| 201 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 202 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 203 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 204 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |
| 205 | Talos Ert LLC | | Oil & Gas Operator | Jan 2025 |
| 206 | Taylor-McIlhenny Oper. Co., Inc. | Lewisville, TX 75029 | Oil & Gas Operator | Jan 1996 |
| 207 | Telico Minerals, L.L.C. | | Oil & Gas Operator | Oct 2019 |
| 208 | Tesla Resources, Inc. | | Oil & Gas Operator | Aug 1996 |
| 209 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Feb 2026 |
| 210 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 211 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 212 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 213 | Texas Pacific Oil Co. | | Oil & Gas Operator | Dec 1980 |
| 214 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 215 | The WM G Helis Company, L.L.C. | | Oil & Gas Operator | Nov 2003 |
| 216 | Transcontinental Oil Corp. | | Oil & Gas Operator | Sep 1985 |
| 217 | Traver Oil & Gas Corporation | | Oil & Gas Operator | Sep 2000 |
| 218 | Traver Oil Company | | Oil & Gas Operator | Sep 2000 |
| 219 | Traver-Patterson Petroleum Inc | | Oil & Gas Operator | May 1990 |
| 220 | Treber Oil Corporation | | Oil & Gas Operator | Sep 2000 |
| 221 | Unifid Oil & Gas Corp. | | Oil & Gas Operator | Mar 1994 |
| 222 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 223 | United Gas Pipe Line Co. | | Oil Operator | Aug 1993 |
| 224 | Us Oil & Gas Inc | Marietta, OH 45750 | Oil & Gas Operator | Jan 2026 |
| 225 | Vamos Oil & Gas, LLC | Miami, FL 33129 | Oil & Gas Operator | Feb 2026 |
| 226 | Vernon E. Faulconer, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Dec 2024 |
| 227 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 228 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 229 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 230 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | Feb 2026 |
| 231 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 232 | Westall Oil & Gas Co. | | Oil & Gas Operator | May 1982 |
| 233 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 234 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Feb 2026 |
| 235 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 236 | Wichita River Oil Corporation | Englewood, CO 80111 | Oil & Gas Operator | Apr 2009 |
| 237 | Wilco Oil Gas & Expl. Corp. | | Oil & Gas Operator | Mar 1979 |
| 238 | World Producers, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1994 |
| 239 | WRT Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | May 1998 |
| 240 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 241 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 242 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |