| 601 | Ausanka Oil Operations | Wichita Falls, TX 76308 | Oil & Gas Operator | Jun 1995 |
| 602 | Ausland Production Company | Midland, TX 79702 | Oil & Gas Operator | May 1999 |
| 603 | Austex Energy, Inc. | Granbury, TX 76048 | Oil & Gas Operator | Apr 1993 |
| 604 | Austin Energy Operations, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jul 2025 |
| 605 | Austin Minerals Inc. | Austin, TX 78720 | Oil & Gas Operator | Jul 2025 |
| 606 | Austin Operating, LLC. | Chicago, IL 60622 | Oil Operator | Jul 2025 |
| 607 | Austin Production Company, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Mar 2015 |
| 608 | Austin Resources Corporation | Houston, TX 77027 | Oil & Gas Operator | Mar 2008 |
| 609 | Austin Ridge Energy Corporation | Houston, TX 77224 | Oil & Gas Operator | Jul 2025 |
| 610 | Austin, Dewey | Burkburnett, TX 76354 | Oil & Gas Operator | Nov 1996 |
| 611 | Austral Oil Company Incorporated | Sulphur, LA 70663 | Oil & Gas Operator | Mar 2008 |
| 612 | Auten Operating Company, Inc. | Houston, TX 77242 | Oil & Gas Operator | May 1998 |
| 613 | Auterra Operating, LLC | Friendswood, TX 77546 | Oil & Gas Operator | Jul 2025 |
| 614 | Autry Producing Co. | Cisco, TX 76437 | Oil & Gas Operator | Aug 2008 |
| 615 | Autry Producing Inc. | Cisco, TX 76437 | Oil Operator | Jul 2025 |
| 616 | Autry, Martin | Seguin, TX 78155 | Oil Operator | Jul 2025 |
| 617 | Autumn Energy LLC | Andrews, TX 79714 | Oil Operator | Aug 2017 |
| 618 | Autumn Energy Operating | Midland, TX 79710 | Oil & Gas Operator | Jul 2025 |
| 619 | Av-Tech Resources Corporation | Kerrville, TX 78028 | Oil & Gas Operator | Jul 2022 |
| 620 | Avad Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 621 | Avalanche Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Jul 2025 |
| 622 | Avalon TX Operating, LLC | Andrews, TX 79714 | Oil & Gas Operator | Jan 2023 |
| 623 | Aven Gas & Oil Inc | Oklahoma City, OK 73113-0491 | Oil & Gas Operator | Nov 2021 |
| 624 | Averill, W. M. Inc. | Victoria, TX 77902 | Oil & Gas Operator | Jun 2003 |
| 625 | Avery Oil & Gas, L.P. | Buena VIsta, CO 81211 | Gas Operator | Dec 2006 |
| 626 | Avery, Irving W. | Buena VIsta, CO 81211 | Oil & Gas Operator | Mar 2008 |
| 627 | Avian Tech International, Inc. | Euless, TX 76040 | Oil & Gas Operator | Apr 1995 |
| 628 | Aviara Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2002 |
| 629 | Avid Energy Assets LLC | Midland, TX 79708 | Oil Operator | Jul 2025 |
| 630 | Avighna Energy Inc | Sugar Land, TX 77487 | Oil & Gas Operator | Jan 2019 |
| 631 | Avips Petroleum, Inc. | Abilene, TX 79605 | Oil & Gas Operator | Jun 1996 |
| 632 | Avra Oil Co | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 633 | Awp Operating Company | George West, TX 78022 | Oil & Gas Operator | Jul 2025 |
| 634 | Axia Energy II LLC | HGHLNDS Ranch, CO 80129 | Oil & Gas Operator | Jan 2020 |
| 635 | Axio Production Company, L.P. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2006 |
| 636 | Axis Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | Jul 2025 |
| 637 | Axtel Energy, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Jul 2025 |
| 638 | Ayers Oil Co. | Crystal City, TX 78839 | Oil & Gas Operator | Sep 1995 |
| 639 | Ayers, R.B. | Sidney, TX 76474 | Oil & Gas Operator | Apr 2003 |
| 640 | Ayres, C. D. | Iowa Park, TX 76367 | Oil & Gas Operator | Jul 2025 |
| 641 | Ayres, Joe D. | Holliday, TX 76366 | Oil & Gas Operator | Dec 2004 |
| 642 | Azimuth Energy, LLC | Denver, CO 80203 | Oil & Gas Operator | Sep 2006 |
| 643 | Aztec Drilling & Operating, LLC | Houston, TX 77056 | Oil & Gas Operator | Sep 2015 |
| 644 | Aztec Energy, LLC | Wichita Falls, TX 76301 | Oil Operator | Jul 2025 |
| 645 | Aztec Oil & Gas Company "A" | Wichita Falls, TX 76309 | Oil & Gas Operator | Sep 2010 |
| 646 | Azteca Operating, Inc. | Electra, TX 76360 | Oil Operator | Jul 2025 |
| 647 | Azteca Petroleum, LLC | Fort Worth, TX 76106 | Oil & Gas Operator | Jul 2025 |
| 648 | Aztel Operating Inc. | Windthorst, TX 76389 | Oil Operator | Oct 2003 |
| 649 | Aztex Petroleum | Chandler, AZ 85249 | Oil & Gas Operator | Jul 2025 |
| 650 | Azul, Inc. | Buffalo Gap, TX 79508 | Oil & Gas Operator | Aug 1995 |