| 301 | Kstone Energy, LLC | Oklahoma City, OK 73106 | Oil Operator | Aug 2025 |
| 302 | La VIda Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 1993 |
| 303 | Ladd LLC | El Reno, OK 73036 | Oil & Gas Operator | Nov 2018 |
| 304 | Laguna Petroleum Corporation | Houston, TX 77046 | Oil & Gas Operator | Aug 2025 |
| 305 | Lawrence, C. F. & Assoc. Inc. | Lubbock, TX 79401 | Oil & Gas Operator | Aug 2025 |
| 306 | LCX Energy, LLC | Midland, TX 79701 | Oil & Gas Operator | Jan 2010 |
| 307 | Leede Oil & Gas Inc. | Greenwood VLG, CO 80111 | Oil & Gas Operator | Aug 2003 |
| 308 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Aug 2025 |
| 309 | Limark Corporation | Midland, TX 79702 | Oil & Gas Operator | Dec 2003 |
| 310 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 311 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 312 | Lion Production, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2006 |
| 313 | Llano Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2025 |
| 314 | Lomak Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1998 |
| 315 | Long Trusts, The | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2025 |
| 316 | Lorac, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Aug 2025 |
| 317 | LZB Energy, LLC | Austin, TX 78737 | Gas Operator | Jul 2020 |
| 318 | M-T Petroleum, Inc. | Andrews, TX 79714 | Oil & Gas Operator | Mar 2008 |
| 319 | M2 Squared Operating, LLC | Rockwall, TX 75032 | Oil Operator | Aug 2025 |
| 320 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 2025 |
| 321 | Manning, Jack | Odessa, TX 79760 | Oil & Gas Operator | Dec 2003 |
| 322 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Jun 2025 |
| 323 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 324 | Mariner Energy, Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 325 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | May 2025 |
| 326 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jun 2025 |
| 327 | Marshfield Oil & Gas, LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2025 |
| 328 | Martin, Jimmy Inc | San Angelo, TX 76904 | Oil & Gas Operator | Aug 2025 |
| 329 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | Aug 2025 |
| 330 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 331 | Maxwell Resources Corporation | Oklahoma City, OK 73116-7746 | Oil & Gas Operator | Apr 2009 |
| 332 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 333 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 334 | McCammon Oil & Gas, Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Aug 2025 |
| 335 | McCann Corporation | Midland, TX 79710 | Oil & Gas Operator | Aug 2025 |
| 336 | McClure Oil Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2025 |
| 337 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Jun 2025 |
| 338 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 339 | McDaniel Oil Co. | Marble Falls, TX 78654 | Oil & Gas Operator | Aug 2025 |
| 340 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 341 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 342 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 343 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 344 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Aug 2025 |
| 345 | Meritage Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | May 2013 |
| 346 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Aug 2025 |
| 347 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 348 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 349 | MHM Pipeline Co., Inc. | Dallas, TX 75252 | Oil & Gas Operator | Aug 2025 |
| 350 | Mid-Continent Energy, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2020 |
| 351 | Mid-States Operating Company | Midland, TX 79702 | Oil & Gas Operator | Aug 2025 |
| 352 | Midenergy Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | Aug 2025 |
| 353 | Midkiff, John | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 354 | Midland Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 2025 |
| 355 | Midland Oil And Gas, Inc. | Midland, TX 79705 | Oil & Gas Operator | Aug 2025 |
| 356 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 357 | Miltex Oil Company | Boerne, TX 78006 | Oil & Gas Operator | Aug 2025 |
| 358 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 359 | Mito Resources TX LLC | Edmond, OK 73013 | Oil & Gas Operator | Aug 2025 |
| 360 | MLC Co., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Dec 1996 |
| 361 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 362 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Aug 2025 |
| 363 | Mogul Resources, LLC | Cisco, TX 76437 | Oil & Gas Operator | Aug 2025 |
| 364 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Aug 2025 |
| 365 | Momentum Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2004 |
| 366 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | Aug 2025 |
| 367 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 368 | Mosaic Midland LLC | Dallas, TX 75367 | Oil Operator | Aug 2025 |
| 369 | Mulloy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2025 |
| 370 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |
| 371 | Nadel And Gussman Permian,L.L.C. | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 372 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 373 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | Aug 2025 |
| 374 | Nec Operating, LLC | Southlake, TX 76092 | Oil & Gas Operator | Aug 2025 |
| 375 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 376 | North Central Casing Pullers,Inc | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 377 | O & O Operators, LLC. | Fate, TX 75132 | Oil & Gas Operator | Aug 2025 |
| 378 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2025 |
| 379 | Oasis Petroleum Permian LLC | Houston, TX 77002 | Oil & Gas Operator | Aug 2025 |
| 380 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 381 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Aug 2025 |
| 382 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 383 | Octane Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2025 |
| 384 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 2025 |
| 385 | Oga Operating L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jan 2000 |
| 386 | Ogx Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Aug 2025 |
| 387 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 388 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 389 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | Aug 2025 |
| 390 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | May 2025 |
| 391 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 392 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 393 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Aug 2025 |
| 394 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 395 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Aug 2025 |
| 396 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 397 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 398 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Jun 2025 |
| 399 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 400 | Owens Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |