| 1 | M. Grace, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Oct 2025 |
| 2 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Oct 2025 |
| 3 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 4 | Majestic Petroleum Corporation | Dallas, TX 75230 | Oil & Gas Operator | Oct 1996 |
| 5 | Manziel Management Corporation | Tyler, TX 75711 | Oil Operator | Feb 2014 |
| 6 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 7 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 8 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 9 | Marino, Charles B. | Tomball, TX 77377 | Oil & Gas Operator | Oct 2025 |
| 10 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 11 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 12 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 13 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 14 | McBride, Jerrel L Enterprise Inc | Kilgore, TX 75663 | Oil & Gas Operator | Jun 1999 |
| 15 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 16 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 17 | McMoran Oil & Gas LLC | New Orleans, LA 70160 | Oil & Gas Operator | Oct 2021 |
| 18 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 19 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 20 | MD America Energy, LLC | Houston, TX 77224 | Oil & Gas Operator | Apr 2022 |
| 21 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 22 | Merritt Operating, Inc. | Mineola, TX 75773 | Oil & Gas Operator | Oct 2025 |
| 23 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 24 | Mid-Gulf, Inc. | Brenham, TX 77834 | Oil & Gas Operator | Mar 2008 |
| 25 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 26 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Oct 2025 |
| 27 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 28 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 29 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 30 | Mitsui E&P USA LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 31 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 32 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Oct 2025 |
| 33 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 34 | Moss Petroleum Company | Dallas, TX 75207 | Oil & Gas Operator | Oct 2025 |
| 35 | Musselman, Owen & King Oper.,Inc | Houston, TX 77002 | Oil & Gas Operator | Feb 1998 |
| 36 | Mustang Drilling, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Aug 2024 |
| 37 | Myung And Associates, Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2000 |