| 20201 | Moncrief, C. B. | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2021 |
| 20202 | Monday Creek Resources LTD | Logan, OH 43138 | Oil Operator | Dec 2024 |
| 20203 | Mondiale Energy, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Feb 2026 |
| 20204 | Mondo Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 20205 | Monex | | Oil Operator | Apr 1988 |
| 20206 | Monexco | Edmond, OK 73034-3776 | Oil & Gas Operator | Mar 2008 |
| 20207 | Monexco LLC | Dallas, TX 75204-2634 | Oil & Gas Operator | Nov 2025 |
| 20208 | Monexco Operating Company | Dallas, TX 75204-2634 | Oil & Gas Operator | Nov 2025 |
| 20209 | Monexco, Inc. | | Oil Operator | Dec 2003 |
| 20210 | Monfort, Roy C. | Iola, KS 66749 | Oil & Gas Operator | Sep 1989 |
| 20211 | Monge Oil Corp. | | Oil & Gas Operator | Dec 2021 |
| 20212 | Mongoose Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 20213 | Mongrue Oil Company, Inc. | | Oil & Gas Operator | Oct 1999 |
| 20214 | Mongrue, Roland, Inc | | Oil & Gas Operator | Mar 1979 |
| 20215 | Monitor O&G, L.L.C. | Frisco, TX 75034 | Oil & Gas Operator | Jan 2016 |
| 20216 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Dec 2025 |
| 20217 | Monroe Gas Associates-1 | | Gas Operator | Mar 2000 |
| 20218 | Monroe Gas Associates-2 | | Gas Operator | Mar 2000 |
| 20219 | Monroe Gas Joint Venture | | Gas Operator | Sep 2011 |
| 20220 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Nov 2025 |
| 20221 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 20222 | Monroe Well Ser-Amsterdam | | Oil Operator | Dec 1988 |
| 20223 | Monroe Well Ser-La Petr Assoc | | Oil Operator | Dec 1988 |
| 20224 | Monroe Well Ser-La Petro II | | Oil Operator | Dec 1988 |
| 20225 | Monroe Well Ser-New American85 | | Oil Operator | Dec 1988 |
| 20226 | Monroe Well Ser-Ocean Petr '84 | | Oil & Gas Operator | Dec 1988 |
| 20227 | Monroe Well Ser-Ocean Yacht II | | Oil Operator | May 1989 |
| 20228 | Monroe Well Ser-Oceanyacht1985 | | Oil Operator | Dec 1988 |
| 20229 | Monroe Well Ser-Riverside 1985 | | Oil Operator | Dec 1988 |
| 20230 | Monroe Well Serv-New American | | Oil Operator | Dec 1988 |
| 20231 | Monroe Well Serv-Northern La | | Oil Operator | Dec 1988 |
| 20232 | Monroe Well Serv-Omega 1985 | | Oil Operator | Dec 1988 |
| 20233 | Monroe Well Service | | Oil & Gas Operator | Apr 1998 |
| 20234 | Monroe Well Service-Ajk | | Oil Operator | Dec 1988 |
| 20235 | Monroe Well Service-Apk | | Oil Operator | Dec 1988 |
| 20236 | Monroe Well Service-Beaver1985 | | Oil Operator | Nov 1991 |
| 20237 | Monroe Well Service-Broadway | | Oil Operator | Dec 1988 |
| 20238 | Monroe Well Service-BWK | | Oil Operator | Dec 1988 |
| 20239 | Monroe Well Service-Columbus | | Oil Operator | Dec 1988 |
| 20240 | Monroe Well Service-Das | | Oil Operator | Mar 1989 |
| 20241 | Monroe Well Service-Derrick | | Oil Operator | Dec 1988 |
| 20242 | Monroe Well Service-East End | | Oil Operator | Dec 1988 |
| 20243 | Monroe Well Service-Empire | | Oil Operator | Dec 1988 |
| 20244 | Monroe Well Service-Energy | | Oil Operator | Dec 1988 |
| 20245 | Monroe Well Service-Energy 84 | | Oil Operator | Aug 1989 |
| 20246 | Monroe Well Service-Ged | | Oil Operator | Dec 1988 |
| 20247 | Monroe Well Service-Gotham | | Oil Operator | Apr 1992 |
| 20248 | Monroe Well Service-Gramercy | | Oil Operator | May 1992 |
| 20249 | Monroe Well Service-HGC | | Oil Operator | Dec 1988 |
| 20250 | Monroe Well Service-Lebo | | Oil Operator | Jun 1989 |
| 20251 | Monroe Well Service-Lexington | | Oil Operator | Feb 1989 |
| 20252 | Monroe Well Service-Newtown | | Oil Operator | Aug 1990 |
| 20253 | Monroe Well Service-Ocean | | Oil Operator | Feb 1989 |
| 20254 | Monroe Well Service-Oceanyacht | | Oil Operator | Jan 1989 |
| 20255 | Monroe Well Service-Oil City | | Oil Operator | Aug 1992 |
| 20256 | Monroe Well Service-Omega | | Oil Operator | Aug 1992 |
| 20257 | Monroe Well Service-Par | | Oil Operator | Jan 1990 |
| 20258 | Monroe Well Service-Petrol | | Oil Operator | Sep 1992 |
| 20259 | Monroe Well Service-Petrovest | | Oil Operator | Dec 1988 |
| 20260 | Monroe Well Service-PRG | | Oil Operator | Nov 1990 |
| 20261 | Monroe Well Service-Redstone | | Oil Operator | Jul 1989 |
| 20262 | Monroe Well Service-RVS | | Oil Operator | Dec 1990 |
| 20263 | Monroe Well Service-Shemen | | Oil Operator | Dec 1988 |
| 20264 | Monroe Well Service-Shemen1984 | | Oil Operator | Jan 1989 |
| 20265 | Monroe Well Service-Shemen1985 | | Oil Operator | Nov 1990 |
| 20266 | Monroe Well Service-Sla | | Oil Operator | Mar 1989 |
| 20267 | Monroe Well Service-SPD | | Oil Operator | Dec 1988 |
| 20268 | Monroe Well Service-SPD 1985 | | Oil Operator | Dec 1988 |
| 20269 | Monroe Well Service-TBR | | Oil Operator | Aug 1991 |
| 20270 | Monroe Well Service-TG I | | Oil Operator | Oct 1990 |
| 20271 | Monroe Well Service-TG II | | Oil Operator | Oct 1990 |
| 20272 | Monroe Well Service-TG III | | Oil Operator | Jul 1992 |
| 20273 | Monroe Well Service-TG VI | | Oil Operator | Aug 1989 |
| 20274 | Monroe Well Service-Tpa 1985 | | Oil Operator | Dec 1990 |
| 20275 | Monroe Well Service-Vista | | Oil Operator | Nov 1990 |
| 20276 | Monroe Well Service-West End | | Oil Operator | Dec 1988 |
| 20277 | Monroe Well Service-York | | Oil Operator | Dec 1988 |
| 20278 | Monroe, Cameron | Westfield, NY 14787 | Gas Operator | Dec 2024 |
| 20279 | Monroe,Eugene R. | Midland, TX 79702 | Oil & Gas Operator | Jul 1999 |
| 20280 | Monsanto | Englewood, CO 80111 | Oil & Gas Operator | Apr 1986 |
| 20281 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 20282 | Monsanto Oil Com | | Oil Operator | Nov 1996 |
| 20283 | Monsanto Oil Company | | Oil & Gas Operator | Apr 1986 |
| 20284 | Mont Rouge Inc | | Gas Operator | Feb 2020 |
| 20285 | Mont-Land Co. | Graham, TX 76450 | Oil & Gas Operator | Mar 2008 |
| 20286 | Montalban Oil & Gas Operations, Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Dec 2025 |
| 20287 | Montana Energy Company, LLC | McAllen, TX 78504 | Oil & Gas Operator | Nov 2025 |
| 20288 | Montana Heartland LLC | Bismarck, ND 58504 | Oil & Gas Operator | Nov 2025 |
| 20289 | Montana Land & Exploration, Inc. | Calgary, AB T2P 3E7 | Oil & Gas Operator | Apr 2019 |
| 20290 | Montana Land & Mineral Co. | Billings, MT 59105 | Gas Operator | Sep 2025 |
| 20291 | Montana Oil Field Acquisition I, LLC | Rutherford, NJ 07070 | Oil Operator | Jun 2016 |
| 20292 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 20293 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 20294 | Montare Operating, LTD. | Flower Mound, TX 75022 | Oil & Gas Operator | Feb 2026 |
| 20295 | Montclair Energy LLC | Edmond, OK 73034-7291 | Oil & Gas Operator | Dec 2025 |
| 20296 | Montclair Production Company | Austin, TX 78755 | Oil & Gas Operator | Feb 2026 |
| 20297 | Montco Oil & Gas, Inc. | Pampa, TX 79066 | Oil & Gas Operator | May 1999 |
| 20298 | Monte Carlo Exploration Inc. | | Oil & Gas Operator | Oct 1984 |
| 20299 | Monte Grande Exploration, Inc. | Cut Bank, MT 59427 | Oil Operator | Oct 2000 |
| 20300 | Montego Resources Inc | Oklahoma City, OK 73172-0192 | Oil & Gas Operator | Mar 2015 |