| 301 | M A S Operators | Kilgore, TX 75663 | Oil & Gas Operator | Jul 1999 |
| 302 | M-C Production & Drilling Co,Inc | Longview, TX 75608 | Oil & Gas Operator | Mar 2025 |
| 303 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 304 | Magnolia Production Co | Atlanta, TX 75551 | Oil & Gas Operator | Mar 2025 |
| 305 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 306 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 307 | Mass Energy, Inc | Houston, TX 77056 | Oil & Gas Operator | Mar 2008 |
| 308 | Maxima Energy Corp. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2012 |
| 309 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 310 | McBee Operating Company, L.L.C. | Dallas, TX 75209 | Oil & Gas Operator | Mar 2025 |
| 311 | McBrayer Oil Corporation | Rockport, TX 78381 | Oil & Gas Operator | Nov 1994 |
| 312 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 313 | McCutchin, Gene | Dallas, TX 75380 | Oil & Gas Operator | Aug 2003 |
| 314 | McCutchin, Jerry | Dallas, TX 75380 | Oil & Gas Operator | Mar 2008 |
| 315 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 316 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 317 | Meadows Oil Company | Plano, TX 75075 | Oil & Gas Operator | Aug 2004 |
| 318 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 319 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 320 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Jan 2025 |
| 321 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 322 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 323 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 324 | Miken Oil, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 325 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 326 | Miller, R. A. Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2003 |
| 327 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 328 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 329 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2025 |
| 330 | Montex Drilling Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 331 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 332 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 333 | Moss Petroleum Company | Dallas, TX 75207 | Oil & Gas Operator | Mar 2025 |
| 334 | Muirfield Resources Company | Tulsa, OK 74101-3166 | Oil & Gas Operator | Jun 2024 |
| 335 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2024 |
| 336 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 337 | Murphy Exploration & Production | Houston, TX 77024 | Oil Operator | Oct 2024 |
| 338 | Murphy Oil USA Inc | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 339 | Mustang Drilling, Inc. | Henderson, TX 75653 | Oil & Gas Operator | Aug 2024 |
| 340 | Mustang Drilling, LTD. | Henderson, TX 75653 | Oil & Gas Operator | May 2008 |
| 341 | Mustang Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2006 |
| 342 | Nadel And Gussman | Tulsa, OK 74103 | Oil & Gas Operator | May 2007 |
| 343 | Nadel And Gussman, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2025 |
| 344 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 345 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 346 | Neches Exploration, L.L.C. | Flint, TX 75762 | Oil & Gas Operator | Mar 2025 |
| 347 | Neches Oil & Gas Company, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 348 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 349 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | Mar 2025 |
| 350 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 351 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | Mar 2025 |
| 352 | NFR Energy, LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2017 |
| 353 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 354 | Nolte, Mike E. | Longview, TX 75606 | Oil & Gas Operator | Jun 1995 |
| 355 | Nolte, Mike E., Inc. | Longview, TX 75606 | Oil & Gas Operator | Feb 2006 |
| 356 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Mar 2025 |
| 357 | North American Drilling Corp | Plano, TX 75093 | Oil & Gas Operator | Mar 2025 |
| 358 | North American Resources Company | Billings, MT 59101 | Oil & Gas Operator | Dec 2019 |
| 359 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Mar 2025 |
| 360 | North Star Energy, Inc. | Strawn, TX 76475 | Oil & Gas Operator | Jan 2010 |
| 361 | Now Development Co., Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2017 |
| 362 | Nuevo Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2002 |
| 363 | O.T. Oil | Kilgore, TX 75663 | Oil Operator | Mar 2025 |
| 364 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 365 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 366 | Oily Dog Operators Texas, LLC | Austin, TX 78746 | Oil Operator | Mar 2025 |
| 367 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 368 | Optimum Exploration LLC | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 369 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 370 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 371 | Palmer Petroleum Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Mar 2025 |
| 372 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 373 | Pardee Production Co. | Skiatook, OK 74070 | Oil & Gas Operator | Mar 2021 |
| 374 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 375 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 376 | Patrick Production Company | Houston, TX 77266 | Oil & Gas Operator | Mar 2025 |
| 377 | Patton Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Nov 1997 |
| 378 | Payne-Johnston | Tyler, TX 75702 | Oil & Gas Operator | Nov 1996 |
| 379 | Peak Energy Corporation | Plano, TX 75093 | Oil & Gas Operator | Oct 2018 |
| 380 | Pedernales Petroleum Op, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 381 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 382 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 383 | Penroc Oil Corp. | Hobbs, NM 88241 | Oil & Gas Operator | Dec 2024 |
| 384 | Petralis Energy Resources, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 385 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2025 |
| 386 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Mar 2025 |
| 387 | Petromining, Inc. | Plano, TX 75026 | Oil & Gas Operator | Mar 2025 |
| 388 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 389 | Phillips Energy, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2018 |
| 390 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 391 | Phillips, B. F. Jr., Estate Of | Dallas, TX 75201 | Oil & Gas Operator | Mar 2011 |
| 392 | Phillips, Jack L. | Gladewater, TX 75647 | Oil & Gas Operator | Dec 1997 |
| 393 | Phillips, Jack L. Co. | Gladewater, TX 75647 | Oil & Gas Operator | Mar 2025 |
| 394 | Pickens Company, Inc., The | Dallas, TX 75225 | Oil & Gas Operator | Jul 2024 |
| 395 | Pine Creek Operating LLC | Colorado SPGS, CO 80903 | Oil & Gas Operator | Jul 2021 |
| 396 | Plains Marketing, LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 397 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 398 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 399 | Powell, Gene Investments, Inc. | Longview, TX 75608 | Oil & Gas Operator | Apr 2024 |
| 400 | Powell, N. P. Estate | Tyler, TX 75702 | Oil & Gas Operator | Aug 1997 |