| 301 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2026 |
| 302 | Keystone Energy Oil & Gas Inc | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2016 |
| 303 | Kinder Morgan Production Co LLC | Midland, TX 79705 | Oil & Gas Operator | May 2026 |
| 304 | Kneupper Oil, LLC | MC Camey, TX 79752 | Oil & Gas Operator | May 2026 |
| 305 | Kodiak Oil & Gas Inc | Muenster, TX 76252 | Oil & Gas Operator | May 2026 |
| 306 | Kokomo Oil Company | Houston, TX 77227 | Oil & Gas Operator | Apr 1998 |
| 307 | KRF Production Company LLC | Houston, TX 77269 | Oil & Gas Operator | May 2026 |
| 308 | Kstone Energy, LLC | Oklahoma City, OK 73106 | Oil Operator | May 2026 |
| 309 | La VIda Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 1993 |
| 310 | Laguna Petroleum Corporation | Houston, TX 77046 | Oil & Gas Operator | May 2026 |
| 311 | Lawrence, C. F. & Assoc. Inc. | Lubbock, TX 79401 | Oil & Gas Operator | May 2026 |
| 312 | Lawson Petroleum Co. | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2009 |
| 313 | LCX Energy, LLC | Midland, TX 79701 | Oil & Gas Operator | Jan 2010 |
| 314 | Leede Oil & Gas Inc. | Greenwood VLG, CO 80111 | Oil & Gas Operator | Aug 2003 |
| 315 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | May 2026 |
| 316 | Limark Corporation | Midland, TX 79702 | Oil & Gas Operator | Dec 2003 |
| 317 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Jun 2025 |
| 318 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 319 | Lion Production, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2006 |
| 320 | Llano Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 2026 |
| 321 | Lomak Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1998 |
| 322 | Long Trusts, The | Kilgore, TX 75663 | Oil & Gas Operator | May 2026 |
| 323 | Lorac, Inc. | Dallas, TX 75252 | Oil & Gas Operator | May 2026 |
| 324 | LZB Energy, LLC | Austin, TX 78737 | Gas Operator | Jul 2020 |
| 325 | M-T Petroleum, Inc. | Andrews, TX 79714 | Oil & Gas Operator | Mar 2008 |
| 326 | M2 Squared Operating, LLC | Rockwall, TX 75032 | Oil Operator | May 2026 |
| 327 | Magnum Producing, LP | Corpus Christ, TX 78401 | Oil & Gas Operator | May 2026 |
| 328 | Manning, Jack | Odessa, TX 79760 | Oil & Gas Operator | Dec 2003 |
| 329 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2026 |
| 330 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 331 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 332 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Jan 2026 |
| 333 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2026 |
| 334 | Marshfield Oil & Gas, LLC | Houston, TX 77070 | Oil & Gas Operator | May 2026 |
| 335 | Martin, Jimmy Inc | San Angelo, TX 76904 | Oil & Gas Operator | May 2026 |
| 336 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | May 2026 |
| 337 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 338 | Maxwell Resources Corporation | Oklahoma City, OK 73159 | Oil & Gas Operator | Apr 2009 |
| 339 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 340 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 341 | McCammon Oil & Gas, Inc. | San Angelo, TX 76902 | Oil & Gas Operator | May 2026 |
| 342 | McCann Corporation | Midland, TX 79710 | Oil & Gas Operator | May 2026 |
| 343 | McClure Oil Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 344 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Feb 2026 |
| 345 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 346 | McDaniel Oil Co. | Marble Falls, TX 78654 | Oil & Gas Operator | May 2026 |
| 347 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 348 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 349 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 350 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 351 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2026 |
| 352 | Meritage Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | May 2013 |
| 353 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | May 2026 |
| 354 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 355 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 356 | MHM Pipeline Co., Inc. | Dallas, TX 75252 | Oil & Gas Operator | May 2026 |
| 357 | Mid-Continent Energy, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2020 |
| 358 | Mid-States Operating Company | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 359 | Midenergy Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | May 2026 |
| 360 | Midkiff, John | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 361 | Midland Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 362 | Midland Oil And Gas, Inc. | Midland, TX 79705 | Oil & Gas Operator | May 2026 |
| 363 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 364 | Midway Energy Partners Operating LLC | Midland, TX 79701 | Oil Operator | May 2026 |
| 365 | Miltex Oil Company | Boerne, TX 78006 | Oil & Gas Operator | May 2026 |
| 366 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 367 | Mito Resources TX LLC | Edmond, OK 73013 | Oil & Gas Operator | May 2026 |
| 368 | MLC Co., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Dec 1996 |
| 369 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 370 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 371 | Mogul Resources, LLC | Cisco, TX 76437 | Oil & Gas Operator | May 2026 |
| 372 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | May 2026 |
| 373 | Momentum Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2004 |
| 374 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2026 |
| 375 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 376 | Mosaic Midland LLC | Dallas, TX 75367 | Oil Operator | May 2026 |
| 377 | Mulloy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 378 | Murex Petroleum Corporation | Humble, TX 77347 | Oil & Gas Operator | Mar 2026 |
| 379 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |
| 380 | Nadel And Gussman Permian,L.L.C. | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 381 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 382 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | May 2026 |
| 383 | Nec Operating, LLC | Southlake, TX 76092 | Oil & Gas Operator | May 2026 |
| 384 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 385 | North Central Casing Pullers,Inc | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 386 | O & O Operators, LLC. | Fate, TX 75132 | Oil & Gas Operator | May 2026 |
| 387 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | May 2026 |
| 388 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 389 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | May 2026 |
| 390 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 391 | Octane Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 392 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 393 | Oga Operating L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jan 2000 |
| 394 | Ogx Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 395 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 396 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 397 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | May 2026 |
| 398 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Dec 2025 |
| 399 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 400 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |