| 501 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2024 |
| 502 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Apr 2024 |
| 503 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 504 | Northwest Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Jun 2014 |
| 505 | O G & E | Oklahoma City, OK 73124-0300 | Oil & Gas Operator | Feb 2014 |
| 506 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Feb 2024 |
| 507 | Obele Operating Company LLC | Sedona, AZ 86336-5745 | Oil & Gas Operator | Jan 2024 |
| 508 | Ofs-Tulsa Corporation | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 509 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Apr 2024 |
| 510 | Oil Recovery Systems Inc | | Oil & Gas Operator | Jan 2024 |
| 511 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 512 | Oklahoma & Northwestern Co. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 1997 |
| 513 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 514 | Oklahoma Liquid Resources Inc | Owasso, OK 74055-0841 | Oil & Gas Operator | Jan 2024 |
| 515 | Oklahoma Oil & Gas MGMT Inc | | Oil & Gas Operator | Jan 2024 |
| 516 | Oklahoma Petroleum Allies LLC | Ardmore, OK 73401 | Oil Operator | Oct 2023 |
| 517 | Oklahoma Prime Energy LLC | | Oil Operator | May 2020 |
| 518 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Feb 2024 |
| 519 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 520 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 521 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 522 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 523 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 524 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2024 |
| 525 | Oryx Crude Trading & Transporation LP | Dallas, TX 75221 | Oil & Gas Operator | Jun 1999 |
| 526 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2024 |
| 527 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jan 2024 |
| 528 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Apr 2024 |
| 529 | Oxley Petroleum | Tulsa, OK 74119-3609 | Oil & Gas Operator | Jan 2020 |
| 530 | Oxley Petroleum Co | Oklahoma City, OK 73118-1044 | Oil & Gas Operator | Sep 2017 |
| 531 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2024 |
| 532 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 533 | P O & G Operating LLC | Houston, TX 77057 | Oil & Gas Operator | Apr 2024 |
| 534 | Pacific Enterprise Oil Co USA | Los Angeles, CA 90071-2005 | Oil & Gas Operator | Aug 2012 |
| 535 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 536 | Panenergy Services Inc | Houston, TX 77525 | Oil & Gas Operator | May 2001 |
| 537 | Para Pro Corporation | Sedona, AZ 86336-5745 | Oil & Gas Operator | Jan 2005 |
| 538 | Paramount Petroleum Corp | Dallas, TX 75374 | Oil Operator | Dec 2000 |
| 539 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 540 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 541 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 542 | Parks Jack Concrete Co | Hominy, OK 74035 | Oil Operator | Jan 2024 |
| 543 | Parks James L | Edmond, OK 73034 | Oil & Gas Operator | Aug 2005 |
| 544 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 545 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 546 | Payne Exploration Company | Crescent, OK 73028-0502 | Oil & Gas Operator | Jan 2024 |
| 547 | Payne W C Family Trust | Oklahoma City, OK 73116-9044 | Oil & Gas Operator | Mar 2015 |
| 548 | PBT Enterprises Inc | Garber, OK 73738-0262 | Oil & Gas Operator | May 2023 |
| 549 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 550 | Pegasus Energy Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Mar 2015 |
| 551 | Pelican Production Company | New Orleans, LA 70130-2477 | Oil & Gas Operator | Mar 2014 |
| 552 | Pengo Petroleum, Inc. | | Oil & Gas Operator | Dec 2013 |
| 553 | Penn VIrginia MC Operating Co LLC | Houston, TX 77084-7213 | Oil & Gas Operator | Feb 2024 |
| 554 | Penner Energy Inc | Oklahoma City, OK 73120-1930 | Oil & Gas Operator | Feb 2024 |
| 555 | Pennmark Resources Company | Edmond, OK 73013 | Oil & Gas Operator | Jan 2024 |
| 556 | Perkins Energy Company | Duncan, OK 73533-3853 | Oil & Gas Operator | Feb 2024 |
| 557 | Pet-Ex, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2023 |
| 558 | Petro Speed Inc | Norman, OK 73069-8116 | Oil & Gas Operator | Mar 2015 |
| 559 | Petro-Haley | Borger, TX 79008 | Oil & Gas Operator | Apr 2024 |
| 560 | Petro-Management Assoc., Inc. | Edmond, OK 73083-2346 | Oil & Gas Operator | Jun 2007 |
| 561 | Petroco Inc | | Oil & Gas Operator | Nov 1996 |
| 562 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 563 | Petroleum Exploration Company LTD LP | | Oil & Gas Operator | Feb 2024 |
| 564 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 565 | Petroleum Production MGMT., Inc. | Kansas City, MO 64112 | Oil & Gas Operator | Apr 2024 |
| 566 | Phoenix Oil & Gas Inc | Seminole, OK 74818-1859 | Oil & Gas Operator | Jan 2024 |
| 567 | Phoenix Petrocorp, Inc. | McKinney, TX 75070 | Oil & Gas Operator | Feb 2024 |
| 568 | Phoenix Production Inc | Burneyville, OK 73430-2158 | Oil & Gas Operator | Jan 2024 |
| 569 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | Apr 2024 |
| 570 | Pixley Carlis D | Marlow, OK 73055 | Oil & Gas Operator | Sep 1999 |
| 571 | Plains Liquids Transport Inc | Houston, TX 77002 | Oil & Gas Operator | May 1996 |
| 572 | Plains Marketing & Trans Inc | Houston, TX 76002 | Oil & Gas Operator | Oct 1998 |
| 573 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 574 | Polaris Energy Dev Co | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2000 |
| 575 | Post Oak Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2013 |
| 576 | Presidio Petroleum LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2024 |
| 577 | Pri Producing Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2006 |
| 578 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 579 | Primary Natural Resources Inc. | Tulsa, OK 74136-6351 | Oil & Gas Operator | Mar 2023 |
| 580 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 581 | Prospective Investment & Trading | Scottsdale, AZ 85261-4190 | Oil & Gas Operator | Jun 2016 |
| 582 | Protege Energy LLC | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2018 |
| 583 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Jan 2024 |
| 584 | Pruitt Operating Company LLC | Ratliff City, OK 73481-5802 | Oil & Gas Operator | Feb 2024 |
| 585 | Psec Inc | Tulsa, OK 74102-0871 | Oil & Gas Operator | Dec 2016 |
| 586 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 587 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Jan 2024 |
| 588 | Quail Creek Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 589 | Quail Creek Petro MGMT Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 590 | Questa Oil & Gas Co. | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2015 |
| 591 | Questar Energy Trading | Salt Lake City, UT 84145-0601 | Oil & Gas Operator | Mar 2020 |
| 592 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 593 | R & C Oil And Gas Inc | Ada, OK 74820-3150 | Oil Operator | Jul 2016 |
| 594 | R & H LLC | Ardmore, OK 73401-6329 | Oil & Gas Operator | Mar 2015 |
| 595 | R C Taylor Operating Company LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2024 |
| 596 | R L Clampitt & Associates LLC | Bartlesville, OK 74006-3313 | Oil & Gas Operator | Feb 2024 |
| 597 | Ra-Jac LLC | Norman, OK 73070-4656 | Oil & Gas Operator | Feb 2024 |
| 598 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 599 | Ramsey Nichols Operating Company LLC | | Oil & Gas Operator | Feb 2024 |
| 600 | Ramsey Property Management LLC | Oklahoma City, OK 73120-1955 | Oil & Gas Operator | Jan 2024 |