| 301 | Tindall Operating Company | Englewood, CO 80112 | Oil & Gas Operator | Jan 2025 |
| 302 | Toc-Rocky Mountain Inc | | Oil & Gas Operator | Oct 2013 |
| 303 | Transhorizon Energy Inc | Cheyenne, WY 82003 | Oil & Gas Operator | Jul 2023 |
| 304 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 305 | Trout Kye Jr | | Oil & Gas Operator | Dec 2010 |
| 306 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Jan 2026 |
| 307 | Twin Eagle Petro Corp | | Gas Operator | Feb 1990 |
| 308 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 309 | Tyl Oil | Canon City, CO 81212 | Gas Operator | May 1994 |
| 310 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 311 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 312 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 313 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 314 | Vaquero Energy Inc | Bakersfield, CA 93309 | Oil & Gas Operator | May 2023 |
| 315 | Vast Oil Inc | Fullerton, CA 92832 | Oil & Gas Operator | Mar 2024 |
| 316 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Sep 2025 |
| 317 | Vector Minerals Corporation | Aurora, CO 80015 | Oil & Gas Operator | Nov 2025 |
| 318 | Warren E & P Inc | Dallas, TX 75240 | Oil & Gas Operator | Nov 2025 |
| 319 | Washington Energy Exploration | | Oil & Gas Operator | Dec 1997 |
| 320 | Wesco Operating Inc | Casper, WY 82602 | Oil & Gas Operator | Jan 2026 |
| 321 | Western American Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2024 |
| 322 | Western Interior Oil & Gas Corp | Casper, WY 82602 | Oil & Gas Operator | May 2015 |
| 323 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 324 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Dec 2025 |
| 325 | Wexpro Development Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Nov 2025 |
| 326 | Wexpro II Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Nov 2025 |
| 327 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 328 | Wilbanks Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 329 | Winter Ridge Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2011 |
| 330 | Woods Petroleum Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 331 | WPX Energy Rocky Mountain LLC | Tulsa, OK 74101 | Oil & Gas Operator | Dec 2025 |
| 332 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 333 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 334 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 335 | Yegen E C | Casper, WY 82604 | Oil & Gas Operator | Mar 2015 |
| 336 | Young Marshall R Oil Co | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2011 |