| 201 | Eastern American Energy Corp | | Oil & Gas Operator | Dec 2008 |
| 202 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 203 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Feb 2026 |
| 204 | Ellbogen John P LTD | Casper, WY 82602 | Oil & Gas Operator | Jan 2026 |
| 205 | Emc Energy | | Oil & Gas Operator | Jun 1985 |
| 206 | Emep II Operating LLC | | Oil & Gas Operator | Feb 2026 |
| 207 | Emerald Operating Company | Plano, TX 75075 | Oil & Gas Operator | Feb 2026 |
| 208 | Emerald Restoration & Prod | Gillette, WY 82718 | Oil & Gas Operator | Jul 2000 |
| 209 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | Feb 2024 |
| 210 | Energen Resources Maq Inc | Birmingham, AL 35203 | Oil & Gas Operator | Sep 2000 |
| 211 | Energetics Inc | Englewood, CO 80155 | Oil & Gas Operator | Aug 1985 |
| 212 | Energy Equity Company | Columbus, MT 59019 | Oil & Gas Operator | Feb 2026 |
| 213 | Energy Operating Company Inc | Lakewood, CO 80235 | Oil & Gas Operator | Dec 2012 |
| 214 | Enpro LLC | Cottonwood, UT 84047 | Oil & Gas Operator | Nov 2017 |
| 215 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Apr 2026 |
| 216 | EOG Y Resources Inc | Artesia, NM 88210 | Oil & Gas Operator | Feb 2019 |
| 217 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 218 | Equitable Resources Energy Company | Big Stone Gap, VA 24219 | Oil & Gas Operator | Dec 1997 |
| 219 | Equity Oil Company | Salt Lake City, UT 84110-095 | Oil & Gas Operator | Aug 2004 |
| 220 | Escalera Resources Co | Casper, WY 82602 | Oil & Gas Operator | May 2018 |
| 221 | Evergreen Operating Company | Denver, CO 80202 | Oil & Gas Operator | Apr 1996 |
| 222 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Jan 2026 |
| 223 | Exeter Drilling Company | Denver, CO 80217 | Oil & Gas Operator | Sep 1997 |
| 224 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 225 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jan 2026 |
| 226 | Family Tree Corporation | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2013 |
| 227 | Fancher Oil LLC | Greenwood, CO 80111 | Oil & Gas Operator | Nov 2006 |
| 228 | Faulconer, Vernon E., Inc. | Tyler, TX 75711 | Oil & Gas Operator | Feb 2026 |
| 229 | FDL Operating, LLC | Judson, TX 75660 | Oil & Gas Operator | Apr 2026 |
| 230 | Federated Oil & Gas Properties | Traverse City, MI 49685 | Gas Operator | Mar 2014 |
| 231 | Felmont Oil Corporation | Walnut Creek, CA 94596-3568 | Oil & Gas Operator | Feb 1990 |
| 232 | Ferguson Oil Company Inc | | Oil & Gas Operator | Apr 1994 |
| 233 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 234 | First Energy Corporation | | Oil & Gas Operator | Jun 1993 |
| 235 | First Sourcenergy Wyoming Inc | Gillette, WY 82718 | Gas Operator | Jul 2003 |
| 236 | Flag-Redfern Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2002 |
| 237 | Flahive Oil & Gas LLC | Golden, CO 80401 | Oil Operator | Oct 1995 |
| 238 | Florida Gas Exploration Co | | Oil & Gas Operator | Feb 1985 |
| 239 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 240 | Forcenergy Inc | Miami, FL 33129 | Oil & Gas Operator | Mar 2015 |
| 241 | Foree R L | Dallas, TX 75225 | Oil & Gas Operator | Aug 2001 |
| 242 | Forest Oil Permian Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 243 | Forestar Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2017 |
| 244 | Frank Louis L | Kingsville, TX 78364 | Oil & Gas Operator | Aug 2003 |
| 245 | Frickey Investment MGT Co LLC | Lakewood, CO 80215 | Oil & Gas Operator | Feb 2026 |
| 246 | Fuel Resources Development Co | Denver, CO 80202 | Oil & Gas Operator | Feb 1994 |
| 247 | G & H Production Company LLC | Denver, CO 80202 | Oil Operator | Jan 2008 |
| 248 | Galaxy Oil Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2015 |
| 249 | Gallagher Drilling Inc | Evansville, IN 47730 | Oil Operator | Dec 2020 |
| 250 | Gary-Williams Production Company | Denver, CO 80202 | Oil & Gas Operator | May 2000 |
| 251 | General American Oil Co Of Texas | | Oil & Gas Operator | Mar 1983 |
| 252 | General Atlantic Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 253 | Genesis Production Company | | Oil & Gas Operator | May 1991 |
| 254 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 255 | Germany Operating Company | Houston, TX 77090 | Oil & Gas Operator | Sep 2011 |
| 256 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 257 | Gibbs William | | Oil Operator | Feb 2000 |
| 258 | Gilmore Oil & Gas | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 259 | GKM Inc | | Oil & Gas Operator | Mar 1990 |
| 260 | GLG Energy LP | Austin, TX 78701 | Oil & Gas Operator | Jun 1994 |
| 261 | Goodstein Fred | Casper, WY 82602 | Oil & Gas Operator | Mar 1984 |
| 262 | Gorman Construction LLC | Gillette, WY 82716 | Oil Operator | Nov 2025 |
| 263 | Gould Joseph B | Las Vegas, NV 89101 | Oil & Gas Operator | Apr 2001 |
| 264 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 265 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 266 | Granite Creek Energy LLC | Cody, WY 82414 | Oil & Gas Operator | Feb 2026 |
| 267 | Grayling Resources LTD | Lakewood, CO 80235 | Oil & Gas Operator | Jul 2020 |
| 268 | Grayson Mill Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Aug 2025 |
| 269 | Great Northern Drilling Company | Billings, MT 59103 | Oil & Gas Operator | Jun 2016 |
| 270 | Great Western Drilling Company | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 271 | Greenwood Resources | | Oil & Gas Operator | Jan 1992 |
| 272 | Grey Hawk Operating LLC | Birmingham, AL 35242 | Oil Operator | Jan 2024 |
| 273 | Grizzly Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jan 2026 |
| 274 | Gulf Exploration, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2026 |
| 275 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 276 | Gulf Production Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2015 |
| 277 | H & H Star Energy Inc | Traverse City, MI 49684 | Oil & Gas Operator | Aug 2016 |
| 278 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 279 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 280 | H C M Energy LLC | Billings, MT 59102 | Oil Operator | Jul 2003 |
| 281 | Hamon Jake L | Dallas, TX 75201-3902 | Oil & Gas Operator | Nov 1997 |
| 282 | Harper Oil Co. | Denver, CO 80217 | Oil & Gas Operator | Dec 2025 |
| 283 | Harrell Oil Company LLC | Ardmore, OK 73402 | Oil Operator | Jan 2025 |
| 284 | Harvey E Yates Company | Roswell, NM 88202 | Oil & Gas Operator | Feb 2015 |
| 285 | Havoco Inc | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2005 |
| 286 | Hawks Industries Inc | Casper, WY 82601 | Oil & Gas Operator | Jun 1993 |
| 287 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 288 | Heartland Energy Company | Big Horn, WY 82833 | Gas Operator | Jun 2012 |
| 289 | Helis Oil & Gas Company LLC Estate | New Orleans, LA 70130 | Oil & Gas Operator | Jul 2022 |
| 290 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 291 | Hi-Pro Production | Gillette, WY 82717 | Gas Operator | Nov 2003 |
| 292 | High Plains Gas LLC | Gillette, WY 82717 | Gas Operator | Aug 2014 |
| 293 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Apr 2026 |
| 294 | HNG Oil Company | | Oil & Gas Operator | Jun 1987 |
| 295 | Hodge T F | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2007 |
| 296 | Holly Energy Inc | | Oil Operator | Apr 1983 |
| 297 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Apr 2026 |
| 298 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 299 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 300 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |