| 301 | Llog Exploration Company, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 302 | Llog Production Company | Metairie, LA 70005 | Oil & Gas Operator | Nov 2025 |
| 303 | Logan Oil, LLC | | Oil & Gas Operator | May 2010 |
| 304 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 305 | LPB Oil Co. | | Oil & Gas Operator | Apr 1991 |
| 306 | Lyle Cashion Co. | | Oil & Gas Operator | Sep 1989 |
| 307 | Lynx Operating Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2026 |
| 308 | Mammoth Service Group, LLC | | Oil & Gas Operator | Nov 2025 |
| 309 | Manchester Oil Co | | Oil Operator | Jan 2000 |
| 310 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Jan 2026 |
| 311 | Marion Corporation | | Oil & Gas Operator | Jan 2001 |
| 312 | Marlin Exploration, LLC | | Oil & Gas Operator | Nov 2025 |
| 313 | Marshall Production Co Inc | | Oil & Gas Operator | Jun 1989 |
| 314 | Marshall Young Oil Co | | Oil & Gas Operator | Jan 2007 |
| 315 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 316 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 317 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | Mar 2026 |
| 318 | Meason Oper. Co. For Cinco Energy Corp. | | Oil & Gas Operator | Sep 2000 |
| 319 | Meason Operating Company | Natchez, MS 39121 | Oil & Gas Operator | Dec 2011 |
| 320 | Meng Oper & Expl Co | | Oil & Gas Operator | Dec 1989 |
| 321 | Merit Field LLC | | Oil & Gas Operator | Dec 2001 |
| 322 | Meyer, Ruskin H. Et Al | | Oil Operator | Oct 1980 |
| 323 | Midco Energy, Inc. | | Oil & Gas Operator | Dec 1992 |
| 324 | Midroc Oil Company Et Al | | Oil Operator | Nov 1984 |
| 325 | Midroc Operating Company | | Oil & Gas Operator | Apr 2013 |
| 326 | Midstate Energy Inc | | Oil & Gas Operator | Aug 2017 |
| 327 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 328 | Miss Basin Oil & Gas Company | | Oil Operator | Jan 1985 |
| 329 | Miss-Lou Oil Producers Inc | | Oil & Gas Operator | Dec 1998 |
| 330 | Miss-Lou Operating LLC | | Oil & Gas Operator | Dec 2025 |
| 331 | Missala Inc | | Oil & Gas Operator | Dec 1995 |
| 332 | Mississippi Valley Gas Co | | Oil & Gas Operator | Aug 1984 |
| 333 | Mitchell And R. E. Mitchel | | Oil Operator | Feb 2000 |
| 334 | Mitchell Resources, Inc. | Addison, TX 75001 | Oil & Gas Operator | Aug 2003 |
| 335 | Mize Energy Producers, LLC | | Oil & Gas Operator | Oct 2025 |
| 336 | Mize Operations, LLC. | | Oil & Gas Operator | Dec 2018 |
| 337 | Mobil Oil Expl & Prod S E | | Oil & Gas Operator | Dec 1979 |
| 338 | Moon-Hines-Tigrett Operating Co., Inc. | | Oil & Gas Operator | Dec 2025 |
| 339 | Morris Operating Co | Lovington, NM 88260 | Oil & Gas Operator | Mar 2026 |
| 340 | Morrow Oil & Gas Co. | Terry, MS 39170 | Oil & Gas Operator | Dec 2025 |
| 341 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2026 |
| 342 | MS United, LLC | | Oil & Gas Operator | Sep 2025 |
| 343 | MT. Crescent Operating Company, LLC | | Oil & Gas Operator | Dec 2025 |
| 344 | Mullen Exploration Inc | | Oil & Gas Operator | Dec 2002 |
| 345 | Mullen-Hathorn-Bass | | Oil & Gas Operator | Mar 1985 |
| 346 | Murphy Oil USA, Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 347 | Natchez Operating, LLC | | Oil & Gas Operator | Nov 2023 |
| 348 | Natchez Pipe & Equip. Co. Inc | | Oil Operator | Nov 1981 |
| 349 | Nevanen Energy, Inc. | | Oil & Gas Operator | Dec 2022 |
| 350 | New & Brasher | | Oil Operator | Mar 1982 |
| 351 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2026 |
| 352 | New York Petroleum Corp. | | Oil & Gas Operator | Nov 1982 |
| 353 | Northland Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2003 |
| 354 | Norton Oil Co. | | Oil & Gas Operator | Jun 1984 |
| 355 | O'Brien Resources LLC | Shreveport, LA 71136 | Oil Operator | Nov 2017 |
| 356 | O'Malley Production Co Inc. | | Oil & Gas Operator | Mar 1988 |
| 357 | Odom, Claude | | Oil Operator | Jul 1983 |
| 358 | Odyssey Petroleum Corp. | | Oil & Gas Operator | Jun 2011 |
| 359 | Ogden Oil Co., Inc. | | Oil Operator | May 1981 |
| 360 | Oglesby Oil Company | | Oil & Gas Operator | Nov 2023 |
| 361 | Oglesby Prod & Expl Co Inc | | Oil & Gas Operator | Nov 1987 |
| 362 | Oilfield Services And Supply Co. Inc. | | Oil Operator | Sep 1989 |
| 363 | Oilwell Acquisition Co | | Oil & Gas Operator | Jun 1999 |
| 364 | Orion Energy Partners LP | Denver, CO 80202 | Oil & Gas Operator | Nov 2010 |
| 365 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 366 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Jan 2026 |
| 367 | Owco Production Co., Inc. | | Oil Operator | Aug 1997 |
| 368 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 369 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2026 |
| 370 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2026 |
| 371 | P.R.P., Inc. | | Oil & Gas Operator | Nov 2025 |
| 372 | Pacesetter Energy, Inc. | Flower Mound, TX 75028 | Oil & Gas Operator | May 2008 |
| 373 | Palmer Petroleum, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jun 2025 |
| 374 | Paloma Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 375 | Par Minerals Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Mar 2026 |
| 376 | Par-Co Drilling Inc. | | Oil Operator | Dec 2023 |
| 377 | Paradigm Energy-Mississippi, LLC | | Oil Operator | Nov 2025 |
| 378 | Parish Operating, LLC | Covington, LA 70433 | Oil & Gas Operator | Jan 2026 |
| 379 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 380 | Peak Energy Co Inc | | Oil & Gas Operator | Mar 1985 |
| 381 | Penn VIrginia Oil & Gas Corp | Houston, TX 77024 | Oil & Gas Operator | Dec 2023 |
| 382 | Pennzoil Expl & Prod Co -TX | | Oil & Gas Operator | May 1993 |
| 383 | Pennzoil Expl & Prod Co. -MS | | Oil Operator | Jan 1988 |
| 384 | Pennzoil Producing Company | | Oil & Gas Operator | Oct 1992 |
| 385 | Petra, Inc. | | Oil & Gas Operator | Apr 1987 |
| 386 | Petro Harvester Operating Company, LLC | | Oil & Gas Operator | Nov 2022 |
| 387 | Petro Producers Corporation | | Oil & Gas Operator | Mar 1993 |
| 388 | Petro-Can, Inc. | | Oil & Gas Operator | Apr 1998 |
| 389 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 390 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 391 | Petroleum Corp Of Delaware The | | Oil & Gas Operator | May 1991 |
| 392 | Petroleum Development LLC | | Oil Operator | Jul 2018 |
| 393 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Mar 2026 |
| 394 | Petrotx Operating, LLC | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2026 |
| 395 | PF Operating Company | Wichita Falls, TX 76302 | Oil & Gas Operator | Aug 2003 |
| 396 | Phoenix Operating, Inc | | Oil & Gas Operator | Dec 2025 |
| 397 | Phoenix Petroleum Corp. | | Gas Operator | Aug 1985 |
| 398 | Pine Ridge Operating, L.P. | Waelder, TX 78959 | Oil & Gas Operator | Mar 2026 |
| 399 | Pistol Ridge Partners, LLC | | Oil & Gas Operator | Nov 2025 |
| 400 | Pita Oil & Gas, LLC | | Oil Operator | Jul 2004 |