| 1 | Bayswater Exploration & Production LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2025 |
| 2 | Big Sky Energy, LLC | Cody, WY 82414 | Oil & Gas Operator | May 2024 |
| 3 | Blackstone Operating | Red Lodge, MT 59068 | Gas Operator | Dec 2006 |
| 4 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 5 | Energy Corporation Of America | Charleston, WV 25311 | Oil & Gas Operator | Dec 2023 |
| 6 | Energy Equity Company | Columbus, MT 59019 | Oil & Gas Operator | Oct 2025 |
| 7 | Equitable Resources Energy Co, Western Region | Billings, MT 59102 | Oil & Gas Operator | May 1997 |
| 8 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 9 | Herco Exploration LLC | Billings, MT 59103 | Gas Operator | Oct 2024 |
| 10 | Midway Energy, LLC | Thermopolis, WY 82443 | Oil Operator | Jul 2025 |
| 11 | Montana Energy Company, LLC | McAllen, TX 78501 | Oil & Gas Operator | May 2025 |
| 12 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 13 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 14 | Mountain Pacific General Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Jun 2022 |
| 15 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 16 | S & L Energy, Inc.C/O John D. Lawrence, Jr. | Fishtail, MT 59028 | Oil Operator | Jun 2025 |
| 17 | Saga Petroleum, LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2018 |
| 18 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 19 | West Gas Inc | | Oil & Gas Operator | Dec 2017 |
| 20 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |