| 201 | Seely Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 202 | Seguro Well Service, Inc. | Gonzales, TX 78629 | Oil & Gas Operator | May 2025 |
| 203 | Sei Operating, LLC | Mandeville, LA 70471 | Oil & Gas Operator | May 2025 |
| 204 | Shoco Production LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 205 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 206 | Silver Oak Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2016 |
| 207 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 208 | Sisters Operating Company | Victoria, TX 77904 | Oil & Gas Operator | Nov 2010 |
| 209 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2025 |
| 210 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 211 | Sonat Exploration Company -Tyler | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 212 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 213 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 214 | Spur Operating Co. | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 215 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 216 | Square One Corporation | Giddings, TX 78942 | Oil & Gas Operator | Dec 2012 |
| 217 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 218 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | May 2025 |
| 219 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 220 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |
| 221 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | May 2025 |
| 222 | TCF Energy, Inc. | Midland, TX 79704 | Oil & Gas Operator | Dec 2004 |
| 223 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | May 2025 |
| 224 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | May 2025 |
| 225 | Texakota, Inc. | Houston, TX 77098 | Oil & Gas Operator | Mar 2021 |
| 226 | Texas Meridian Res. Expl., Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 1998 |
| 227 | Texas Oil And Gas Operating, LLC | Friendswood, TX 77546 | Oil & Gas Operator | May 2025 |
| 228 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | May 2025 |
| 229 | Tharp Operating Company | Houston, TX 77070 | Oil & Gas Operator | Nov 2014 |
| 230 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | May 2025 |
| 231 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 232 | Transatlantic Petr (USA) Corp. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |
| 233 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 234 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 235 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 236 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 237 | Union Gas Operating Company | Houston, TX 77014 | Oil & Gas Operator | May 2025 |
| 238 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 239 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 240 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 241 | Unknown | Houston, TX 77208 | Oil & Gas Operator | Dec 2023 |
| 242 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 243 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Jan 2025 |
| 244 | W & T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 245 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 246 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 247 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 248 | Walker, Tigner | Shreveport, LA 71138 | Oil & Gas Operator | Feb 2005 |
| 249 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | May 2025 |
| 250 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 251 | Whitehead Resources, LTD. | Buna, TX 77612 | Oil & Gas Operator | May 2025 |
| 252 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | Jan 2025 |
| 253 | Wild Cat Operating Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 254 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | May 2025 |
| 255 | Wing Corporation | Houston, TX 77002 | Oil & Gas Operator | Jun 2000 |
| 256 | Wright Brothers Petroleum, LTD. | San Antonio, TX 78212 | Oil & Gas Operator | May 2002 |
| 257 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 258 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 259 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |