| 301 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 302 | Maverick Brothers Operating,Inc. | Enid, OK 73702 | Oil & Gas Operator | Jul 2025 |
| 303 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 304 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 305 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Apr 2025 |
| 306 | McGuffin, Joe Jr. | Christoval, TX 76935 | Oil & Gas Operator | Jul 2025 |
| 307 | McMinn Operating Company, Inc. | Hempstead, TX 77445 | Oil & Gas Operator | Jul 2025 |
| 308 | McNic Oil & Gas Midcontinent,Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 1999 |
| 309 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 310 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 311 | Merex Resources, Inc. | Amarillo, TX 79159 | Oil & Gas Operator | Sep 2019 |
| 312 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 313 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 314 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Jul 2025 |
| 315 | MFP Petroleum LTD. Partnership | Oklahoma City, OK 73142 | Oil & Gas Operator | Nov 2017 |
| 316 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Apr 2025 |
| 317 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 318 | Midstates Petroleum Company LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 319 | Midwestern Exploration Co. | Edmond, OK 73013 | Oil & Gas Operator | Mar 2025 |
| 320 | Milam, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 321 | Mineral Development, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 1996 |
| 322 | Mitchell Ehrlich Oil & Gas, LLC | Austin, TX 78746 | Oil & Gas Operator | Jul 2025 |
| 323 | MMGL TXPH, LLC | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 324 | Mobeetie Resource Dev LLC | Perryton, TX 79070 | Oil & Gas Operator | Jul 2025 |
| 325 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 326 | Mote Resources, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Dec 2004 |
| 327 | MRR Oil Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jun 2002 |
| 328 | Munson Operating, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |
| 329 | Munson, Charles C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2002 |
| 330 | Natural Gas Anadarko Company | Perryton, TX 79070 | Oil & Gas Operator | Jul 2025 |
| 331 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 332 | Neas Operating | Pampa, TX 79065 | Oil & Gas Operator | Oct 2011 |
| 333 | Neas Operating, LLC | Wimberley, TX 78676 | Oil & Gas Operator | Jul 2025 |
| 334 | New Arch Energy, LLC | Gruver, TX 79040 | Oil & Gas Operator | Jul 2025 |
| 335 | New London Oil Inc. | Houston, TX 77253 | Oil & Gas Operator | Aug 2002 |
| 336 | Newfield Expl. Mid-Con. Inc | Tulsa, OK 74172 | Oil & Gas Operator | Jan 2015 |
| 337 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |
| 338 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2025 |
| 339 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Jul 2025 |
| 340 | Norcen Explorer, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 1998 |
| 341 | North Operating Company | Canton, TX 75103 | Oil & Gas Operator | Jul 2025 |
| 342 | Oasis Operating, Inc. | Lubbock, TX 79404 | Oil & Gas Operator | Nov 2020 |
| 343 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 344 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Jul 2025 |
| 345 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2025 |
| 346 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 347 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 348 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Jul 2025 |
| 349 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Jul 2025 |
| 350 | Oringderff, Alma Oil Properties | Dallas, TX 75225 | Oil & Gas Operator | Mar 2012 |
| 351 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 352 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 353 | Overflow Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Jul 2025 |
| 354 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Jul 2025 |
| 355 | P. L. O. | Boerne, TX 78006 | Oil & Gas Operator | Jun 2016 |
| 356 | Paleo, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Jul 2025 |
| 357 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 358 | Parallel Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Jan 2010 |
| 359 | Paramount Producing, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Oct 1996 |
| 360 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 361 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 362 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 363 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 364 | Patrick & Vaughn | Oklahoma City, OK 73154 | Oil & Gas Operator | Sep 2005 |
| 365 | Peak Operating Of Texas, LLC | Denver, CO 80202 | Oil & Gas Operator | May 2005 |
| 366 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Jul 2025 |
| 367 | Pearson, A. K. | Amarillo, TX 79114 | Oil & Gas Operator | Aug 2023 |
| 368 | Peckenpaugh Farms | Farnsworth, TX 79033 | Oil & Gas Operator | Jul 2025 |
| 369 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 370 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 371 | Pennzoil Petroleum Company | Houston, TX 77252 | Oil & Gas Operator | Nov 1999 |
| 372 | Perdure Petroleum LLC | Allen, TX 75013 | Oil & Gas Operator | Oct 2021 |
| 373 | Perryton Operating Co., Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jul 2025 |
| 374 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 375 | Petroleum Inc | Wichita, KS 67202 | Oil & Gas Operator | Oct 2021 |
| 376 | Petroleum Reserve Corporation | Plymouth MTNG, PA 19462 | Oil & Gas Operator | May 2008 |
| 377 | Philcon Development Co. | Amarillo, TX 79101 | Oil & Gas Operator | Sep 2014 |
| 378 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 379 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 380 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 381 | Pitchfork Investments, LLC | Amarillo, TX 79109 | Oil & Gas Operator | Jul 2025 |
| 382 | Pitco Investments, LTD. | Scottsdale, AZ 85261 | Oil & Gas Operator | Jan 2013 |
| 383 | PK Petroleum LLC | Pampa, TX 79065 | Oil & Gas Operator | Jul 2025 |
| 384 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 385 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 386 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 387 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 388 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 389 | PNG Operating Company | Oklahoma City, OK 73172 | Oil & Gas Operator | Jul 2025 |
| 390 | Pony Oil Company | Borger, TX 79008 | Oil & Gas Operator | Jul 2001 |
| 391 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Jul 2025 |
| 392 | Prairie Well Service, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Mar 1995 |
| 393 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 394 | Presidio Petroleum LLC | Canadian, TX 79014 | Oil & Gas Operator | Jul 2025 |
| 395 | Princess Three Corporation | Henderson, TX 75653 | Oil & Gas Operator | Apr 2020 |
| 396 | Princess Three Operating, LLC | Henderson, TX 75653 | Oil & Gas Operator | Jul 2025 |
| 397 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 398 | Prospctv Invstmnt & TRDG Co, LTD | Tulsa, OK 74170 | Oil & Gas Operator | May 2001 |
| 399 | Protege Energy LLC | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2018 |
| 400 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |