| 601 | Arris Operating Company LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2016 |
| 602 | Arrow Energy, Incorporated | Houston, TX 77008 | Oil & Gas Operator | Jun 2025 |
| 603 | Arrow Exploration Company | Plano, TX 75075 | Oil & Gas Operator | Dec 2004 |
| 604 | Arrow Oil & Gas, LLC | Norman, OK 73070 | Oil & Gas Operator | Oct 2025 |
| 605 | Arrow Operating Company | Dallas, TX 75231 | Oil & Gas Operator | Jun 2025 |
| 606 | Arrow Rock Energy, LLC | Houston, TX 77079 | Oil & Gas Operator | Mar 2018 |
| 607 | Arrow S Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 608 | Arrowhead Energy Exp., LLC | Baton Rouge, LA 70816 | Oil & Gas Operator | Nov 2006 |
| 609 | Arrowhead Enterprises, Inc. | Baton Rouge, LA 70816 | Oil & Gas Operator | Apr 2001 |
| 610 | Arrowhead Exploration Company | Olney, TX 76374 | Oil Operator | Dec 1995 |
| 611 | Arrowhead Operating Inc. | Argyle, TX 76226 | Oil & Gas Operator | Oct 2025 |
| 612 | Arrowhead Productions, LP | Fort Worth, TX 76109 | Oil & Gas Operator | Oct 2025 |
| 613 | Arrowhead Resources, Inc. | Fort Worth, TX 76107 | Oil & Gas Operator | Oct 2025 |
| 614 | Arrowood Production Inc | Cross Plains, TX 76443 | Oil & Gas Operator | Mar 2008 |
| 615 | Aruba Petroleum, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Jun 2025 |
| 616 | Aruba Petroleum, LTD. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2003 |
| 617 | Ary, J. Kirk | Midland, TX 79708 | Oil & Gas Operator | Jun 1993 |
| 618 | Arya Resources, LLC | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 619 | Asa Oil & Gas, Inc. | Brady, TX 76825 | Oil & Gas Operator | Oct 2025 |
| 620 | Asante Operating Company, LLC | Austin, TX 78703 | Oil Operator | Oct 2025 |
| 621 | Ascent Energy, Inc | McKinney, TX 75069 | Oil & Gas Operator | Nov 2008 |
| 622 | Ascent Operating, LP | Plano, TX 75093 | Oil & Gas Operator | Aug 2008 |
| 623 | Ashbrook Oil Co. | Big Spring, TX 79721 | Oil & Gas Operator | Apr 2020 |
| 624 | Ashby, Andrew M. | Golden, CO 80401 | Oil & Gas Operator | Jul 1998 |
| 625 | Asher Resources | Boerne, TX 78006 | Oil & Gas Operator | May 2015 |
| 626 | Ashland Exploration Inc | Houston, TX 77218 | Oil & Gas Operator | Nov 2000 |
| 627 | Ashtola Exploration Company,Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Oct 2025 |
| 628 | Asm Oil & Gas Company, Inc. | Dallas, TX 75367 | Oil & Gas Operator | May 2020 |
| 629 | Aspect Abundant Shale LP | Denver, CO 80203 | Oil & Gas Operator | Nov 2012 |
| 630 | Aspect Energy, LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 631 | Aspect Resources LLC | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 632 | Aspen Energy Group, Inc. | Santa Ynez, CA 93460 | Oil & Gas Operator | Mar 2015 |
| 633 | Aspen Energy, Inc. | Seguin, TX 78156 | Oil & Gas Operator | Jul 2019 |
| 634 | Aspen Exploration, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2012 |
| 635 | Aspen Land & Exploration Co | Tulsa, OK 74159-0335 | Oil & Gas Operator | Jul 2001 |
| 636 | Aspen Operating Company LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Oct 2025 |
| 637 | Assent Energy Partners, LLC | College Sta, TX 77840 | Oil & Gas Operator | Oct 2025 |
| 638 | At Oil & Gas, LLC | Eastland, TX 76448 | Oil & Gas Operator | Oct 2025 |
| 639 | Atapco | Houston, TX 77040 | Oil & Gas Operator | Feb 1999 |
| 640 | Atasca Resources Inc | Houston, TX 77219 | Oil & Gas Operator | Oct 2025 |
| 641 | Atascosa Exploration, LLC | San Antonio, TX 78209 | Oil Operator | Apr 2020 |
| 642 | Atchley Resources, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 643 | Atco Prod. Co., Inc. | Winnie, TX 77665 | Oil & Gas Operator | Nov 2020 |
| 644 | Atex Exploration & Operating Co. | Whitesboro, TX 76273 | Oil & Gas Operator | Oct 2025 |
| 645 | Atf Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 646 | Athanor Texas Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2002 |
| 647 | Athena Energy, Inc. | Gallatin, TN 37066 | Oil & Gas Operator | Oct 2025 |
| 648 | Athena Resources, Inc. | Dallas, TX 75248 | Oil & Gas Operator | Oct 2025 |
| 649 | Athlon Energy Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2014 |
| 650 | Athlon Fe Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2015 |
| 651 | Athlon Holdings LP | Denver, CO 80202 | Oil & Gas Operator | Jan 2015 |
| 652 | Atinum Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 653 | Atinum Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 654 | Atkins Oil L.C. | Conroe, TX 77303 | Oil Operator | Oct 2025 |
| 655 | Atkinson Energy Corporation | Giddings, TX 78942 | Oil & Gas Operator | Jan 2010 |
| 656 | Atkinson Operations LLC | Three Rivers, TX 78071 | Oil Operator | Oct 2025 |
| 657 | Atkinson, Clifford III | San Antonio, TX 78217 | Oil & Gas Operator | Dec 1996 |
| 658 | Atkinson, Jim | Nocona, TX 76255 | Oil & Gas Operator | Oct 2025 |
| 659 | Atlantic & Gulf Petroleum Co. | Houston, TX 77002 | Gas Operator | Mar 1991 |
| 660 | Atlantic Exploration, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2015 |
| 661 | Atlantic Oil Corporation | Denver, CO 80206 | Oil & Gas Operator | Dec 1982 |
| 662 | Atlantic Operating II, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 663 | Atlantic Operating, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 664 | Atlantic Resources Company, LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 665 | Atlantic Richfield Company | Plano, TX 75074 | Oil & Gas Operator | Dec 2016 |
| 666 | Atlantis Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Oct 2025 |
| 667 | Atlas Barnett, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2019 |
| 668 | Atlas Eagle Ford Oper Co, LLC | Fort Worth, TX 76116 | Oil & Gas Operator | May 2020 |
| 669 | Atlas Energy Corporation (Del.) | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2025 |
| 670 | Atlas Fuel Supply, LTD. | Houston, TX 77269 | Oil Operator | Oct 2025 |
| 671 | Atlas Growth Texas, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2019 |
| 672 | Atlas Oil & Gas Exploration, LLC | Cedar Park, TX 78613 | Oil & Gas Operator | Aug 2003 |
| 673 | Atlas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 674 | Atmic, Inc. | Houston, TX 77002 | Oil & Gas Operator | Jun 2008 |
| 675 | Atmos Pipeline - Texas | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 676 | Atnipp, H. L. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 677 | Atoka Energy LLC | Gainesville, TX 76241 | Oil & Gas Operator | Oct 2025 |
| 678 | Atoka Operating Permian, LLC | Addison, TX 75001 | Oil & Gas Operator | Sep 2023 |
| 679 | Atoka Operating, Inc. | Gainesville, TX 76241 | Oil & Gas Operator | Oct 2025 |
| 680 | Atp Oil & Gas Corporation | Houston, TX 77027 | Oil & Gas Operator | Jun 2008 |
| 681 | Atropos Exploration Company | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 682 | Atropos Production Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 683 | Atwa Energy Co. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 1996 |
| 684 | Atwell Oil & Gas, Inc. | Cross Plains, TX 76443 | Oil & Gas Operator | Oct 2025 |
| 685 | Atwell Technical Services, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2025 |
| 686 | Atwell, David L. | Duncan, OK 73533 | Oil & Gas Operator | Jul 2003 |
| 687 | Auburn Enterprises, Inc. | Kyle, TX 78640 | Oil & Gas Operator | Aug 2003 |
| 688 | Auden Oil Inc. | Hardin, TX 77561 | Oil Operator | Oct 2025 |
| 689 | Audrey Oil & Gas LLC | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 690 | August Oil | Plano, TX 75093 | Oil & Gas Operator | Aug 2003 |
| 691 | Augusta Oil & Gas | Abilene, TX 79604 | Oil & Gas Operator | Nov 2002 |
| 692 | Augusta Oil & Gas Inc | Abilene, TX 79604 | Oil & Gas Operator | Dec 2015 |
| 693 | Augustus Oil And Gas Corporation | Austin, TX 78731 | Oil & Gas Operator | Oct 2025 |
| 694 | Aunix Operating, LLC | Tomball, TX 77377 | Oil Operator | Oct 2025 |
| 695 | Aurivos LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 696 | Aurora Exploration & Prod Co | Whitesboro, TX 76273 | Oil Operator | Oct 2025 |
| 697 | Aurora Gas, Inc. | Houston, TX 77057 | Oil & Gas Operator | Jan 2000 |
| 698 | Aurora Operating, LLC | Houston, TX 77010 | Oil Operator | Oct 2025 |
| 699 | Aurora Power Resources, Inc. | Houston, TX 77042 | Oil & Gas Operator | Aug 2018 |
| 700 | Aurora Resources Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |