| 101 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 102 | Enstar Petroleum Inc | | Oil & Gas Operator | Apr 1985 |
| 103 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 104 | EOG Y Resources Inc | Artesia, NM 88210 | Oil & Gas Operator | Feb 2019 |
| 105 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 106 | Equitable Resources Energy Company | Big Stone Gap, VA 24219 | Oil & Gas Operator | Dec 1997 |
| 107 | Equity Oil Company | Salt Lake City, UT 84110-095 | Oil & Gas Operator | Aug 2004 |
| 108 | Escalera Resources Co | Casper, WY 82602 | Oil & Gas Operator | May 2018 |
| 109 | Euroamerican Energy Group Inc | | Oil & Gas Operator | Oct 1993 |
| 110 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 111 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | May 2025 |
| 112 | Fancher Oil LLC | Greenwood, CO 80111 | Oil & Gas Operator | Nov 2006 |
| 113 | FDL Operating, LLC | Judson, TX 75660 | Oil & Gas Operator | Jul 2025 |
| 114 | Fidelity Exploration & Production Company | Denver, CO 80203 | Oil & Gas Operator | Jun 2025 |
| 115 | Finaly Resources LLC | Sunset Beach, CA 90742 | Oil & Gas Operator | Jul 2025 |
| 116 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Jul 2025 |
| 117 | Florida Gas Exploration Co | | Oil & Gas Operator | Feb 1985 |
| 118 | Flow Production Company | Midland, TX 79708 | Oil & Gas Operator | Mar 2005 |
| 119 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 120 | FMC Corporation | Green River, WY 82935 | Oil & Gas Operator | Dec 2008 |
| 121 | Forcenergy Inc | Miami, FL 33129 | Oil & Gas Operator | Mar 2015 |
| 122 | Forcenergy Onshore Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2012 |
| 123 | Forestar Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2017 |
| 124 | Foundation Energy Managment LLC | Addison, TX 74119 | Oil & Gas Operator | May 2025 |
| 125 | Fuel Resources Development Co | Denver, CO 80202 | Oil & Gas Operator | Feb 1994 |
| 126 | G & H Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2009 |
| 127 | Gasco Inc | | Oil & Gas Operator | Jun 1998 |
| 128 | General Atlantic Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 129 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 130 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 131 | GKM Inc | | Oil & Gas Operator | Mar 1990 |
| 132 | GLG Energy LP | Austin, TX 78701 | Oil & Gas Operator | Jun 1994 |
| 133 | GMT Energy Corporation | Houston, TX 77042 | Oil & Gas Operator | Feb 2005 |
| 134 | GMT Exploration Company LLC | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 135 | Golden Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2010 |
| 136 | Goldmark Engineering Inc | Casper, WY 82602 | Oil & Gas Operator | Oct 2004 |
| 137 | Gpo Operations LLC | Labarge, WY 83123 | Oil & Gas Operator | Jun 2025 |
| 138 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 139 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 140 | Grayhorse Operating Inc | Tulsa, OK 74103-4439 | Oil & Gas Operator | Apr 2025 |
| 141 | Grayson Mill Operating LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 142 | Great Northern Gas Company | Denver, CO 80293-0602 | Oil & Gas Operator | Jul 2017 |
| 143 | Great Western Drilling Co | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 144 | Greylock Production LLC | Charleston, WV 25311-1264 | Oil & Gas Operator | May 2025 |
| 145 | Grizzly Operating LLC | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 146 | Grynberg Petroleum Company | Greenwood Vge, CO 80111-3326 | Oil & Gas Operator | Oct 2019 |
| 147 | Grynberg, Jack J. | Denver, CO 80237 | Oil & Gas Operator | Jun 2021 |
| 148 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 149 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 150 | Hawks Industries Inc | Casper, WY 82601 | Oil & Gas Operator | Jun 1993 |
| 151 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 152 | Helena Resources Inc | Lakewood, CO 80215 | Oil & Gas Operator | Jun 2025 |
| 153 | Herbaly Petroleum Corp | FT Worth, TX 76102 | Oil & Gas Operator | Feb 2002 |
| 154 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2025 |
| 155 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 156 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Jul 2025 |
| 157 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 158 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 159 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 160 | HRM Resources II, LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 161 | HRM Resources III LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2022 |
| 162 | HRM Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2015 |
| 163 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 164 | Hudson Group LLC | Casper, WY 82601 | Oil & Gas Operator | May 2025 |
| 165 | Hughes Oil Company Inc | Odessa, TX 79765 | Oil & Gas Operator | Feb 2004 |
| 166 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 167 | Husky Oil Company | Cody, WY 82414 | Oil & Gas Operator | Dec 1984 |
| 168 | Ibex Resources Operating LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2007 |
| 169 | Independent Production Company | Greenwood VIllage, CO 80121 | Oil & Gas Operator | May 2003 |
| 170 | Industrial Gas Services Inc | Wheat Ridge, CO 80033 | Oil & Gas Operator | Feb 2023 |
| 171 | Inexco Oil Company | Houston, TX 77210 | Oil & Gas Operator | Mar 2013 |
| 172 | Infinity Oil & Gas Of Wyoming | Rock Springs, WY 82902 | Oil & Gas Operator | Feb 2009 |
| 173 | Integrated Petroleum Corporation | Denver, CO 80202 | Oil Operator | Jan 2010 |
| 174 | Interline Resources Corp | Casper, WY 82601 | Oil & Gas Operator | Oct 2009 |
| 175 | Intrepid Oil & Gas LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2021 |
| 176 | Intrepid Production Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 177 | Ip Petroleum Company, Inc. | Houston, TX 77210 | Oil & Gas Operator | Mar 2008 |
| 178 | Itr Petroleum Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 179 | J-W Operating Company | Christoval, TX 76935 | Oil & Gas Operator | Jul 2025 |
| 180 | Jims Water Service Inc | Gillette, WY 82717 | Oil & Gas Operator | Oct 2016 |
| 181 | JM Cox Resources LP | Midland, TX 79702 | Oil & Gas Operator | Apr 2019 |
| 182 | Joemar Wyoming Operating LLC | | Oil & Gas Operator | May 2025 |
| 183 | Juniper Petroleum Corporation | | Oil & Gas Operator | Aug 1983 |
| 184 | K N Energy Inc | Lakewood, CO 80228 | Oil & Gas Operator | Nov 2000 |
| 185 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 186 | KCS Mountain Resources Inc | Manderson, WY 82432 | Oil & Gas Operator | Nov 2006 |
| 187 | Keba Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2015 |
| 188 | Kem Ventures, LP | Katy, TX 77450 | Oil & Gas Operator | May 2025 |
| 189 | Kenai Oil & Gas Inc | | Oil & Gas Operator | Jun 1987 |
| 190 | Kennedy Oil | Gillette, WY 82716 | Oil & Gas Operator | May 2025 |
| 191 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 192 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |
| 193 | Kerr-McGee Rocky Mountain Corp | Denver, CO 80202 | Oil & Gas Operator | Jan 2007 |
| 194 | Kestrel Energy Inc | Lakewood, CO 80401 | Oil & Gas Operator | Jan 2008 |
| 195 | Klabzuba Oil & Gas Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2012 |
| 196 | Koch Exploration Company | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 197 | Kodiak Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2020 |
| 198 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 199 | Labarge Minerals Inc | Labarge, WY 83123 | Oil & Gas Operator | Jan 2020 |
| 200 | Lagniappe Interest Inc | Evergreen, CO 80439 | Oil & Gas Operator | Jun 2006 |