| 301 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 302 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 303 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 304 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | Mar 2025 |
| 305 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 306 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 307 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 308 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Jan 2025 |
| 309 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 310 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | Mar 2025 |
| 311 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 312 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 313 | Mid Texas Natural Gas | Kyle, TX 78640 | Oil & Gas Operator | May 2019 |
| 314 | Middleton Oil Company | Houston, TX 77006 | Oil & Gas Operator | Mar 2025 |
| 315 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 316 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 317 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 318 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | Mar 2025 |
| 319 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 320 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 321 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 322 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 323 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 324 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Mar 2025 |
| 325 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 326 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 327 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Mar 2025 |
| 328 | Monitor O&G, L.L.C. | Frisco, TX 75034 | Oil & Gas Operator | Jan 2016 |
| 329 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | Mar 2025 |
| 330 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 331 | Mowata Oil Company | Victoria, TX 77903 | Oil & Gas Operator | Oct 1996 |
| 332 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 333 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 334 | Nasser Oil & Gas, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Apr 1998 |
| 335 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | Mar 2025 |
| 336 | Neff, Mickey Oil Company | Colorado City, TX 79512 | Oil & Gas Operator | Jul 2023 |
| 337 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 338 | Neuhaus, V. F. Properties, Inc. | Palmhurst, TX 78573 | Oil & Gas Operator | Dec 2022 |
| 339 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | Mar 2025 |
| 340 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | Mar 2025 |
| 341 | New Source Oil & Gas, LLC | Victoria, TX 77903 | Oil & Gas Operator | Mar 2025 |
| 342 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 343 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 344 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Mar 2025 |
| 345 | Nueces Reserves, Inc. | Houston, TX 77019 | Oil & Gas Operator | Oct 2002 |
| 346 | Nye Exploration & Prod, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 347 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 348 | Oblaen Resources LLC | Wallis, TX 77485 | Oil & Gas Operator | Mar 2025 |
| 349 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 350 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 351 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | Mar 2025 |
| 352 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Mar 2025 |
| 353 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 354 | Oxenergy Incorporated | Flower Mound, TX 75022 | Oil & Gas Operator | Mar 2025 |
| 355 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 356 | Oxy USA WTP LP | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 357 | Padon, Frank B. Oil Oper., Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1998 |
| 358 | Palmer Petroleum Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Mar 2025 |
| 359 | Panhandle Oil & Gas Inc | Oklahoma City, OK 73112-5688 | Oil & Gas Operator | May 2007 |
| 360 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 361 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 362 | Patterson Energy Corporation | Dallas, TX 75205 | Oil & Gas Operator | Mar 2025 |
| 363 | Pegasus Operating, Inc. | Coldspring, TX 77331 | Oil & Gas Operator | Mar 2025 |
| 364 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 365 | Perlman,I.H.Oil & Gas Properties | Houston, TX 77056 | Oil & Gas Operator | Mar 2008 |
| 366 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 367 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Nov 2024 |
| 368 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 369 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 370 | Petromac, Inc. | Onalaska, TX 77360 | Oil & Gas Operator | Mar 2025 |
| 371 | Petronomics, Inc. | Houston, TX 77074 | Oil & Gas Operator | Aug 2003 |
| 372 | Petropro Energy Partners, L.P. | Houston, TX 77024 | Oil & Gas Operator | Jan 2013 |
| 373 | Petrosearch Operating Co, LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 374 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 375 | Phoenix Hydrocarbons Operating | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 376 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | Mar 2025 |
| 377 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 378 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 379 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 380 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 381 | Powell-McCarroll Partnership | Sachse, TX 75048 | Oil & Gas Operator | Mar 2025 |
| 382 | Poynor Corporation | Beaumont, TX 77706 | Oil & Gas Operator | Mar 2025 |
| 383 | Premier Natural Resources II,LLC | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2015 |
| 384 | Premier Natural Resources, L.P. | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2007 |
| 385 | Premier Natural Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2025 |
| 386 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 387 | Prime Time Oil & Gas Co., LTD. | Ruidoso, NM 88345 | Oil & Gas Operator | Mar 2003 |
| 388 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 389 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Mar 2025 |
| 390 | Property Producing Co. | Columbus, TX 78934 | Gas Operator | Mar 2025 |
| 391 | Pyramid Exploration | Houston, TX 77241 | Oil & Gas Operator | Sep 1995 |
| 392 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 393 | Ram Operating Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Sep 2012 |
| 394 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | Mar 2025 |
| 395 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 396 | Ranger Oil Company | Canada, 00100 | Oil & Gas Operator | Sep 2001 |
| 397 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 398 | Reb Petroleum Company | Sugar Land, TX 77478 | Oil & Gas Operator | Mar 2025 |
| 399 | Remora Management, LLC | The Woodlands, TX 77382 | Oil & Gas Operator | Mar 2025 |
| 400 | Renaissance Petroleum Co LLC | Houston, TX 77058 | Oil & Gas Operator | Nov 2011 |