| 101 | Cleveland Production Company | Summit, MS 39666 | Oil & Gas Operator | Jul 1999 |
| 102 | Clide Oil Corp. | Iraan, TX 79744 | Oil & Gas Operator | Nov 2015 |
| 103 | CLS Interests, Incorporated | Austin, TX 78734 | Oil & Gas Operator | Jan 1997 |
| 104 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 105 | Coal Creek Energy, LLC | Overland Park, KS 66221 | Oil Operator | Dec 2019 |
| 106 | Coastal Expanse Oil & Gas | Austin, TX 78704 | Oil & Gas Operator | Oct 2025 |
| 107 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 108 | Coastal Production Company, Inc. | El Campo, TX 77437 | Oil & Gas Operator | Aug 1995 |
| 109 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 110 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2025 |
| 111 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 112 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 113 | Concord Operating Incorporated | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2008 |
| 114 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 115 | Contango Resources LLC | Andrews, TX 79714 | Oil & Gas Operator | Oct 2025 |
| 116 | Contango Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2025 |
| 117 | Contract Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Oct 2012 |
| 118 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 119 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 120 | Cornerstone Energy, Inc. | Houston, TX 77060 | Oil & Gas Operator | Nov 2011 |
| 121 | Corum Production Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 122 | Crawford Energy Operating Co | Houston, TX 77056 | Oil & Gas Operator | Aug 2008 |
| 123 | Crawford Hughes Operating Co. | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 124 | Crest Resources & Expl. Corp. | Houston, TX 77079 | Oil & Gas Operator | Dec 1998 |
| 125 | Crimson Exploration Inc. | Houston, TX 77060 | Oil & Gas Operator | Apr 2006 |
| 126 | Crimson Exploration Oper., Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2019 |
| 127 | Crosspoint Energy Company | Dallas, TX 75205 | Oil & Gas Operator | Oct 2007 |
| 128 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 129 | D & P Operating & Prod. Corp. | Cedar Park, TX 78613 | Oil & Gas Operator | Dec 2003 |
| 130 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 131 | Dallas Operating Corp. | Dallas, TX 75205 | Oil & Gas Operator | Nov 2006 |
| 132 | Daniels Corporation, The | Seabrook, TX 77586 | Oil & Gas Operator | Oct 2025 |
| 133 | Dantex Oil & Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Aug 2003 |
| 134 | Dartex Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 135 | Davis Bros. Oil Producers, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2020 |
| 136 | Davis Energy Services LLC | La Grange, TX 78945 | Oil Operator | Oct 2025 |
| 137 | Davis Gulf Coast, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 138 | Davis Operating Company | Elysian Field, TX 75642 | Oil & Gas Operator | Oct 2025 |
| 139 | Davis Southern Operating Co LLC | Houston, TX 77004 | Oil & Gas Operator | Oct 2025 |
| 140 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Oct 2025 |
| 141 | Daystar Operating Company, LLC | Austin, TX 78750 | Oil & Gas Operator | Apr 2008 |
| 142 | Deguello Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 143 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 144 | Delco Operating Company LP | Houston, TX 77056 | Oil & Gas Operator | May 2020 |
| 145 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 146 | Delta Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 147 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 148 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 149 | Derrick Oil & Gas, Inc. | Rosharon, TX 77583 | Oil & Gas Operator | Aug 2003 |
| 150 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 151 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Oct 2025 |
| 152 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 153 | Drillmar Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | Nov 2014 |
| 154 | Drillmar Operating Company | Houston, TX 77019 | Oil & Gas Operator | Jun 2013 |
| 155 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2025 |
| 156 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 157 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 158 | Dune Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2016 |
| 159 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 160 | Eca Holdings, L.P. | Sugar Land, TX 77478 | Oil & Gas Operator | Mar 2010 |
| 161 | Edinger Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2007 |
| 162 | Edwards, Gus Co. | Abilene, TX 79603 | Oil & Gas Operator | Jun 2004 |
| 163 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 164 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 165 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 166 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 167 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 168 | Elliott Oil Company, L.P. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 169 | Eminent Oil & Gas, Inc. | Houston, TX 77077 | Oil & Gas Operator | Oct 2025 |
| 170 | Endeavor Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2015 |
| 171 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 172 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 173 | Energy Oil & Gas Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 174 | Energy Reserves Group LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2018 |
| 175 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | May 2025 |
| 176 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Jun 2025 |
| 177 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 178 | Engroup Resources, L.P. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 179 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 180 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 181 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 182 | Erg Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2015 |
| 183 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 184 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 185 | European-Southwest Co. | Houston, TX 77254 | Oil & Gas Operator | Oct 2025 |
| 186 | Evergreen Energy, Inc | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 187 | Exotic Oil & Gas LLC | Indiana, PA 15701-3634 | Oil & Gas Operator | Dec 2024 |
| 188 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | Oct 2025 |
| 189 | Expro Engineering, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Oct 2025 |
| 190 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 191 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 192 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jul 2025 |
| 193 | Famcor Oil, Inc. | Scottsdale, AZ 85260 | Oil & Gas Operator | Sep 2020 |
| 194 | Fenn, Bill Inc. | Giddings, TX 78942 | Oil & Gas Operator | Mar 2008 |
| 195 | Ferreira Oil Properties LLC | Carefree, AZ 85377 | Oil Operator | Apr 2014 |
| 196 | Ffa Petroleum Services, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2018 |
| 197 | Finley Oil Company, LLC | Liberty, TX 77575 | Oil Operator | Oct 2025 |
| 198 | Five-Jab, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Oct 2025 |
| 199 | Fore Oil, LLC | Manvel, TX 77578 | Oil Operator | May 2021 |
| 200 | Forney & McCombs | Houston, TX 77056 | Oil & Gas Operator | Jan 1998 |