| 101 | Caspen Operating Company | Somerset, TX 78069 | Oil & Gas Operator | Mar 2008 |
| 102 | Century Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 103 | Chaparral Natural Resources,Inc. | Austin, TX 78746 | Oil & Gas Operator | Jul 2025 |
| 104 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jul 2025 |
| 105 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2025 |
| 106 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2025 |
| 107 | Cheyenne Petroleum Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 108 | Chmelar, Eugene Oil & Gas | Caldwell, TX 77836 | Oil & Gas Operator | Jul 2025 |
| 109 | Christico Petroleum Company | San Antonio, TX 78216 | Oil & Gas Operator | Jul 2025 |
| 110 | Cico Oil & Gas Company | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 111 | Cinco Natural Resources Corp | La Grange, TX 78945 | Oil & Gas Operator | Jul 2025 |
| 112 | Cinco Oil & Gas, LLC | Dallas, TX 75204 | Oil & Gas Operator | Jul 2025 |
| 113 | Civron Petroleum Res., LLC | San Antonio, TX 78229 | Oil & Gas Operator | Jul 2025 |
| 114 | Clamp Operating | San Antonio, TX 78264 | Oil & Gas Operator | Apr 2002 |
| 115 | Clamp Operating Incorporated | San Antonio, TX 78264 | Oil & Gas Operator | Mar 2011 |
| 116 | Clark, G. A., Trustee | San Antonio, TX 78210 | Oil & Gas Operator | Nov 2017 |
| 117 | Clipper Operating Co., Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jan 2000 |
| 118 | CM TX Production, LLC | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2023 |
| 119 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 120 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | May 2025 |
| 121 | Cole, Frank W Engineering | Dallas, TX 75254 | Oil & Gas Operator | Mar 2006 |
| 122 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 123 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 124 | Comanche Well Service Corp. | Plano, TX 75093 | Oil & Gas Operator | Jul 2025 |
| 125 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 126 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 127 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 128 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | Jul 2025 |
| 129 | Corpus Christi Leaseholds, Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Sep 1996 |
| 130 | Corsicana Field Fund | Corsicana, TX 75110 | Oil & Gas Operator | Dec 1993 |
| 131 | Cottonwood Resources, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2003 |
| 132 | Creative Oil And Gas Op II, LLC | Santa Anna, TX 76878 | Oil Operator | Jul 2025 |
| 133 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 134 | D.C. Oil | Natalia, TX 78059 | Oil Operator | Jul 2025 |
| 135 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 136 | Dawsey Operating Company | Georgetown, TX 78628 | Oil & Gas Operator | Mar 2016 |
| 137 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Jul 2025 |
| 138 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Apr 2025 |
| 139 | Deep Rock Resources, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 140 | Delcar, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 1995 |
| 141 | Delgado, Emil A | San Antonio, TX 78223 | Oil & Gas Operator | Sep 2016 |
| 142 | Delong, Horace | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2025 |
| 143 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 144 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2025 |
| 145 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 146 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jul 2025 |
| 147 | Diamond Energy Services, LP | Tulsa, OK 74103 | Oil Operator | Jul 2025 |
| 148 | Dickson Petroleum, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2000 |
| 149 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Jul 2025 |
| 150 | Discorbis Oil Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2019 |
| 151 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Jul 2025 |
| 152 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Jul 2025 |
| 153 | Dodson, Inc. | San Antonio, TX 78232 | Oil & Gas Operator | Oct 1998 |
| 154 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 155 | Dorchester Operating Company LLC | Refugio, TX 78377 | Oil & Gas Operator | Jul 2025 |
| 156 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Jul 2025 |
| 157 | Drachen Oil Company | San Antonio, TX 78258 | Oil & Gas Operator | Jul 2025 |
| 158 | Duplantis Energy, LLC | Pleasanton, TX 78064 | Oil Operator | Jul 2025 |
| 159 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Jul 2025 |
| 160 | E P C Oil & Gas, Inc. | Caldwell, TX 77836 | Oil & Gas Operator | Jul 2025 |
| 161 | E.A.T.E. Operating | Natalia, TX 78059 | Oil & Gas Operator | Jul 2025 |
| 162 | Eagle Ford Hunter Resources,Inc. | Houston, TX 77024 | Oil & Gas Operator | Apr 2013 |
| 163 | Eagle Ford Oil Co., Inc. | Houston, TX 77057 | Oil & Gas Operator | Jul 2025 |
| 164 | Eagle Rock Operating Company,LLC | Houston, TX 77252 | Oil & Gas Operator | Oct 2015 |
| 165 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2025 |
| 166 | Eastland Exploration, Inc. | Austin, TX 78763 | Oil & Gas Operator | Apr 1997 |
| 167 | Eei Operating Inc. | Plano, TX 75093 | Oil & Gas Operator | May 2015 |
| 168 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 169 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 170 | Ef Energy, L.L.C. | Houston, TX 77084 | Oil & Gas Operator | Jun 2015 |
| 171 | Eise Oil, Inc. | San Antonio, TX 78213 | Oil Operator | Jul 2025 |
| 172 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 173 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Jul 2025 |
| 174 | Emerald Bay Energy, Inc. | San Antonio, TX 78230 | Oil Operator | Jul 2025 |
| 175 | Emerson Oil Company | Rindge, NH 03461 | Oil & Gas Operator | Feb 2008 |
| 176 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 177 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 178 | Energy Equity Company | Columbus, MT 59019 | Oil & Gas Operator | May 2025 |
| 179 | Energy Resources Oil & Gas Corp. | Amarillo, TX 79102 | Oil & Gas Operator | Jun 1994 |
| 180 | Energy Transfer Fuel, LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2005 |
| 181 | Energypro, Inc. | Magnolia, TX 77354 | Oil & Gas Operator | Jul 2025 |
| 182 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 183 | Enhanced Energy Partners Corp | Tomball, TX 77377 | Oil & Gas Operator | Jul 2025 |
| 184 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 185 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 186 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 187 | EP Energy E&P Company, LLC | Houston, TX 77210 | Oil & Gas Operator | Apr 2025 |
| 188 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 189 | EP Operating Limited Partnership | Dallas, TX 75201 | Oil & Gas Operator | Feb 1995 |
| 190 | Escondido Operating, Inc. | Carrollton, TX 75011 | Oil & Gas Operator | Jun 2013 |
| 191 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 192 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 193 | Etc Texas Pipeline, LTD. | Dallas, TX 75225 | Oil Operator | Sep 2023 |
| 194 | Everett Oil | San Antonio, TX 78258 | Oil & Gas Operator | Apr 2015 |
| 195 | Everett Oil, Inc. | San Antonio, TX 78258 | Oil Operator | Jul 2025 |
| 196 | Excalibur E & P, LLC | Johnson City, TX 78636 | Oil & Gas Operator | Jul 2025 |
| 197 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Jul 2025 |
| 198 | Exxcel Operating Company | San Antonio, TX 78227 | Oil & Gas Operator | Jul 2025 |
| 199 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 200 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |