| 301 | Shell Western E&P | Houston, TX 77001 | Oil & Gas Operator | May 2025 |
| 302 | Showdown Energy Corporation | Dallas, TX 75230 | Oil & Gas Operator | Aug 2003 |
| 303 | Silver Rock Energy, LLC | Terrell, TX 75160 | Oil Operator | May 2025 |
| 304 | Skidmore Energy,Inc. | Salado, TX 76571 | Oil & Gas Operator | Jun 1999 |
| 305 | SN Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 306 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 307 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 308 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 309 | Southwest Oil & Land, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 1999 |
| 310 | Spartan Operating Company, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Feb 2013 |
| 311 | Spiller Operating Co., Inc. | Round Rock, TX 78665 | Oil & Gas Operator | May 2015 |
| 312 | Spiller, H. G. | San Antonio, TX 78213 | Oil & Gas Operator | Oct 1993 |
| 313 | Spiller, J.A. | Austin, TX 78735 | Oil & Gas Operator | Jan 2016 |
| 314 | Spiller, Robert S. | San Antonio, TX 78213 | Oil & Gas Operator | Oct 1995 |
| 315 | Spur Operating Co. | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 316 | Square One Corporation | Giddings, TX 78942 | Oil & Gas Operator | Dec 2012 |
| 317 | Stonegate Operators, Inc. | Addison, TX 75001 | Oil Operator | May 2025 |
| 318 | STP Production, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | May 2025 |
| 319 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 320 | Strata Star Petroleum Corp. | Uvalde, TX 78801 | Oil Operator | May 2025 |
| 321 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 322 | Stratex Oil & Gas Holdings, Inc. | Watertown, CT 06795 | Oil Operator | Jun 2015 |
| 323 | Stringer Oil & Gas Co., Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Oct 1996 |
| 324 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 325 | Tanglewood Oil & Gas Co. | Gouldbusk, TX 76845 | Oil & Gas Operator | May 2025 |
| 326 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 327 | Terrafina Energy, LLC | San Antonio, TX 78280 | Oil & Gas Operator | May 2025 |
| 328 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | May 2025 |
| 329 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 330 | Texokan Operating, Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |
| 331 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | May 2025 |
| 332 | Thalmann Oil Field Service, Inc. | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Mar 2008 |
| 333 | Thalmann Oilfield | Carrizo SPGS, TX 78834 | Oil Operator | May 2025 |
| 334 | Thalmann, David Vac Service Inc | Carrizo SPGS, TX 78834 | Oil & Gas Operator | May 2025 |
| 335 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | May 2025 |
| 336 | Tidelands Oil Corporation | Crystal City, TX 78839 | Oil & Gas Operator | Aug 2003 |
| 337 | Tidemark Petroleum, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2002 |
| 338 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 339 | Tiza Energy, Inc. | Austin, TX 78715 | Oil & Gas Operator | May 2025 |
| 340 | Touchstone Resources USA, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2006 |
| 341 | Trans-Texas Resources, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Feb 1993 |
| 342 | Travers Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 343 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 344 | Trinity Operating (Usg), LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 345 | Trium, LTD. | Laredo, TX 78041 | Oil Operator | May 2025 |
| 346 | Txco Resources Inc. | San Antonio, TX 78280 | Oil & Gas Operator | May 2025 |
| 347 | U. S. Operating, Inc. | Dallas, TX 75252 | Oil & Gas Operator | May 2025 |
| 348 | U.S. Enercorp, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2019 |
| 349 | U.S. Energy Development Corp | Fort Worth, TX 76164 | Oil & Gas Operator | May 2025 |
| 350 | U.S.A. Plugging Company | Pearsall, TX 78061 | Oil & Gas Operator | May 2025 |
| 351 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 352 | USA Superior Energy LLC | Houston, TX 77077 | Oil Operator | Mar 2010 |
| 353 | Uvalde Energy Co. | Austin, TX 78747 | Oil & Gas Operator | Nov 1994 |
| 354 | V/J Oil Company | Yancey, TX 78886 | Oil & Gas Operator | Oct 2015 |
| 355 | Venus Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2002 |
| 356 | Verdun Oil & Gas LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 357 | Vernor, Milburn | Uvalde, TX 78801 | Oil & Gas Operator | Aug 2008 |
| 358 | Viceroy Petroleum, LP | College Sta, TX 77845 | Oil & Gas Operator | May 2025 |
| 359 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 360 | Virtex Operating Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2023 |
| 361 | Virtex Petroleum Company, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Jan 2008 |
| 362 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 363 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 364 | Wallis Energy, Inc. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 365 | Waters Eng. & Operating, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Sep 2013 |
| 366 | WCS Oil & Gas Corporation | Dallas, TX 75209 | Oil & Gas Operator | Aug 2021 |
| 367 | Weatherston, George D. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2001 |
| 368 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 369 | Weldon Corporation | Houston, TX 77056 | Oil Operator | Feb 2020 |
| 370 | Wen-Be | Jourdanton, TX 78026 | Oil & Gas Operator | May 2025 |
| 371 | Western Gulf Oil & Gas Inc. | Dallas, TX 75360 | Oil & Gas Operator | Jul 2000 |
| 372 | Western Pride Resources, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Jan 2011 |
| 373 | White Marlin Operating Company, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 374 | Wilbanks Energy Corporation | Houston, TX 77036 | Oil & Gas Operator | Dec 2001 |
| 375 | Wilbanks, Bruce A. | Midland, TX 79701 | Oil & Gas Operator | Aug 1996 |
| 376 | Williamson Operating Co. | Uvalde, TX 78801 | Oil & Gas Operator | May 2025 |
| 377 | Windsor Exploration Company | Dallas, TX 75204 | Oil & Gas Operator | Jan 1994 |
| 378 | Winn Exploration Co., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 379 | Wiser Oil Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2023 |
| 380 | Witherspoon Oil Co | Iowa Park, TX 76367 | Oil & Gas Operator | May 2025 |
| 381 | Wolverine Exploration Company | Houston, TX 77002 | Oil & Gas Operator | May 2019 |
| 382 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 383 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 384 | Yarborough, W. B. | Midland, TX 79701 | Oil & Gas Operator | Nov 1995 |
| 385 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 386 | Zavala Independent Gas, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2007 |