| 101 | M V Ventures, G. P. | | Oil & Gas Operator | Dec 2000 |
| 102 | M W Petroleum Company | Houston, TX 77056 | Oil & Gas Operator | Dec 1995 |
| 103 | M W Production Co. | New Braunfels, TX 78130 | Oil & Gas Operator | Aug 2003 |
| 104 | M&M Energy, LLC | El Paso, TX 79902 | Oil Operator | Dec 2020 |
| 105 | M&M Oil, LLC | Artesia, NM 88210254 | Oil & Gas Operator | Sep 2025 |
| 106 | M&M Services LLC | Neodesha, KS 66757 | Gas Operator | Jun 2025 |
| 107 | M'Red Petroleum, LLC | Pampa, TX 79065 | Oil & Gas Operator | Dec 2010 |
| 108 | M-2 Oil Company | Wichita Falls, TX 76306 | Oil & Gas Operator | May 2006 |
| 109 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Sep 2025 |
| 110 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Dec 2025 |
| 111 | M-B SWD Inc | Crescent, OK 73028-0533 | Oil Operator | Jul 1997 |
| 112 | M-C Production & Drilling Co,Inc | Longview, TX 75608 | Oil & Gas Operator | Dec 2025 |
| 113 | M-Five Oil Company | Seguin, TX 78155 | Oil & Gas Operator | Apr 2002 |
| 114 | M-G Gas Company, Inc. | Plano, TX 75086 | Oil & Gas Operator | Jun 1999 |
| 115 | M-J Oil Company Inc. | Minerva, OH 44657 | Oil & Gas Operator | Dec 2008 |
| 116 | M-P Petroleum, Inc. | McPherson, KS 67460 | Oil & Gas Operator | Jan 2013 |
| 117 | M-S-C Corporation | Houston, TX 77027 | Oil Operator | May 1994 |
| 118 | M-T Petroleum, Inc. | Andrews, TX 79714 | Oil & Gas Operator | Mar 2008 |
| 119 | M-Tex Resources, Inc. | Merkel, TX 79536 | Oil & Gas Operator | Dec 2025 |
| 120 | M-V Company | Refugio, TX 78377 | Oil & Gas Operator | Jun 2004 |
| 121 | M-W-D Oil Co. | Odessa, TX 79760 | Oil & Gas Operator | Jul 1999 |
| 122 | M. A. B. Production | | Oil Operator | Nov 2009 |
| 123 | M. A. Robison | | Oil & Gas Operator | Oct 1998 |
| 124 | M. B. And D. I. Dupree | | Oil Operator | Nov 1992 |
| 125 | M. D. & G. Partnership | | Oil & Gas Operator | Dec 1996 |
| 126 | M. E. Fitzgerald | | Oil & Gas Operator | May 1993 |
| 127 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2025 |
| 128 | M. F. McCain, Inc. | | Oil & Gas Operator | Jul 1987 |
| 129 | M. Grace, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Dec 2025 |
| 130 | M. H. Whittier Energy LLC | | Oil & Gas Operator | Sep 1996 |
| 131 | M. H.Marr | | Oil & Gas Operator | Mar 1998 |
| 132 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 133 | M. J. McCaffery Oil Co. | Allegany, NY 14706 | Oil Operator | Dec 2017 |
| 134 | M. J. T. Enterprises | | Oil Operator | Jun 2025 |
| 135 | M. K. Fuhrman LLC | | Oil Operator | May 2025 |
| 136 | M. K. Production | Caldwell, TX 77836 | Oil & Gas Operator | Mar 2008 |
| 137 | M. L. Mayfield | | Oil & Gas Operator | Oct 1990 |
| 138 | M. L. Mayfield Co. | | Oil & Gas Operator | Aug 1991 |
| 139 | M. M. & M. Resources, Inc. | Wetumka, OK 74883 | Oil & Gas Operator | Apr 2020 |
| 140 | M. M. Miller & Sons, LTD. | Alice, TX 78333 | Oil & Gas Operator | Jan 2023 |
| 141 | M. P. O'Meara Oil Co. | | Oil & Gas Operator | Apr 1991 |
| 142 | M. P. S. Prod. Co. | Houston, TX 77225 | Oil & Gas Operator | Dec 1996 |
| 143 | M. Parker Production Co. | | Oil Operator | Dec 2024 |
| 144 | M. S. Delone | | Oil Operator | Nov 1990 |
| 145 | M. S. Productions, Inc. | Pittsburg, KS 66762 | Oil & Gas Operator | Nov 2019 |
| 146 | M. T. R. Production | | Oil Operator | Mar 2006 |
| 147 | M. W. Maxwell | | Oil & Gas Operator | Apr 1990 |
| 148 | M.A. Yost Operations, Inc | Russell, KS 67665 | Oil Operator | Jun 2025 |
| 149 | M.A.E. Resources, Inc. | Parker, KS 66072 | Oil Operator | Sep 2011 |
| 150 | M.A.R.S. Energy | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 151 | M.B. Properties, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Oct 1995 |
| 152 | M.B.J. Operating | Argyle, TX 76226 | Oil & Gas Operator | Jun 2022 |
| 153 | M.C.E. Trust Group, A General Partnership | Cherryvale, KS 67335 | Oil & Gas Operator | Sep 2009 |
| 154 | M.D. Skroopka Operating, LLC | Oakland, CA 94611 | Oil & Gas Operator | Dec 2025 |
| 155 | M.J. Bernos, Jr./PKR Oil, Inc. | | Gas Operator | Aug 1990 |
| 156 | M.J.O.G., Inc. | Fort Smith, AR 72903 | Oil Operator | Mar 2015 |
| 157 | M.O.K.A.T. | Bartlesville, OK 74003 | Oil Operator | Jun 2001 |
| 158 | M.R.M. Operating, Inc. | Midland, TX 79707 | Oil & Gas Operator | Aug 2003 |
| 159 | M.T.M. Petroleum | | Oil & Gas Operator | Oct 1995 |
| 160 | M2 Louisiana Gas Service, LLC | | Oil Operator | Apr 2010 |
| 161 | M2 Squared Operating, LLC | Rockwall, TX 75032 | Oil Operator | Dec 2025 |
| 162 | M2S Oil LLC | | Oil Operator | Sep 2025 |
| 163 | M3 Helium Corp | | Gas Operator | Jun 2025 |
| 164 | M3V Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Dec 2025 |
| 165 | M4 Energy, LLC | Watsontown, PA 17777-1133 | Oil & Gas Operator | Dec 2024 |
| 166 | M5 Standing Energy, LLC | Decatur, TX 76234 | Oil & Gas Operator | Dec 2025 |
| 167 | M5oexit, LLC | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 168 | M7 Resources LLC | Santa Fe, NM 87505 | Oil Operator | May 2025 |
| 169 | Ma-Si, Inc. | | Oil & Gas Operator | May 1998 |
| 170 | Mac 5 Operating, LLC | Pampa, TX 79065 | Oil & Gas Operator | Feb 2021 |
| 171 | Mac Engineering & Operating Co | | Oil & Gas Operator | May 2005 |
| 172 | Mac Oil Field Service Inc | Millersburg, OH 44654 | Oil & Gas Operator | Dec 2024 |
| 173 | Mac Operating | Graham, TX 76450 | Oil & Gas Operator | Jun 2023 |
| 174 | Mace, T. A. | Oklahoma City, OK 73127 | Oil & Gas Operator | Feb 2008 |
| 175 | Macfarlan Oil And Gas, LLC | Ellenboro, WV 26346-0058 | Oil & Gas Operator | Dec 2021 |
| 176 | Mach Petroleum, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | Nov 2014 |
| 177 | Macha Enterprises, Inc. | Wichita Falls, TX 76309 | Oil Operator | Dec 2025 |
| 178 | Machii-Ross Petroleum Co | | Oil & Gas Operator | Apr 2014 |
| 179 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2025 |
| 180 | Macina, P.T. | Shamrock, TX 79079 | Gas Operator | Dec 2025 |
| 181 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Sep 2025 |
| 182 | Mack Energy Comp | | Oil & Gas Operator | Nov 1994 |
| 183 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | Sep 2025 |
| 184 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 185 | Mack Oil Corp | | Oil & Gas Operator | Nov 1998 |
| 186 | Mack Oil Corp And Delta Oil Co Inc Great Lakes Nia | | Oil & Gas Operator | Feb 1986 |
| 187 | Mack Oil Corp And Neyer Oil Inc | | Oil & Gas Operator | May 1988 |
| 188 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Sep 2025 |
| 189 | Mackenco Inc | Columbus, OH 43235 | Oil & Gas Operator | Dec 2020 |
| 190 | Mackey Consulting & Leasing LLC | Cleveland, OK 74020 | Oil & Gas Operator | Aug 2025 |
| 191 | Mackinaw Two, LLC | | Oil & Gas Operator | May 2020 |
| 192 | Maclane Gas Company L.P. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Mar 1994 |
| 193 | Macmart Inc | Wynnewood, OK 73098 | Oil & Gas Operator | Jan 2016 |
| 194 | Macnichols, Jennifer | Akron, NY 14001 | Gas Operator | Dec 2024 |
| 195 | Maco Incorporate | | Oil Operator | Jun 1984 |
| 196 | Macpherson Oil Company LLC | | Oil & Gas Operator | Sep 2025 |
| 197 | Macpherson Operating Company L.P. | | Oil & Gas Operator | Sep 2025 |
| 198 | Macro Oil Company | Bartlesville, OK 74006 | Oil Operator | Aug 1999 |
| 199 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 200 | Mad Dog Oil Co. | | Oil Operator | Mar 2016 |