 77056 | Oil & Gas Operator | Sep 1998 |
| 408 | Sikes Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2003 |
| 409 | Sinclair Oil & Gas Company | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Sep 2026 |
| 410 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2026 |
| 411 | Smith Oil Co. | Smackover, AR 71762 | Oil Operator | Jan 2025 |
| 412 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 413 | SND Operating, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 414 | Sonat Exploration Company -Tyler | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 415 | Southwest Operating, Inc.-Tyler | Tyler, TX 75701 | Oil & Gas Operator | Sep 2026 |
| 416 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 417 | Speller Oil Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | May 2026 |
| 418 | Spence Energy Company | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 419 | Spicer Oil Company, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Dec 2008 |
| 420 | Spicewood Operating Company, LLC | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 421 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Sep 2026 |
| 422 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 423 | Stallion Oil Company | Lafayette, LA 70505 | Oil & Gas Operator | Jun 2004 |
| 424 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Sep 2026 |
| 425 | STS Petroleum LLC | Houston, TX 77289 | Oil & Gas Operator | Sep 2026 |
| 426 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Sep 2026 |
| 427 | SW Operating, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Sep 2000 |
| 428 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 429 | T Investments Inc | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Mar 2011 |
| 430 | T-Bar-X Limited Company | Houston, TX 77057 | Oil & Gas Operator | Dec 2005 |
| 431 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | Sep 2026 |
| 432 | Tahiti PTRS Enrgy Solutions Corp | Long Beach, CA 90807 | Oil Operator | Sep 2026 |
| 433 | Taleeho Energy Co. | Normangee, TX 77871 | Oil & Gas Operator | Jun 2003 |
| 434 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 435 | Tanos Exploration II, LLC | Tyler, TX 75701 | Oil & Gas Operator | Sep 2023 |
| 436 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Sep 2026 |
| 437 | TDT Production, Inc. | Capitola, CA 95010 | Oil & Gas Operator | Aug 2003 |
| 438 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 439 | Teco Operating Company | Athens, TX 75751 | Oil & Gas Operator | Jun 2001 |
| 440 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 441 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Sep 2026 |
| 442 | Texas Royalty Corp. | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 443 | Texla Operating Co | Jonesville, TX 75659 | Oil & Gas Operator | Sep 2026 |
| 444 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 445 | TGNR Gulf Coast LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 446 | Thomfield Energy LLC | Kilgore, TX 75663 | Oil Operator | Sep 2026 |
| 447 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |
| 448 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 449 | Trailblazer Energy Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2026 |
| 450 | Trans-Tex Operating LLC | Dallas, TX 75367 | Oil & Gas Operator | Sep 2026 |
| 451 | Travis Operating, LLC | Kingwood, TX 77345 | Oil & Gas Operator | Sep 2026 |
| 452 | Treadstone Energy Partners, LLC | Houston, TX 77070 | Oil & Gas Operator | Jun 2016 |
| 453 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Sep 2026 |
| 454 | Triad Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Oct 2011 |
| 455 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 456 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Sep 2026 |
| 457 | Trivium Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Sep 2026 |
| 458 | Tuleta Energy Partners, LLC | Norman, OK 73072 | Oil & Gas Operator | Sep 2026 |
| 459 | Ty-Tex Exploration, Inc. | Tyler, TX 75711 | Oil Operator | Dec 2000 |
| 460 | Tyler Oil & Gas Inc. | Tyler, TX 75702 | Oil & Gas Operator | Sep 2004 |
| 461 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 462 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 463 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 464 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |
| 465 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 466 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 467 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 468 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 469 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Sep 2026 |
| 470 | Vess Oil Corporation | Dallas, TX 75201 | Oil & Gas Operator | Sep 2026 |
| 471 | Victory Oil & Gas Inc | Gun Barrel Cy, TX 75156 | Oil & Gas Operator | Sep 2026 |
| 472 | Vinland Texas Services LLC | Electra, TX 76360 | Oil & Gas Operator | Jun 2024 |
| 473 | W&T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2026 |
| 474 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2026 |
| 475 | Weatherly Oil & Gas, LLC | Dallas, TX 75206 | Oil & Gas Operator | Sep 2026 |
| 476 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 477 | West Mountain Operating Co, Inc. | Longview, TX 75604 | Oil & Gas Operator | Feb 2019 |
| 478 | Western Energy Group, LLC | Leander, TX 78641 | Oil & Gas Operator | Sep 2026 |
| 479 | Wheeler Operating Corporation | Fort Worth, TX 76109 | Oil & Gas Operator | Sep 2026 |
| 480 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 481 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 482 | Wildco Resources, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Sep 2026 |
| 483 | Wildfire Energy Operating LLC | Houston, TX 77224 | Oil & Gas Operator | Sep 2026 |
| 484 | Williams Prod. Gulf Coast, L.P. | Benbrook, TX 76126 | Oil & Gas Operator | Jan 2012 |
| 485 | Williams, Clayton Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Sep 2026 |
| 486 | Williams, Clayton W., Jr., Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 487 | Wilson Operating Service Inc | Brownfield, TX 79316 | Oil & Gas Operator | Aug 2003 |
| 488 | Wilson, Don H., Inc. | Elkhart, TX 75839 | Oil & Gas Operator | May 2019 |
| 489 | Wing Corporation | Houston, TX 77002 | Oil & Gas Operator | Jun 2000 |
| 490 | Wisenbaker Production Company | Tyler, TX 75702 | Oil & Gas Operator | Oct 2011 |
| 491 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 492 | WJW Operating Co.,LLC | Austin, TX 78738 | Oil & Gas Operator | May 2002 |
| 493 | Woodbine Production Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 494 | Wortham Oil & Gas | Conroe, TX 77301 | Oil & Gas Operator | Sep 2026 |
| 495 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 496 | York & Price Petroleum Corp. | San Antonio, TX 78218 | Oil & Gas Operator | Jul 2004 |
| 497 | ZTC Petro Investments LP | Houston, TX 77056 | Oil & Gas Operator | May 2020 |