| 501 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 502 | Samson Gas Producing Company | Tulsa, OK 74103 | Oil & Gas Operator | May 2001 |
| 503 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 504 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 505 | Sandridge Energy, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2018 |
| 506 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Feb 2026 |
| 507 | Sanook Inc | Oklahoma City, OK 73156-0548 | Oil & Gas Operator | Jan 2007 |
| 508 | Santo Resources Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Nov 1998 |
| 509 | Scoggins Production LLC | Enid, OK 73703-3002 | Oil & Gas Operator | Dec 2025 |
| 510 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 511 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 512 | Seagull Midcon Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 513 | Sec Production Inc | Edmond, OK 73013-3709 | Oil & Gas Operator | Nov 2025 |
| 514 | Sensor Oil & Gas, Inc. | Duncan, OK 73534 | Oil & Gas Operator | May 2013 |
| 515 | Seven Horses LLC | Alva, OK 73717-5004 | Oil & Gas Operator | Dec 2025 |
| 516 | Shaw Thomas P | Tulsa, OK 74105-7327 | Oil & Gas Operator | Mar 2015 |
| 517 | Shelly Energy Inc | Berwyn, PA 19312 | Oil & Gas Operator | Dec 2025 |
| 518 | Sherman Oil & Gas Co Inc | Chandler, OK 74834-0571 | Oil & Gas Operator | Apr 2020 |
| 519 | Sidwell Oil & Gas, Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Sep 2014 |
| 520 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Nov 2025 |
| 521 | Silverridge Corp | Van Buren, AR 72956 | Oil & Gas Operator | Mar 2015 |
| 522 | Simcoe Oil Company | Scottsdale, AZ 85258-2553 | Oil & Gas Operator | May 2020 |
| 523 | Skycap Energy, LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2025 |
| 524 | Slawson Donald C | Wichita, KS 67202 | Oil & Gas Operator | Apr 2025 |
| 525 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 526 | Sloan Petroleum Service Inc | Guthrie, OK 73044 | Oil & Gas Operator | Dec 2025 |
| 527 | Smokey Trail LLC | Thornton, CO 80241 | Oil & Gas Operator | Dec 2025 |
| 528 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 529 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | Nov 2025 |
| 530 | Sooner Exploration & Development Co Inc | Enid, OK 73702-3525 | Oil & Gas Operator | Oct 2023 |
| 531 | Southern Star Central Gas Pipeline Inc | Owensboro, KY 42301 | Oil & Gas Operator | Nov 2025 |
| 532 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 533 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 534 | Special Energy Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Feb 2026 |
| 535 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | Dec 2025 |
| 536 | Splawn & Splawn | Saint Louis, OK 74866-0098 | Oil & Gas Operator | Mar 2025 |
| 537 | Spring Valley Oil & Gas Inc | Drummond, OK 73735 | Oil & Gas Operator | Dec 2025 |
| 538 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 539 | Staab Alan R | Tulsa, OK 74114-4213 | Oil & Gas Operator | Sep 2010 |
| 540 | Staghorn Energy, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 541 | Staghorn Petroleum II LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Dec 2025 |
| 542 | Staghorn Petroleum LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Nov 2025 |
| 543 | Star Oil Company | Wichita, KS 67230 | Oil & Gas Operator | Mar 2025 |
| 544 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 545 | Steele Jr Guy M Test Trust | Dallas, TX 75230 | Gas Operator | Mar 2018 |
| 546 | Stephen Michael Inc | Midwest City, OK 73130-5200 | Oil & Gas Operator | Oct 2015 |
| 547 | Stephens Exploration, Inc. | Dallas, TX 75367 | Oil & Gas Operator | Dec 2025 |
| 548 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Dec 2025 |
| 549 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 550 | Stone Oak Operating LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Nov 2025 |
| 551 | Stoneriver Energy, LLC | Lubbock, TX 79424 | Oil & Gas Operator | Feb 2026 |
| 552 | Stover Company | Tulsa, OK 74152-0786 | Oil & Gas Operator | Jan 2013 |
| 553 | Stride Energy LLC | Piedmont, OK 73078 | Oil & Gas Operator | Dec 2025 |
| 554 | Sullivan & Co. | Tulsa, OK 74114 | Oil & Gas Operator | May 2022 |
| 555 | Sunterra Energy Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2009 |
| 556 | Superior Oil & Gas LLC | Ringwood, OK 73768-9658 | Oil & Gas Operator | Dec 2025 |
| 557 | Sweetwater Exploration LLC | Norman, OK 73069-5636 | Oil & Gas Operator | Nov 2025 |
| 558 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 559 | Tag Oil Co LLC | Ringling, OK 73456 | Oil & Gas Operator | Nov 2025 |
| 560 | Tapoil Inc | Elmore City, OK 73433-9077 | Oil & Gas Operator | Jul 2021 |
| 561 | Tapstone Energy LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Dec 2025 |
| 562 | Taylor R C Companies Inc | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | May 2021 |
| 563 | TD Operating Inc | Hinton, OK 73047 | Oil & Gas Operator | Dec 2025 |
| 564 | Te-Ray Resources, LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Feb 2026 |
| 565 | Tekenergy Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 566 | Tema Oil Company | Amarillo, TX 79101 | Oil & Gas Operator | Jun 2009 |
| 567 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Nov 2025 |
| 568 | Teocalli Exploration LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2025 |
| 569 | Tessera Energy LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Nov 2025 |
| 570 | Tex-Ok Energy, Limited Partnership | Cody, WY 82414 | Oil & Gas Operator | Dec 2025 |
| 571 | Tex-Star Production | Dallas, TX 75206 | Oil & Gas Operator | Dec 2025 |
| 572 | Texaco Exploration & Prod Inc | Houston, TX 77236 | Oil & Gas Operator | Dec 2025 |
| 573 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 574 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Dec 2025 |
| 575 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 576 | Tidemark Exploration | Tulsa, OK 74170 | Oil & Gas Operator | May 2005 |
| 577 | Titan Resources LTD | Limaville, OH 44640 | Oil & Gas Operator | Dec 2025 |
| 578 | Toklan Oil And Gas Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 579 | Tomlinson Interest | | Oil & Gas Operator | Jun 2013 |
| 580 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 581 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 582 | Trans Pacific Oil Corporation | Wichita, KS 67202 | Oil & Gas Operator | Dec 2025 |
| 583 | Transok LLC | Oklahoma City, OK 73124-0300 | Oil & Gas Operator | Jul 2020 |
| 584 | Trey Resources Inc. | Midland, TX 79710 | Oil & Gas Operator | Nov 2025 |
| 585 | Triad Energy, Inc. | Oklahoma City, OK 73105-1401 | Oil & Gas Operator | Dec 2025 |
| 586 | Trigg Drilling Company Inc | Oklahoma City, OK 73105 | Oil & Gas Operator | Jan 2013 |
| 587 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 588 | Triumph Resources Inc | Oklahoma City, OK 73114 | Oil & Gas Operator | Nov 2004 |
| 589 | Tulsa Energy Partners LLC | Tulsa, OK 74103-4461 | Oil & Gas Operator | Dec 2025 |
| 590 | Tuthill S Keith & Bill Barbee | Amarillo, TX 79101-1427 | Oil & Gas Operator | Dec 2004 |
| 591 | Twain Energy LLC | Ridgeland, MS 39157 | Oil & Gas Operator | Dec 2025 |
| 592 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 593 | Txok Energy Resources Company | Tulsa, OK 74172-0140 | Oil & Gas Operator | Feb 2017 |
| 594 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 595 | Union Texas Petroleum Corp | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 596 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 597 | United Oil Corporation | Denver, CO 80202-3813 | Oil & Gas Operator | Nov 2025 |
| 598 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Nov 2025 |
| 599 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 600 | Valar Petroleum Inc | Houston, TX 77069 | Oil & Gas Operator | May 2006 |