| 1 | M & K Oil Company LLC | Gillette, WY 82716 | Oil & Gas Operator | Aug 2025 |
| 2 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | Aug 2025 |
| 3 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 4 | Majestic Petroleum Operations Inc | Story, WY 82842 | Gas Operator | Mar 2007 |
| 5 | Mallon Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 6 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 7 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 8 | Marlin Oil Company LLC | Gillette, WY 82718 | Oil & Gas Operator | Mar 2023 |
| 9 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 10 | Martens & Peck Operating Co | | Gas Operator | Feb 1997 |
| 11 | Martens & Peck Production Co | Denver, CO 80222 | Oil & Gas Operator | Feb 1997 |
| 12 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Aug 2025 |
| 13 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | Aug 2025 |
| 14 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 15 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | Aug 2025 |
| 16 | McAdams Roux & Associates | Denver, CO 80202 | Oil & Gas Operator | Dec 1999 |
| 17 | McClure Enterprises | Recluse, WY 82725 | Oil & Gas Operator | Jul 2025 |
| 18 | McGuire John C | Gillette, WY 82717 | Oil & Gas Operator | Oct 2005 |
| 19 | McKenzie Production Company | Houston, TX 77063 | Oil & Gas Operator | May 1995 |
| 20 | MCL 1 Oil & Gas Wyoming LLC | Minneapolis, MN 55402 | Oil & Gas Operator | Jul 2018 |
| 21 | McMahon-Bullington LP | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2009 |
| 22 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 23 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 24 | MDS Energy Development LLC | | Oil & Gas Operator | Aug 2025 |
| 25 | Medallion Exploration | Holladay, UT 84117 | Oil & Gas Operator | Dec 2015 |
| 26 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 27 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 28 | Mega Energy LLC | Gillette, WY 82718 | Gas Operator | Aug 2025 |
| 29 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 30 | Meritage Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 31 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Aug 2025 |
| 32 | Methane Productions Inc | Recluse, WY 82725 | Oil & Gas Operator | Apr 2007 |
| 33 | Meyer Douglas P | Longmont, CO 80501 | Oil & Gas Operator | Aug 2006 |
| 34 | Michigan-Wisconsin Pipe Line Co | | Oil & Gas Operator | Dec 1983 |
| 35 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2025 |
| 36 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 37 | Minnelusa Oil LLC | Temecula, CA 92589 | Oil Operator | Feb 2002 |
| 38 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 39 | Mitchell M J | | Oil & Gas Operator | Jan 1983 |
| 40 | Mobil Expl & Producing North America Inc | | Oil & Gas Operator | Nov 1986 |
| 41 | Monahan Rex | Sterling, CO 80751 | Oil & Gas Operator | Jun 2002 |
| 42 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2025 |
| 43 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 44 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 45 | Montex Exploration | Sugarland, TX 77478 | Oil Operator | Apr 2003 |
| 46 | Mosbacher Production Co. | Houston, TX 77001 | Oil & Gas Operator | Aug 1984 |
| 47 | Mountain Hawk Energy LLC | Athens, TX 75751 | Gas Operator | Jan 2015 |
| 48 | MTG Operating Inc | Ridgeland, MS 39158 | Gas Operator | Apr 2011 |
| 49 | Mull Drilling Company | Wichita, KS 67206 | Oil & Gas Operator | Aug 2025 |
| 50 | Murphy Oil USA Inc | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 51 | Murphy Sheldon L & Loretta | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2025 |
| 52 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |