| 501 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 502 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 503 | Natomas North America Inc | | Oil & Gas Operator | Aug 1993 |
| 504 | Natural Gas Pipeline Co Of Am LLC | Downers Grove, IL 60515-3708 | Oil & Gas Operator | Mar 2015 |
| 505 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | May 2025 |
| 506 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 507 | Neok Production Company LLC | Nowata, OK 74048 | Oil & Gas Operator | Feb 2025 |
| 508 | NFC Petroleum Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1996 |
| 509 | Nielson & Associates Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 510 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 511 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | May 2025 |
| 512 | Noble Operating, LLC | Flower Mound, TX 75028 | Oil & Gas Operator | Sep 2013 |
| 513 | Northbrook Oil & Gas Co LLC | Norman, OK 73072 | Oil & Gas Operator | Nov 2014 |
| 514 | Northbrook Oil & Gas Company | Norman, OK 73070-4916 | Oil & Gas Operator | Jun 2016 |
| 515 | Northport Production Company | Oklahoma City, OK 73113 | Oil & Gas Operator | Mar 2025 |
| 516 | Nova Energy Corporation | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 517 | Nyc Resources LTD | Tulsa, OK 74133-5700 | Oil & Gas Operator | Sep 2014 |
| 518 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 519 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Mar 2025 |
| 520 | Oil Investors Inc | Crescent, OK 73028 | Oil & Gas Operator | Mar 2025 |
| 521 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 522 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 523 | Oklahoma O & G Royalties Inc | Duncan, OK 73533 | Oil & Gas Operator | Nov 2000 |
| 524 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Feb 2025 |
| 525 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Mar 2025 |
| 526 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 527 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |
| 528 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 529 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 530 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 531 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 532 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 533 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Feb 2025 |
| 534 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | May 2025 |
| 535 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Mar 2025 |
| 536 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 537 | Oxley John C | Tulsa, OK 74103 | Oil & Gas Operator | Sep 1996 |
| 538 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 539 | Oxley Petroleum Co | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 540 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 541 | P O & G Panhandle LP | Houston, TX 77057 | Oil & Gas Operator | Feb 2025 |
| 542 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 543 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 544 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 545 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Dec 2024 |
| 546 | Pap Oil Company Inc | Cement, OK 73017-0240 | Oil & Gas Operator | Nov 1998 |
| 547 | Park Avenue Exploration Corp | Oklahoma City, OK 73102-5604 | Oil & Gas Operator | Sep 2011 |
| 548 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 549 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 550 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 551 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 552 | Payne Exploration Company | Crescent, OK 73028 | Oil & Gas Operator | Feb 2025 |
| 553 | Payne W C Family Trust | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Mar 2015 |
| 554 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 555 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 556 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 557 | Pemex Inc | Dallas, TX 75367-0249 | Oil & Gas Operator | Nov 2015 |
| 558 | Penn VIrginia MC Operating Co LLC | Houston, TX 77084-7213 | Oil & Gas Operator | Jan 2025 |
| 559 | Pennmark Resources Company | Edmond, OK 73013 | Oil & Gas Operator | Feb 2025 |
| 560 | Perkins Energy Company | Duncan, OK 73533-3853 | Oil & Gas Operator | Mar 2025 |
| 561 | Perkins, Earl | | Oil & Gas Operator | Aug 2013 |
| 562 | Petro Speed Inc | Norman, OK 73069-8116 | Oil & Gas Operator | Mar 2015 |
| 563 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 564 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 565 | Petrodudes | Crescent, OK 73028-8706 | Oil & Gas Operator | Aug 2024 |
| 566 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 567 | Petroleum International, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2000 |
| 568 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | May 2025 |
| 569 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | May 2025 |
| 570 | PHD Oil & Gas Inc | Rush Springs, OK 73082-0218 | Oil & Gas Operator | May 2021 |
| 571 | Phoenix Petrocorp, Inc. | McKinney, TX 75070 | Oil & Gas Operator | Mar 2025 |
| 572 | Pierce O M Operations | Duncan, OK 73533 | Oil & Gas Operator | Nov 1998 |
| 573 | Pierce Patsey R The Estate Of | Duncan, OK 73533-4900 | Oil Operator | Mar 2007 |
| 574 | Pine Ridge Energy Inc | Cyril, OK 73029 | Oil & Gas Operator | Feb 2025 |
| 575 | Pioneer Exploration Company | Houston, TX 77090 | Oil & Gas Operator | Mar 2025 |
| 576 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | May 2025 |
| 577 | Pletcher Oil Limited Liability Company | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2025 |
| 578 | Poblano Energy LLC | Houston, TX 77024-2217 | Oil & Gas Operator | Feb 2025 |
| 579 | Polaris Energy Dev Co | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2000 |
| 580 | Positive Energy LLC | Ada, OK 74820 | Oil & Gas Operator | Mar 2025 |
| 581 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 582 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 583 | Primary Natural Resources Inc. | Tulsa, OK 74136-6351 | Oil & Gas Operator | Mar 2023 |
| 584 | Prime Energy Corp | Charleston, WV 25301-1707-1707 | Oil & Gas Operator | Sep 2015 |
| 585 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 586 | Prospective Investment & Trading | Scottsdale, AZ 85261-4190 | Oil & Gas Operator | Jun 2016 |
| 587 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Feb 2025 |
| 588 | Providence Oil & Gas Corp | Tulsa, OK 74135-5463 | Oil & Gas Operator | May 2005 |
| 589 | Pulliam Melvin | Mannford, OK 74044 | Oil & Gas Operator | Jul 2019 |
| 590 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 591 | Pyramid Oil Of America, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Feb 2025 |
| 592 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Feb 2025 |
| 593 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Feb 2025 |
| 594 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 595 | R & B Trucking | Crescent, OK 73028-0775 | Oil & Gas Operator | Nov 2021 |
| 596 | R & N Associates | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2025 |
| 597 | R D T Properties | Tulsa, OK 74105-7122 | Oil & Gas Operator | Sep 2017 |
| 598 | R.D. Oil Company | Austin, TX 78755 | Oil & Gas Operator | May 2025 |
| 599 | Raker Resources LLC | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 600 | Ram Asset Management Co | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |