| 501 | Mogul Energy Corp | Los Angeles, CA 90024 | Oil & Gas Operator | Jan 2001 |
| 502 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | May 2026 |
| 503 | Moore W T | Sapulpa, OK 74067-0946 | Oil & Gas Operator | Jan 2021 |
| 504 | Moran Pipe & Supply Co Inc | Seminole, OK 74868 | Oil & Gas Operator | Jan 2019 |
| 505 | Moran-K Oil LLC | Seminole, OK 74868 | Oil & Gas Operator | May 2026 |
| 506 | Moze Inc | Ochelata, OK 74051 | Oil & Gas Operator | Jan 2001 |
| 507 | Mullins, John S | | Oil Operator | Nov 2014 |
| 508 | Murphy Jack L | Tulsa, OK 74104-4915 | Oil Operator | Mar 2015 |
| 509 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 510 | Myers, Robert L | | Oil Operator | Apr 2026 |
| 511 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jul 2026 |
| 512 | Natural Gas Compression Corp | Cleveland, OK 74020 | Oil & Gas Operator | Jan 2025 |
| 513 | Natural Gas Resources Inc | Davenport, IA 52809-1675 | Oil & Gas Operator | Oct 2022 |
| 514 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Jul 2026 |
| 515 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2026 |
| 516 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Jul 2026 |
| 517 | Noble Resources Inc | Mannford, OK 74044 | Oil & Gas Operator | May 2026 |
| 518 | Northam Oil Company Inc | Ada, OK 74820-3334 | Oil & Gas Operator | Apr 2026 |
| 519 | Northcote Cleveland LLC | Borger, TX 79008 | Oil & Gas Operator | Apr 2026 |
| 520 | Northeast Shelf Energy, L.L.C. | | Oil & Gas Operator | Jun 2017 |
| 521 | Northwind Development Company | | Oil Operator | Oct 1995 |
| 522 | NTR Energy LLC (Osage Cty Only) | | Oil & Gas Operator | Apr 2020 |
| 523 | NV O&G Investments LLC /Osage Only | | Oil Operator | Sep 2022 |
| 524 | O'Donnell Bill C | Tulsa, OK 74135-4241 | Oil & Gas Operator | Oct 2014 |
| 525 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | May 2026 |
| 526 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Jul 2026 |
| 527 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 528 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 529 | Oil Lift Inc | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 530 | Oil Operations Inc | | Oil & Gas Operator | Apr 2011 |
| 531 | Oil Patch Energy LLC | Broken Arrow, OK 74014 | Oil & Gas Operator | Nov 2025 |
| 532 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Jul 2026 |
| 533 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 534 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 535 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 536 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Apr 2026 |
| 537 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | May 2026 |
| 538 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Apr 2025 |
| 539 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2026 |
| 540 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Apr 2026 |
| 541 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 542 | Ole Crow Operating | Wichita Falls, TX 76308 | Oil Operator | Apr 2026 |
| 543 | Oliphant Operating Co,LTD,LLC | | Oil Operator | Apr 2026 |
| 544 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 545 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 546 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Nov 2025 |
| 547 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Apr 2026 |
| 548 | Otc Investors Inc | | Oil Operator | Mar 2026 |
| 549 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 550 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 551 | Oxco, LLC | | Oil & Gas Operator | Feb 2015 |
| 552 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 553 | Pan Petroleum MLP | Kansas City, MO 64114 | Oil & Gas Operator | Aug 1997 |
| 554 | Park Kenneth Y | Skiatook, OK 74070-6060 | Oil & Gas Operator | Apr 2026 |
| 555 | Park William M | Sperry, OK 74073 | Oil & Gas Operator | Apr 2026 |
| 556 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 557 | Parker James A | Sand Springs, OK 74063 | Oil & Gas Operator | Apr 2026 |
| 558 | Parks Jack Concrete Co | Hominy, OK 74035 | Oil Operator | Aug 2025 |
| 559 | Parsage Oil Company, L.L.C. | | Oil & Gas Operator | Apr 2026 |
| 560 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 561 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 562 | Patrick Exploration Company | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 563 | Payne, Frank O | | Oil Operator | Aug 1999 |
| 564 | Paystone Oil Corporation | Tulsa, OK 74105 | Oil Operator | Mar 2009 |
| 565 | Pe - Osage, LLC | | Oil Operator | Apr 2026 |
| 566 | Pease George W Jr | Fairfax, OK 74637 | Oil & Gas Operator | Mar 1998 |
| 567 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 568 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 569 | Pemco LLC | Skiatook, OK 74070 | Oil Operator | Apr 2026 |
| 570 | Pemex Inc | Dallas, TX 75367-0249 | Oil & Gas Operator | Nov 2015 |
| 571 | Performance Energy Partners LLC | Barnsdall, OK 74002-0628 | Oil & Gas Operator | Sep 2025 |
| 572 | Performance Operating Company LLC | Barnsdall, OK 74002 | Oil & Gas Operator | Apr 2026 |
| 573 | Performance Petroleum Company LLC | Barnsdall, OK 74002 | Oil & Gas Operator | Apr 2026 |
| 574 | Perkins Energy Company | Duncan, OK 73533-3853 | Oil & Gas Operator | Apr 2026 |
| 575 | Perkins Production Company Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2006 |
| 576 | Perrin, Mary L | | Oil & Gas Operator | Oct 2005 |
| 577 | Petrogas Exploration Inc | | Oil Operator | Apr 2026 |
| 578 | Petroleum Corporation Of Texas | Breckenridge, TX 76024 | Oil & Gas Operator | May 2002 |
| 579 | Petroleum Properties Co Inc | Tulsa, OK 74132-4010 | Oil & Gas Operator | Sep 2012 |
| 580 | Petroleum Reserve Corporation | Plymouth MTNG, PA 19462 | Oil & Gas Operator | May 2008 |
| 581 | Petroleum Resources Co | Wichita, KS 67206 | Oil & Gas Operator | May 2000 |
| 582 | Petromerica Operating LLC | Oklahoma City, OK 73102-4613 | Oil Operator | Apr 2026 |
| 583 | Petron Energy Inc | Dallas, TX 75252 | Oil & Gas Operator | Jul 2026 |
| 584 | PHD Oil & Gas Inc | Rush Springs, OK 73082-0218 | Oil & Gas Operator | May 2021 |
| 585 | Phillips, Warren P | | Oil & Gas Operator | Apr 2011 |
| 586 | Phoenix Hydrocarbons Operating Co | Midland, TX 79702-3638 | Oil & Gas Operator | Jul 2018 |
| 587 | Pierce Oil Company | Skiatook, OK 74070 | Oil & Gas Operator | Nov 2017 |
| 588 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 589 | Pinnacle Operating Company LLC | Tulsa, OK 74137 | Oil & Gas Operator | Apr 2026 |
| 590 | Pinnacle Operating Company, Inc. | Shreveport, LA 71135 | Oil & Gas Operator | Jul 2026 |
| 591 | Pitcock, Inc. | Graham, TX 76450 | Oil & Gas Operator | Jul 2026 |
| 592 | Pittencrieff America Inc | Abilene, TX 79608 | Oil & Gas Operator | Feb 2003 |
| 593 | Plenergy Dev LTD | | Oil & Gas Operator | Jun 2004 |
| 594 | Powell James S | Cleveland, OK 74020 | Oil Operator | Apr 2026 |
| 595 | Presco Inc | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2020 |
| 596 | Prime Energy Corp | Charleston, WV 25301-1707 | Oil & Gas Operator | Sep 2015 |
| 597 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 598 | Pringle Operating Co. | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2015 |
| 599 | Producers Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2007 |
| 600 | Putnam Phyllis L | Bartlesville, OK 74006-7326 | Oil & Gas Operator | May 2021 |