| 201 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 202 | Marquis-Allred Eng Inc | | Oil & Gas Operator | Apr 1992 |
| 203 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Jun 2026 |
| 204 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | Jul 2026 |
| 205 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | Jun 2026 |
| 206 | McCulliss Resource Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jun 1999 |
| 207 | McMurry Energy Company | | Oil & Gas Operator | Dec 2001 |
| 208 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 209 | McO Resources Corporation | | Oil & Gas Operator | Feb 1986 |
| 210 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 211 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 212 | MDS Energy Development LLC | | Oil & Gas Operator | Jun 2026 |
| 213 | Medallion Exploration | Holladay, UT 84117 | Oil & Gas Operator | Dec 2015 |
| 214 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 215 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Sep 2026 |
| 216 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Jul 2026 |
| 217 | Methane Productions Inc | Recluse, WY 82725 | Oil & Gas Operator | Apr 2007 |
| 218 | Michigan-Wisconsin Pipe Line Co | | Oil & Gas Operator | Dec 1983 |
| 219 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jul 2026 |
| 220 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 221 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 222 | Mobil Expl & Producing North America Inc | | Oil & Gas Operator | Nov 1986 |
| 223 | Mon-Oil Inc | | Oil & Gas Operator | Apr 1996 |
| 224 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2026 |
| 225 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2026 |
| 226 | Morgan Energy Corporation | Englewood, CO 80110 | Oil & Gas Operator | Mar 2006 |
| 227 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |
| 228 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |
| 229 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 230 | National Pride Operating | Parker, CO 80134 | Oil & Gas Operator | Dec 2017 |
| 231 | Nautilus Exploration LLC | Denver, CO 80218 | Oil Operator | Mar 2011 |
| 232 | Navigation Powder River LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2026 |
| 233 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Sep 2026 |
| 234 | Neward Corporation | FT. Worth, TX 76102 | Oil & Gas Operator | Dec 1997 |
| 235 | Newfield Production Company | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2021 |
| 236 | Newwoods Petroleum LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2016 |
| 237 | Nicolaysen G G Jr | | Oil & Gas Operator | Dec 1995 |
| 238 | Nielson & Associates, Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 239 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Sep 2026 |
| 240 | Nonsuch Natural Gas Inc | Naples, FL 34108 | Oil & Gas Operator | Jul 2026 |
| 241 | Nortex Gas & Oil Co | Tulsa, OK 74135 | Oil & Gas Operator | Sep 1993 |
| 242 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 243 | North Finn LLC | Casper, WY 82605 | Oil & Gas Operator | Jul 2026 |
| 244 | Northern Production Co | Gillette, WY 82717 | Oil & Gas Operator | Apr 2013 |
| 245 | Northern Pump Company | Denver, CO 80202-3130 | Oil & Gas Operator | Feb 2006 |
| 246 | Northstar Operating Company Of Texas | Midland, TX 79702 | Oil & Gas Operator | Feb 2008 |
| 247 | Northwoods Land Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 248 | Norton Frickey | Lakewood, CO 80215 | Oil & Gas Operator | Dec 2023 |
| 249 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 250 | Oedekoven Water & Hot Oil | Recluse, WY 82725 | Oil & Gas Operator | Jul 2026 |
| 251 | Oilfield Salvage & Service Company | Littleton, CO 80120 | Oil & Gas Operator | Jul 2026 |
| 252 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2026 |
| 253 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 254 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 255 | Oxtex Inc | | Oil & Gas Operator | Oct 1989 |
| 256 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Sep 2026 |
| 257 | P & M Petroleum Management LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2021 |
| 258 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Sep 2026 |
| 259 | Pacific Enterprises Oil Co USA | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 260 | Pancanadian Petroleum Company | | Oil & Gas Operator | Oct 1989 |
| 261 | Panther Energy Company III LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jul 2020 |
| 262 | Paoli Investors LTD | | Oil & Gas Operator | Aug 1985 |
| 263 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 264 | Pathfinder Energy Inc | Casper, WY 82605 | Oil & Gas Operator | May 2024 |
| 265 | Peak Powder River Resources LLC | Durango, CO 81301 | Oil & Gas Operator | Jun 2026 |
| 266 | Penneco Exploration Company Of Wyo LLC | Delmont, PA 15626 | Oil Operator | Aug 2021 |
| 267 | Petcon Associates LTD | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 268 | Peterson Energy Operating Inc | Loveland, CO 80537 | Oil & Gas Operator | Jul 2026 |
| 269 | Petra Petroleum Inc | Littleton, CO 80160-0319 | Oil & Gas Operator | Jun 2005 |
| 270 | Petro-Canada Resources (USA) Inc | Denver, CO 80202-472 | Oil & Gas Operator | Feb 2010 |
| 271 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 272 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 273 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 274 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 275 | Pioneer Natural Resources USA Inc | Irving, TX 75039 | Oil & Gas Operator | May 2026 |
| 276 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 277 | Polfam Exploration Co | Denver, CO 80204 | Oil & Gas Operator | Mar 2007 |
| 278 | Prima Exploration, Inc. | Denver, CO 80206 | Oil & Gas Operator | Jul 2026 |
| 279 | Prospective Invest & Trad Co LTD | Tulsa, OK 74170 | Oil & Gas Operator | Aug 2005 |
| 280 | Proven Petroleum, Inc. | Lakewood, CO 80228 | Oil & Gas Operator | Jun 2026 |
| 281 | Provident Resources LTD | | Oil & Gas Operator | Dec 1986 |
| 282 | Pure Petroleum LLC | Gillette, WY 82717 | Oil & Gas Operator | Aug 2011 |
| 283 | Ranch Oil Company | West Linn, OR 97068 | Oil & Gas Operator | Jul 2026 |
| 284 | Rathbun Roger | | Oil & Gas Operator | Dec 1993 |
| 285 | Rathpro Inc | Douglas, WY 82633 | Oil & Gas Operator | Feb 1994 |
| 286 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 287 | Reading & Bates Petroleum | | Oil & Gas Operator | Apr 1989 |
| 288 | Red Rock Resources Corporation | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Jul 2026 |
| 289 | Remuda Energy Development LLC | Billings, MT 59104 | Oil & Gas Operator | Jul 2026 |
| 290 | Renos Land & Minerals Company | Casper, WY 82601 | Oil & Gas Operator | Oct 2021 |
| 291 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 292 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 293 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Jul 2026 |
| 294 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Sep 2026 |
| 295 | Rki Exploration & Production LLC | Tulsa, OK 74172 | Oil & Gas Operator | Sep 2026 |
| 296 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 297 | Robert Hawkins Inc | Kevin, MT 59454 | Oil & Gas Operator | Jun 2026 |
| 298 | Rochelle Oil & Gas | Gillette, WY 82717 | Oil & Gas Operator | Mar 2024 |
| 299 | Rockies Resources Holdings LLC | Lakewood, CO 80228 | Oil & Gas Operator | Jul 2026 |
| 300 | Rocky Mountain Gas Inc | Sheridan, WY 82801 | Gas Operator | Nov 2009 |