| 301 | Tenaska Marketing Ventures | Omaha, NE 68154 | Oil & Gas Operator | Mar 2021 |
| 302 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2024 |
| 303 | Teocalli Exploration LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2025 |
| 304 | Texaco Expl. And Prod. Inc. | Houston, TX 77236 | Oil & Gas Operator | Feb 2025 |
| 305 | Texas Southwest Gas LLC | Tulsa, OK 74121 | Oil & Gas Operator | Oct 2022 |
| 306 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 307 | The Quintin Little Company Inc | Ardmore, OK 73401 | Oil & Gas Operator | Feb 2025 |
| 308 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 309 | TLS Oil & Gas Inc | Kingfisher, OK 73750-0901 | Oil & Gas Operator | Jan 2025 |
| 310 | Torch Energy MKT Inc | Houston, TX 77010 | Oil & Gas Operator | Aug 1996 |
| 311 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 312 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 313 | Trail Ridge Energy Partners, LLC | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2025 |
| 314 | Transok LLC | Oklahoma City, OK 73124-0300 | Oil & Gas Operator | Jul 2020 |
| 315 | Twisted Resources Inc | Blanchard, OK 73010-8463 | Oil & Gas Operator | Feb 2025 |
| 316 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 317 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 318 | Unbridled Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 319 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 320 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2025 |
| 321 | Valero Marketing & Supply Co | San Antonio, TX 78269-6000 | Oil & Gas Operator | Sep 2023 |
| 322 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Dec 2024 |
| 323 | Viersen & Cochran Drilling Company | | Oil & Gas Operator | May 2015 |
| 324 | Vitol Inc | Houston, TX 77002 | Oil & Gas Operator | Sep 2023 |
| 325 | Walsh Jr F Howard | Fort Worth, TX 76102-4773 | Oil & Gas Operator | Jan 2025 |
| 326 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2025 |
| 327 | Weatherly Oil & Gas, LLC | Dallas, TX 75206 | Oil & Gas Operator | Apr 2025 |
| 328 | Western Oil And Gas Development Corp | Oklahoma City, OK 73103-3735 | Oil & Gas Operator | Feb 2025 |
| 329 | Wheeler Midstream LLC | Houston, TX 77002 | Oil & Gas Operator | May 2018 |
| 330 | Wil-Mar Operations | Duncan, OK 73534-1566 | Oil & Gas Operator | Oct 2016 |
| 331 | WM KS Energy Resources LLC | Shreveport, LA 71101 | Oil & Gas Operator | Nov 2019 |
| 332 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 333 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2025 |
| 334 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Feb 2025 |
| 335 | Z G Operating LLC | Oklahoma City, OK 73134-5038 | Oil & Gas Operator | Nov 2009 |
| 336 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 337 | Zephyr Operating Co LLC | Oklahoma City, OK 73118-6035 | Oil & Gas Operator | Feb 2025 |
| 338 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |