| 101 | Amax Petroleum Corporation | Houston, TX 77042 | Oil & Gas Operator | Dec 2012 |
| 102 | Ambrit Energy Corporation | Garland, TX 75044 | Oil & Gas Operator | Jun 2003 |
| 103 | Amcole Energy Corporation | Dallas, TX 75231 | Oil & Gas Operator | Aug 2000 |
| 104 | Amer. Intl. Petroleum Corp. | | Oil & Gas Operator | Dec 1990 |
| 105 | Amerada Hess Corp-Placid | | Gas Operator | Sep 1990 |
| 106 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 107 | Amerada Hess-Ethyl Corporation | | Oil & Gas Operator | Sep 1990 |
| 108 | American B. C. Resources | | Oil & Gas Operator | Oct 1985 |
| 109 | American Casing Crews, Inc. | | Oil Operator | Dec 1979 |
| 110 | American Coastal Energy, Inc. | Houston, TX 77225 | Oil & Gas Operator | May 2008 |
| 111 | American Exploration Company | Houston, TX 77010 | Oil & Gas Operator | Jan 2000 |
| 112 | American Exploration Oper. Co. | | Oil & Gas Operator | May 1990 |
| 113 | American Explorer, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Jan 1999 |
| 114 | American Intl Production Inc. | | Oil & Gas Operator | Apr 1993 |
| 115 | American National Petroleum Co. | Houston, TX 77057 | Oil & Gas Operator | Aug 1995 |
| 116 | American Natural Energy Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 117 | American Petrofina Co Of Texas | | Oil & Gas Operator | Jun 1985 |
| 118 | American Quasar Petroleum Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2014 |
| 119 | American Quasar-Southland Roy. | | Oil & Gas Operator | Oct 1980 |
| 120 | American Trading | | Oil & Gas Operator | Dec 1995 |
| 121 | American Trading & Prod Corp | Houston, TX 77040-6471 | Oil & Gas Operator | Nov 2014 |
| 122 | American Trading Et Al | | Oil & Gas Operator | May 1979 |
| 123 | Americus Resources, Inc. | | Oil & Gas Operator | Feb 1993 |
| 124 | Ameritech Oil & Gas Corporation | Dallas, TX 75248 | Oil & Gas Operator | May 1996 |
| 125 | Aminex USA, Inc. | Somerset, TX 78069 | Oil & Gas Operator | May 2018 |
| 126 | Aminoil Of Louisiana, Inc. | | Oil & Gas Operator | Dec 1981 |
| 127 | Aminoil USA Inc | | Oil & Gas Operator | Jan 1985 |
| 128 | Amity Oil Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1977 |
| 129 | Amkay Petroleum Co., Inc. | | Oil Operator | Dec 1991 |
| 130 | Amoco Prod Co-Banner Pet LTD | | Oil & Gas Operator | Mar 1981 |
| 131 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 132 | Amplify Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2025 |
| 133 | Ampolex (Texas), Inc. | | Oil & Gas Operator | May 1993 |
| 134 | An-Son Corporation | Oklahoma City, OK 73124 | Oil & Gas Operator | Jan 2006 |
| 135 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 136 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 137 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Mar 2025 |
| 138 | Anderson Exploration Co., Inc. | | Oil & Gas Operator | Sep 2023 |
| 139 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 140 | Anderson Operating LLC Of Mississippi | | Oil & Gas Operator | Jul 2018 |
| 141 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 142 | Andover Oil Company | | Oil Operator | Sep 1982 |
| 143 | Andries Oil Company | | Oil Operator | Jan 2025 |
| 144 | Anglo Production Company | | Oil & Gas Operator | Nov 1983 |
| 145 | Anglo-Dutch Energy, LLC | | Oil & Gas Operator | Sep 2022 |
| 146 | Ankor E&P Holdings Corporation | | Oil & Gas Operator | Jan 2021 |
| 147 | Annco Pet. Co & Equipment, Inc | | Oil & Gas Operator | Sep 1982 |
| 148 | Annona Productions, Inc. | | Gas Operator | May 2019 |
| 149 | Anr Pipeline Company | | Oil & Gas Operator | Jan 2025 |
| 150 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 151 | Anschutz Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2016 |
| 152 | Ansythe Exploration Co., Inc. | | Oil & Gas Operator | Oct 1982 |
| 153 | Antara Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 2004 |
| 154 | Antares Ventures, L.L.C. | | Oil Operator | Oct 2016 |
| 155 | Anthony Oil & Gas Co. | Shreveport, LA 71135 | Oil Operator | May 1993 |
| 156 | Anthony Oil Company | | Oil & Gas Operator | Oct 1987 |
| 157 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 158 | Apache Energy Resources Corp | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 159 | Apache Natural Gas Co., Inc. | | Oil Operator | Nov 1992 |
| 160 | Apache Shelf, Inc. | Houston, TX 77056 | Oil & Gas Operator | Jan 2014 |
| 161 | Apb Oil Corporation | Houston, TX 77052 | Oil & Gas Operator | Apr 1996 |
| 162 | Apco Oil Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jun 1993 |
| 163 | Apd Company | | Oil & Gas Operator | Apr 1987 |
| 164 | Apex Oil & Gas, Inc. | Houston, TX 77067 | Oil & Gas Operator | Oct 2009 |
| 165 | Apexco, Inc. | Sand Springs, OK 74063 | Oil & Gas Operator | Mar 2025 |
| 166 | Apexco-McCormick-Coastal | | Oil & Gas Operator | Dec 1977 |
| 167 | Apexway Corp. | | Oil Operator | Dec 2024 |
| 168 | Apollo Energy Operating Co, LP | Lake Charles, LA 70601 | Oil & Gas Operator | Dec 2024 |
| 169 | Apollo Energy Operating, LP | | Oil & Gas Operator | Mar 2011 |
| 170 | Apollo Energy, L.L.C. | | Oil & Gas Operator | Jul 2018 |
| 171 | Apollo Petroleum Corporation | | Oil & Gas Operator | Dec 2012 |
| 172 | April Rain Prod. Co., Inc. | | Oil & Gas Operator | Jul 1992 |
| 173 | Apv Caddo Pine LLC | | Oil & Gas Operator | Dec 2024 |
| 174 | Aquila Energy Resources Corp. | Houston, TX 77042 | Oil & Gas Operator | Nov 2013 |
| 175 | Aracca Petroleum Company | | Oil Operator | May 1984 |
| 176 | Aracca Petroleum Corporation | | Oil Operator | Dec 1987 |
| 177 | Aralpa Corporation | | Oil & Gas Operator | May 1987 |
| 178 | Aran Energy USA Inc. | | Oil & Gas Operator | Apr 1997 |
| 179 | Arapaho Petroleum Inc | Englewood, CO 80155 | Oil & Gas Operator | Nov 1998 |
| 180 | Arapahoe SPV LLC | | Oil & Gas Operator | Feb 2023 |
| 181 | Araxas Exploration, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Apr 1998 |
| 182 | Arbco, Inc. | | Oil & Gas Operator | Jan 1996 |
| 183 | Arbol Resources, Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 2025 |
| 184 | Arbor Petroleum Corporation | Oklahoma City, OK 73102-4003 | Oil & Gas Operator | Mar 2011 |
| 185 | Arcadia Operating, LLC | Dallas, TX 75219 | Oil & Gas Operator | Jun 2025 |
| 186 | Arcadia Refining Company | Tyler, TX 75701 | Oil & Gas Operator | Jan 1994 |
| 187 | Arch Bend Oil & Gas Operators, LLC | | Oil Operator | Jan 2025 |
| 188 | Arco O & G Co-Div Atl Rich Co | | Oil & Gas Operator | Feb 1994 |
| 189 | Arena Resources LLC | Longview, TX 75608 | Oil & Gas Operator | Apr 2025 |
| 190 | Argos Properties, Inc. | | Oil & Gas Operator | Apr 1992 |
| 191 | Aries Oil & Gas Company, Inc. | | Oil Operator | Dec 1986 |
| 192 | Aries Operating LP | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 193 | Aries Operating, LLC | Houston, TX 77010 | Oil & Gas Operator | Feb 2010 |
| 194 | Ark-La-Tex Anchor, Inc. | | Oil & Gas Operator | Mar 1999 |
| 195 | Ark-La-Tex Energy Partners, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2013 |
| 196 | Ark-La-Tex Energy, L.L.C. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2025 |
| 197 | Ark-La-Tex Gas Gathering Co | | Oil Operator | Mar 2000 |
| 198 | Arkla Energy Resources | Shreveport, LA 71151 | Oil & Gas Operator | Mar 2015 |
| 199 | Arkla Expl.Co & George E Woods | | Oil & Gas Operator | Dec 1992 |
| 200 | Arkla Exploration Co. | Shreveport, LA 71151 | Oil & Gas Operator | Jan 1993 |