| 1 | American Quasar Petroleum | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 1985 |
| 2 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 3 | Amoco Rocmount Company | Denver, CO 80201 | Oil & Gas Operator | Jan 1998 |
| 4 | Anschutz Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2016 |
| 5 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 6 | Apc Operating Partnership | Tulsa, OK 74136 | Oil & Gas Operator | Oct 1996 |
| 7 | Bayless Robert L Producer | Denver, CO 80293 | Oil & Gas Operator | Sep 2003 |
| 8 | BP America Production Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 9 | Bta Oil Producers | Midland, TX 79701 | Oil & Gas Operator | Sep 2009 |
| 10 | Burton/Hawks Inc | Casper, WY 82602 | Oil & Gas Operator | Sep 1993 |
| 11 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 12 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Oct 2025 |
| 13 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 14 | Davis Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 1988 |
| 15 | Enerquest Operating, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Oct 2025 |
| 16 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 17 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 18 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 19 | JN Exploration & Production | Billings, MT 59103-0159 | Oil & Gas Operator | Apr 2001 |
| 20 | Kings Peak Energy LLC | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 21 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 22 | Mountain Fuel Supply Co | Salt Lake City, UT 84139 | Oil & Gas Operator | May 1984 |
| 23 | North Shore Exploration & Prod LLC | Broomfield, CO 80021 | Oil & Gas Operator | Aug 2025 |
| 24 | Phillips Oil Company | Casper, WY 82602 | Oil & Gas Operator | Sep 1986 |
| 25 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 26 | Prima Exploration, Inc. | Denver, CO 80206 | Oil & Gas Operator | Aug 2025 |
| 27 | Proven Petroleum, Inc. | Lakewood, CO 80228 | Oil & Gas Operator | Aug 2025 |
| 28 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Jul 2025 |
| 29 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Oct 2025 |
| 30 | Sohio-Stand Oil Prod Co | Houston, TX 77210-9928 | Oil & Gas Operator | Jan 1989 |
| 31 | Toc Oil Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 32 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Aug 2025 |
| 33 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 34 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |