| 101 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 102 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 103 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2026 |
| 104 | Dietrich Resources Corporation | | Oil & Gas Operator | Jun 2007 |
| 105 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Jan 2026 |
| 106 | Dol Resources Inc | Rowlett, TX 75088 | Oil & Gas Operator | Feb 2026 |
| 107 | Duer Wagner & Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1998 |
| 108 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Jan 2026 |
| 109 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 110 | Dyer J G | | Oil & Gas Operator | May 1985 |
| 111 | Felmont Oil Corporation | Walnut Creek, CA 94596-3568 | Oil & Gas Operator | Feb 1990 |
| 112 | Ferguson & Bosworth | | Oil & Gas Operator | May 2007 |
| 113 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 114 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Mar 2026 |
| 115 | Flag-Redfern Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2002 |
| 116 | Flahive Oil & Gas LLC | Golden, CO 80401 | Oil Operator | Oct 1995 |
| 117 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 118 | Forcenergy Inc | Miami, FL 33129 | Oil & Gas Operator | Mar 2015 |
| 119 | Forestar Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2017 |
| 120 | Fossil Creek Resources LLC | Arlington, TX 76011-5597 | Oil & Gas Operator | Mar 2015 |
| 121 | Frickey Investment MGT Co LLC | Lakewood, CO 80215 | Oil & Gas Operator | Jan 2026 |
| 122 | General American Oil Co Of Texas | | Oil & Gas Operator | Mar 1983 |
| 123 | General Atlantic Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 124 | General Crude Oil Co | Houston, TX 77005 | Oil & Gas Operator | Dec 1979 |
| 125 | Genesis Production Company | | Oil & Gas Operator | May 1991 |
| 126 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 127 | Gibson J W | | Oil & Gas Operator | Sep 1999 |
| 128 | GLG Energy LP | Austin, TX 78701 | Oil & Gas Operator | Jun 1994 |
| 129 | Goodstein Fred | Casper, WY 82602 | Oil & Gas Operator | Mar 1984 |
| 130 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 131 | Grayling Resources LTD | Lakewood, CO 80235 | Oil & Gas Operator | Jul 2020 |
| 132 | Grayson Mill Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Aug 2025 |
| 133 | Great Northern Drilling Company | Billings, MT 59103 | Oil & Gas Operator | Jun 2016 |
| 134 | Great Western Drilling Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2026 |
| 135 | Great Western Oil Company | | Oil & Gas Operator | Dec 1984 |
| 136 | Gross Todd | Pine Bluffs, WY 82082 | Oil & Gas Operator | Mar 2007 |
| 137 | Grynberg, Jack J. | Denver, CO 80237 | Oil & Gas Operator | Jun 2021 |
| 138 | Gulf Exploration, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Feb 2026 |
| 139 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 140 | Gulf Production Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2015 |
| 141 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 142 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 143 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 144 | Harpel John P Jr | FT. Collins, CO 80525 | Oil & Gas Operator | May 1998 |
| 145 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 146 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 147 | Hedges Spencer | Casper, WY 82604 | Oil Operator | Mar 2024 |
| 148 | Helis Oil & Gas Company LLC Estate | New Orleans, LA 70130 | Oil & Gas Operator | Jul 2022 |
| 149 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 150 | Hi-Pro Production | Gillette, WY 82717 | Gas Operator | Nov 2003 |
| 151 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Mar 2026 |
| 152 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 153 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 154 | Hyperion Oil & Gas LLC | Dallas, TX 75251 | Oil & Gas Operator | Mar 2026 |
| 155 | Impact Exploration & Production LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Dec 2025 |
| 156 | Independent Production Company | Greenwood VIllage, CO 80121 | Oil & Gas Operator | May 2003 |
| 157 | Inexco Oil Company | Houston, TX 77210 | Oil & Gas Operator | Mar 2013 |
| 158 | Integrated Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 159 | Integrity Oil & Gas | Golden, CO 80401 | Oil & Gas Operator | May 2011 |
| 160 | Interline Resources Corp | Casper, WY 82601 | Oil & Gas Operator | Oct 2009 |
| 161 | Internorth Inc | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2014 |
| 162 | Intoil, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Dec 2002 |
| 163 | Itr Petroleum Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 164 | K N Energy Inc | Lakewood, CO 80228 | Oil & Gas Operator | Nov 2000 |
| 165 | Kachina Exploration Inc | Cheyenne, WY 82003 | Oil & Gas Operator | Jul 2000 |
| 166 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Mar 2026 |
| 167 | Keiths Pumping Service | Douglas, WY 82633 | Oil & Gas Operator | Aug 2003 |
| 168 | Kenai Oil & Gas Inc | | Oil & Gas Operator | Jun 1987 |
| 169 | Kennedy Oil | Gillette, WY 82716 | Oil & Gas Operator | Jan 2026 |
| 170 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Sep 2025 |
| 171 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Mar 2026 |
| 172 | Kissack Resources. LLC | | Oil & Gas Operator | Jan 2026 |
| 173 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2025 |
| 174 | L & J Operating Inc | Gillette, WY 82718 | Oil & Gas Operator | Aug 2016 |
| 175 | L R Company | Casper, WY 82602 | Oil & Gas Operator | Sep 2007 |
| 176 | La Prele Exploration | | Oil & Gas Operator | Oct 1979 |
| 177 | Lappin Oil LLC | Douglas, WY 82633 | Oil & Gas Operator | Feb 2026 |
| 178 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | Mar 2026 |
| 179 | Lawson Oil Company | Buckeye, AR 85326 | Oil Operator | Mar 1996 |
| 180 | Lear Petroleum Exploration | | Oil & Gas Operator | Jul 2013 |
| 181 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 182 | Lexicon Resources Corporation | | Oil & Gas Operator | Apr 1986 |
| 183 | Loil Oil LLC | Golden, CO 80402 | Oil & Gas Operator | Jan 2026 |
| 184 | Long Trust The | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2008 |
| 185 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 186 | M & K Oil Company LLC | Gillette, WY 82716 | Oil & Gas Operator | Jan 2026 |
| 187 | M & K Oil Operations | | Oil & Gas Operator | Sep 1994 |
| 188 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Dec 2025 |
| 189 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | Jan 2026 |
| 190 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 191 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 192 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Jan 2026 |
| 193 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 194 | Marquis-Allred Eng Inc | | Oil & Gas Operator | Apr 1992 |
| 195 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Dec 2025 |
| 196 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | Jan 2026 |
| 197 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | Jan 2026 |
| 198 | McCulliss Resource Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jun 1999 |
| 199 | McMurry Energy Company | | Oil & Gas Operator | Dec 2001 |
| 200 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |