| 501 | Staples, James W. Prod. Co. | Tuleta, TX 78162 | Oil & Gas Operator | Sep 2026 |
| 502 | Staples, Tommy Oil Co. | Pettus, TX 78146 | Oil & Gas Operator | Mar 2008 |
| 503 | Starco Exploration, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 504 | Stark Petroleum | Tuleta, TX 78162 | Oil & Gas Operator | Sep 2026 |
| 505 | Statoil Texas Onshore Prop LLC | Austin, TX 78730 | Oil & Gas Operator | Dec 2018 |
| 506 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2026 |
| 507 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 508 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Sep 2026 |
| 509 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Sep 2026 |
| 510 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 511 | Suemaur Exploration, Inc. | Corpus Chrsti, TX 78470 | Oil & Gas Operator | Mar 2008 |
| 512 | Suemaur Operating LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Sep 2026 |
| 513 | Sun Exploration, Inc. | Alice, TX 78333 | Oil & Gas Operator | Sep 2026 |
| 514 | SV Energy Company, LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Mar 2017 |
| 515 | SW Operating, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Sep 2000 |
| 516 | Sydson Energy, Inc. | Houston, TX 77019 | Oil & Gas Operator | Sep 2026 |
| 517 | Syj Oil & Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2026 |
| 518 | T - C Oil Company | Refugio, TX 78377 | Oil & Gas Operator | Jan 2012 |
| 519 | T-C Oil Company, LLC | Refugio, TX 78377 | Oil & Gas Operator | Sep 2026 |
| 520 | T.D. Operating Company, Inc. | New Braunfels, TX 78130 | Oil & Gas Operator | Nov 1999 |
| 521 | Talisman Energy USA Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2016 |
| 522 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 523 | Tare Resources, LLC | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Sep 2026 |
| 524 | Tasca Exploration Company | Houston, TX 77257 | Oil & Gas Operator | Jun 2002 |
| 525 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Sep 2026 |
| 526 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 527 | Texacal, Inc. | Newport Beach, CA 92660 | Oil & Gas Operator | Sep 2026 |
| 528 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Sep 2026 |
| 529 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 530 | Texas Southern Petroleum Corp. | Corpus Christ, TX 78410 | Oil & Gas Operator | Sep 2026 |
| 531 | Texas Sunset Energy And Ent Inc | Victoria, TX 77904 | Oil Operator | Aug 2003 |
| 532 | Texas, Les & Co. | Brenham, TX 77833 | Oil & Gas Operator | Sep 2026 |
| 533 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Sep 2026 |
| 534 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jun 2026 |
| 535 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Sep 2026 |
| 536 | Tidewater Minerals Corporation | Orange Grove, TX 78372 | Oil & Gas Operator | Sep 2026 |
| 537 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 538 | Trailblazer Oil & Gas LLC | Goliad, TX 77963 | Oil & Gas Operator | Sep 2026 |
| 539 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Sep 2026 |
| 540 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 541 | Trident Corporation | Woodsboro, TX 78393 | Oil & Gas Operator | Sep 2026 |
| 542 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 543 | Triple L Oil Company | Corpus Christ, TX 78469 | Oil & Gas Operator | Jan 1998 |
| 544 | Tschoepe, Arthur J. | Leakey, TX 78873 | Oil & Gas Operator | Jun 2001 |
| 545 | Tsoco | Tuleta, TX 78162 | Oil & Gas Operator | Apr 2017 |
| 546 | Tsoco & W. M. Null | Pettus, TX 78146 | Oil & Gas Operator | Aug 2002 |
| 547 | Tucker Petroleum, Inc. | Corpus Chrsti, TX 78468 | Oil & Gas Operator | Sep 2026 |
| 548 | TX Petroleum Company | Corpus Christ, TX 78412 | Oil & Gas Operator | Apr 1996 |
| 549 | U.S. Enercorp, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2004 |
| 550 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 551 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | Sep 2026 |
| 552 | Union Gas Operating Company | Spring, TX 77391 | Oil & Gas Operator | Sep 2026 |
| 553 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 554 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |
| 555 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 556 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 557 | United Texas Petroleum Inc. | McKinney, TX 75070 | Oil & Gas Operator | Sep 2026 |
| 558 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Sep 2026 |
| 559 | Valley Gathering Company | Midland, TX 79702 | Oil & Gas Operator | Feb 1997 |
| 560 | Vaquero Operating | FT Stockton, TX 79735 | Oil & Gas Operator | Sep 2026 |
| 561 | Ventex Operating Corp. | Addison, TX 75001 | Oil & Gas Operator | Sep 2026 |
| 562 | Ventura Oil & Gas Company | San Antonio, TX 78205 | Oil & Gas Operator | Mar 2002 |
| 563 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 564 | Viper S.W.D., LLC | El Campo, TX 77437 | Oil & Gas Operator | Sep 2026 |
| 565 | Vision Oil And Gas LLC | Laredo, TX 78041 | Oil & Gas Operator | Sep 2026 |
| 566 | Vista Exploration, LLC | Abilene, TX 79601 | Oil & Gas Operator | May 2017 |
| 567 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2026 |
| 568 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 569 | Wallis Energy, Inc. | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 570 | Warwick-Artemis, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2026 |
| 571 | Waters Eng. & Operating, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Sep 2013 |
| 572 | Welder Exploration & Prod., Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Dec 2022 |
| 573 | Welder Operating, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Mar 2001 |
| 574 | Welder-Heyer Energy, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Feb 2001 |
| 575 | Welderxp LTD. | San Antonio, TX 78212 | Oil & Gas Operator | Sep 2026 |
| 576 | West Petroleum Corp. | San Antonio, TX 78205 | Oil & Gas Operator | Oct 2009 |
| 577 | West Tuleta Operating Corp. | Tuleta, TX 78162 | Oil & Gas Operator | May 2019 |
| 578 | Western Gulf Oil & Gas Inc. | Dallas, TX 75360 | Oil & Gas Operator | Jul 2000 |
| 579 | Western Gulf Oil & Gas, LLC | Bishop, TX 78343 | Oil & Gas Operator | Sep 2026 |
| 580 | Westhall Associates, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Aug 1997 |
| 581 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 582 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Sep 2026 |
| 583 | Whitesands Operating, L.L.C. | Corpus Chrsti, TX 78466 | Oil & Gas Operator | Mar 2025 |
| 584 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 585 | Winn Exploration Co., Inc. | Corpus Christ, TX 78401 | Oil & Gas Operator | Sep 2026 |
| 586 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 587 | Wofford, C. J. | El Campo, TX 77437 | Oil & Gas Operator | Sep 2026 |
| 588 | Wolverine Exploration Company | Houston, TX 77002 | Oil & Gas Operator | May 2019 |
| 589 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 590 | York & Price Petroleum Corp. | San Antonio, TX 78218 | Oil & Gas Operator | Jul 2004 |
| 591 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | Sep 2026 |
| 592 | Yuma Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | Aug 2002 |
| 593 | Zachry Exploration, LLC | San Antonio, TX 78224 | Oil & Gas Operator | Sep 2026 |
| 594 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |