| 401 | T-Bar Exploration, Inc. | Sterling, KS 67579 | Oil Operator | Apr 1998 |
| 402 | T-N-T Engineering, Inc. | Fort Worth, TX 76107 | Oil & Gas Operator | Apr 2026 |
| 403 | Te-Pe Oil & Gas | | Oil & Gas Operator | Dec 2025 |
| 404 | Tengasco, Inc. | Houston, TX 77063 | Oil & Gas Operator | Dec 2025 |
| 405 | Texaco Explorati | | Oil & Gas Operator | Dec 1996 |
| 406 | Texas Energies I | | Oil & Gas Operator | Aug 1994 |
| 407 | Thomas Garner, Inc. | St John, KS 67576 | Oil & Gas Operator | Dec 2025 |
| 408 | Thomason Oil Com | | Oil Operator | Oct 1984 |
| 409 | Thoroughbred Associates LLC | Wichita, KS 67226 | Oil & Gas Operator | Dec 2025 |
| 410 | Tidal Wave Energy, Inc. | New Castle, PA 16105 | Oil & Gas Operator | Jun 2022 |
| 411 | Tomkat Limited | | Oil & Gas Operator | Jul 1995 |
| 412 | Tomlinson Oil Co Inc | Great Bend, KS 67530 | Oil & Gas Operator | May 2025 |
| 413 | Toto Energy, LLC | Spring, TX 77380 | Oil & Gas Operator | Dec 2019 |
| 414 | Touchstone Trading & Transportation Inc | | Oil Operator | Mar 2025 |
| 415 | Tower Oil & Gas Company Inc | Englewood, CO 80111 | Oil & Gas Operator | May 2001 |
| 416 | Trans Pacific Oi | | Oil & Gas Operator | May 1995 |
| 417 | Trans Pacific Oil Corporation | Wichita, KS 67202 | Oil & Gas Operator | Feb 2026 |
| 418 | Trek Aec, LLC | Wichita, KS 67202 | Oil & Gas Operator | Dec 2025 |
| 419 | Tri-J Tubulars, Inc. | Wichita, KS 67202 | Oil Operator | Aug 1996 |
| 420 | Turnco Drilling, Inc. | Portland, OR 97208 | Oil & Gas Operator | Dec 2009 |
| 421 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 422 | United Reserve G | | Oil Operator | Aug 1987 |
| 423 | Unknown | Houston, TX 77208 | Oil & Gas Operator | Dec 2024 |
| 424 | Val Energy, Inc. | Wichita, KS 67202 | Oil & Gas Operator | Dec 2025 |
| 425 | Vamco Operations | | Oil & Gas Operator | Dec 2025 |
| 426 | Veenker Resources Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2026 |
| 427 | Vess Oil Corporation | Dallas, TX 75201 | Oil & Gas Operator | Apr 2026 |
| 428 | Vess Transpacifi | | Oil & Gas Operator | Jul 1995 |
| 429 | Vess-Transpacific Operating Co., Inc. | Wichita, KS 67201 | Oil & Gas Operator | May 2024 |
| 430 | Vji Natural Resources, Inc. | | Oil & Gas Operator | Dec 2025 |
| 431 | Voigt O & G Comp | | Oil & Gas Operator | Nov 1993 |
| 432 | Voigt Oil & Gas Co., Inc. | McPherson, KS 67460 | Oil Operator | Aug 2025 |
| 433 | Vonfeldt Oil Ope | | Oil Operator | Oct 1994 |
| 434 | Walcher Oil, LC | Bellevue, WA 98009 | Oil & Gas Operator | Nov 2025 |
| 435 | Wapiti Petroleum, LLC | | Oil & Gas Operator | Dec 2025 |
| 436 | Warren Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Jan 2016 |
| 437 | Webco Oil Compan | | Oil Operator | Sep 1989 |
| 438 | Webco Oil Company, Inc. | Hoisington, KS 67544 | Oil Operator | Dec 2025 |
| 439 | Westmore Drillin | | Oil & Gas Operator | Oct 1995 |
| 440 | Wheatbelt Invest | | Oil Operator | Mar 1991 |
| 441 | White & Ellis DR | | Oil & Gas Operator | Aug 1995 |
| 442 | White & Ellis Drilling, Inc. | Wichita, KS 67206 | Oil & Gas Operator | Dec 2025 |
| 443 | White Eagle Resources Corp. | Taos, NM 87571 | Oil & Gas Operator | Jun 2016 |
| 444 | White Exploration Inc | Wichita, KS 67278 | Oil & Gas Operator | Dec 2025 |
| 445 | White Hawk Oil C | | Oil & Gas Operator | Sep 1995 |
| 446 | White Hawk Oil Company, A General Partnership | Tulsa, OK 74101 | Oil Operator | Dec 2025 |
| 447 | White Hawk Oil Company, LLP | Tulsa, OK 74103 | Oil Operator | Dec 2025 |
| 448 | White Pine Petroleum Corporation | Wichita, KS 67202 | Oil & Gas Operator | Dec 2019 |
| 449 | White, Kenneth S. | Wichita, KS 67220 | Oil & Gas Operator | Sep 2022 |
| 450 | White, Robert F. | Wichita, KS 67220 | Oil & Gas Operator | Feb 2007 |
| 451 | Whitetail Crude Inc | Ness City, KS 67560 | Oil & Gas Operator | Dec 2025 |
| 452 | Widener, A.C. Farms, Inc. | Hudson, KS 67545 | Oil Operator | Dec 2009 |
| 453 | Wiedemann K T TR | | Oil Operator | Jul 1992 |
| 454 | Wineland Oil - LLC | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 455 | Woodman & Iannit | | Oil & Gas Operator | Sep 1996 |
| 456 | Woodman & Iannitti Oil Company | Great Bend, KS 67530 | Oil & Gas Operator | Jan 2003 |
| 457 | Woolsey Operating Company, LLC | Wichita, KS 67226 | Oil & Gas Operator | Dec 2025 |
| 458 | Woolsey Petroleum Corporation | Wichita, KS 67202 | Oil & Gas Operator | Dec 2025 |
| 459 | Wren Investments | | Oil Operator | Feb 1991 |
| 460 | Xanadu Exploration Company | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2026 |
| 461 | Yager Company | Hutchinson, KS 67502 | Oil & Gas Operator | Dec 2000 |
| 462 | Yost Oil Operati | | Oil Operator | Jul 1990 |
| 463 | Younger Energy Company | Wichita, KS 67206 | Oil & Gas Operator | Apr 2026 |
| 464 | Zenith Drilling | | Oil & Gas Operator | Aug 1995 |
| 465 | Zenith Drilling Corporation | Wichita, KS 67206 | Oil & Gas Operator | Dec 2025 |
| 466 | Zu, LLC | Hays, KS 67601 | Oil Operator | Nov 2025 |