| 501 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 502 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 503 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | Nov 2025 |
| 504 | South Forty Inc (The) | Laverne, OK 73848 | Oil & Gas Operator | Mar 2015 |
| 505 | Southwest Exploration Company | Oklahoma City, OK 73132-2230 | Oil & Gas Operator | Jun 2017 |
| 506 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 507 | Sparks Petroleum Company | Oklahoma City, OK 73128 | Oil & Gas Operator | Mar 1998 |
| 508 | Special Energy Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Feb 2026 |
| 509 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | Dec 2025 |
| 510 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 511 | Spur Operating Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2026 |
| 512 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 513 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 514 | Staab Alan R | Tulsa, OK 74114-4213 | Oil & Gas Operator | Sep 2010 |
| 515 | Staghorn Energy, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 516 | Statex Operating, LLC | Dallas, TX 75229 | Oil & Gas Operator | Mar 2007 |
| 517 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 518 | Stephens Exploration, Inc. | Dallas, TX 75367 | Oil & Gas Operator | Dec 2025 |
| 519 | Stewart K Petroleum Corp | Edmond, OK 73013 | Oil & Gas Operator | Mar 2015 |
| 520 | Stone Oak Operating LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Nov 2025 |
| 521 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 522 | Stricker Resources Inc | Morris, OK 74445 | Oil & Gas Operator | Nov 2025 |
| 523 | Summit Resources, Inc. | Houston, TX 77077 | Oil & Gas Operator | Sep 2016 |
| 524 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Feb 2026 |
| 525 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 526 | Sunterra Energy Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2009 |
| 527 | Suoco Oil Corporation | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 528 | Sweetwater Exploration LLC | Norman, OK 73069-5636 | Oil & Gas Operator | Nov 2025 |
| 529 | Tack Operating LLC | Oklahoma City, OK 73172-1492 | Oil & Gas Operator | Aug 2021 |
| 530 | Tapstone Energy LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Dec 2025 |
| 531 | Taylor R C Companies Inc | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | May 2021 |
| 532 | Te-Ray Energy Inc | Oklahoma City, OK 73108 | Oil & Gas Operator | Nov 2025 |
| 533 | Te-Ray Resources, LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Feb 2026 |
| 534 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Nov 2025 |
| 535 | Tex-Ok Energy, Limited Partnership | Cody, WY 82414 | Oil & Gas Operator | Dec 2025 |
| 536 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 537 | Texaco Exploration & Prod Inc | Houston, TX 77236 | Oil & Gas Operator | Dec 2025 |
| 538 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 539 | The Quintin Little Company Inc | Ardmore, OK 73401 | Oil & Gas Operator | Dec 2025 |
| 540 | Three D Resources Inc | Liberal, KS 67905 | Oil & Gas Operator | Sep 2025 |
| 541 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 542 | Tidemark Exploration | Tulsa, OK 74170 | Oil & Gas Operator | May 2005 |
| 543 | Titan Resources LTD | Limaville, OH 44640 | Oil & Gas Operator | Dec 2025 |
| 544 | TLM Resources Inc | Enid, OK 73706-0641 | Gas Operator | Mar 2015 |
| 545 | Todd John C | Oklahoma City, OK 73112-8049 | Oil & Gas Operator | May 2015 |
| 546 | Toklan Oil And Gas Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 547 | Toklan Oil Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 548 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 549 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 550 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 551 | Trail Ridge Energy Partners, LLC | Grapevine, TX 76051 | Oil & Gas Operator | Dec 2025 |
| 552 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Feb 2026 |
| 553 | Trey Resources Inc. | Midland, TX 79710 | Oil & Gas Operator | Nov 2025 |
| 554 | Triad Energy, Inc. | Oklahoma City, OK 73105-1401 | Oil & Gas Operator | Dec 2025 |
| 555 | Trueblood Resources, Inc. | Denver, CO 80222 | Oil & Gas Operator | Feb 2026 |
| 556 | Tulsa Minerals Inc | Tulsa, OK 74136-1045 | Oil & Gas Operator | May 2013 |
| 557 | Turner Resources Inc | Hennessey, OK 73742 | Oil & Gas Operator | Nov 2025 |
| 558 | Tuthill S Keith & Bill Barbee | Amarillo, TX 79101-1427 | Oil & Gas Operator | Dec 2004 |
| 559 | Twain Energy LLC | Ridgeland, MS 39157 | Oil & Gas Operator | Dec 2025 |
| 560 | Twin Eagle Petroleum Corp | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2002 |
| 561 | Twisted Oak Operating LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 562 | Twisted Resources Inc | Blanchard, OK 73010-8463 | Oil & Gas Operator | Dec 2025 |
| 563 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 564 | Txok Energy Resources Company | Tulsa, OK 74172-0140 | Oil & Gas Operator | Feb 2017 |
| 565 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 566 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 567 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 568 | United Oil Corporation | Denver, CO 80202-3813 | Oil & Gas Operator | Nov 2025 |
| 569 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 570 | Vanon Energy Inc | Fort Worth, TX 76162 | Oil & Gas Operator | Jul 2022 |
| 571 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Sep 2025 |
| 572 | Viersen & Cochran Drilling Company | | Oil & Gas Operator | May 2015 |
| 573 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 574 | Waggoner Oil & Gas Corp | Enid, OK 73703-1152 | Oil & Gas Operator | Dec 2025 |
| 575 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 576 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Feb 2026 |
| 577 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Nov 2025 |
| 578 | Washita Oil And Gas, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 579 | Waterford Energy Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 1998 |
| 580 | Weinkauf Petroleum, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 581 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 582 | Wheeler Energy Co. | Tulsa, OK 74101 | Oil & Gas Operator | Nov 2025 |
| 583 | Wheeler Energy, LLC | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 584 | Whitaker Energy Inc | Humble, TX 77346-1798 | Oil & Gas Operator | Dec 2025 |
| 585 | Whitdale Inc | Cushing, OK 74023 | Oil & Gas Operator | Aug 2023 |
| 586 | Whitestone Petroleum Corp | Edmond, OK 73083-7914 | Oil & Gas Operator | May 2015 |
| 587 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 588 | Whitley Oil & Gas Inc | Owasso, OK 74055 | Oil & Gas Operator | Jun 2009 |
| 589 | Will Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2025 |
| 590 | Williford Energy Company | Tulsa, OK 74135 | Oil & Gas Operator | Feb 2026 |
| 591 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 592 | WLW Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2025 |
| 593 | Wolf Creek Enterprises Inc | Stillwater, OK 74074-6965 | Oil Operator | Apr 2009 |
| 594 | Woods Petroleum Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 595 | Woodward Iodine Corporation | Woodward, OK 73801 | Oil & Gas Operator | Dec 2025 |
| 596 | Wynn-Crosby Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Nov 2025 |
| 597 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 598 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 599 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Dec 2025 |
| 600 | Yarhola Production Company | Drumright, OK 74030 | Oil & Gas Operator | Dec 2025 |