| 1 | Maertins Production, LLC | Queen City, TX 75572 | Oil Operator | Mar 2025 |
| 2 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 3 | Magnum Hunter Production, Inc. | Irving, TX 75014 | Oil & Gas Operator | Dec 2019 |
| 4 | Mahfouz Energy Company | Houston, TX 77255 | Oil & Gas Operator | Nov 2020 |
| 5 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 6 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 7 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 8 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 9 | McBride, Jerrel L Enterprise Inc | Kilgore, TX 75663 | Oil & Gas Operator | Jun 1999 |
| 10 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 11 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 12 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 13 | MHM Pipeline Co., Inc. | Dallas, TX 75252 | Oil & Gas Operator | Mar 2025 |
| 14 | Midcoast G & P (East Texas) L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 15 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 16 | Miller, R. A. Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2003 |
| 17 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 18 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 19 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 20 | Mud Creek Operating, LLC | Tyler, TX 75702 | Oil & Gas Operator | Mar 2025 |
| 21 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 22 | Murphy, K. P. Oil Operator | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 23 | Mustang Drilling, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Aug 2024 |
| 24 | Mustang Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2006 |