| 101 | Cross Timbers Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2025 |
| 102 | Crosstex Lig, LLC | | Oil Operator | Mar 2014 |
| 103 | Crystal Gas, L.L.C. | | Oil & Gas Operator | Apr 2000 |
| 104 | Crystal Oil And Land Company | | Oil & Gas Operator | May 1992 |
| 105 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 106 | CSM, Inc. | | Gas Operator | Oct 1990 |
| 107 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2025 |
| 108 | Cypress Partners, Inc. | Houston, TX 77068 | Oil & Gas Operator | May 1999 |
| 109 | D H & L Operating, Inc. | | Oil & Gas Operator | Sep 1983 |
| 110 | D. B. Braddock | | Oil & Gas Operator | Jan 1986 |
| 111 | D. B. McConnell | | Oil & Gas Operator | Oct 1991 |
| 112 | D. B. McConnell Et Al | | Oil & Gas Operator | Nov 1993 |
| 113 | D. J. Fritz | | Oil & Gas Operator | Feb 1982 |
| 114 | D.J.F. Petroleum Corporation | | Oil & Gas Operator | Oct 1992 |
| 115 | Dalen Resources Oil & Gas Co | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 116 | Dallas DRLG. & Development Co. | | Oil & Gas Operator | Apr 1987 |
| 117 | Danos Oil & Gas LLC | | Oil & Gas Operator | Oct 2024 |
| 118 | Decker & Associates | | Oil & Gas Operator | Mar 1991 |
| 119 | Delhi Gas Pipeline Corporation | Palestine, TX 75802 | Oil & Gas Operator | Feb 1998 |
| 120 | Desoto Gas Corporation | | Oil & Gas Operator | Oct 1986 |
| 121 | Desoto Gas Prod Co Inc-Zadeck | | Gas Operator | Jan 1990 |
| 122 | Desoto Gas Producing Co. Inc | | Oil & Gas Operator | Jan 1990 |
| 123 | Desoto Oil & Gas Corporation | | Oil & Gas Operator | Dec 1990 |
| 124 | Desperation Oil & Gas Co. | | Gas Operator | Jan 1989 |
| 125 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 126 | Diversified Natural Res., Inc. | | Oil Operator | May 2000 |
| 127 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Dec 2025 |
| 128 | Dome De Sel LLC | | Oil & Gas Operator | Nov 2024 |
| 129 | Dominion Midstream Services, LP | | Oil Operator | Dec 2006 |
| 130 | Donald J. Zadeck | | Oil & Gas Operator | Feb 1998 |
| 131 | Dorchester Exploration, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2001 |
| 132 | Dorothy F. Hamlin | | Oil Operator | Dec 1985 |
| 133 | DRD Operating Company | | Oil & Gas Operator | Feb 2014 |
| 134 | Dual Energy, Inc. | | Oil & Gas Operator | Oct 2022 |
| 135 | Duke Energy Field Services Inc | | Oil Operator | Mar 2000 |
| 136 | Duke Energy Field Services LLC | | Oil Operator | Dec 2006 |
| 137 | Dzurik Interests, Inc. | | Oil & Gas Operator | Dec 2024 |
| 138 | E Texas Production MGMT Co Inc | | Oil & Gas Operator | Oct 1996 |
| 139 | E. Conway Butts, Inc. | | Oil & Gas Operator | Apr 1991 |
| 140 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Dec 2025 |
| 141 | Eclipse Petroleum Corporation | La Grange, TX 78945 | Oil & Gas Operator | Aug 2003 |
| 142 | Eddy Enterprises, Inc. | | Oil & Gas Operator | Sep 2023 |
| 143 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 144 | Egh Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 145 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 146 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 147 | Eli Rebich | | Oil & Gas Operator | Dec 1986 |
| 148 | Ellora Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 149 | Ellora Operating, L.P. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2011 |
| 150 | Empresa Energy IV, LLC | | Oil & Gas Operator | Aug 2019 |
| 151 | Empresa Energy, LP | Houston, TX 77024 | Oil & Gas Operator | Jul 2009 |
| 152 | Enable Midstream Partners, LP | Oklahoma City, OK 73124 | Oil Operator | Sep 2023 |
| 153 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 154 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 155 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 156 | Enerco Exploration & MGMT. Co. | | Oil & Gas Operator | Aug 1981 |
| 157 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 158 | Energy Finders, Inc. | | Oil & Gas Operator | Dec 1981 |
| 159 | Energy Reserves GP-Kanaba Oil | | Oil & Gas Operator | Aug 1985 |
| 160 | Energy Reserves Group | Houston, TX 770563020 | Oil & Gas Operator | Apr 1996 |
| 161 | Energy Sources, Inc. | | Oil & Gas Operator | Nov 1990 |
| 162 | Enlink Lig, LLC | | Oil Operator | Jan 2025 |
| 163 | Enpower Resources Inc. | Sugar Land, TX 77479 | Oil & Gas Operator | Dec 2025 |
| 164 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 165 | Ensight IV Energy Management,LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 166 | Enterprise Gathering LLC | | Oil Operator | Dec 2024 |
| 167 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 168 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 169 | Equinox Oil Company Inc | Plainville, KS 67663 | Oil & Gas Operator | Dec 2019 |
| 170 | Eroc Gathering Company, LP | | Oil Operator | Jul 2014 |
| 171 | Et Gathering & Processing LLC | Dallas, TX 75225 | Oil Operator | Dec 2024 |
| 172 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 173 | Etc Texas Pipeline, LTD. | Dallas, TX 75225 | Oil Operator | Sep 2023 |
| 174 | Ettco Enterprises, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 175 | Evans Brothers | | Oil & Gas Operator | Jan 2025 |
| 176 | Excalibur Resources, Inc. | | Oil & Gas Operator | Apr 1986 |
| 177 | Excel Oil & Gas, Inc. | Waxahachie, TX 75168 | Oil & Gas Operator | Dec 2025 |
| 178 | Excel Royalty Company, LLC | | Oil Operator | Jun 2022 |
| 179 | Exco Operating Company, LP | Dallas, TX 75251 | Oil & Gas Operator | Dec 2025 |
| 180 | Exco Partners Operating PTSHP LP | Dallas, TX 75251 | Oil & Gas Operator | Jan 2009 |
| 181 | Exco Production Company, LP | Dallas, TX 75251 | Oil & Gas Operator | Dec 2009 |
| 182 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Aug 2025 |
| 183 | Exco/Hgi JV Assets, LLC | Dallas, TX 75251 | Oil & Gas Operator | Jun 2014 |
| 184 | F.S.M. Oil Co. | | Oil Operator | Aug 1979 |
| 185 | Fair Oil Company | Tyler, TX 75710 | Oil & Gas Operator | Dec 2000 |
| 186 | Fair Oil, LC | Tyler, TX 75710 | Oil & Gas Operator | Oct 2001 |
| 187 | Fair Oil, LTD. | Tyler, TX 75710 | Oil & Gas Operator | Dec 2025 |
| 188 | Finaly Resources LLC | Sunset Beach, CA 90742 | Oil & Gas Operator | Dec 2025 |
| 189 | Fite Oil & Gas, Inc. | Shreveport, LA 71163 | Oil & Gas Operator | Dec 2025 |
| 190 | Fontainebleau Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 191 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 192 | Fortune Operating Company | Willis, TX 77378 | Oil & Gas Operator | Dec 2025 |
| 193 | Fortune Resources LLC | Longview, TX 75604 | Oil & Gas Operator | Dec 2025 |
| 194 | Forza Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2025 |
| 195 | Fossil Operating, Inc. | Dallas, TX 75238 | Oil & Gas Operator | Dec 2025 |
| 196 | Four Star Oil Company | | Oil & Gas Operator | May 2015 |
| 197 | Fran Oil, Inc. | | Oil & Gas Operator | Dec 2024 |
| 198 | Franks Operating Company, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 199 | Franks Petroleum Inc. | | Oil & Gas Operator | Nov 1994 |
| 200 | Fredonia Resources Inc. | Longview, TX 75606 | Oil & Gas Operator | Aug 2003 |