| 301 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 302 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2026 |
| 303 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 304 | Diamond B Industries Inc | Belle Fourche, SD 57717 | Oil & Gas Operator | Apr 2010 |
| 305 | Diamond Oil & Gas LLC | Casper, WY 82604 | Oil & Gas Operator | Jul 2026 |
| 306 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Sep 2016 |
| 307 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 308 | Dietrich Resources Corporation | | Oil & Gas Operator | Jun 2007 |
| 309 | Discovery Oil LTD | Los Angeles, CA 90067 | Oil & Gas Operator | Jan 1993 |
| 310 | DJ Resources Inc | Bowie, TX 76230 | Oil & Gas Operator | Nov 2017 |
| 311 | DKM Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2011 |
| 312 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Jul 2026 |
| 313 | Dol Resources Inc | Rowlett, TX 75088 | Oil & Gas Operator | Aug 2026 |
| 314 | Dolezal George Jr | Littleton, CO 80163 | Oil & Gas Operator | Sep 2006 |
| 315 | Dome Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 316 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 317 | Dominion Oklahoma Texas Expl & Prod Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 318 | Duer Wagner & Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1998 |
| 319 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Jul 2026 |
| 320 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 321 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 322 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 323 | Dyer J G | | Oil & Gas Operator | May 1985 |
| 324 | E & B Natural Resources Management | Guilderland Centek, NY 12085 | Oil & Gas Operator | Jul 2026 |
| 325 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Sep 2026 |
| 326 | Earthstone Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2017 |
| 327 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2026 |
| 328 | Eason Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2012 |
| 329 | Eastern American Energy Corp | | Oil & Gas Operator | Dec 2008 |
| 330 | Eberspecher Drilling Inc | Casper, WY 82601 | Oil & Gas Operator | Dec 2000 |
| 331 | Eblen Frank Syndicate Inc | Atlantic, IA 50022 | Oil & Gas Operator | Jul 2014 |
| 332 | Edge Energy II LLC | Golden, CO 80401 | Oil & Gas Operator | Nov 2025 |
| 333 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 334 | El Paso Natural Gas Company | El Paso, TX 79978 | Oil & Gas Operator | Apr 2013 |
| 335 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Sep 2026 |
| 336 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jun 2026 |
| 337 | Elephant Operating LLC | Dallas, TX 75204 | Oil & Gas Operator | Mar 2026 |
| 338 | Elf Aquitaine Inc | Houston, TX 77002 | Oil & Gas Operator | May 1991 |
| 339 | Elk Energy Corporation | Denver, CO 80218 | Oil & Gas Operator | Mar 2008 |
| 340 | Elk Petroleum Inc | Casper, WY 82601 | Oil & Gas Operator | Aug 2014 |
| 341 | Ellbogen John P LTD | Casper, WY 82602 | Oil & Gas Operator | Jul 2026 |
| 342 | Ellwood Exploration LLC | San Antonio, TX 78217 | Oil Operator | Jun 2026 |
| 343 | Elm Ridge Exploration Company LLC | Bloomfield, NM 87413 | Oil & Gas Operator | Nov 2017 |
| 344 | Emc Energies Inc | Casper, WY 82604 | Oil Operator | May 1989 |
| 345 | Emc Energy | | Oil & Gas Operator | Jun 1985 |
| 346 | Eme Wyoming LLC | Lakewood, CO 80401 | Oil & Gas Operator | May 2026 |
| 347 | Emep II Operating LLC | | Oil & Gas Operator | Jun 2026 |
| 348 | Emerald Operating Company | Plano, TX 75075 | Oil & Gas Operator | Jun 2026 |
| 349 | Emerald Restoration & Prod | Gillette, WY 82718 | Oil & Gas Operator | Jul 2000 |
| 350 | Empire Petroleum Corporation | Tulsa, OK 74137 | Oil & Gas Operator | Dec 2005 |
| 351 | Emre Oil LLC | Moorcroft, WY 82721 | Oil Operator | Jun 2026 |
| 352 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | May 2026 |
| 353 | Encore Operating LP | Plano, TX 75024 | Oil & Gas Operator | Jun 2026 |
| 354 | Endeavor Energy LLC | | Oil Operator | Sep 2023 |
| 355 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 356 | Enduro Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2018 |
| 357 | Enerex Limited Liability Co | Craig, CO 81625 | Oil & Gas Operator | Sep 2025 |
| 358 | Energas Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Jul 2025 |
| 359 | Energen Resources Maq Inc | Birmingham, AL 35203 | Oil & Gas Operator | Sep 2000 |
| 360 | Energetics Inc | Englewood, CO 80155 | Oil & Gas Operator | Aug 1985 |
| 361 | Energy Equity Company | Columbus, MT 59019 | Oil & Gas Operator | Jun 2026 |
| 362 | Energy Operating Company Inc | Lakewood, CO 80235 | Oil & Gas Operator | Dec 2012 |
| 363 | Energy Production Co | Pittsburgh, PA 15241-3949 | Oil & Gas Operator | Dec 1994 |
| 364 | Energy Reserves Group | Houston, TX 770563020 | Oil & Gas Operator | Apr 1996 |
| 365 | Energy Resources LLC | Owensboro, KY 42301 | Oil Operator | Jul 2026 |
| 366 | Energy Search Company Inc | Aurora, CO 80011 | Oil & Gas Operator | Jun 2021 |
| 367 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 368 | Enpro LLC | Cottonwood, UT 84047 | Oil & Gas Operator | Nov 2017 |
| 369 | Enre LP | Kingwood, TX 77339 | Oil & Gas Operator | Feb 2004 |
| 370 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 371 | Enstar Petroleum Inc | | Oil & Gas Operator | Apr 1985 |
| 372 | Entek GRB LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2021 |
| 373 | Envirosearch Corporation | | Oil Operator | Dec 1992 |
| 374 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 375 | EOG Y Resources Inc | Artesia, NM 88210 | Oil & Gas Operator | Feb 2019 |
| 376 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 377 | Equitable Resources Energy Company | Big Stone Gap, VA 24219 | Oil & Gas Operator | Dec 1997 |
| 378 | Equity Oil Company | Salt Lake City, UT 84110-095 | Oil & Gas Operator | Aug 2004 |
| 379 | Erg Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2015 |
| 380 | Escalera Resources Co | Casper, WY 82602 | Oil & Gas Operator | May 2018 |
| 381 | Essex Energy Inc | Yukon, OK 73099-5126 | Oil & Gas Operator | Apr 2014 |
| 382 | Euroamerican Energy Group Inc | | Oil & Gas Operator | Oct 1993 |
| 383 | Everest Oil & Gas LLC | Santa Barbara, CA 93101 | Oil Operator | Jun 2026 |
| 384 | Evergreen Operating Company | Denver, CO 80202 | Oil & Gas Operator | Apr 1996 |
| 385 | Evertson Operating Company Inc | Kimball, NE 69145 | Oil & Gas Operator | Nov 2022 |
| 386 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | May 2026 |
| 387 | Exeter Drilling Company | Denver, CO 80217 | Oil & Gas Operator | Sep 1997 |
| 388 | Extraction Oil & Gas LLC | Denver, CO 80202 | Oil & Gas Operator | May 2026 |
| 389 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 390 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jun 2026 |
| 391 | F & J Oil LLC | Newcastle, WY 82701 | Oil & Gas Operator | Oct 2015 |
| 392 | Fairways Offshore Expl Inc | Houston, TX 77040 | Oil & Gas Operator | Mar 2016 |
| 393 | Falcon Creek Resources, Inc. | Tulsa, OK 74137 | Oil & Gas Operator | Apr 2001 |
| 394 | Family Tree Corporation | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2013 |
| 395 | Fancher Oil LLC | Greenwood, CO 80111 | Oil & Gas Operator | Nov 2006 |
| 396 | Farnsworth & Kaiser Oil Company | Newcastle, WY 82701 | Oil & Gas Operator | Sep 2012 |
| 397 | Faulconer, Vernon E., Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2026 |
| 398 | FDF Resources | Newcastle, WY 82701 | Oil & Gas Operator | Jul 2026 |
| 399 | FDL Operating, LLC | Judson, TX 75660 | Oil & Gas Operator | Sep 2026 |
| 400 | Federated Oil & Gas Properties | Traverse City, MI 49685 | Gas Operator | Mar 2014 |