| 401 | Resource Operations Inc | Tulsa, OK 74157 | Oil & Gas Operator | May 2016 |
| 402 | Richland Oil Investments, LLC | Palco, KS 67657 | Oil Operator | Dec 2025 |
| 403 | Ritchie Explorat | | Oil & Gas Operator | Dec 1996 |
| 404 | Ritchie Exploration | | Oil Operator | Aug 1995 |
| 405 | Ritchie Exploration, Inc. | Wichita, KS 67278 | Oil & Gas Operator | Dec 2025 |
| 406 | Roberts Brothers | | Oil Operator | Oct 1993 |
| 407 | Robinowitz Oil C | | Oil Operator | Dec 1996 |
| 408 | Rock Creek Resources LLC | Englewood, CO 80112 | Oil & Gas Operator | Dec 2021 |
| 409 | Royal Drilling Inc | Russell, KS 67665 | Oil Operator | Dec 2025 |
| 410 | Russell Oil, Inc. | Edmond, OK 73083 | Oil Operator | Dec 2025 |
| 411 | S & M Oil - Craw | | Oil Operator | Dec 1995 |
| 412 | S & S Oil | Ponca City, OK 74601 | Oil & Gas Operator | Dec 2009 |
| 413 | S & W Oil Compan | | Oil Operator | Dec 1986 |
| 414 | S.B. Oil Company, A General Partnership | Hays, KS 67601 | Oil Operator | Sep 2019 |
| 415 | Sabre Exploratio | | Oil Operator | Oct 1988 |
| 416 | Samson Resources | | Oil Operator | Jan 1994 |
| 417 | Samuel Gary Jr. & Associates, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 418 | Sandlin Oil Corp | Dacono, CO 80514 | Oil & Gas Operator | Jan 2026 |
| 419 | Saxon Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Oct 2009 |
| 420 | Scheck Oil Operation | | Oil & Gas Operator | Dec 2025 |
| 421 | Schlobohm Starr | | Oil Operator | Dec 1996 |
| 422 | Schlobohm, Starr F. | Wolfeboro, NH 03894 | Oil Operator | Jul 2004 |
| 423 | Schmeid Ranch, LLC | Hays, KS 67601 | Oil Operator | Jun 2024 |
| 424 | Schmitt Carmen I | | Oil Operator | Dec 1996 |
| 425 | Schneltz Oil Com | | Oil Operator | May 1992 |
| 426 | Scott Services LLC | Plainville, KS 67663 | Oil Operator | Dec 2025 |
| 427 | Shaida, John H. | Wichita, KS 67226 | Oil & Gas Operator | Apr 2026 |
| 428 | Shelby Resources LLC | Denver, CO 80207 | Oil & Gas Operator | Dec 2025 |
| 429 | Shields Oil Prod | | Oil & Gas Operator | Aug 1995 |
| 430 | Shields Oil Producers Inc. | Russell, KS 67665 | Oil Operator | Dec 2025 |
| 431 | Sierra Drilling | | Oil Operator | Sep 1988 |
| 432 | Slawson Donald C | Wichita, KS 67202 | Oil & Gas Operator | Oct 2025 |
| 433 | Smith Todd W Oil | | Oil Operator | Jan 1994 |
| 434 | Source Petroleum | Wichita, KS 67202 | Oil & Gas Operator | Oct 1993 |
| 435 | Southern States | | Oil & Gas Operator | Jul 1988 |
| 436 | Spiral Energy Corp. | Midland, TX 79705 | Oil & Gas Operator | Dec 2019 |
| 437 | Staab Oil Co., A General Partnership | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 438 | Star Oil Company | Wichita, KS 67230 | Oil & Gas Operator | Mar 2025 |
| 439 | Star Resources, LTD. | Wichita, KS 67202 | Oil Operator | Nov 2002 |
| 440 | Stecklein Oil Co | | Oil Operator | Jul 1993 |
| 441 | Stecklein Oil Company, A General Partnership | Hays, KS 67601 | Oil Operator | Sep 2025 |
| 442 | Sterling Petrole | | Oil & Gas Operator | Sep 1992 |
| 443 | Stratakan Exploration, LLC | Plainville, KS 67663 | Oil & Gas Operator | Dec 2025 |
| 444 | Stull Crude Co, LLC | | Oil Operator | Dec 2025 |
| 445 | Stull Oil LLC | Natoma, KS 67651 | Oil Operator | Dec 2025 |
| 446 | Super Oilwell Service | Russell, KS 67665 | Oil Operator | Dec 2025 |
| 447 | T & D Oil Co. | Victoria, KS 67671 | Oil Operator | Apr 1996 |
| 448 | T & D Oil Compan | | Oil Operator | Jan 1992 |
| 449 | T & P Oil & Gas, L.L.C. | Overland Park, KS 66212 | Oil Operator | Dec 2009 |
| 450 | Talon Group LLC | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 451 | Taurus Oil Compa | | Oil Operator | Oct 1994 |
| 452 | Tdi, Inc. | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 453 | Tengasco, Inc. | Houston, TX 77063 | Oil & Gas Operator | Dec 2025 |
| 454 | Tenneco Oil Comp | | Oil & Gas Operator | Aug 1995 |
| 455 | Terra Max Energy | | Oil Operator | Mar 1986 |
| 456 | Tet Energy | | Oil Operator | Nov 2025 |
| 457 | Texkan Resources, LLC | Odessa, TX 79765 | Oil & Gas Operator | Jun 2025 |
| 458 | TGT Petroleum Co | | Oil & Gas Operator | Apr 1995 |
| 459 | The Bill Bowman Oil Company | | Oil Operator | Dec 2025 |
| 460 | Thomason Oil Com | | Oil Operator | Oct 1984 |
| 461 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Feb 2026 |
| 462 | Thunderbird Dril | | Oil & Gas Operator | Nov 1995 |
| 463 | Tom'S Oil | | Oil Operator | Dec 2025 |
| 464 | Tomkat Limited | | Oil & Gas Operator | Jul 1995 |
| 465 | Tomlinson Oil Co Inc | Great Bend, KS 67530 | Oil & Gas Operator | May 2025 |
| 466 | Tomlinson Operating, LLC | Ketchum, ID 83340 | Oil & Gas Operator | Oct 2014 |
| 467 | Tomlinson, Sid | Hays, KS 67601 | Oil & Gas Operator | Sep 2002 |
| 468 | Trans Pacific Oil Corporation | Wichita, KS 67202 | Oil & Gas Operator | Feb 2026 |
| 469 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Apr 2026 |
| 470 | Tri United, Inc | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 471 | Trich Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2025 |
| 472 | Tritex Resc Inco | | Oil Operator | Dec 1985 |
| 473 | Triunited Investors, LLC | Monte Sereno, CA 95030 | Oil Operator | May 2012 |
| 474 | Trumart Oil Comp | | Oil Operator | May 1990 |
| 475 | Trumart Oil Company | Ellis, KS 67637 | Oil Operator | Dec 2000 |
| 476 | Tyluka Operations, LLC | Hays, KS 67601 | Oil Operator | Sep 2025 |
| 477 | Union Pacific Re | | Oil & Gas Operator | Dec 1996 |
| 478 | Universal Resour | | Oil & Gas Operator | Dec 1996 |
| 479 | Unknown | Houston, TX 77208 | Oil & Gas Operator | Dec 2024 |
| 480 | Unrein Oil Co | | Oil Operator | Dec 2025 |
| 481 | V. Francis Weigel Family Partnership LLC | Gorham, KS 67640 | Oil Operator | Dec 2025 |
| 482 | Venture Resources | Denver, CO 80202 | Oil Operator | Dec 1993 |
| 483 | Venture Resources, Inc. | Denver, CO 80250 | Oil Operator | Dec 2025 |
| 484 | Vess Oil Corporation | Dallas, TX 75201 | Oil & Gas Operator | Apr 2026 |
| 485 | Vincent Oil Corp | Wichita, KS 67202 | Oil & Gas Operator | Dec 2025 |
| 486 | Vji Natural Resources, Inc. | | Oil & Gas Operator | Dec 2025 |
| 487 | Vonfeldt Oil Ope | | Oil Operator | Oct 1994 |
| 488 | W.J., Inc. | Ellis, KS 67637 | Oil Operator | Jan 2001 |
| 489 | Walcher Oil, LC | Bellevue, WA 98009 | Oil & Gas Operator | Nov 2025 |
| 490 | Wallace Energy Inc | Denver, CO 80202-4327 | Oil Operator | Jun 2015 |
| 491 | Walters Drilling | | Oil Operator | Mar 1988 |
| 492 | War Cry, LLC | Russell, KS 67665 | Oil Operator | Dec 2025 |
| 493 | Weigel Oil Company, LLC | Gorham, KS 67640 | Oil Operator | Dec 2025 |
| 494 | Weigel V Francis | | Oil Operator | Mar 1994 |
| 495 | Weigel, V. Francis - Family Partnership | Gorham, KS 67640 | Oil Operator | Jul 2004 |
| 496 | Weilert Enterpri | | Oil Operator | Sep 1988 |
| 497 | Weilert Michael | | Oil Operator | Oct 1993 |
| 498 | Werth Exploration Trust | | Oil Operator | Dec 2013 |
| 499 | West X, Inc. | Hays, KS 67601 | Oil Operator | Aug 1997 |
| 500 | White & Ellis DR | | Oil & Gas Operator | Aug 1995 |