| 601 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 602 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 603 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 604 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2026 |
| 605 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 606 | Overflow Energy Stack LLC | Booker, TX 79005 | Oil Operator | Sep 2022 |
| 607 | Overflow Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Sep 2026 |
| 608 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jun 2026 |
| 609 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2026 |
| 610 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Sep 2026 |
| 611 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 612 | Palm Oil & Gas Company | Sedona, AZ 86340 | Oil & Gas Operator | Jun 2026 |
| 613 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Mar 2026 |
| 614 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Sep 2026 |
| 615 | Pappe Court Jr | Kingfisher, OK 73750-0688 | Oil & Gas Operator | Nov 2001 |
| 616 | Paragon Production Company | Edmond, OK 73013-5051 | Oil & Gas Operator | Feb 2021 |
| 617 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 618 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 619 | Pasco Oil Company | Oklahoma City, OK 73172-0454 | Oil & Gas Operator | Aug 2000 |
| 620 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 621 | Payne Exploration Company | Crescent, OK 73028 | Oil & Gas Operator | May 2026 |
| 622 | Payne W C Family Trust | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Mar 2015 |
| 623 | Payrock Energy LLC | Oklahoma City, OK 73134-2612 | Oil & Gas Operator | Feb 2023 |
| 624 | Pearl Oil Company | Nichols Hills, OK 73120-1408 | Oil & Gas Operator | Nov 2023 |
| 625 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 626 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 627 | Penn VIrginia MC Operating Co LLC | Houston, TX 77084-7213 | Oil & Gas Operator | Sep 2025 |
| 628 | Penner Energy Inc | Oklahoma City, OK 73120-1930 | Oil & Gas Operator | Jun 2026 |
| 629 | Pennmark Resources Company | Edmond, OK 73013 | Oil & Gas Operator | May 2026 |
| 630 | Pet-Ex Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 631 | Petro Speed Inc | Norman, OK 73069-8116 | Oil & Gas Operator | Mar 2015 |
| 632 | Petro-Management Assoc., Inc. | Edmond, OK 73083-2346 | Oil & Gas Operator | Jun 2007 |
| 633 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 634 | Petroleum Investment Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Nov 1998 |
| 635 | Petroleum Management Prof Inc | Oklahoma City, OK 73120-1848 | Oil & Gas Operator | Apr 2009 |
| 636 | Petroleum Production MGMT., Inc. | Kansas City, MO 64112 | Oil & Gas Operator | Sep 2026 |
| 637 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 638 | Petroleum Reserve Corporation | Plymouth MTNG, PA 19462 | Oil & Gas Operator | May 2008 |
| 639 | Phillips Oil Operating Co | Enid, OK 73703-4921 | Oil & Gas Operator | May 2019 |
| 640 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 641 | Pioneer Trucking, LLC | | Oil Operator | Jun 2026 |
| 642 | Plainsmen Energy LLC | Enid, OK 73703-5747 | Oil & Gas Operator | Jun 2026 |
| 643 | Plotner Ralph Oil & Gas Inv Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2021 |
| 644 | Polaris Energy Dev Co | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2000 |
| 645 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 646 | Potter J And D Oil LLC | Kingfisher, OK 73750-3832 | Oil & Gas Operator | Mar 2015 |
| 647 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Sep 2026 |
| 648 | Prentice, Napier & Green, Inc. | Oklahoma City, OK 73142 | Oil & Gas Operator | Jun 2026 |
| 649 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |
| 650 | Primary Natural Resources Inc. | Tulsa, OK 74136-6351 | Oil & Gas Operator | Mar 2023 |
| 651 | Prime Energy Corp | Charleston, WV 25301-1707 | Oil & Gas Operator | Sep 2015 |
| 652 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Sep 2026 |
| 653 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 654 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Sep 2026 |
| 655 | Protege Energy LLC | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2018 |
| 656 | PT II LTD | | Oil & Gas Operator | Oct 2004 |
| 657 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 658 | Quad J Oil & Gas LLC | Crescent, OK 73028 | Oil & Gas Operator | Jun 2026 |
| 659 | Quail Creek Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 660 | Quail Creek Petro MGMT Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 661 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | May 2026 |
| 662 | Quest Property Inc | Yukon, OK 73099 | Oil & Gas Operator | May 2026 |
| 663 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 664 | R & A Moore, Inc. | Cleburne, TX 76033 | Oil & Gas Operator | Sep 2026 |
| 665 | R & B Trucking | Crescent, OK 73028-0775 | Oil & Gas Operator | Nov 2021 |
| 666 | R & L Properties Inc | Richmond, MO 64085-0228 | Oil & Gas Operator | Apr 2001 |
| 667 | R & N Associates | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2025 |
| 668 | R & N Oil Company | Fairfax, OK 74637 | Oil & Gas Operator | May 2013 |
| 669 | Ra-Jac LLC | Norman, OK 73069 | Oil & Gas Operator | Jun 2026 |
| 670 | Raf Oil Company | Oklahoma City, OK 73120-1944 | Oil & Gas Operator | Jul 2013 |
| 671 | Ram Asset Management Co | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 672 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 673 | Ramco Oil Company | Pawhuska, OK 74056 | Oil & Gas Operator | Feb 2012 |
| 674 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 675 | Randy Inc | Hennessey, OK 73742 | Oil & Gas Operator | May 2026 |
| 676 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 677 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2026 |
| 678 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 679 | Raven Resources LLC | Oklahoma City, OK 73172 | Oil & Gas Operator | May 2026 |
| 680 | Raw Crude Oil & Gas, L.L.C. | Norman, OK 73069 | Oil & Gas Operator | May 2026 |
| 681 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 682 | Reading & Bates Petroleum Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 683 | Rebellion Energy LLC | Tulsa, OK 74135-6241 | Oil & Gas Operator | Jun 2022 |
| 684 | Red Bluff Resources Operating LLC | Oklahoma City, OK 73112-5468 | Oil & Gas Operator | May 2026 |
| 685 | Red Eagle Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2005 |
| 686 | Red Hawk Disposal LLC | Oklahoma City, OK 73172 | Oil Operator | Jun 2023 |
| 687 | Red Plains Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Oct 2017 |
| 688 | Red Rock Resources, L.L.C. | Wichita Falls, TX 76310 | Oil & Gas Operator | Apr 2026 |
| 689 | Redfork Operations LLC | Dover, OK 73734 | Oil & Gas Operator | Jun 2026 |
| 690 | Redland Resources LLC | Oklahoma City, OK 73127 | Oil & Gas Operator | Jun 2026 |
| 691 | Redline Energy LLC | Dover, OK 73734 | Oil & Gas Operator | Jun 2026 |
| 692 | Regency Exploration Inc | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 1999 |
| 693 | Republic Resources Corporation | Oklahoma City, OK 73102-3081 | Oil & Gas Operator | May 2021 |
| 694 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | May 2026 |
| 695 | Review Oil & Gas Inc | Edmond, OK 73034-7648 | Oil & Gas Operator | May 2026 |
| 696 | Revolution Resources LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2023 |
| 697 | Rhoades Oil Co | Tulsa, OK 74136-5575 | Oil & Gas Operator | Aug 2013 |
| 698 | Richard Charles J | | Oil & Gas Operator | May 1996 |
| 699 | Ricks Expl Acquisition LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2013 |
| 700 | Ricks Exploration Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |