| 301 | Proton Energy, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2005 |
| 302 | Puls Operating Company | Boerne, TX 78006 | Oil & Gas Operator | Jul 2026 |
| 303 | Puls, W. L. | Houston, TX 77084 | Oil & Gas Operator | Sep 2002 |
| 304 | Pyramid Exploration | Houston, TX 77241 | Oil & Gas Operator | Sep 1995 |
| 305 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 306 | Radley, Terry R., Operator | Sourlake, TX 77659 | Oil & Gas Operator | Apr 2006 |
| 307 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 308 | Red Wolf Oil Company, Inc. | Brenham, TX 77833 | Oil & Gas Operator | Jul 2026 |
| 309 | Redman Operating Company | Houston, TX 77042 | Oil & Gas Operator | May 2008 |
| 310 | Redwood Operating, Inc. | Houston, TX 77058 | Oil & Gas Operator | Jul 2026 |
| 311 | Reef Exploration, Inc. (A-1) | Richardson, TX 75080 | Oil & Gas Operator | Oct 2006 |
| 312 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Jul 2026 |
| 313 | Republic Resources, LLC. | Longview, TX 75605 | Oil & Gas Operator | Jul 2026 |
| 314 | Rheaco Oil Company, LTD. | Sourlake, TX 77659 | Oil Operator | Jul 2026 |
| 315 | Rock Creek Oil, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Nov 2019 |
| 316 | Rockbridge Oil And Gas, Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1997 |
| 317 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | Apr 2026 |
| 318 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Jul 2026 |
| 319 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Jul 2026 |
| 320 | Royal Production Company, Inc. | Corpus Christ, TX 78401 | Oil & Gas Operator | Jul 2026 |
| 321 | Rusk Energy Operating LLC | Houston, TX 77040 | Oil & Gas Operator | Jul 2026 |
| 322 | Rutherford Oil Corporation | Houston, TX 77046 | Oil & Gas Operator | Jun 2019 |
| 323 | S & S Operating Company, Inc. | Winnie, TX 77665 | Oil & Gas Operator | Jul 2026 |
| 324 | Sabco Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2011 |
| 325 | Sabco Operating Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2018 |
| 326 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2026 |
| 327 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 328 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | May 2026 |
| 329 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 330 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 331 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2026 |
| 332 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 333 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Jul 2026 |
| 334 | Santana Energy Services, LLC | Baton Rouge, LA 70809 | Oil & Gas Operator | Jul 2026 |
| 335 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |
| 336 | Sawtooth Operating Co., Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2026 |
| 337 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Jul 2026 |
| 338 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 339 | Seneca Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 340 | Senora Resources, Inc. | Dime Box, TX 77853 | Oil & Gas Operator | Jul 2026 |
| 341 | Serco Operating LLC | Katy, TX 77450 | Oil Operator | Jul 2026 |
| 342 | Service Production Company, Inc. | Santa Fe, TX 77510 | Oil & Gas Operator | May 1999 |
| 343 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 344 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Jul 2026 |
| 345 | Shoco Production LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 346 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 347 | Shore Petroleum Corp. | Corpus Christ, TX 78401 | Oil & Gas Operator | Jul 2026 |
| 348 | Siana Oil & Gas | Conroe, TX 77305 | Oil & Gas Operator | Jul 2026 |
| 349 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Apr 2026 |
| 350 | Silverbrook Operating II LLC | Barker, TX 77413 | Oil & Gas Operator | Jul 2026 |
| 351 | Silverbrook Operating, LLC | Barker, TX 77413 | Oil & Gas Operator | Jul 2026 |
| 352 | Sizemore, James | Hardin, TX 77561 | Oil & Gas Operator | Jun 2003 |
| 353 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 354 | Smith, L. C. | Jacksonville, TX 75766 | Oil & Gas Operator | Jul 2026 |
| 355 | Smyth Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2003 |
| 356 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 357 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Jul 2026 |
| 358 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 359 | Southern G Holdings, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2007 |
| 360 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 361 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Jul 2026 |
| 362 | Stealth Onsite Solutions LLC | Pasadena, TX 77505 | Oil Operator | Jul 2026 |
| 363 | Sterling Expl. & Prod. Co., LLC | Houston, TX 77057 | Oil & Gas Operator | Jul 2026 |
| 364 | Stone, M. L. | Kerrville, TX 78029 | Oil & Gas Operator | Aug 2003 |
| 365 | Stonegate Operators, Inc. | Addison, TX 75001 | Oil Operator | Jul 2026 |
| 366 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Jul 2026 |
| 367 | Stroud Production LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 368 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Jul 2026 |
| 369 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 370 | SV Energy Company, LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Mar 2017 |
| 371 | Synergy Oil & Gas, Inc. (A) | Houston, TX 77024 | Oil & Gas Operator | Aug 2001 |
| 372 | T & G Oil, Inc. | White Oak, TX 75693 | Oil & Gas Operator | Dec 2010 |
| 373 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Jul 2026 |
| 374 | Texana Operating Company | Houston, TX 77090 | Oil & Gas Operator | Jul 2026 |
| 375 | Texas Sunset Energy And Ent Inc | Victoria, TX 77904 | Oil Operator | Aug 2003 |
| 376 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 377 | Texegy Operating Company LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Dec 2024 |
| 378 | Tharp Operating Company | Houston, TX 77070 | Oil & Gas Operator | Nov 2014 |
| 379 | Thorp Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 380 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 381 | Touchstone Resources USA, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2006 |
| 382 | Travis Operating, LLC | Kingwood, TX 77345 | Oil & Gas Operator | Jul 2026 |
| 383 | Tri City Oil Co., LLC | Winnie, TX 77665 | Oil Operator | Jul 2026 |
| 384 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 385 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2026 |
| 386 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | Jul 2026 |
| 387 | Triax Energy LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2018 |
| 388 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |
| 389 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 390 | Tucker Operating Co., Inc. | Victoria, TX 77903 | Oil & Gas Operator | Jul 2026 |
| 391 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 392 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2026 |
| 393 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 394 | Universal Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2002 |
| 395 | Us Ecology Winnie, LLC | Winnie, TX 77665 | Oil Operator | Jul 2026 |
| 396 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 397 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Mar 2026 |
| 398 | Venus Exploration, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 399 | Vestige Energy, LLC | Alvin, TX 77511 | Oil & Gas Operator | Jul 2026 |
| 400 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |