| 501 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 502 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 503 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2026 |
| 504 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Apr 2026 |
| 505 | Oklahoma Petroleum MGMT Corp | Tulsa, OK 74119 | Oil & Gas Operator | Jun 1993 |
| 506 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 507 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 508 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 509 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 510 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 511 | Osa Oil & Gas LLC | Tulsa, OK 74131 | Oil & Gas Operator | Aug 2023 |
| 512 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 513 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 514 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | May 2026 |
| 515 | Pace Exploration LLC | Tulsa, OK 74133 | Oil & Gas Operator | Apr 2026 |
| 516 | Pal Kids Inc | Coronado, CA 92118 | Oil & Gas Operator | Nov 2000 |
| 517 | Palm Oil & Gas Company | Sedona, AZ 86340 | Oil & Gas Operator | May 2026 |
| 518 | Palm Operating LLC | Oklahoma City, OK 73106-5646 | Oil & Gas Operator | Nov 2019 |
| 519 | Pan Western Energy Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2026 |
| 520 | Papal Enterprises Inc | Oklahoma City, OK 73154-1555 | Oil & Gas Operator | Apr 2015 |
| 521 | Paradigm Twenty LLC | Stillwater, OK 74074-1745 | Oil & Gas Operator | Mar 2026 |
| 522 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 523 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 524 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 525 | Parsons Engineering Corporation | Tulsa, OK 74137-7505 | Oil & Gas Operator | Oct 2017 |
| 526 | Parwest Land Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Apr 2026 |
| 527 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 528 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 529 | Patron Energy LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2015 |
| 530 | Patterson & Patterson Oil Co | Cushing, OK 74023 | Oil Operator | Aug 1995 |
| 531 | Patton Dale | Stillwater, OK 74074 | Oil & Gas Operator | Dec 2011 |
| 532 | Pawnee Oil And Gas, Inc. | Richardson, TX 75083 | Oil & Gas Operator | May 2023 |
| 533 | Payne Exploration Company | Crescent, OK 73028 | Oil & Gas Operator | Apr 2026 |
| 534 | Payne W C Family Trust | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Mar 2015 |
| 535 | Pedco Inc | | Oil & Gas Operator | Nov 1997 |
| 536 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 537 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 538 | Pelto Oil Company | Houston, TX 77002 | Oil & Gas Operator | Nov 1998 |
| 539 | Penn Production Company Inc | | Oil & Gas Operator | Nov 2014 |
| 540 | Pepin Oil Co | Stillwater, OK 74076 | Oil & Gas Operator | Oct 2013 |
| 541 | Pepin Operating Company Inc | Stillwater, OK 74075-9535 | Oil & Gas Operator | May 2009 |
| 542 | Petra Petroleum Inc | Littleton, CO 80160-0319 | Oil & Gas Operator | Jun 2005 |
| 543 | Petro Oilfield Equipment Inc | Drumright, OK 74030-1233 | Oil & Gas Operator | Dec 2010 |
| 544 | Petro Warrior LLC | Wichita, KS 67206 | Oil & Gas Operator | May 2026 |
| 545 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 546 | Petroflow Energy Corporation | Tulsa, OK 74119-5405 | Oil & Gas Operator | Oct 2016 |
| 547 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 548 | Petroleum Production MGMT., Inc. | Kansas City, MO 64112 | Oil & Gas Operator | Jul 2026 |
| 549 | Petroleum Reserve Corporation | Plymouth MTNG, PA 19462 | Oil & Gas Operator | May 2008 |
| 550 | Petroleum Resources Co | Wichita, KS 67206 | Oil & Gas Operator | May 2000 |
| 551 | Pierce G R Oil Properties Inc | Oklahoma City, OK 73106 | Oil Operator | Feb 1999 |
| 552 | Pilgrim & Smith Inc | Tulsa, OK 74152 | Oil & Gas Operator | Apr 2015 |
| 553 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 554 | Pinnacle Exploration Inc | Edmond, OK 73003 | Oil & Gas Operator | Mar 2024 |
| 555 | Pinnacle Operating Company LLC | Tulsa, OK 74137 | Oil & Gas Operator | Apr 2026 |
| 556 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 557 | PMD Oil Recovery LLC | Perry, OK 73077 | Oil & Gas Operator | May 2026 |
| 558 | Polaris Energy Dev Co | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2000 |
| 559 | Porter John B | Ketchum, OK 74349-0207 | Oil & Gas Operator | May 2000 |
| 560 | Pregler Oil Company LLC | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2026 |
| 561 | Presley Operating LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 562 | Presley Petroleum Company | Newport Beach, CA 92658-2200 | Oil & Gas Operator | Oct 1999 |
| 563 | Prime Energy Corp | Charleston, WV 25301-1707 | Oil & Gas Operator | Sep 2015 |
| 564 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 565 | Producers Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2007 |
| 566 | Providence Oil & Gas Corp | Tulsa, OK 74135-5463 | Oil & Gas Operator | May 2005 |
| 567 | Pryor VIctor W Jr | Holdenville, OK 74848 | Oil & Gas Operator | Apr 2017 |
| 568 | Pullers Oil Company LLC | Blackwell, OK 74631-9512 | Oil & Gas Operator | May 2026 |
| 569 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 570 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 571 | Quanah Company | Tulsa, OK 74159-0469 | Oil & Gas Operator | May 2020 |
| 572 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 573 | R & B Trucking | Crescent, OK 73028-0775 | Oil & Gas Operator | Nov 2021 |
| 574 | R & D Oil & Gas | Exeter, CA 93221-9697 | Oil & Gas Operator | Aug 2019 |
| 575 | R A M Corporation | Blackwell, OK 74631-0045 | Oil & Gas Operator | Apr 2026 |
| 576 | R C Taylor Operating Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | May 2026 |
| 577 | Rainbow Oil & Gas | Pawhuska, OK 74056-0056 | Oil Operator | Oct 2010 |
| 578 | Rainbow Oil & Gas LLC | Coolville, OH 45723 | Oil & Gas Operator | Dec 2025 |
| 579 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 580 | Ramey L E SR | Mounds, OK 74047 | Oil Operator | Jan 2000 |
| 581 | Ranken Energy Corporation | Edmond, OK 73013 | Oil & Gas Operator | Apr 2026 |
| 582 | Raper Brice Oil Company LLC | Yale, OK 74085-6865 | Oil & Gas Operator | Apr 2015 |
| 583 | Ratex Resources Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | May 2000 |
| 584 | Raydon Exploration, Inc. | Oklahoma City, OK 73118 | Oil & Gas Operator | Jul 2026 |
| 585 | RCK Oil And Gas LLC | Denton, TX 76207 | Oil & Gas Operator | May 2026 |
| 586 | Rebel Oil Company | Keaton, KY 41226 | Oil & Gas Operator | Jan 2025 |
| 587 | Red Eagle Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2005 |
| 588 | Red Fork (USA) Investments Inc | Midland, TX 79710-0272 | Oil & Gas Operator | May 2019 |
| 589 | Red Fork Oil Production Inc | Mannford, OK 74044-0492 | Oil & Gas Operator | Feb 2017 |
| 590 | Red Fork Valley Oil & Gas Co | Cushing, OK 74023 | Oil Operator | Dec 2014 |
| 591 | Red Rocks Oil & Gas Operating LLC | Oklahoma City, OK 73103 | Oil & Gas Operator | May 2026 |
| 592 | Red Tail Properties, LLC | Tulsa, OK 74107-3443 | Oil Operator | Apr 2026 |
| 593 | Redtail Investments LLC | Oklahoma City, OK 73179 | Oil & Gas Operator | May 2026 |
| 594 | Remco Energy Corporation | Independence, MO 64055 | Oil & Gas Operator | Nov 2009 |
| 595 | Remo Production Co | Stillwater, OK 74074-9333 | Oil Operator | Apr 2014 |
| 596 | Renegade Oil And Gas LLC | Helena, OK 73741-0162 | Oil & Gas Operator | Dec 2019 |
| 597 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | Apr 2026 |
| 598 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 599 | Rhoades Oil Co | Tulsa, OK 74136-5575 | Oil & Gas Operator | Aug 2013 |
| 600 | Rhoads Brothers Oil & Gas Inc | Tulsa, OK 74136 | Oil & Gas Operator | May 1996 |