| 401 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 402 | Oklahoma Petroleum Allies LLC | Ardmore, OK 73401 | Oil Operator | Oct 2023 |
| 403 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Feb 2024 |
| 404 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 405 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 406 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 407 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 408 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Apr 2024 |
| 409 | Oryx Crude Trading & Transporation LP | Dallas, TX 75221 | Oil & Gas Operator | Jun 1999 |
| 410 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Apr 2024 |
| 411 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jan 2024 |
| 412 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 413 | Oxley Petroleum Co | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 414 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2024 |
| 415 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 416 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 417 | Paleo, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Apr 2024 |
| 418 | Palo Duro Midstream (Texas Gathreing) L.P | Houston, TX 77002 | Oil & Gas Operator | Aug 2022 |
| 419 | Panhandle Oil & Gas Inc | Oklahoma City, OK 73112-5688 | Oil & Gas Operator | May 2007 |
| 420 | Panhandle Trading Company | Houston, TX 77251-1642 | Oil & Gas Operator | Jun 2003 |
| 421 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Apr 2024 |
| 422 | Panther Energy Company, LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2022 |
| 423 | Paramount Petroleum Corp | Dallas, TX 75374 | Oil Operator | Dec 2000 |
| 424 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 425 | Park Avenue Exploration Corp | Oklahoma City, OK 73102-5604 | Oil & Gas Operator | Sep 2011 |
| 426 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 427 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 428 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 429 | PBT Enterprises Inc | Garber, OK 73738-0262 | Oil & Gas Operator | May 2023 |
| 430 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 431 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 432 | Pennzoil Company | Midland, TX 79710-0090 | Oil & Gas Operator | Mar 2000 |
| 433 | Pennzoil Explor & Prod Co | Houston, TX 77002 | Oil & Gas Operator | Mar 2000 |
| 434 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 435 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 436 | Petroleum Development Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2024 |
| 437 | Petroleum International, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2000 |
| 438 | Petroleum Investment Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Nov 1998 |
| 439 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 440 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Apr 2024 |
| 441 | Petrotex, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 442 | Pioneer Resources Prod LP | Irving, TX 75039-3745 | Oil & Gas Operator | Feb 2005 |
| 443 | Piper Operating LLC | | Oil & Gas Operator | Feb 2024 |
| 444 | Plains Liquids Transport Inc | Houston, TX 77002 | Oil & Gas Operator | May 1996 |
| 445 | Plains Marketing & Trans Inc | Houston, TX 76002 | Oil & Gas Operator | Oct 1998 |
| 446 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 447 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 448 | Plainsmen Energy LLC | | Oil & Gas Operator | Feb 2024 |
| 449 | Plano Petroleum LLC | Plano, TX 75093-8773 | Oil & Gas Operator | Apr 2013 |
| 450 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 451 | PPP Petroleum LP | | Oil & Gas Operator | Jan 2024 |
| 452 | Prentice Napier & Green Inc | Oklahoma City, OK 73172-1424 | Oil & Gas Operator | Feb 2024 |
| 453 | Presidio Petroleum LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2024 |
| 454 | Pri Producing Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2006 |
| 455 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 456 | Primary Natural Resources Inc. | Tulsa, OK 74136-6351 | Oil & Gas Operator | Mar 2023 |
| 457 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 458 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 459 | Prospective Investment & Trading | Scottsdale, AZ 85261-4190 | Oil & Gas Operator | Jun 2016 |
| 460 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Jan 2024 |
| 461 | Providence Oil & Gas Corp | Tulsa, OK 74135-5463 | Oil & Gas Operator | May 2005 |
| 462 | PVR Gas Processing LLC | | Oil & Gas Operator | Feb 2015 |
| 463 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 464 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Jan 2024 |
| 465 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Jan 2024 |
| 466 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 467 | Questar Energy Trading | Salt Lake City, UT 84145-0601 | Oil & Gas Operator | Mar 2020 |
| 468 | R C Taylor Operating Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2024 |
| 469 | R L Clampitt & Associates LLC | Bartlesville, OK 74006-3313 | Oil & Gas Operator | Feb 2024 |
| 470 | Raker Resources LLC | Houston, TX 77042 | Oil & Gas Operator | Apr 2024 |
| 471 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 472 | Ramsey Property MGMT Inc | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Mar 2019 |
| 473 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 474 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2024 |
| 475 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 476 | Reading & Bates Petroleum Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 477 | Red Hawk Disposal LLC | | Oil Operator | Jun 2023 |
| 478 | Red Hawk Resources Inc | Edmond, OK 73003-3207 | Oil & Gas Operator | Feb 2024 |
| 479 | Red Rocks Oil & Gas Operating LLC | | Oil & Gas Operator | Feb 2024 |
| 480 | Redland Resources, LLC | Oklahoma City, OK 73127 | Oil & Gas Operator | Feb 2024 |
| 481 | Redstone Oil & Gas Company | Dallas, TX 75225 | Oil & Gas Operator | Jan 2020 |
| 482 | Redwine Resources Inc | Dallas, TX 75225 | Oil & Gas Operator | Feb 2015 |
| 483 | Reid Williams Operating Inc | Shreveport, LA 71106-6223 | Oil & Gas Operator | Jan 2024 |
| 484 | Remnant Energy, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Apr 2024 |
| 485 | Reserve Acquisition Group | Tulsa, OK 74153 | Oil & Gas Operator | Dec 1993 |
| 486 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | Jan 2024 |
| 487 | Richland Resources Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2024 |
| 488 | Ricks Expl Acquisition LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2013 |
| 489 | Ricks Exploration Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 490 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2024 |
| 491 | RKK Production Company | Mustang, OK 73064 | Oil & Gas Operator | Feb 2024 |
| 492 | RMS Monte Christo, LLC | Snowmass VLG., CO 81615 | Oil & Gas Operator | Mar 2023 |
| 493 | Rockford Energy Partners III,LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2012 |
| 494 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 495 | Roy G Oil Company | Drumright, OK 74030-1236 | Oil & Gas Operator | Oct 1995 |
| 496 | Royal Oaks Petroleum Corp | Fort Worth, TX 76116 | Oil & Gas Operator | Dec 2001 |
| 497 | RTC Resources, LLP | Weatherford, OK 73096 | Oil & Gas Operator | Apr 2024 |
| 498 | Rupe Oil Company, Inc. | Wichita, KS 67278 | Oil & Gas Operator | Dec 2023 |
| 499 | S & G Operating LLC | Kingfisher, OK 73750-0256 | Oil & Gas Operator | Feb 2024 |
| 500 | S & S Star Operating LLC | | Oil & Gas Operator | Jun 2023 |