| 301 | Advance Oil Corporation | Kiefer, OK 74041-4105 | Oil & Gas Operator | Feb 2026 |
| 302 | Advanced Petro Corp | Hamburg, NY 14075-5003 | Oil & Gas Operator | Dec 1992 |
| 303 | Advanced Petroleum Enhancement, Inc | Madisonville, KY 42431 | Oil & Gas Operator | Dec 2021 |
| 304 | Advanced Recovery Services Co | Denver, CO 80265 | Oil & Gas Operator | Apr 2007 |
| 305 | Advanced Wireless Communications, L.L.C. | Farmington, NM 87401 | Oil & Gas Operator | Feb 2026 |
| 306 | Advantage Oil & Gas, Inc. | Pinehurst, TX 77362 | Oil & Gas Operator | Apr 2026 |
| 307 | Advantage Resour | | Oil & Gas Operator | May 1994 |
| 308 | Advantage Resources Inc | Broomfield, CO 80020 | Oil & Gas Operator | Dec 2025 |
| 309 | Advantagewon Oil, Us, Corp. | Batson, TX 77519 | Oil Operator | Dec 2019 |
| 310 | Advent Oil & Operating Inc | Gulfport, MS 39506-7115 | Oil & Gas Operator | Nov 2014 |
| 311 | Adventure Expl Partners II, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2014 |
| 312 | Adventure Exploration Partners, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2011 |
| 313 | Adventure Exploration PTRS, LLC | Midland, TX 79702 | Oil & Gas Operator | Aug 2012 |
| 314 | Adventure Operating Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Jan 2021 |
| 315 | Adventure Properties Inc | Ada, OK 74820 | Oil & Gas Operator | Feb 2026 |
| 316 | Aec Operating Company | Roswell, NM 88202 | Oil & Gas Operator | Sep 2006 |
| 317 | Aed Development Inc | Columbus, OH 43220 | Oil & Gas Operator | Dec 1995 |
| 318 | Aeg Operating, LLC | Austin, TX 78746 | Oil Operator | Jun 2012 |
| 319 | Aegean Oil & Gas Inc | Brunswick, OH 44212 | Oil & Gas Operator | Dec 1993 |
| 320 | Aegean Petroleum | | Oil Operator | Mar 1982 |
| 321 | Aegis Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Sep 1998 |
| 322 | Aegis Fluids Management, LLC | Plano, TX 75093 | Oil & Gas Operator | Apr 2026 |
| 323 | Aei Corporation-Oklahoma | Oklahoma City, OK 73101-1945 | Oil & Gas Operator | Sep 2014 |
| 324 | Aei Production Company | Edmond, OK 73083 | Oil & Gas Operator | Mar 2014 |
| 325 | Aeon Energy Corp. | | Oil & Gas Operator | Mar 2026 |
| 326 | Aeon Energy Inc | Claremore, OK 74017 | Oil Operator | May 2009 |
| 327 | Aeon Operating, Inc. | Fate, TX 75132 | Oil & Gas Operator | Apr 2026 |
| 328 | Aera Energy LLC | | Oil & Gas Operator | Dec 2025 |
| 329 | Aerie Energy | Cedar Creek, TX 78612 | Oil Operator | Apr 2026 |
| 330 | Aesir Energy | | Oil Operator | Oct 2007 |
| 331 | Aeternum Energy, LLC | Tyler, TX 75713 | Oil & Gas Operator | Apr 2026 |
| 332 | Aethon Energy Operating LLC | Dallas, TX 75251 | Oil & Gas Operator | Apr 2026 |
| 333 | Aethon I LP | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 334 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 335 | Af Operating, LLC | Tuscaloosa, AL 35404 | Oil Operator | Sep 2012 |
| 336 | Afco Energy Prod Co | Indiana, PA 15701-0538 | Oil & Gas Operator | Dec 2019 |
| 337 | Afe Management Limited | Concord, Ontario, L4K 4G4 | Oil & Gas Operator | Sep 1987 |
| 338 | Afe Oil & Gas Consultants | Addison, TX 75001 | Gas Operator | Jan 2003 |
| 339 | Affiliated Holdings, Inc. | | Oil Operator | Dec 2010 |
| 340 | Afg Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 341 | Afo LLC | Velma, OK 73491 | Oil & Gas Operator | Dec 2024 |
| 342 | Afoc, LLC | Midland, TX 79710 | Oil & Gas Operator | Apr 2026 |
| 343 | Agape Energy Inc. | San Antonio, TX 78280 | Oil Operator | Apr 2026 |
| 344 | Agape Inc | Broken Arrow, OK 74011-4256 | Oil & Gas Operator | Feb 2026 |
| 345 | Agape Service Incorporated | Denver, CO 80201 | Gas Operator | Dec 2025 |
| 346 | Agar & Agar Inc | Norman, OK 73070 | Oil & Gas Operator | Oct 1996 |
| 347 | Agate Petroleum, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2015 |
| 348 | Agave Energy Inc | Stigler, OK 74462 | Oil & Gas Operator | Jan 2026 |
| 349 | Agave Operating Company, Inc. | Holliday, TX 76366 | Oil Operator | Apr 2026 |
| 350 | Agent Oil Corporation | Bison, OK 73720-0116 | Oil & Gas Operator | Mar 2005 |
| 351 | Ageron Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2026 |
| 352 | Agey Petroleum Co. | | Oil & Gas Operator | Dec 1998 |
| 353 | Aggie Oil Company | Lakewood, CO 80226 | Oil & Gas Operator | May 2001 |
| 354 | Aggietech Oil, LTD. | Midland, TX 79701 | Oil & Gas Operator | Aug 2016 |
| 355 | Aghorn Operating, Inc. | Odessa, TX 79768 | Oil & Gas Operator | Apr 2026 |
| 356 | Agip Petroleum Co., Inc. | | Oil & Gas Operator | Jan 2003 |
| 357 | Agis Energy Inc. | Lafayette, LA 70508 | Oil & Gas Operator | Apr 2026 |
| 358 | Agis Energy LLC | Lafayette, LA 70508 | Oil & Gas Operator | Apr 2026 |
| 359 | Agp Energy Services LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 360 | Agri-Acres Inc | Billings, MT 59103 | Oil Operator | Jun 1996 |
| 361 | Agricultural Energy Services | Edmond, OK 73003 | Oil & Gas Operator | Dec 2025 |
| 362 | Agricultural Energy Services Inc | Edmond, OK 73012 | Oil Operator | Jan 2026 |
| 363 | Agroil, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Apr 2026 |
| 364 | Agua Sucia LLC | Lovington, NM 88260 | Oil & Gas Operator | Jul 2018 |
| 365 | Aguila Operating Company LLC | Edmond, OK 73034 | Oil & Gas Operator | Feb 2026 |
| 366 | Agv Corp. | Attica, KS 67009 | Oil & Gas Operator | Dec 2025 |
| 367 | Ah Operating, LLC | Midland, TX 79710 | Gas Operator | Apr 2026 |
| 368 | Ahabb Oil | Luling, TX 78648 | Oil & Gas Operator | Dec 1998 |
| 369 | Aicr LLC | Odessa, TX 79768 | Oil Operator | Apr 2026 |
| 370 | Aiello Bros Oil & Gas Inc | Bradford, PA 16701-2925 | Oil & Gas Operator | Dec 2025 |
| 371 | Aikins Drilling Company | Mohave Valley, AZ 86440 | Oil Operator | Dec 2019 |
| 372 | Aikman Brothers, LLC | Amarillo, TX 79109 | Oil & Gas Operator | Jan 2026 |
| 373 | Aikman Oil Corp. | Oklahoma City, OK 73157 | Oil & Gas Operator | Apr 2026 |
| 374 | Ailey A C | Stroud, OK 74079-9209 | Oil & Gas Operator | Nov 2021 |
| 375 | Aim Consultants Inc. | Rockville, MD 20852 | Oil & Gas Operator | Mar 2008 |
| 376 | Aim Energy LLC | North Canton, OH 44720 | Oil & Gas Operator | Dec 2025 |
| 377 | Ainsworth Operat | | Oil Operator | Apr 1995 |
| 378 | Ainsworth Operating Co. | Salem, OR 97302 | Oil Operator | Dec 2025 |
| 379 | Ainsworth Prod Co. | | Oil Operator | Aug 1986 |
| 380 | Ainsworth Rig Service, LLC | | Oil Operator | Nov 2024 |
| 381 | Ainsworth, Otis | | Oil & Gas Operator | Jun 1987 |
| 382 | Airdale Oil & Gas LLC | Oil City, PA 16301-3771 | Oil & Gas Operator | Dec 2025 |
| 383 | Aix Energy Inc | | Oil & Gas Operator | Jul 2016 |
| 384 | Aix Energy LLC | | Oil & Gas Operator | Feb 2026 |
| 385 | Aj Oil, Inc. | Springfield, LA 70462 | Oil Operator | Oct 2019 |
| 386 | Aj'S Pump Truck Service, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Apr 2026 |
| 387 | Ajar International, Inc. | Randolph, NY 14772 | Gas Operator | Dec 2024 |
| 388 | Ajax Oil & Gas C | | Oil & Gas Operator | Jun 1989 |
| 389 | Ajax Oil Company | Billings, MT 59103 | Oil & Gas Operator | Dec 2003 |
| 390 | Ajax Resources, LLC | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 391 | Ajb Oil LLC | Tulsa, OK 74114-5218 | Oil Operator | Jan 2026 |
| 392 | Ak Operating Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Apr 2026 |
| 393 | Ak Pearson Family Trust | Amarillo, TX 79114 | Oil Operator | Apr 2026 |
| 394 | Akandas, Inc. | Chanute, KS 66720 | Oil Operator | Aug 2002 |
| 395 | Akea, Inc. | Holliday, TX 76366 | Oil Operator | Apr 2026 |
| 396 | Aker Oil & Gas Company | Tulsa, OK 74105-2216 | Oil & Gas Operator | Aug 2013 |
| 397 | Akers & Fultz, Inc. | Graham, TX 76450 | Oil & Gas Operator | Jun 2003 |
| 398 | Akers, B. F. | Graham, TX 76450 | Oil & Gas Operator | Apr 2026 |
| 399 | Akers, Bill | Hebbronville, TX 78361 | Oil & Gas Operator | Aug 2003 |
| 400 | Akg Operating Company | Austin, TX 78701 | Oil & Gas Operator | Apr 2026 |