| 301 | Ames Oil | Cross Plains, TX 76443 | Oil & Gas Operator | Mar 2025 |
| 302 | Ames Oil Corporation Of Texas | Austin, TX 78720 | Oil & Gas Operator | Mar 2015 |
| 303 | Amexco, LLC | San Antonio, TX 78259 | Oil & Gas Operator | Mar 2025 |
| 304 | Amherst Energy Holdings, LLC | Highland VLG, TX 75077 | Oil Operator | Mar 2025 |
| 305 | Aminex USA, Inc. | Somerset, TX 78069 | Oil & Gas Operator | May 2018 |
| 306 | Amirmex Inc. | Denver, CO 80234 | Oil & Gas Operator | Mar 2025 |
| 307 | Amistad Energy Services, LLC | Katy, TX 77450 | Oil & Gas Operator | Oct 2017 |
| 308 | Amity Oil Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1977 |
| 309 | Ammo Energy, LLC | Oklahoma City, OK 73160 | Oil & Gas Operator | Feb 2009 |
| 310 | Ammonite Energy Texas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2003 |
| 311 | Amoco Production Co-Ratliff City | Ratliff City, OK 73081 | Oil Operator | May 1998 |
| 312 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 313 | Ampak Oil Company | Plano, TX 75074 | Oil & Gas Operator | Mar 2025 |
| 314 | Amplify Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 315 | Amron Petroleum, Inc. | Midland, TX 79708 | Oil & Gas Operator | Jan 1996 |
| 316 | Amt Resources, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Mar 2025 |
| 317 | Amtex Energy | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 318 | Amtex Energy, Inc. | Fort Worth, TX 76147 | Oil & Gas Operator | Mar 2025 |
| 319 | Amx Energy, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Mar 2025 |
| 320 | Anadarko Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Feb 2006 |
| 321 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 322 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 323 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2025 |
| 324 | Anadarko Ogc Company | Houston, TX 77251 | Oil & Gas Operator | Dec 1998 |
| 325 | Anadarko Petroleum Co | Houston, TX 77227 | Oil & Gas Operator | Feb 1998 |
| 326 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Jan 2025 |
| 327 | Ananda Energy Inc. | Pampa, TX 79065 | Oil & Gas Operator | Jan 2021 |
| 328 | Anaqua Oil & Gas, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2008 |
| 329 | Anaqua Operating Company LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 330 | Anatexas Offshore, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 331 | Anathema, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Dec 1994 |
| 332 | Ancell Oil Co. | Wichita Falls, TX 76309 | Oil & Gas Operator | Dec 2018 |
| 333 | Anchor B Production, Inc. | Orla, TX 79770 | Oil & Gas Operator | Aug 2003 |
| 334 | Anchor Oil Company | Gruver, TX 79040 | Gas Operator | Mar 2025 |
| 335 | Anchor Operating Co. | Houston, TX 77055 | Oil & Gas Operator | Mar 2025 |
| 336 | Anchor Petroleum, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Jan 1996 |
| 337 | Anco Account | Wichita Falls, TX 76301 | Oil & Gas Operator | Oct 1995 |
| 338 | Andalucia Oil Company | San Antonio, TX 78258 | Oil Operator | Mar 2025 |
| 339 | Andector Exploration Company | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 340 | Anderman/Smith Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 1995 |
| 341 | Anderson Energy Corporation | Arvada, CO 80004 | Oil & Gas Operator | Mar 2025 |
| 342 | Anderson Oil & Gas Account | Wichita Falls, TX 76301 | Oil & Gas Operator | Nov 2013 |
| 343 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 344 | Anderson Oil Corporation | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Nov 1999 |
| 345 | Anderson Oil LTD. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 346 | Anderson Petro-Equipment, Inc. | Montgomery, TX 77356 | Oil & Gas Operator | Mar 2025 |
| 347 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 348 | Anderson Production | Cisco, TX 76437 | Oil & Gas Operator | Mar 2025 |
| 349 | Anderson, Carl T. | Wichita Falls, TX 76301 | Oil & Gas Operator | Feb 2014 |
| 350 | Anderson, Dorman | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 2012 |
| 351 | Anderson, E D | Cisco, TX 76437 | Oil & Gas Operator | Nov 2009 |
| 352 | Anderson, James K. Inc. | Abilene, TX 79608 | Oil & Gas Operator | Mar 2025 |
| 353 | Anderson, Roger W. Corp. | Clyde, TX 79510 | Oil & Gas Operator | Apr 2020 |
| 354 | Anderson, Steven C. | Victoria, TX 77902 | Gas Operator | Jun 2004 |
| 355 | Ando Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 1998 |
| 356 | Andrew Alan Exploration, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2017 |
| 357 | Andrew, Robert Oneal | Olney, TX 76374 | Oil & Gas Operator | Sep 1998 |
| 358 | Andrews & Corkran, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Feb 2000 |
| 359 | Andrews, B. C. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 360 | Andrus Resources Corporation | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 361 | Anegada Resources | Kerrville, TX 78029 | Oil & Gas Operator | Jan 2002 |
| 362 | Anejo Production, LLC | Electra, TX 76360 | Oil & Gas Operator | Mar 2025 |
| 363 | Angel Operating LLC | Metairie, LA 70033 | Oil Operator | Mar 2025 |
| 364 | Angelo, Ernest, Jr. | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 365 | Angle Oil Company | Hays, KS 67601 | Oil Operator | Sep 2002 |
| 366 | Anloc, LLC | Houston, TX 77024 | Oil & Gas Operator | Apr 2019 |
| 367 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 368 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 369 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 370 | Antara Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 2004 |
| 371 | Antares Energy Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2025 |
| 372 | Antares Oil Corp | Denver, CO 80202 | Oil & Gas Operator | Oct 2015 |
| 373 | Antelope Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 374 | Antelope Energy Partners, LLC | Houston, TX 77043 | Oil & Gas Operator | Mar 2025 |
| 375 | Antelope Production Co. | Midland, TX 79701 | Oil & Gas Operator | Oct 1995 |
| 376 | Antelope Resources Inc | Billings, MT 59101 | Oil & Gas Operator | May 2017 |
| 377 | Antero Resources I, LP | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 378 | Antero Resources II, LP | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 379 | Anthony Oil & Gas Co. | Shreveport, LA 71135 | Oil Operator | May 1993 |
| 380 | Anthony, Bob G. Inc. | Brookhaven, MS 39601 | Oil & Gas Operator | Mar 2025 |
| 381 | Antilley, Joe | Abilene, TX 79602 | Oil & Gas Operator | Jan 2024 |
| 382 | Antle Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 383 | Antle, E. | Graham, TX 76450 | Oil & Gas Operator | Oct 1994 |
| 384 | Aoco Operating Company, L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Feb 2005 |
| 385 | Aoco Operating, L.P. | Houston, TX 77008 | Oil & Gas Operator | Mar 2008 |
| 386 | Aog, Inc. | Norman, OK 73070 | Oil & Gas Operator | Nov 2014 |
| 387 | Aogp, LLC | Turtle Lake, WI 54889 | Oil & Gas Operator | Sep 2019 |
| 388 | Aop Operating Corporation | Dallas, TX 75313 | Oil & Gas Operator | Aug 2003 |
| 389 | Ap Operating, Inc. | Plano, TX 75074 | Oil & Gas Operator | Mar 2025 |
| 390 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Mar 2025 |
| 391 | Apache Energy Resources Corp | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 392 | Apache Oil Company | San Antonio, TX 78227 | Oil & Gas Operator | Jun 2023 |
| 393 | Apache Production Company | Holliday, TX 76366 | Oil & Gas Operator | Mar 2025 |
| 394 | Apache Shelf, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jan 2014 |
| 395 | Apb Oil Corporation | Houston, TX 77052 | Oil & Gas Operator | Apr 1996 |
| 396 | Apc Operating Partnership | Tulsa, OK 74136 | Oil & Gas Operator | Oct 1996 |
| 397 | Apco Oil Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jun 1993 |
| 398 | Apex Energy, Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Mar 2025 |
| 399 | Apex Oil & Gas, Inc. | Houston, TX 77067 | Oil & Gas Operator | Oct 2009 |
| 400 | Apex Operating & Equip. Co. | Bowie, TX 76230 | Oil & Gas Operator | Nov 2003 |