| 301 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 302 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 303 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 304 | Marino, Charles B. | Tomball, TX 77377 | Oil & Gas Operator | Dec 2025 |
| 305 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Sep 2025 |
| 306 | Maroon Energy LLC | Spring, TX 77379 | Oil & Gas Operator | Feb 2025 |
| 307 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 308 | Marshall Petroleum, Inc. | Houston, TX 77040 | Oil & Gas Operator | Aug 2003 |
| 309 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Dec 2025 |
| 310 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | Dec 2025 |
| 311 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Oct 2025 |
| 312 | Mayfield Energy, LLC | Austin, TX 78732 | Oil & Gas Operator | Dec 2025 |
| 313 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 314 | MBX Operating LLC | Houston, TX 77007 | Oil & Gas Operator | Dec 2025 |
| 315 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 316 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Dec 2025 |
| 317 | McLelland Engineering & MGMT. | Houston, TX 77042 | Oil & Gas Operator | Mar 1999 |
| 318 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 319 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 320 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 321 | Merlon Texas, Inc. | Houston, TX 77056 | Oil Operator | Jun 2013 |
| 322 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Oct 2025 |
| 323 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 324 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 325 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 326 | Middleton Oil Company | Houston, TX 77006 | Oil & Gas Operator | Dec 2025 |
| 327 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 328 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 329 | Minexprod LLC | Katy, TX 77494 | Oil Operator | Dec 2025 |
| 330 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 331 | MJ Oil, Inc. | Houston, TX 77265 | Oil & Gas Operator | Dec 2025 |
| 332 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 333 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 334 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | Dec 2025 |
| 335 | Moses, Tom | Beaumont, TX 77702 | Oil Operator | Dec 2025 |
| 336 | Muroz International Group Inc | Houston, TX 77056 | Oil Operator | Dec 2025 |
| 337 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 338 | Murphy Oil USA, Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 339 | Nance Engineering Inc. | Houston, TX 77058 | Oil & Gas Operator | Mar 2002 |
| 340 | Neches Transport Inc. | Spurger, TX 77660 | Oil & Gas Operator | Dec 2025 |
| 341 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | Dec 2025 |
| 342 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 343 | Newbridge Resources, LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 344 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 345 | Newman, John A. | Joplin, MO 64804 | Oil & Gas Operator | Jan 2001 |
| 346 | Newturn Oil Company | Houston, TX 77208 | Oil & Gas Operator | Jan 2004 |
| 347 | Nitschke, Dan E. | Henrietta, TX 76365 | Oil & Gas Operator | Dec 2025 |
| 348 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 349 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 350 | Noxxe Oil And Gas, LLC | Houston, TX 77269 | Oil & Gas Operator | Dec 2025 |
| 351 | Nueces Petroleum Corporation | Sugar Land, TX 77496 | Oil Operator | Dec 2025 |
| 352 | Nuevo Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2002 |
| 353 | O'Connor & Hewitt, LTD. | Victoria, TX 77901 | Oil & Gas Operator | Jun 1998 |
| 354 | Odum Oil & Gas Co. | Harper, TX 78631 | Oil & Gas Operator | Dec 2025 |
| 355 | Oil Well Buyers Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 356 | Oily Dog Operators Texas, LLC | Allen, TX 75002 | Oil Operator | Dec 2025 |
| 357 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 358 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Dec 2025 |
| 359 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 360 | Oro Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 361 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 362 | Osyka Producing Company, Inc. | Houston, TX 77242 | Oil & Gas Operator | Dec 2025 |
| 363 | Otex LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Dec 2025 |
| 364 | Otex Resources LLC | Baytown, TX 77520 | Oil & Gas Operator | Dec 2025 |
| 365 | P & WG Resources L.L.C. | Batson, TX 77519 | Oil & Gas Operator | Jan 2011 |
| 366 | Padon, Frank B. Oil Oper., Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1998 |
| 367 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 368 | Parallel Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Jan 2010 |
| 369 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 370 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 371 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 372 | Partners Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Aug 1995 |
| 373 | Patriot Operating Company, Inc. | Houston, TX 77008 | Oil & Gas Operator | Sep 2003 |
| 374 | Patterson Petroleum LLC | Snyder, TX 79550 | Oil & Gas Operator | Oct 2007 |
| 375 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 376 | Peak Operating Of Texas, LLC | Denver, CO 80202 | Oil & Gas Operator | May 2005 |
| 377 | Penn VIrginia Oil & Gas Corp | Houston, TX 77024 | Oil & Gas Operator | Dec 2023 |
| 378 | Penn VIrginia Oil & Gas, L.P. | Houston, TX 77084 | Oil & Gas Operator | Nov 2022 |
| 379 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 380 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 381 | Pennzoil Petroleum Company | Houston, TX 77252 | Oil & Gas Operator | Nov 1999 |
| 382 | Permian Pacific Resources, Inc. | Dallas, TX 75230 | Oil & Gas Operator | Aug 2003 |
| 383 | Petro-Chem Operating Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2025 |
| 384 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2025 |
| 385 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Jun 2025 |
| 386 | Petronomics, Inc. | Houston, TX 77074 | Oil & Gas Operator | Aug 2003 |
| 387 | Petrotex Engineering Company | Cypress, TX 77429 | Oil & Gas Operator | Dec 2025 |
| 388 | Petrovybe Opco LLC | Plano, TX 75093 | Oil & Gas Operator | Dec 2025 |
| 389 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 390 | Phoenix Hydrocarbons Operating | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 391 | Pierce Junction Petroleum Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2010 |
| 392 | Pioneer Natural Res. (GPC), Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 1998 |
| 393 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 394 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 395 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 396 | PNG Operating Company | Oklahoma City, OK 73172 | Oil & Gas Operator | Dec 2025 |
| 397 | Poco Oil Co. | Houston, TX 77069 | Oil & Gas Operator | Mar 1997 |
| 398 | Poynor Corporation | Beaumont, TX 77706 | Oil & Gas Operator | Dec 2025 |
| 399 | Preferred Pipeline Corp. | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 400 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |