| 101 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 102 | H & R Oil Company | | Oil & Gas Operator | Dec 2000 |
| 103 | H G H Oil Company | | Oil Operator | Dec 1990 |
| 104 | Havoco Inc | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2005 |
| 105 | Hershey Oil Corporation | | Oil & Gas Operator | Jul 1992 |
| 106 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Apr 2026 |
| 107 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 108 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Apr 2026 |
| 109 | Hyco Oil Inc | Newcastle, WY 82701 | Oil & Gas Operator | Dec 2006 |
| 110 | Independent Production Company | Greenwood VIllage, CO 80121 | Oil & Gas Operator | May 2003 |
| 111 | Indian Creek Resources Inc | Loveland, CO 80538 | Oil & Gas Operator | Dec 2024 |
| 112 | Inexco Oil Company | Houston, TX 77210 | Oil & Gas Operator | Mar 2013 |
| 113 | Infield Discovery LLC | Madison, MS 39110 | Oil & Gas Operator | Sep 2025 |
| 114 | Inland Production Company | Vernal, UT 84079 | Oil & Gas Operator | Dec 2004 |
| 115 | Intoil, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Dec 2002 |
| 116 | Itr Petroleum Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 117 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Apr 2026 |
| 118 | Kennedy George C | Upton, WY 82730 | Oil & Gas Operator | Oct 2018 |
| 119 | Kennedy Oil | Gillette, WY 82716 | Oil & Gas Operator | Jan 2026 |
| 120 | Kerry Petroleum Co Inc | Midland, TX 79708 | Oil & Gas Operator | Jun 2010 |
| 121 | Kiesling Oil Company | Osage, WY 82723 | Oil & Gas Operator | Oct 2007 |
| 122 | Kings X Oil Company LLC | Gillette, WY 82717 | Oil Operator | Aug 2016 |
| 123 | Kissack Water & Oil Service Inc | Rozet, WY 82727 | Oil & Gas Operator | Feb 2026 |
| 124 | L & J Operating Inc | Gillette, WY 82718 | Oil & Gas Operator | Aug 2016 |
| 125 | L & R Drilling Company | Belle Fourche, SD 57717 | Oil & Gas Operator | Dec 1999 |
| 126 | L R Company | Casper, WY 82602 | Oil & Gas Operator | Sep 2007 |
| 127 | Ladd & Lukowicz | | Oil & Gas Operator | May 1983 |
| 128 | Lagniappe Interest Inc | Evergreen, CO 80439 | Oil & Gas Operator | Jun 2006 |
| 129 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | Apr 2026 |
| 130 | Lear Petroleum Exploration | | Oil & Gas Operator | Jul 2013 |
| 131 | Leeman Don J | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 1998 |
| 132 | Lewis Yale H | | Oil & Gas Operator | Aug 1986 |
| 133 | Lissolo J W | Yuma, AZ 85365 | Oil & Gas Operator | Feb 2017 |
| 134 | Lissolo Timothy C | Newcastle, WY 82701 | Oil Operator | Jan 2026 |
| 135 | Low D J | Littleton, CO 80127 | Oil Operator | Dec 1999 |
| 136 | M & K Oil Company LLC | Gillette, WY 82716 | Oil & Gas Operator | Feb 2026 |
| 137 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Dec 2025 |
| 138 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 139 | Maha Energy Us Inc | | Oil Operator | Nov 2023 |
| 140 | Manewal Bradley Oil Company | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2013 |
| 141 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 142 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Feb 2026 |
| 143 | Marlin Oil Company LLC | Gillette, WY 82718 | Oil & Gas Operator | Mar 2023 |
| 144 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | Jan 2026 |
| 145 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 146 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 147 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 148 | Moco Oil Inc | | Oil Operator | May 1984 |
| 149 | Mon-Oil Inc | | Oil & Gas Operator | Apr 1996 |
| 150 | Mueller Fred W | | Oil & Gas Operator | Dec 1995 |
| 151 | Mundell F E | Watertown, SD 57201 | Oil & Gas Operator | Aug 1994 |
| 152 | Murphy Sheldon L & Loretta | Newcastle, WY 82701 | Oil & Gas Operator | Jan 2026 |
| 153 | Mystique Developments | Denver, CO 80202 | Oil & Gas Operator | Dec 1997 |
| 154 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 155 | Newcastle Oil & Gas Inc | | Oil Operator | Dec 1988 |
| 156 | Noarko Resources | | Oil & Gas Operator | Mar 1990 |
| 157 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2026 |
| 158 | Nor-Am Exploration | | Oil Operator | Jun 1981 |
| 159 | North Finn LLC | Casper, WY 82605 | Oil & Gas Operator | Feb 2026 |
| 160 | Northern Michigan Expl Co | | Oil & Gas Operator | Jul 1990 |
| 161 | Oil & Gas Acquisition Group Inc | Austin, TX 78716 | Oil & Gas Operator | May 2003 |
| 162 | Oildigger Resources Fund L LLLP | Billings, MT 59101 | Oil & Gas Operator | Feb 2026 |
| 163 | Oilfield Salvage & Service Company | Littleton, CO 80120 | Oil & Gas Operator | Jan 2026 |
| 164 | Omimex Petroleum Inc (Co) | Newcastle, WY 82701 | Oil & Gas Operator | May 2001 |
| 165 | Omni Operating Company | Osage, WY 82723 | Oil & Gas Operator | Sep 2001 |
| 166 | Osage Hot Oil Service | Newcastle, WY 82701 | Oil & Gas Operator | Jul 1997 |
| 167 | Osage Operating Company LLC | Seattle, WA 98133 | Oil Operator | May 2006 |
| 168 | Osage Partners LLC | | Oil & Gas Operator | Mar 2026 |
| 169 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 170 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 171 | P & M Petroleum Management LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2021 |
| 172 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 173 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Apr 2026 |
| 174 | Pacific Enterprises Oil Co USA | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 175 | Par Oil Company Inc | Denver, CO 80201 | Oil & Gas Operator | Jun 2003 |
| 176 | Park Oil Properties LLC | Plano, TX 75025 | Oil Operator | Oct 2019 |
| 177 | Pathfinder Energy Inc | Casper, WY 82605 | Oil & Gas Operator | May 2024 |
| 178 | Penneco Exploration Company Of Wyo LLC | Delmont, PA 15626 | Oil Operator | Aug 2021 |
| 179 | Petro Energy Inc | Farmington, NM 87499 | Oil & Gas Operator | Sep 2025 |
| 180 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 181 | Petrocarbon Energy Corporation | | Oil Operator | Sep 1996 |
| 182 | Petrocarbon Energy Trust | | Oil Operator | Sep 1996 |
| 183 | Petrolero Corp. | San Antonio, TX 78205 | Oil & Gas Operator | Feb 1998 |
| 184 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 185 | Pine Haven Resources LLC | Boulder, CO 80305 | Oil Operator | Feb 2026 |
| 186 | Pittencrieff America Inc | Abilene, TX 79608 | Oil & Gas Operator | Feb 2003 |
| 187 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 188 | Poc-I LLC | Casper, WY 82605 | Oil & Gas Operator | Feb 2026 |
| 189 | Polfam Exploration Co | Denver, CO 80204 | Oil & Gas Operator | Mar 2007 |
| 190 | Prenalta Corporation | Terrytown, NY 10591 | Oil & Gas Operator | Jan 1997 |
| 191 | Prima Exploration, Inc. | Denver, CO 80206 | Oil & Gas Operator | Feb 2026 |
| 192 | Provident Resources LTD | | Oil & Gas Operator | Dec 1986 |
| 193 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Jan 2026 |
| 194 | Quinoco Petroleum Inc | | Oil & Gas Operator | Dec 1990 |
| 195 | Rainbow Resources, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2007 |
| 196 | Red River Oil & Gas LLC | Cherry Hills, CO 80110 | Oil & Gas Operator | Feb 2025 |
| 197 | Reserve Oil & Gas Company | | Oil & Gas Operator | Jul 1981 |
| 198 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 199 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 200 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Apr 2026 |