| 401 | South Houston Production Company | Muenster, TX 76252 | Oil & Gas Operator | Feb 2026 |
| 402 | Southcoast Production Inc | Houston, TX 77010 | Oil & Gas Operator | Feb 2026 |
| 403 | Spectral Oil & Gas Corporation | Humble, TX 77338 | Oil Operator | Feb 2026 |
| 404 | Stanton Mineral Development Inc | Austin, TX 78759 | Oil & Gas Operator | Feb 2026 |
| 405 | Starr Operating Company | Austin, TX 78759 | Oil & Gas Operator | Feb 2026 |
| 406 | Startap, Inc. | Conroe, TX 77305 | Oil Operator | Feb 2026 |
| 407 | Startex Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 408 | Stealth Onsite Solutions LLC | Pasadena, TX 77505 | Oil Operator | Feb 2026 |
| 409 | Stewardship Resources | Roanoke, TX 76262 | Oil & Gas Operator | Jun 2022 |
| 410 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 411 | SWS | Humble, TX 77338 | Oil Operator | Feb 2026 |
| 412 | T & T Production Co. | Victoria, TX 77902 | Oil & Gas Operator | Feb 1995 |
| 413 | T.D. Operating Company, Inc. | New Braunfels, TX 78130 | Oil & Gas Operator | Nov 1999 |
| 414 | Tabbs Bay Production Company | Houston, TX 77019 | Oil Operator | Feb 2026 |
| 415 | Tandem Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 416 | Tap Operating Company, Inc. | Mexia, TX 76667 | Oil & Gas Operator | May 1995 |
| 417 | Tartan Resources Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 1995 |
| 418 | Tecolote Petroleum Corp.,Inc. | Friendswood, TX 77546 | Oil & Gas Operator | Mar 2011 |
| 419 | Tejas Gas Pipeline Company | Houston, TX 77010 | Oil & Gas Operator | Apr 1998 |
| 420 | Tejas Gas Pipeline, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2002 |
| 421 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Feb 2026 |
| 422 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 423 | Texakota, Inc. | Houston, TX 77098 | Oil & Gas Operator | Mar 2021 |
| 424 | Texana Operating Company | Houston, TX 77090 | Oil & Gas Operator | Feb 2026 |
| 425 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Feb 2026 |
| 426 | Texas Gas Resources, Inc. | Houston, TX 77292 | Oil & Gas Operator | Jul 2009 |
| 427 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 428 | Texas Oil Resources Oper, LLC | Houston, TX 77024 | Oil Operator | Feb 2026 |
| 429 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 430 | Texstar North America, Inc. | Waynesboro, MS 39367 | Oil & Gas Operator | Aug 1994 |
| 431 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 432 | Thornberry Oilfield Service, Inc | Conroe, TX 77302 | Oil & Gas Operator | Aug 2003 |
| 433 | Thorp Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 434 | Titan Petroleum, Inc. | Tomball, TX 77375 | Oil & Gas Operator | Nov 2004 |
| 435 | Tomlinson, Thomas K. Inc. | Port Lavaca, TX 77979 | Oil & Gas Operator | Jul 2003 |
| 436 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 437 | Torrent Oil LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 438 | Tortuga Operating Company | Houston, TX 77055 | Oil & Gas Operator | Feb 2026 |
| 439 | Trace Operating, LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Feb 2026 |
| 440 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 441 | Traton Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2019 |
| 442 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Feb 2026 |
| 443 | Tri City Oil Co., LLC | Winnie, TX 77665 | Oil Operator | Feb 2026 |
| 444 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 445 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 446 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 447 | TT Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 448 | Tucker Operating Co., Inc. | Victoria, TX 77903 | Oil & Gas Operator | Feb 2026 |
| 449 | Txco Resources Inc. | San Antonio, TX 78280 | Oil & Gas Operator | Feb 2026 |
| 450 | U. D. Man, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Feb 2026 |
| 451 | Union Crude Operating Co. | Baytown, TX 77521 | Oil Operator | Aug 2003 |
| 452 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 453 | Universal Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2002 |
| 454 | Upstream Properties, LLC | Southlake, TX 76092 | Oil & Gas Operator | Feb 2026 |
| 455 | Valley Gathering Company | Midland, TX 79702 | Oil & Gas Operator | Feb 1997 |
| 456 | Vantage Operating, LLC | San Antonio, TX 78230 | Oil & Gas Operator | Feb 2026 |
| 457 | Vondra Energy Corp. | Alvin, TX 77512 | Oil & Gas Operator | Feb 2026 |
| 458 | W. R. G. Oil & Gas, Inc. | Arlington, TX 76013 | Oil & Gas Operator | Dec 1993 |
| 459 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 460 | Waldrop, L. E. | Houston, TX 77024 | Oil & Gas Operator | Jun 1996 |
| 461 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 462 | WBR, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 1995 |
| 463 | Western Energy Group, LLC | Leander, TX 78641 | Oil & Gas Operator | Feb 2026 |
| 464 | Western Gulf Oil & Gas Inc. | Dallas, TX 75360 | Oil & Gas Operator | Jul 2000 |
| 465 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 466 | WFMMS, Inc. | Batson, TX 77519 | Oil & Gas Operator | Feb 2026 |
| 467 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Feb 2026 |
| 468 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 469 | Williams, H. E. | Houston, TX 77002 | Oil & Gas Operator | Dec 1994 |
| 470 | Wilson Oil Co. | Houston, TX 77263 | Oil & Gas Operator | Feb 2026 |
| 471 | Womack Energy, Inc. | Houston, TX 77057 | Oil & Gas Operator | Nov 2025 |
| 472 | Wood Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Jun 1999 |
| 473 | WRD Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 474 | WRT Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | May 1998 |
| 475 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 476 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | Feb 2026 |
| 477 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |