| 301 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 302 | Southwest Energy LP | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 303 | Sparks Petroleum Company | Oklahoma City, OK 73128 | Oil & Gas Operator | Mar 1998 |
| 304 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | Feb 2026 |
| 305 | Spring Resources, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2007 |
| 306 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 307 | Stalwart Energy Co | Tulsa, OK 74103-3518 | Oil & Gas Operator | Apr 2014 |
| 308 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2026 |
| 309 | Sunwest Oklahoma, Inc | Dallas, TX 75231 | Oil & Gas Operator | May 2023 |
| 310 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 311 | Tag Team Resources LLC | Eufaula, OK 74432 | Oil & Gas Operator | Jan 2026 |
| 312 | Texaco Exploration & Prod Inc | Houston, TX 77236 | Oil & Gas Operator | Dec 2025 |
| 313 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 314 | Texaco Oils Inc | Tulsa, OK 74102-2420 | Oil & Gas Operator | Jan 2003 |
| 315 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 316 | Texinia Limited Partnership | Dallas, TX 75201 | Gas Operator | Jan 2017 |
| 317 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 318 | Tiger Trucks Inc | Seminole, OK 74868 | Oil & Gas Operator | Feb 2026 |
| 319 | Titan Resources LTD | Limaville, OH 44640 | Oil & Gas Operator | Feb 2026 |
| 320 | Toklan Oil And Gas Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 321 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 322 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 323 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Apr 2026 |
| 324 | Tucker Ron & Co | Norman, OK 73069-8511 | Gas Operator | Sep 2017 |
| 325 | Twenty First Century Res Inc | Lajolla, CA 92037-7044 | Oil & Gas Operator | Mar 2015 |
| 326 | Twin Eagle Petroleum Corp | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2002 |
| 327 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 328 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 329 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 330 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Dec 2025 |
| 331 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 332 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Dec 2025 |
| 333 | Vectra CBM LLC | Littleton, CO 80128-4557 | Gas Operator | Jan 2014 |
| 334 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2026 |
| 335 | Vitruvian Exploration LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2016 |
| 336 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 337 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2026 |
| 338 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2026 |
| 339 | Wente Exploration Inc | Oklahoma City, OK 73102 | Gas Operator | Oct 2011 |
| 340 | Wentworth Operating Company | Oklahoma City, OK 73162-1863 | Oil & Gas Operator | Feb 2026 |
| 341 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 342 | Wheeler Energy Co. | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 343 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 344 | Whitmar Operating Company | Tulsa, OK 74103-3515 | Oil & Gas Operator | Apr 2009 |
| 345 | Williford Energy Company | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2026 |
| 346 | Williford Resources LLC | Tulsa, OK 74136-1020 | Oil & Gas Operator | Feb 2026 |
| 347 | Wohlford Properties Inc | Barling, AR 72923 | Gas Operator | Apr 2022 |
| 348 | WPX Energy Mid-Continent Co | Oklahoma City, OK 73102-5010 | Oil & Gas Operator | Apr 2016 |
| 349 | Wright V Gerald | Cushing, OK 74023 | Oil & Gas Operator | Nov 2003 |
| 350 | Wytex Production Corporation | Fort Smith, AR 72903 | Oil & Gas Operator | Jan 2026 |
| 351 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 352 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Feb 2026 |
| 353 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 354 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 355 | Zinke & Trumbo LTD | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2017 |
| 356 | ZZ Energy LLC | Norman, OK 73070 | Gas Operator | Jan 2026 |