| 401 | Apex Resources LLC | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2025 |
| 402 | Apex Royalties, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 1997 |
| 403 | Apexco, Inc. | Sand Springs, OK 74063 | Oil & Gas Operator | Mar 2025 |
| 404 | API Operating Co. | Houston, TX 77036 | Oil & Gas Operator | Sep 2025 |
| 405 | Apollo Energy Operating Co, LP | Lake Charles, LA 70601 | Oil & Gas Operator | Dec 2024 |
| 406 | Appling, J. B. | Midland, TX 79702 | Oil & Gas Operator | Jul 1997 |
| 407 | Approach Operating LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Sep 2020 |
| 408 | Apr Operating LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2022 |
| 409 | Apv McCamey LLC | MC Camey, TX 79752 | Oil & Gas Operator | Sep 2025 |
| 410 | Apx & Assoc. | FT Stockton, TX 79735 | Oil & Gas Operator | Sep 1998 |
| 411 | Aquila Energy Resources Corp. | Houston, TX 77042 | Oil & Gas Operator | Nov 2013 |
| 412 | Aquinas Oil & Gas, LLC | Muenster, TX 76252 | Oil Operator | Sep 2025 |
| 413 | Arabella Operating, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2025 |
| 414 | Arabella Petroleum Company, LLC | Austin, TX 78701 | Oil & Gas Operator | Sep 2025 |
| 415 | Arabie, Inc. | Lake Charles, LA 70605 | Oil & Gas Operator | Apr 2025 |
| 416 | Araluen Energy, Inc. | Houston, TX 77094 | Oil Operator | Jun 2022 |
| 417 | Aramco Petroleum LLC | Burkburnett, TX 76354 | Oil Operator | Sep 2025 |
| 418 | Aransas DRLG & Workover Co Inc | Corpus Chrsti, TX 78409 | Oil & Gas Operator | Jul 2019 |
| 419 | Aransas Oil Company, Inc. | San Antonio, TX 78253 | Oil & Gas Operator | Jan 1999 |
| 420 | Aransas Resources, Inc | Houston, TX 77083 | Oil & Gas Operator | Dec 2005 |
| 421 | Aransas Resources, LP | Houston, TX 77006 | Oil & Gas Operator | Oct 2006 |
| 422 | Arapahoe Prod. Co. | Borger, TX 79008 | Oil & Gas Operator | May 2012 |
| 423 | Arapahoe Resources LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Jun 2025 |
| 424 | Aratex Production Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2003 |
| 425 | Araxas Exploration, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Apr 1998 |
| 426 | Arben Oil, Inc. | Coleman, TX 76834 | Oil & Gas Operator | Sep 2025 |
| 427 | Arbol Resources, Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2025 |
| 428 | Arcadia Energy Resources, LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2025 |
| 429 | Arcadia Expl. & Prod. Company | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2011 |
| 430 | Arcadia Operating, LLC | Dallas, TX 75219 | Oil & Gas Operator | Sep 2025 |
| 431 | Arcadian Mineral Development | Brownwood, TX 76801 | Oil & Gas Operator | Dec 2013 |
| 432 | Arcadian Mineral Development,LLC | Brownwood, TX 76801 | Oil & Gas Operator | Sep 2025 |
| 433 | Arcadian Resources LLC | Glen Elder, KS 67446 | Oil & Gas Operator | Sep 2025 |
| 434 | Arch Oil & Gas, LLC | Dallas, TX 75254 | Oil & Gas Operator | Sep 2025 |
| 435 | Arch Operating, LLC | Wichita Falls, TX 76308 | Oil Operator | Sep 2025 |
| 436 | Arch Petroleum Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2008 |
| 437 | Archer Drilling & Prod. Co. | Archer City, TX 76351 | Oil & Gas Operator | Nov 2002 |
| 438 | Archer Petroleum | Frisco, TX 75034 | Oil & Gas Operator | Aug 2021 |
| 439 | Archer Reef Oil Co. | Bellevue, TX 76228 | Oil & Gas Operator | Sep 2025 |
| 440 | Archer, Carl M. | Spearman, TX 79081 | Oil & Gas Operator | Feb 2005 |
| 441 | Archer, Carl M. Farms, Inc. | Gruver, TX 79040 | Gas Operator | Mar 2024 |
| 442 | Archer,Carl M Estate Partnership | Gruver, TX 79040 | Oil & Gas Operator | Sep 2022 |
| 443 | Archon Resources LLC | Houston, TX 77074 | Oil & Gas Operator | Jan 2015 |
| 444 | Arco Oil & Gas Co.-Silsbee | Lafayette, LA 70505 | Oil & Gas Operator | Jul 1993 |
| 445 | Arco Oil & Gas Company | Plano, TX 75086 | Oil & Gas Operator | Mar 2006 |
| 446 | Arco Permian | Houston, TX 77079 | Oil & Gas Operator | Dec 2001 |
| 447 | Arcooil Corp | San Antonio, TX 78205 | Oil & Gas Operator | Sep 2025 |
| 448 | Arcotex Oil & Gas Inc | Gainesville, TX 76241-1357 | Oil & Gas Operator | Jun 2025 |
| 449 | Arcturus Operating Company | Addison, TX 75001 | Oil & Gas Operator | Sep 2025 |
| 450 | Ard Drilling Company Inc. | Abilene, TX 79604 | Oil & Gas Operator | Jun 2000 |
| 451 | Ard, Julian | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2002 |
| 452 | Arden Energy Partners, Inc. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2013 |
| 453 | Ardent Energy LLC | Edmond, OK 73083 | Oil & Gas Operator | Sep 2025 |
| 454 | Area Pipe And Equipment | Midland, TX 79702 | Oil & Gas Operator | Apr 2003 |
| 455 | Arena Offshore, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Mar 2009 |
| 456 | Arena Production Company | Midland, TX 79710 | Oil & Gas Operator | Sep 2025 |
| 457 | Arena Resources LLC | Longview, TX 75608 | Oil & Gas Operator | Jun 2025 |
| 458 | Ares Energy, LTD. | Midland, TX 79701 | Oil & Gas Operator | Sep 2025 |
| 459 | Arete Creek Operating, LLC | Midland, TX 79703 | Oil & Gas Operator | Sep 2025 |
| 460 | Arete Operating Company II, LLC | San Antonio, TX 78260 | Oil & Gas Operator | Sep 2025 |
| 461 | Arete Operating Company III, LLC | San Antonio, TX 78260 | Oil & Gas Operator | Sep 2025 |
| 462 | Arete Operating Company, LLC | San Antonio, TX 78260 | Oil & Gas Operator | Sep 2025 |
| 463 | Argali Resources | Dallas, TX 75206 | Oil & Gas Operator | Apr 2003 |
| 464 | Argee Oil Company | Midland, TX 79702 | Gas Operator | May 1994 |
| 465 | Argent Energy (Us) Holdings Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Sep 2021 |
| 466 | Argent Petroleum Corporation | Center, TX 75935 | Oil & Gas Operator | Sep 2025 |
| 467 | Argosy | Carrollton, TX 75010 | Oil & Gas Operator | Aug 2003 |
| 468 | Argus Drilling, LLC | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 469 | Argus Production Company | Dallas, TX 75382 | Oil & Gas Operator | Nov 2023 |
| 470 | Ariel Resources, Inc. | Dallas, TX 75287 | Oil & Gas Operator | May 1997 |
| 471 | Aries Operating LP | Houston, TX 77042 | Oil & Gas Operator | Sep 2025 |
| 472 | Aries Operating, LLC | Houston, TX 77010 | Oil & Gas Operator | Feb 2010 |
| 473 | Arista Novelty, Inc. | Houston, TX 77256 | Oil & Gas Operator | Feb 1995 |
| 474 | Ark Petroleum Inc. | Clyde, TX 79510 | Oil & Gas Operator | Nov 1997 |
| 475 | Ark-La-Tex Energy Partners, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2013 |
| 476 | Ark-La-Tex Energy, L.L.C. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2025 |
| 477 | Ark-La-Tex Production, LLC | Doddridge, AR 71834 | Oil Operator | Jan 2025 |
| 478 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |
| 479 | Arkland Producing Co Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2023 |
| 480 | Arkland, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 1994 |
| 481 | Arkoma Prod Co Of Texas, Inc. | Dallas, TX 75225 | Oil Operator | May 2004 |
| 482 | Arkoma, Sandra | Pampa, TX 79066 | Oil & Gas Operator | May 1995 |
| 483 | Arleand Resources | Overton, TX 75684 | Oil & Gas Operator | Sep 2025 |
| 484 | Arledge & Young, Inc. | Weatherford, TX 76086 | Oil & Gas Operator | Feb 1999 |
| 485 | Arledge, Terry | Rockdale, TX 76567 | Oil & Gas Operator | Sep 2019 |
| 486 | Arlen Corporation | Houston, TX 77077 | Oil & Gas Operator | Mar 2008 |
| 487 | Arlian, Inc. | Denver, CO 80202 | Oil Operator | Feb 1998 |
| 488 | Armidillo Oil Company | Luling, TX 78648 | Oil & Gas Operator | Sep 2025 |
| 489 | Armor Energy LLC | Tulsa, OK 74146 | Oil & Gas Operator | Jun 2022 |
| 490 | Armor Petroleum, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2025 |
| 491 | Armour Resource Holdings, LTD. | Houston, TX 77046 | Oil & Gas Operator | Nov 1994 |
| 492 | Armour, Widd | Graham, TX 76450 | Oil & Gas Operator | Sep 2025 |
| 493 | Armstrong Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | Jun 2025 |
| 494 | Arnold Oil Properties, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | May 2019 |
| 495 | Arnold Oil Properties, L.L.C. | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2025 |
| 496 | Arnot Oil Company, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 2025 |
| 497 | Arnot, W. G., Jr. | Breckenridge, TX 76424 | Oil & Gas Operator | Jan 2017 |
| 498 | Aroc (Texas) Inc | Houston, TX 77090 | Oil & Gas Operator | Dec 2014 |
| 499 | Arp Barnett, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2018 |
| 500 | Arpel, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2014 |