| 501 | NM&O Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 502 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2026 |
| 503 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Jul 2026 |
| 504 | Noble Operating Company Inc | Garden City, KS 67846 | Oil & Gas Operator | Sep 2014 |
| 505 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 506 | Norman Production Company | Chandler, OK 74834-8538 | Oil & Gas Operator | May 2015 |
| 507 | North Star Exploration Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Mar 2026 |
| 508 | Nossaman E Oil Inc | Del City, OK 73155-5449 | Oil Operator | Oct 2002 |
| 509 | Nye Oil Company | Oklahoma City, OK 73118-1245 | Oil & Gas Operator | Jun 2004 |
| 510 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 511 | Oasis Energy Resources LLC | Norman, OK 73072-9668 | Oil & Gas Operator | Jun 2025 |
| 512 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 513 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 514 | Oil Creek Production Company | Prague, OK 74864-0667 | Oil & Gas Operator | Mar 2026 |
| 515 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 516 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 517 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2026 |
| 518 | Oklahoma Oil And Gas Resources LLC | Guthrie, OK 73044-8095 | Oil & Gas Operator | May 2026 |
| 519 | Oklahoma Petroleum MGMT Corp | Tulsa, OK 74119 | Oil & Gas Operator | Jun 1993 |
| 520 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 521 | Onpoint Oil & Gas, LLC | Oklahoma City, OK 73170 | Oil & Gas Operator | Apr 2026 |
| 522 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 523 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 524 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | May 2026 |
| 525 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 526 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Nov 2025 |
| 527 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 528 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 529 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 530 | P & H Oil & Gas Inc | Stroud, OK 74079 | Oil & Gas Operator | May 2026 |
| 531 | Pace Exploration LLC | Tulsa, OK 74133 | Oil & Gas Operator | Apr 2026 |
| 532 | Paleo, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2026 |
| 533 | Palm Operating LLC | Oklahoma City, OK 73106-5646 | Oil & Gas Operator | Nov 2019 |
| 534 | Pan Western Energy Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2026 |
| 535 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Jul 2026 |
| 536 | Paradigm Twenty LLC | Stillwater, OK 74074-1745 | Oil & Gas Operator | Mar 2026 |
| 537 | Park Avenue Exploration Corp | Oklahoma City, OK 73102-5604 | Oil & Gas Operator | Sep 2011 |
| 538 | Parkway Petroleum, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Jul 1997 |
| 539 | Parsons Engineering Corporation | Tulsa, OK 74137-7505 | Oil & Gas Operator | Oct 2017 |
| 540 | Parwest Land Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Apr 2026 |
| 541 | Patco Investments Inc | Seminole, OK 74868 | Oil Operator | Nov 2007 |
| 542 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 543 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 544 | Paul Gillham Oil Company | Maud, OK 74854 | Oil & Gas Operator | Apr 2026 |
| 545 | PDG Production LLC | Stroud, OK 74079 | Oil & Gas Operator | May 2026 |
| 546 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 547 | Penn Production Company Inc | | Oil & Gas Operator | Nov 2014 |
| 548 | Pepin Oil Co | Stillwater, OK 74076 | Oil & Gas Operator | Oct 2013 |
| 549 | Peterson Charles E SR | Stroud, OK 74079-9718 | Oil & Gas Operator | Apr 2026 |
| 550 | Petro Warrior LLC | Wichita, KS 67206 | Oil & Gas Operator | May 2026 |
| 551 | Petro-Management Assoc., Inc. | Edmond, OK 73083-2346 | Oil & Gas Operator | Jun 2007 |
| 552 | Petroflow Energy Corporation | Tulsa, OK 74119-5405 | Oil & Gas Operator | Oct 2016 |
| 553 | Petroleum Capital, L.C. | Dallas, TX 75367 | Oil & Gas Operator | Jul 2026 |
| 554 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 2026 |
| 555 | Petroleum Production MGMT., Inc. | Kansas City, MO 64112 | Oil & Gas Operator | Jul 2026 |
| 556 | Petroleum Properties Co Inc | Tulsa, OK 74132-4010 | Oil & Gas Operator | Sep 2012 |
| 557 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 558 | Petroleum Resources Co | Wichita, KS 67206 | Oil & Gas Operator | May 2000 |
| 559 | Petrolia Drilling Corporation | | Oil & Gas Operator | Jul 2003 |
| 560 | Phillips Oil Operating Co | Enid, OK 73703-4921 | Oil & Gas Operator | May 2019 |
| 561 | Phoenix Petrocorp, Inc. | McKinney, TX 75070 | Oil & Gas Operator | May 2026 |
| 562 | Pinnacle Corporation (The) | Broken Arrow, OK 74012 | Oil & Gas Operator | Nov 2014 |
| 563 | Plains Oil & Gas | Cushing, OK 74023-4819 | Oil & Gas Operator | Jan 2019 |
| 564 | PMD Oil Recovery LLC | Perry, OK 73077 | Oil & Gas Operator | May 2026 |
| 565 | Power Fuel Producers Inc | Keller, TX 76244-1059 | Oil & Gas Operator | Sep 2001 |
| 566 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Jul 2026 |
| 567 | PRDJ Cockrum Enterprises, Inc. | Okemah, OK 74859-5126 | Oil & Gas Operator | Mar 2022 |
| 568 | Prime Energy Corp | Charleston, WV 25301-1707 | Oil & Gas Operator | Sep 2015 |
| 569 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 570 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 571 | Pryor VIctor W Jr | Holdenville, OK 74848 | Oil & Gas Operator | Apr 2017 |
| 572 | Psa Inc | Chandler, OK 74834-4222 | Oil & Gas Operator | Apr 2026 |
| 573 | Psec Inc | Tulsa, OK 74102-0871 | Oil & Gas Operator | Dec 2016 |
| 574 | Pullers Oil Company LLC | Blackwell, OK 74631-9512 | Oil & Gas Operator | May 2026 |
| 575 | Pumping Services Inc | Seminole, OK 74868-2421 | Oil & Gas Operator | Jul 2025 |
| 576 | Quanah Company | Tulsa, OK 74159-0469 | Oil & Gas Operator | May 2020 |
| 577 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 578 | R & B Trucking | Crescent, OK 73028-0775 | Oil & Gas Operator | Nov 2021 |
| 579 | R C Taylor Operating Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | May 2026 |
| 580 | R I G Producers Inc | Dewey, OK 74029 | Oil & Gas Operator | Jul 1999 |
| 581 | R L Clampitt & Associates LLC | Bartlesville, OK 74006 | Oil & Gas Operator | May 2026 |
| 582 | Rainbo Service Company | Oklahoma City, OK 73129 | Oil & Gas Operator | Apr 2026 |
| 583 | Rainmaker Oil & Gas Corp | Oklahoma City, OK 73112-8883 | Oil & Gas Operator | Apr 2015 |
| 584 | Ram Energy LLC | Tulsa, OK 74152 | Oil & Gas Operator | Apr 2026 |
| 585 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 586 | Ramco Oil Company | Pawhuska, OK 74056 | Oil & Gas Operator | Feb 2012 |
| 587 | Ramey Wayne | Mounds, OK 74047 | Oil & Gas Operator | Apr 2026 |
| 588 | Ramsey Engineering Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Apr 1993 |
| 589 | Ramsey Nichols Operating Company LLC | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Apr 2026 |
| 590 | Ramsey Property Management LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Jan 2026 |
| 591 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 592 | Randy Inc | Hennessey, OK 73742 | Oil & Gas Operator | Apr 2026 |
| 593 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 594 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 595 | Ranken Energy Corporation | Edmond, OK 73013 | Oil & Gas Operator | Apr 2026 |
| 596 | Raper Brice Oil Company LLC | Yale, OK 74085-6865 | Oil & Gas Operator | Apr 2015 |
| 597 | Ratliff City Trucking Inc | Ratliff City, OK 73481-9603 | Oil & Gas Operator | Feb 2018 |
| 598 | Raw Crude Oil & Gas, L.L.C. | Norman, OK 73069 | Oil & Gas Operator | Apr 2026 |
| 599 | Raydon Exploration, Inc. | Oklahoma City, OK 73118 | Oil & Gas Operator | Jul 2026 |
| 600 | RCK Oil And Gas LLC | Denton, TX 76207 | Oil & Gas Operator | May 2026 |