| 501 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 502 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 503 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 504 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Dec 2024 |
| 505 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 506 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Jan 2025 |
| 507 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 508 | Omimex International Corp | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Dec 2024 |
| 509 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 510 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 511 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 512 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 513 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2025 |
| 514 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 515 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2025 |
| 516 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 517 | Overflow Energy Stack LLC | Booker, TX 79005 | Oil Operator | Sep 2022 |
| 518 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Mar 2025 |
| 519 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jan 2025 |
| 520 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 521 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 522 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 523 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 524 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 525 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Dec 2024 |
| 526 | Paluca Petroleum Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Jan 2025 |
| 527 | Panada Exploration, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Jun 1996 |
| 528 | Panadero Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Apr 2002 |
| 529 | Panda Resources Inc | Tulsa, OK 74137-3536 | Oil & Gas Operator | Feb 1994 |
| 530 | Panenergy Services Inc | Houston, TX 77525 | Oil & Gas Operator | May 2001 |
| 531 | Panhandle Oil & Gas Consultants Inc | Woodward, OK 73802-5011 | Oil & Gas Operator | Jul 2015 |
| 532 | Panhandle Trading Company | Houston, TX 77251-1642 | Oil & Gas Operator | Jun 2003 |
| 533 | Panther Energy Company, LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2022 |
| 534 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 535 | Park Avenue Exploration Corp | Oklahoma City, OK 73102-5604 | Oil & Gas Operator | Sep 2011 |
| 536 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 537 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 538 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 539 | Payne Exploration Company | Crescent, OK 73028 | Oil & Gas Operator | Dec 2024 |
| 540 | Pearl Oil Company | Nichols Hills, OK 73120-1408 | Oil & Gas Operator | Nov 2023 |
| 541 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 542 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 543 | Penn Homa Oil & Gas Co | Edmond, OK 73083 | Oil & Gas Operator | Oct 2013 |
| 544 | Penn VIrginia MC Operating Co LLC | Houston, TX 77084-7213 | Oil & Gas Operator | Dec 2024 |
| 545 | Pet-Ex, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2024 |
| 546 | Petro Speed Inc | Norman, OK 73069-8116 | Oil & Gas Operator | Mar 2015 |
| 547 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 548 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 549 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 550 | Petroleum Investment Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Nov 1998 |
| 551 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 552 | Petromark Energy LLC | Oklahoma City, OK 73116-7634 | Oil & Gas Operator | Jun 2000 |
| 553 | Piper Operating LLC | Stigler, OK 74462 | Oil & Gas Operator | Jan 2025 |
| 554 | Pitco Production Company | Tulsa, OK 74170-2320 | Oil & Gas Operator | May 2013 |
| 555 | Plains Liquids Transport Inc | Houston, TX 77002 | Oil & Gas Operator | May 1996 |
| 556 | Plains Marketing & Trans Inc | Houston, TX 76002 | Oil & Gas Operator | Oct 1998 |
| 557 | Plains Marketing, LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 558 | Plainsmen Energy LLC | Enid, OK 73703-5747 | Oil & Gas Operator | Jan 2025 |
| 559 | Plymouth Exploration LLC | Tulsa, OK 74119-1031 | Oil & Gas Operator | Dec 2024 |
| 560 | Positive Energy LLC | Ada, OK 74820 | Oil & Gas Operator | Jan 2025 |
| 561 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 562 | Post Petroleum Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Aug 2013 |
| 563 | Premier Resources LTD | Denver, CO 80237 | Oil & Gas Operator | Jul 2002 |
| 564 | Prenalta Corporation | Terrytown, NY 10591 | Oil & Gas Operator | Jan 1997 |
| 565 | Prentice Napier & Green Inc | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2025 |
| 566 | Presidio Petroleum LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 567 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2025 |
| 568 | Primary Natural Resources Inc. | Tulsa, OK 74136-6351 | Oil & Gas Operator | Mar 2023 |
| 569 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 570 | Princess Three Operating, LLC | Henderson, TX 75653 | Oil & Gas Operator | Mar 2025 |
| 571 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 572 | Prospective Investment & Trading | Scottsdale, AZ 85261-4190 | Oil & Gas Operator | Jun 2016 |
| 573 | Protege Energy LLC | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2018 |
| 574 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Jan 2025 |
| 575 | Providence Oil & Gas Corp | Tulsa, OK 74135-5463 | Oil & Gas Operator | May 2005 |
| 576 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 577 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2024 |
| 578 | Quail Creek Petro MGMT Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 579 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Dec 2024 |
| 580 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 581 | Questa Energy Corporation | Amarillo, TX 79159 | Oil & Gas Operator | Mar 2025 |
| 582 | Questar Energy Trading | Salt Lake City, UT 84145-0601 | Oil & Gas Operator | Mar 2020 |
| 583 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 584 | R & L Properties Inc | Richmond, MO 64085-0228 | Oil & Gas Operator | Apr 2001 |
| 585 | Rafter H Operating LLC | El Reno, OK 73036 | Oil & Gas Operator | Jan 2025 |
| 586 | Ram Asset Management Co | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 587 | Rambler Oil Co | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 1999 |
| 588 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 589 | Ramsey Nichols Operating Company LLC | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Jan 2025 |
| 590 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 591 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 592 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2024 |
| 593 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 594 | Raven Resources LLC | Oklahoma City, OK 73172 | Oil & Gas Operator | Dec 2024 |
| 595 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 596 | Rebellion Energy LLC | Tulsa, OK 74135-6241 | Oil & Gas Operator | Jun 2022 |
| 597 | Red Eagle Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2005 |
| 598 | Red Hawk Resources Inc | Edmond, OK 73003-3207 | Oil & Gas Operator | Jan 2025 |
| 599 | Red Wolf Operating LLC | Edmond, OK 73003-2179 | Oil & Gas Operator | Jan 2025 |
| 600 | Redland Resources, LLC | Oklahoma City, OK 73127 | Oil & Gas Operator | Jan 2025 |