| 201 | Star Resources LLC | Englewood, CO 80155-5185 | Oil & Gas Operator | Dec 2013 |
| 202 | Sterling Energy Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 1995 |
| 203 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 204 | Stringer E M | | Oil Operator | May 1996 |
| 205 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |
| 206 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 207 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2026 |
| 208 | Tara Oil Company | | Oil Operator | Dec 1981 |
| 209 | Tbi Exploration Inc | Englewood, CO 801556525 | Oil & Gas Operator | Jun 2011 |
| 210 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2025 |
| 211 | Territory Resources LLC | Stillwater, OK 74074-1869 | Oil & Gas Operator | Jun 2026 |
| 212 | Texaco Exploration & Prod | Midland, TX 79702 | Oil & Gas Operator | Aug 2002 |
| 213 | Three Forks Resources, LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Aug 2026 |
| 214 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Dec 2025 |
| 215 | Timberline Production Company LLC | Casper, WY 82601 | Oil & Gas Operator | Oct 2020 |
| 216 | Torch Oil & Gas Company | Houston, TX 77010 | Oil & Gas Operator | Aug 1997 |
| 217 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 218 | Tresor Petroleum | | Oil & Gas Operator | Sep 1987 |
| 219 | Tri-Ex Corporation | | Oil & Gas Operator | Jan 1985 |
| 220 | Tripower Resources LLC | Ardmore, OK 73402 | Oil & Gas Operator | Aug 2026 |
| 221 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Jun 2026 |
| 222 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 223 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Dec 2010 |
| 224 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 225 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 226 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Mar 2026 |
| 227 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2026 |
| 228 | Vast Oil Inc | Fullerton, CA 92832 | Oil & Gas Operator | Mar 2024 |
| 229 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 230 | Warren E & P Inc | Dallas, TX 75240 | Oil & Gas Operator | Jun 2026 |
| 231 | Washington Energy Exploration | | Oil & Gas Operator | Dec 1997 |
| 232 | Weaver Oil Inc | | Oil & Gas Operator | Oct 2011 |
| 233 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Jun 2026 |
| 234 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |
| 235 | Western American Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2024 |
| 236 | Western Gas Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 237 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 238 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Apr 2026 |
| 239 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 240 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | May 2026 |
| 241 | Whisler Enterprise Company | Erie, CO 80516 | Oil & Gas Operator | Jun 2026 |
| 242 | White Rock Oil & Gas, LLC | Plano, TX 75024 | Oil & Gas Operator | Aug 2026 |
| 243 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Aug 2026 |
| 244 | Wichita River Oil Corporation | Englewood, CO 80111 | Oil & Gas Operator | Apr 2009 |
| 245 | Wildfire Partners Inc | Ardmore, OK 73402 | Oil & Gas Operator | Dec 2009 |
| 246 | Williams Ted H | | Oil & Gas Operator | Dec 2008 |
| 247 | Win Oil Company | Russell, KS 67665 | Oil & Gas Operator | Jul 2021 |
| 248 | Winter Ridge Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2011 |
| 249 | Wold Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2022 |
| 250 | Wood River Oil & Refining Co | | Oil & Gas Operator | Dec 1998 |
| 251 | WPX Energy Rocky Mountain LLC | Tulsa, OK 74101 | Oil & Gas Operator | May 2026 |
| 252 | Wulf Oil Co | | Oil & Gas Operator | Dec 1984 |
| 253 | Wyoming Resources Corporation | Rapid City, SD 57702 | Oil & Gas Operator | Oct 2018 |
| 254 | Yates Drilling Company | Artesia, NM 88210 | Oil & Gas Operator | Dec 2021 |
| 255 | Yegen E C | Casper, WY 82604 | Oil & Gas Operator | Mar 2015 |