| 301 | Allen & Grace Oil Company | Kingsbury, TX 78638 | Oil & Gas Operator | Jul 1997 |
| 302 | Allen & Shumate, Inc. | Alice, TX 78333 | Oil & Gas Operator | Jan 1996 |
| 303 | Allen Brothers Company | Oil City, LA 71061 | Oil & Gas Operator | Apr 1997 |
| 304 | Allen Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Jun 2016 |
| 305 | Allen, C. L. (Doie) | Wichita Falls, TX 76309 | Oil & Gas Operator | Jul 2026 |
| 306 | Allen, Mabel F. | Corpus Christ, TX 78412 | Oil & Gas Operator | Jul 2002 |
| 307 | Alliance Resources Corporation | Dallas, TX 75367 | Oil & Gas Operator | Nov 2024 |
| 308 | Alliance Resources LLC | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 309 | Allied Energy Operating, LLC | McKinney, TX 75071 | Oil Operator | Jul 2026 |
| 310 | Allied Operating Texas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 311 | Allied-Gulf Energy, LLC | Lafayette, LA 70508 | Oil & Gas Operator | Jul 2026 |
| 312 | Allison Lease Services LLC | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 313 | Allison/Hobbs Inc. | Alba, TX 75410 | Oil & Gas Operator | Jul 2026 |
| 314 | Allsop Oil And Gas Company, Inc. | Farmers BRNCH, TX 75234 | Oil & Gas Operator | Nov 1996 |
| 315 | Alltex Exploration, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jul 2026 |
| 316 | Aln Resources Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 1993 |
| 317 | Alpar Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jul 2011 |
| 318 | Alpha Energy | Anson, TX 79501 | Oil & Gas Operator | Oct 2016 |
| 319 | Alpha Exploration Co. | Wichita Falls, TX 76309 | Oil & Gas Operator | Oct 1998 |
| 320 | Alpha Gamma Onshore, LLC | Midland, TX 79702 | Oil Operator | Jul 2026 |
| 321 | Alpha Omega Petroleum, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Mar 1996 |
| 322 | Alpine Exploration Co, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Nov 2017 |
| 323 | Alpine Gas Company, LLC | Dallas, TX 75201 | Oil & Gas Operator | Oct 2006 |
| 324 | Alpine Petroleum | Abilene, TX 79608 | Oil & Gas Operator | Jul 2018 |
| 325 | Alpine Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 326 | Alps Oil Company | Odessa, TX 79760 | Oil & Gas Operator | Aug 1999 |
| 327 | Alt Production, LLC | Kilgore, TX 75663 | Oil Operator | Jul 2026 |
| 328 | Alta Energy Corporation | Midland, TX 79701 | Oil & Gas Operator | Apr 1995 |
| 329 | Alta Mesa Services, LP | Houston, TX 77084 | Oil & Gas Operator | Jul 2026 |
| 330 | Altair Energy Corp. | Tyler, TX 75702 | Oil & Gas Operator | Jun 1994 |
| 331 | Altalay STX LLC | Guaynabo, PR 00968 | Oil & Gas Operator | Jul 2026 |
| 332 | Altex Resources, Inc. | Carney, OK 74832 | Oil & Gas Operator | Mar 2015 |
| 333 | Altman Energy, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2026 |
| 334 | Alto Minerals, Inc. | Midland, TX 79708 | Oil & Gas Operator | Apr 2019 |
| 335 | Altura Energy LTD. | Houston, TX 77210 | Oil & Gas Operator | Apr 2000 |
| 336 | Alumni Oil LLC | Plano, TX 75024 | Oil Operator | Jul 2026 |
| 337 | Alvarado 2014 LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2026 |
| 338 | Alvey Partners | Slaton, TX 79364 | Gas Operator | Jul 2026 |
| 339 | Alyaha Energy, LLC | Dumas, TX 79029 | Oil & Gas Operator | Jul 2026 |
| 340 | Alyana Energy Corporation | Houston, TX 77227 | Oil & Gas Operator | Apr 1995 |
| 341 | Alyndson Oil & Gas Inc. | Alice, TX 78333 | Oil & Gas Operator | Jun 2000 |
| 342 | Amac Energy, L.L.C. | The Woodlands, TX 77381 | Oil & Gas Operator | Jul 2026 |
| 343 | Amarillo Exploration, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Jul 2026 |
| 344 | Amarillo Natural Gas, Inc. | Amarillo, TX 79119 | Gas Operator | Jul 1996 |
| 345 | Amax Oil & Gas Inc. | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 346 | Amazon Royalties, Inc. | Fulshear, TX 77441 | Oil & Gas Operator | Jul 2026 |
| 347 | Ambassador Oil Company, LLC | Abilene, TX 79604 | Oil & Gas Operator | Jul 2026 |
| 348 | Ambassador Petroleum, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jul 2026 |
| 349 | Amble Petroleum Co., Inc. | Tuscola, TX 79562 | Oil Operator | Sep 2025 |
| 350 | Ambrit Energy Corp. | Garland, TX 75044 | Oil & Gas Operator | Jun 2003 |
| 351 | Amcon Resources, Inc. | Oklahoma City, OK 73101 | Gas Operator | Jun 2016 |
| 352 | Amedan Resources, Inc. | Chickasha, OK 73023 | Oil & Gas Operator | Mar 2008 |
| 353 | Amelia Exploration LLC | Horseshoe Bay, TX 78657 | Oil Operator | Jul 2026 |
| 354 | Amen Oil LLC | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 355 | Amend Energy Company | Houston, TX 77227 | Oil & Gas Operator | Apr 2002 |
| 356 | Amerac Energy Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2013 |
| 357 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 358 | Ameredev Operating, LLC | Austin, TX 78716 | Oil & Gas Operator | Jul 2026 |
| 359 | American Cascade Energy, Inc. | Barker, TX 77413 | Oil & Gas Operator | Jul 2026 |
| 360 | American Coastal Energy, Inc. | Houston, TX 77225 | Oil & Gas Operator | May 2008 |
| 361 | American Cometra, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2008 |
| 362 | American Delta Corporation | Portland, TX 78374 | Oil & Gas Operator | Jun 2013 |
| 363 | American Eagle Operating LLC | Gainesville, TX 76240 | Oil Operator | Jul 2026 |
| 364 | American Eagle Operating, Inc. | Spring, TX 77386 | Oil Operator | Aug 2010 |
| 365 | American Eagle Resources, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2026 |
| 366 | American Energy | Abilene, TX 79604 | Oil & Gas Operator | Jul 2004 |
| 367 | American Energy Op. Corp.,The | Houston, TX 77099 | Oil & Gas Operator | Jul 2026 |
| 368 | American Energy Partners, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Dec 2011 |
| 369 | American Energy Sources, Inc. | Spring, TX 77388 | Oil & Gas Operator | Dec 2008 |
| 370 | American Energy Texas Inc | Mineral Wells, TX 76067 | Oil Operator | Jul 2026 |
| 371 | American Energy-Perm Basin, LLC | Oklahoma City, OK 73113 | Oil & Gas Operator | May 2016 |
| 372 | American Exploration | Houston, TX 77010 | Gas Operator | Apr 1994 |
| 373 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 374 | American Explorer, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Jan 1999 |
| 375 | American Int'L Energy Corp. | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 376 | American National Petroleum Co. | Houston, TX 77057 | Oil & Gas Operator | Aug 1995 |
| 377 | American Natural Energy Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 378 | American Oilfield Systems, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2001 |
| 379 | American Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2003 |
| 380 | American Petrofina Co Of TX | Dallas, TX 75221-2159 | Oil & Gas Operator | Nov 2000 |
| 381 | American Petroleum Corp | Addison, TX 75001 | Oil & Gas Operator | Jul 2026 |
| 382 | American Pumping & Trucking | New Braunfels, TX 78131 | Oil & Gas Operator | Jul 2026 |
| 383 | American Quasar Petroleum Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2014 |
| 384 | American Resources, Inc. | Houston, TX 77079 | Oil & Gas Operator | Jul 2026 |
| 385 | American Royalty | Caldwell, TX 77836 | Oil & Gas Operator | Oct 2005 |
| 386 | American Shoreline, Inc. | Corpus Christ, TX 78401 | Oil & Gas Operator | Jul 2026 |
| 387 | American Star Energy & Min. Corp | Katy, TX 77449 | Oil & Gas Operator | Jul 2026 |
| 388 | American West | Burkett, TX 76828 | Oil & Gas Operator | Jul 2026 |
| 389 | American West Resources, Inc | Fort Worth, TX 76161 | Oil & Gas Operator | Jul 2026 |
| 390 | Americo Energy Resources, LLC | Houston, TX 77063 | Oil & Gas Operator | Jul 2026 |
| 391 | Americo Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2012 |
| 392 | Amerind Oil Company, LTD. | Midland, TX 79701 | Oil & Gas Operator | Nov 2004 |
| 393 | Ameristate Exploration LLC | Austin, TX 78701 | Oil & Gas Operator | Nov 2009 |
| 394 | Ameritech Oil & Gas Corporation | Dallas, TX 75248 | Oil & Gas Operator | May 1996 |
| 395 | Amerril Energy LLC | Houston, TX 77042 | Oil & Gas Operator | Jul 2026 |
| 396 | Ames Financial, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 397 | Ames Oil | Cross Plains, TX 76443 | Oil & Gas Operator | Jul 2026 |
| 398 | Ames Oil Corporation Of Texas | Austin, TX 78720 | Oil & Gas Operator | Mar 2015 |
| 399 | Amexco, LLC | San Antonio, TX 78259 | Oil & Gas Operator | Jul 2026 |
| 400 | Amherst Energy Holdings, LLC | Highland VLG, TX 75077 | Oil Operator | Jul 2026 |