| 201 | La Prele Exploration | | Oil & Gas Operator | Oct 1979 |
| 202 | Lappin Oil LLC | Douglas, WY 82633 | Oil & Gas Operator | Mar 2026 |
| 203 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | May 2026 |
| 204 | Lawson Oil Company | Buckeye, AR 85326 | Oil Operator | Mar 1996 |
| 205 | Lear Petroleum Exploration | | Oil & Gas Operator | Jul 2013 |
| 206 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 207 | Lexicon Resources Corporation | | Oil & Gas Operator | Apr 1986 |
| 208 | Loil Oil LLC | Golden, CO 80402 | Oil & Gas Operator | Feb 2026 |
| 209 | Long Trust The | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2008 |
| 210 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 211 | M & K Oil Company LLC | Gillette, WY 82716 | Oil & Gas Operator | Feb 2026 |
| 212 | M & K Oil Operations | | Oil & Gas Operator | Sep 1994 |
| 213 | M-3 Industries | Casper, WY 82602 | Oil & Gas Operator | Jan 2026 |
| 214 | Mack Energy Corporation | Artesia, NM 88211 | Oil & Gas Operator | Feb 2026 |
| 215 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 216 | Manx Oil Corporation | Casper, WY 82601 | Oil & Gas Operator | Jun 2010 |
| 217 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Feb 2026 |
| 218 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 219 | Marquis-Allred Eng Inc | | Oil & Gas Operator | Apr 1992 |
| 220 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Feb 2026 |
| 221 | Maxim Drilling & Expl Inc | Gillette, WY 82717 | Oil & Gas Operator | Jan 2026 |
| 222 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | Feb 2026 |
| 223 | McCulliss Resource Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jun 1999 |
| 224 | McMurry Energy Company | | Oil & Gas Operator | Dec 2001 |
| 225 | McMurry Oil LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 226 | McO Resources Corporation | | Oil & Gas Operator | Feb 1986 |
| 227 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 228 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 229 | MDS Energy Development LLC | | Oil & Gas Operator | Feb 2026 |
| 230 | Medallion Exploration | Holladay, UT 84117 | Oil & Gas Operator | Dec 2015 |
| 231 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 232 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2026 |
| 233 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Feb 2026 |
| 234 | Methane Productions Inc | Recluse, WY 82725 | Oil & Gas Operator | Apr 2007 |
| 235 | Michigan-Wisconsin Pipe Line Co | | Oil & Gas Operator | Dec 1983 |
| 236 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 237 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 238 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 239 | Mobil Expl & Producing North America Inc | | Oil & Gas Operator | Nov 1986 |
| 240 | Mon-Oil Inc | | Oil & Gas Operator | Apr 1996 |
| 241 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2026 |
| 242 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2026 |
| 243 | Morgan Energy Corporation | Englewood, CO 80110 | Oil & Gas Operator | Mar 2006 |
| 244 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |
| 245 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |
| 246 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 247 | National Pride Operating | Parker, CO 80134 | Oil & Gas Operator | Dec 2017 |
| 248 | Nautilus Exploration LLC | Denver, CO 80218 | Oil Operator | Mar 2011 |
| 249 | Navigation Powder River LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 250 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | May 2026 |
| 251 | Neward Corporation | FT. Worth, TX 76102 | Oil & Gas Operator | Dec 1997 |
| 252 | Newfield Production Company | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jul 2022 |
| 253 | Newwoods Petroleum LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2016 |
| 254 | Nicolaysen G G Jr | | Oil & Gas Operator | Dec 1995 |
| 255 | Nielson & Associates, Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 256 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2026 |
| 257 | Nonsuch Natural Gas Inc | Naples, FL 34108 | Oil & Gas Operator | Feb 2026 |
| 258 | Nortex Gas & Oil Co | Tulsa, OK 74135 | Oil & Gas Operator | Sep 1993 |
| 259 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 260 | North Finn LLC | Casper, WY 82605 | Oil & Gas Operator | Feb 2026 |
| 261 | Northern Production Co | Gillette, WY 82717 | Oil & Gas Operator | Apr 2013 |
| 262 | Northern Pump Company | Denver, CO 80202-3130 | Oil & Gas Operator | Feb 2006 |
| 263 | Northstar Operating Company Of Texas | Midland, TX 79702 | Oil & Gas Operator | Feb 2008 |
| 264 | Norton Frickey | Lakewood, CO 80215 | Oil & Gas Operator | Dec 2023 |
| 265 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 266 | Oedekoven Water & Hot Oil | Recluse, WY 82725 | Oil & Gas Operator | Feb 2026 |
| 267 | Oilfield Salvage & Service Company | Littleton, CO 80120 | Oil & Gas Operator | Jan 2026 |
| 268 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 269 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 270 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 271 | Oxtex Inc | | Oil & Gas Operator | Oct 1989 |
| 272 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2026 |
| 273 | P & M Petroleum Management LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2021 |
| 274 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | May 2026 |
| 275 | Pacific Enterprises Oil Co USA | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 276 | Pancanadian Petroleum Company | | Oil & Gas Operator | Oct 1989 |
| 277 | Panther Energy Company III LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jul 2020 |
| 278 | Paoli Investors LTD | | Oil & Gas Operator | Aug 1985 |
| 279 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 280 | Pathfinder Energy Inc | Casper, WY 82605 | Oil & Gas Operator | May 2024 |
| 281 | Peak Powder River Resources LLC | Durango, CO 81301 | Oil & Gas Operator | Feb 2026 |
| 282 | Penneco Exploration Company Of Wyo LLC | Delmont, PA 15626 | Oil Operator | Aug 2021 |
| 283 | Petcon Associates LTD | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 284 | Peterson Energy Operating Inc | Loveland, CO 80537 | Oil & Gas Operator | Feb 2026 |
| 285 | Petra Petroleum Inc | Littleton, CO 80160-0319 | Oil & Gas Operator | Jun 2005 |
| 286 | Petro-Canada Resources (USA) Inc | Denver, CO 80202-472 | Oil & Gas Operator | Feb 2010 |
| 287 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 288 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 289 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 290 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 291 | Pioneer Natural Resources USA Inc | Irving, TX 75039 | Oil & Gas Operator | Dec 2025 |
| 292 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 293 | Polfam Exploration Co | Denver, CO 80204 | Oil & Gas Operator | Mar 2007 |
| 294 | Prima Exploration, Inc. | Denver, CO 80206 | Oil & Gas Operator | Feb 2026 |
| 295 | Prospective Invest & Trad Co LTD | Tulsa, OK 74170 | Oil & Gas Operator | Aug 2005 |
| 296 | Proven Petroleum, Inc. | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2026 |
| 297 | Provident Resources LTD | | Oil & Gas Operator | Dec 1986 |
| 298 | Pure Petroleum LLC | Gillette, WY 82717 | Oil & Gas Operator | Aug 2011 |
| 299 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Jan 2026 |
| 300 | Quinoco Petroleum Inc | | Oil & Gas Operator | Dec 1990 |