| 601 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 602 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 603 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 604 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 605 | Oso Resources LLC | Edmond, OK 73003 | Oil & Gas Operator | Dec 2025 |
| 606 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Dec 2025 |
| 607 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 608 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Dec 2025 |
| 609 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Mar 2026 |
| 610 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 611 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 612 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2026 |
| 613 | Ozark Oil Corporation | Springfield, MO 65804 | Oil & Gas Operator | Oct 1992 |
| 614 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 615 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2026 |
| 616 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 617 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 618 | Paluca Petroleum Inc | Holdenville, OK 74848 | Oil & Gas Operator | Dec 2025 |
| 619 | Panadero Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Apr 2002 |
| 620 | Panenergy Services Inc | Houston, TX 77525 | Oil & Gas Operator | May 2001 |
| 621 | Panther Operating LLC | Pauls Valley, OK 73075 | Oil & Gas Operator | Dec 2025 |
| 622 | Papal Enterprises Inc | Oklahoma City, OK 73154-1555 | Oil & Gas Operator | Apr 2015 |
| 623 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 624 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 625 | Parkway Petroleum, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Jul 1997 |
| 626 | Passmore Robert W | Ada, OK 74820-5501 | Oil & Gas Operator | May 2022 |
| 627 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 628 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 629 | Pauls Valley Disposal LLC | Kingston, OK 73439-2130 | Oil Operator | Mar 2015 |
| 630 | Payne Exploration Company | Crescent, OK 73028 | Oil & Gas Operator | Dec 2025 |
| 631 | Payne W C Family Trust | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Mar 2015 |
| 632 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 633 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 634 | Pengo Petroleum Inc | | Oil & Gas Operator | Dec 2013 |
| 635 | Penner Energy Inc | Oklahoma City, OK 73120-1930 | Oil & Gas Operator | Jan 2026 |
| 636 | Pennmark Resources Company | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 637 | Perkins Energy Company | Duncan, OK 73533-3853 | Oil & Gas Operator | Dec 2025 |
| 638 | Perkins Production Company Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2006 |
| 639 | Perry L Larson Operating Co | Dallas, TX 75231-4712 | Oil & Gas Operator | Dec 2025 |
| 640 | Pet-Ex Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2025 |
| 641 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 642 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Mar 2026 |
| 643 | Petroleum Exploration Company LTD LP | Breckenridge, TX 76424 | Oil & Gas Operator | Jan 2026 |
| 644 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 645 | Petromark Energy LLC | Oklahoma City, OK 73116-7634 | Oil & Gas Operator | Jun 2000 |
| 646 | Pharoah Bob | Maysville, OK 73057 | Oil & Gas Operator | Jul 1994 |
| 647 | Phoenix Petrocorp, Inc. | McKinney, TX 75070 | Oil & Gas Operator | Jan 2026 |
| 648 | Phoenix Production Inc | Burneyville, OK 73430-2158 | Oil & Gas Operator | Feb 2025 |
| 649 | Pierco Energy Corp. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2026 |
| 650 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 651 | Pinnacle Operating Company, Inc. | Shreveport, LA 71135 | Oil & Gas Operator | Mar 2026 |
| 652 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Mar 2026 |
| 653 | Pixley Carlis D | Marlow, OK 73055 | Oil & Gas Operator | Sep 1999 |
| 654 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 655 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 656 | Pletcher Oil Limited Liability Company | Ardmore, OK 73401 | Oil & Gas Operator | Dec 2025 |
| 657 | Plummer Energy Inc | Pauls Valley, OK 73075-8663 | Oil & Gas Operator | Nov 2016 |
| 658 | Pogue Randall | Ada, OK 74821-1547 | Oil & Gas Operator | Apr 2014 |
| 659 | Polaris Energy Dev Co | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2000 |
| 660 | Poorboy Oil Inc | Velma, OK 73491 | Oil & Gas Operator | Jul 2022 |
| 661 | Positive Energy LLC | Ada, OK 74820 | Oil & Gas Operator | Dec 2025 |
| 662 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 663 | Post Petroleum Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Aug 2013 |
| 664 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Mar 2026 |
| 665 | Premier Oil & Gas LLC | Blanchard, OK 73010-2010 | Oil Operator | Dec 2022 |
| 666 | Prentice, Napier & Green, Inc. | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2026 |
| 667 | Preston Carter Oil Company | Davis, OK 73030 | Oil & Gas Operator | Dec 2025 |
| 668 | Pri Producing Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2006 |
| 669 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2026 |
| 670 | Prime Energy Corp | Charleston, WV 25301-1707 | Oil & Gas Operator | Sep 2015 |
| 671 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Mar 2026 |
| 672 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 673 | Prince Brothers Drilling Co | Electra, TX 76360 | Oil & Gas Operator | Apr 2015 |
| 674 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 675 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Mar 2026 |
| 676 | Prompt Operating LLC | Velma, OK 73491 | Oil Operator | Dec 2025 |
| 677 | Protege Energy LLC | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2018 |
| 678 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Dec 2025 |
| 679 | Pruitt Operating Company LLC | Ratliff City, OK 73481-5802 | Oil & Gas Operator | Jan 2026 |
| 680 | Psec Inc | Tulsa, OK 74102-0871 | Oil & Gas Operator | Dec 2016 |
| 681 | Pulliam Melvin | Mannford, OK 74044 | Oil & Gas Operator | Jul 2019 |
| 682 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 683 | Quad Operating Company | Bulverde, TX 78163 | Oil & Gas Operator | Nov 2025 |
| 684 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Dec 2025 |
| 685 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 686 | R L Clampitt & Associates LLC | Bartlesville, OK 74006 | Oil & Gas Operator | Jan 2026 |
| 687 | R.D. Oil Company | Austin, TX 78755 | Oil & Gas Operator | Mar 2026 |
| 688 | Ra-Jac LLC | Norman, OK 73072 | Oil & Gas Operator | Jan 2026 |
| 689 | Raizen Oil Company | Velma, OK 73091 | Oil & Gas Operator | Feb 2016 |
| 690 | Raizen Oil LLC | Duncan, OK 73533-4657 | Oil & Gas Operator | Nov 2003 |
| 691 | Rama Operating Company Inc | Stafford, KS 67578 | Oil & Gas Operator | Jan 2026 |
| 692 | Rambler Oil Co | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 1999 |
| 693 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 694 | Ramsey Nichols Operating Company LLC | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Jan 2026 |
| 695 | Ramsey Property Management LLC | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Dec 2025 |
| 696 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 697 | Ranken Energy Corporation | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 698 | Raw Crude Oil & Gas, L.L.C. | Norman, OK 73069 | Oil & Gas Operator | Dec 2025 |
| 699 | Raw Production LLC | Lindsay, OK 73052 | Oil & Gas Operator | Dec 2025 |
| 700 | Raydon Exploration, Inc. | Oklahoma City, OK 73118 | Oil & Gas Operator | Mar 2026 |