| 301 | Lancer Petroleum Corporation | Irving, TX 75014 | Oil & Gas Operator | Feb 2014 |
| 302 | Landor Oil Co. | San Marcos, TX 78666 | Oil Operator | Dec 2025 |
| 303 | Larae Operations | Luling, TX 78648 | Oil Operator | Dec 2025 |
| 304 | Latimer, D. Gail Enterprises,Inc | Snyder, TX 79550 | Oil & Gas Operator | Jul 2004 |
| 305 | Lavanco Energy, Inc. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2006 |
| 306 | Lavanco Energy, LTD. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2024 |
| 307 | Lawbar Petroleum, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Aug 2003 |
| 308 | Leede Oil & Gas Inc. | Greenwood VLG, CO 80111 | Oil & Gas Operator | Aug 2003 |
| 309 | Libom Oil Company | Elmsford, NY 10523 | Oil & Gas Operator | Aug 2003 |
| 310 | Lissner, Lindy | Jourdanton, TX 78026 | Oil & Gas Operator | Dec 2025 |
| 311 | Llewellin Operating Company, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2017 |
| 312 | LMN Oil And Gas, Inc. | Luling, TX 78648 | Oil & Gas Operator | Mar 2008 |
| 313 | Longshot Energy LLC | League City, TX 77573 | Oil Operator | Dec 2025 |
| 314 | LP Operating, LLC | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 315 | Lucas Energy, Inc. | Houston, TX 77067 | Oil & Gas Operator | Feb 2017 |
| 316 | Lucros International Corporation | Van Buren, AR 72956 | Oil & Gas Operator | Dec 2025 |
| 317 | M & C Operating, LLC | Poteet, TX 78065 | Oil Operator | Dec 2025 |
| 318 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 319 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 320 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 321 | Magnum Oilfield Services LLC | Bakersfield, CA 93309 | Oil Operator | Dec 2025 |
| 322 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 323 | Manti Operating Company | Covington, LA 70435 | Oil & Gas Operator | Dec 2025 |
| 324 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Nov 2025 |
| 325 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | Dec 2025 |
| 326 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 327 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 328 | Maverick Energy Group, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2025 |
| 329 | Mazco Energy LLC | San Antonio, TX 78266 | Oil & Gas Operator | Dec 2025 |
| 330 | McA Petroleum Corporation | Flatonia, TX 78941 | Oil & Gas Operator | Dec 2025 |
| 331 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Dec 2025 |
| 332 | McOsker Bros., Inc. | San Antonio, TX 78264 | Oil & Gas Operator | Aug 2003 |
| 333 | Mello-Dy Resources, LLC | Devine, TX 78016 | Oil Operator | Dec 2025 |
| 334 | Mercury Exploration Co. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 335 | Merzbacher, George F. Jr. | Robstown, TX 78380 | Oil & Gas Operator | May 1994 |
| 336 | Mesa Energy, Inc. | Austin, TX 78755 | Oil & Gas Operator | Dec 2013 |
| 337 | Mescalero Energy, Inc. | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 338 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 339 | Mims, William S. | Pleasanton, TX 78064 | Oil Operator | Jun 2009 |
| 340 | Mineral Resources, Incorporated | Lewisville, TX 75029 | Oil & Gas Operator | Dec 2025 |
| 341 | Miranda Energy Corporation | Midland, TX 79705 | Oil & Gas Operator | Jun 2016 |
| 342 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 343 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 344 | Mobile Production Systems, Inc. | Austin, TX 78711 | Oil & Gas Operator | Feb 1995 |
| 345 | Mojave Resources, LLC | New Braunfels, TX 78132 | Oil Operator | Dec 2025 |
| 346 | Momentum Oil & Gas, LLC | The Woodlands, TX 77382 | Oil & Gas Operator | May 2015 |
| 347 | Momentum Production Corp. | Baytown, TX 77521 | Oil & Gas Operator | Dec 2025 |
| 348 | More Texas Oil | Von Ormy, TX 78073 | Oil & Gas Operator | Dec 2025 |
| 349 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 350 | Moxy Oil Company | Seguin, TX 78155 | Oil & Gas Operator | Aug 2003 |
| 351 | MPG Petroleum | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2003 |
| 352 | MPG Petroleum, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 353 | MSSK Consulting LLC | San Antonio, TX 78253 | Oil Operator | Dec 2025 |
| 354 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Dec 2025 |
| 355 | Murphy Expl. & Prod. Co. - USA | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 356 | Murphy Exploration & Production | Houston, TX 77024 | Oil Operator | Jan 2025 |
| 357 | Ncey Holdings, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2013 |
| 358 | Nev-Tex Oil & Gas, Inc. | Reno, NV 89504 | Oil & Gas Operator | Dec 2025 |
| 359 | New Voyage Enterprises LLC | San Antonio, TX 78278 | Oil Operator | Dec 2025 |
| 360 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 361 | Nineveh Corp. | Dallas, TX 75208 | Oil & Gas Operator | Dec 2025 |
| 362 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 363 | North Star Energy, Inc. | Strawn, TX 76475 | Oil & Gas Operator | Jan 2010 |
| 364 | Northridge Oil Company | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2025 |
| 365 | Nutek Oil Inc | San Antonio, TX 78254 | Oil & Gas Operator | Feb 2006 |
| 366 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 367 | Oilex Int'L Investments, Inc. | Luling, TX 78648 | Oil & Gas Operator | Dec 2025 |
| 368 | Old Chief Oil, LLC | New Braunfels, TX 78132 | Oil Operator | Dec 2025 |
| 369 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 370 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Dec 2025 |
| 371 | Oro Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 372 | Osr Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Jul 2000 |
| 373 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | Dec 2025 |
| 374 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 375 | Overly Operating Co. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 376 | Overstreet, Jamie L | Hondo, TX 78861 | Oil & Gas Operator | Dec 2025 |
| 377 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 378 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 379 | Paisano Production, Inc. | Somerset, TX 78069 | Oil Operator | Dec 2025 |
| 380 | Pal Energy LLC | Guymon, OK 73942-1950 | Gas Operator | Aug 2009 |
| 381 | Park Avenue Resources, Inc. | San Antonio, TX 78212 | Oil Operator | Dec 2025 |
| 382 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 383 | Partin, Charles | Atascosa, TX 78002 | Oil & Gas Operator | Aug 2005 |
| 384 | Patterson Energy Corporation | Dallas, TX 75367 | Oil & Gas Operator | Dec 2025 |
| 385 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 2025 |
| 386 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 387 | Penrod Oil Company Of Texas, Inc | Milano, TX 76556 | Oil & Gas Operator | Dec 2025 |
| 388 | Petro Lions, LLC | Somerset, TX 78069 | Oil Operator | Dec 2025 |
| 389 | Petro Ventures Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2019 |
| 390 | Petrolero Corp. | San Antonio, TX 78205 | Oil & Gas Operator | Feb 1998 |
| 391 | Petroleum Capital, L.C. | Dallas, TX 75367 | Oil & Gas Operator | Dec 2025 |
| 392 | Petronomics Petroleum, Inc. | Austin, TX 78734 | Oil & Gas Operator | Jan 1995 |
| 393 | Petrosaurus, Inc. | Somerset, TX 78069 | Oil Operator | Dec 2025 |
| 394 | Phoenix Fund, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jun 2000 |
| 395 | Phoenix Oil & Gas, Inc. (A) | Canada, 00100 | Oil & Gas Operator | Oct 2005 |
| 396 | Phylko Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Aug 2003 |
| 397 | Pillar Efs, LLC | Dallas, TX 75204 | Oil & Gas Operator | Dec 2025 |
| 398 | Pintex Operating Inc. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Feb 2005 |
| 399 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 400 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |