| 101 | Caribbean Energy, L.L.C. | Cotulla, TX 78014 | Oil & Gas Operator | Nov 2019 |
| 102 | Carrizo (Eagle Ford) LLC | Houston, TX 77042 | Oil & Gas Operator | Jan 2020 |
| 103 | Carrizo Exploration, Inc. | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Aug 2016 |
| 104 | Carrizo Oil & Gas, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 105 | Catarina Petroleum L. C. | Dallas, TX 75228 | Oil & Gas Operator | Jun 2008 |
| 106 | CCV, Inc. | Houston, TX 77019 | Oil & Gas Operator | Sep 1994 |
| 107 | Ceniza Petroleum, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 108 | Chaparral Natural Resources,Inc. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 109 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | May 2025 |
| 110 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2025 |
| 111 | Cheyenne Petroleum Company | Oklahoma City, OK 73134 | Oil & Gas Operator | May 2025 |
| 112 | Chiodo Corp. | San Antonio, TX 78232 | Oil & Gas Operator | May 2025 |
| 113 | Christico Petroleum Company | San Antonio, TX 78216 | Oil & Gas Operator | May 2025 |
| 114 | Churchill Operating, LLC | Houston, TX 77007 | Oil & Gas Operator | May 2025 |
| 115 | Cibolo Energy Operating, Inc. | Bulverde, TX 78163 | Oil & Gas Operator | May 2025 |
| 116 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | May 2025 |
| 117 | Civron Petroleum Res., LLC | San Antonio, TX 78229 | Oil & Gas Operator | May 2025 |
| 118 | Clamp Operating Incorporated | San Antonio, TX 78264 | Oil & Gas Operator | Mar 2011 |
| 119 | Claron Corporation | Houston, TX 77219 | Oil & Gas Operator | May 2025 |
| 120 | Clear Fork, Incorporated | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 121 | Clipper Operating Co., Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jan 2000 |
| 122 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 123 | Cockrell Production Co., Inc. | Irving, TX 75014 | Oil & Gas Operator | May 2025 |
| 124 | Colt Operating Corporation | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 125 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 126 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 127 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 128 | Concho Oilfield Serv & Oper Co. | Eden, TX 76837 | Oil & Gas Operator | May 2025 |
| 129 | Concord Energy, Inc. | Glen Rose, TX 76043 | Oil & Gas Operator | May 2025 |
| 130 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 131 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 132 | Conway Energy Oper Services Inc. | San Diego, TX 78384 | Oil & Gas Operator | May 2025 |
| 133 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | May 2025 |
| 134 | Costilla Energy Inc | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 135 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 136 | Cox Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1999 |
| 137 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 138 | Creative Oil And Gas Op II, LLC | San Antonio, TX 78246 | Oil Operator | May 2025 |
| 139 | Crimson Energy Partners IV, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2023 |
| 140 | Crimson Energy Partners V, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 141 | Crimson Energy Partners, L.P. | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2009 |
| 142 | Crimson Exploration Inc. | Houston, TX 77060 | Oil & Gas Operator | Apr 2006 |
| 143 | Crimson Exploration Oper., Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2019 |
| 144 | Crossroads Mineral Prod., L.L.C. | Seguin, TX 78155 | Oil Operator | May 2025 |
| 145 | Cuatro Petro Corp. | Richardson, TX 75080 | Oil & Gas Operator | May 2025 |
| 146 | D.J.F. Services, Inc. | Holdenville, OK 74848 | Oil & Gas Operator | May 2025 |
| 147 | D90 Energy, LLC | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 148 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 149 | Dantex Oil & Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Aug 2003 |
| 150 | Daubert Operating, L.L.C. | San Antonio, TX 78209 | Oil Operator | May 2025 |
| 151 | Dawsey Operating Company | Georgetown, TX 78628 | Oil & Gas Operator | Mar 2016 |
| 152 | Dee-Jay Exploration Company | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 153 | Del Petroleum Corporation | Dallas, TX 75219 | Oil & Gas Operator | Jan 2012 |
| 154 | Delcar, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 1995 |
| 155 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 156 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 157 | Diamond Energy Services, LP | Tulsa, OK 74103 | Oil Operator | May 2025 |
| 158 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 159 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | May 2025 |
| 160 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 161 | Dolphin Petroleum, LP | Alice, TX 78333 | Oil & Gas Operator | May 2025 |
| 162 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 163 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 164 | Downing Well Service, Inc. | Devine, TX 78016 | Oil & Gas Operator | May 2025 |
| 165 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | May 2025 |
| 166 | Durst Oil Company | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Sep 2000 |
| 167 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | May 2025 |
| 168 | Eagle Ford Oil Co., Inc. | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 169 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Mar 2025 |
| 170 | Echo Production Inc | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 171 | Eclipse Petroleum Corporation | La Grange, TX 78945 | Oil & Gas Operator | Aug 2003 |
| 172 | Edco Energy, Inc. | Austin, TX 78738 | Oil & Gas Operator | May 2003 |
| 173 | Ef Energy, L.L.C. | Houston, TX 77084 | Oil & Gas Operator | Jun 2015 |
| 174 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 175 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | May 2025 |
| 176 | Emlou Oil Co. | Atascosa, TX 78002 | Oil & Gas Operator | Jul 2011 |
| 177 | Energy Corporation Of America | Charleston, WV 25311 | Oil & Gas Operator | Dec 2023 |
| 178 | Energy Equity Company | Columbus, MT 59019 | Oil & Gas Operator | Mar 2025 |
| 179 | Energy Frontiers Partners, LP | Grapevine, TX 76051 | Oil Operator | May 2008 |
| 180 | Energy Resources Oil & Gas Corp. | Amarillo, TX 79102 | Oil & Gas Operator | Jun 1994 |
| 181 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Jan 2025 |
| 182 | Enhanced RS, Inc. | Luling, TX 78648 | Oil Operator | May 2025 |
| 183 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 184 | EP Energy E&P Company, LLC | Houston, TX 77210 | Oil & Gas Operator | May 2025 |
| 185 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | May 2022 |
| 186 | Ernest Operating Company | Rockdale, TX 76567 | Oil & Gas Operator | May 2025 |
| 187 | Espada Operating LLC | San Antonio, TX 78209 | Oil Operator | May 2025 |
| 188 | Exco Operating Company, LP | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 189 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Feb 2025 |
| 190 | Explo Oil, Inc. | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 191 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | May 2025 |
| 192 | Express Oil And Gas | La Grange, TX 78945 | Oil & Gas Operator | May 2025 |
| 193 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | May 2025 |
| 194 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 195 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 196 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Feb 2025 |
| 197 | Fair Oil Company | Tyler, TX 75710 | Oil & Gas Operator | Dec 2000 |
| 198 | Fair Oil, LTD. | Tyler, TX 75710 | Oil & Gas Operator | May 2025 |
| 199 | Fenn, Bill Inc. | Giddings, TX 78942 | Oil & Gas Operator | Mar 2008 |
| 200 | Ferguson Oil & Gas Inc. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |