| 301 | Linn Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 302 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 303 | Lodestone Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 304 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 305 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 306 | Magnum Operating, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 307 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 308 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 309 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 310 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 311 | Mamerow Energy Corp | Ganado, TX 77962 | Oil & Gas Operator | May 2025 |
| 312 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2025 |
| 313 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 314 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 315 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 316 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | May 2025 |
| 317 | McCarter, A. Nelson | Houston, TX 77063 | Oil & Gas Operator | Aug 2003 |
| 318 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | May 2025 |
| 319 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 320 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 321 | Mellon Creek Operating Co. | Victoria, TX 77901 | Oil & Gas Operator | Jun 1993 |
| 322 | Merenco | Midland, TX 79702 | Oil & Gas Operator | Dec 1996 |
| 323 | Meridian Resource & Expl Co, The | Houston, TX 77077 | Oil & Gas Operator | Dec 2000 |
| 324 | Meridian Resource & Expl LLC,The | Houston, TX 77094 | Oil & Gas Operator | Nov 2012 |
| 325 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 326 | MFP Petroleum LTD. Partnership | Oklahoma City, OK 73142 | Oil & Gas Operator | Nov 2017 |
| 327 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 328 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 329 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | May 2025 |
| 330 | Minyak Producing Company, Inc. | Sabine Pass, TX 77655 | Oil & Gas Operator | May 2025 |
| 331 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 332 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 333 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 334 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 335 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 336 | Mojac Energy Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 1997 |
| 337 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 338 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 339 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 340 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |
| 341 | Nadsoilco LLC | Chicago, IL 60606 | Oil & Gas Operator | May 2025 |
| 342 | Ncey Holdings, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2013 |
| 343 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 344 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | May 2025 |
| 345 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 346 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 347 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | May 2025 |
| 348 | Northridge Oil Company | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 349 | Northwest Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Jun 2014 |
| 350 | Nupower Energy, LLC | Houston, TX 77058 | Oil & Gas Operator | May 2025 |
| 351 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 352 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 353 | Oil, Gas, Etc. LLC | Katy, TX 77449 | Oil & Gas Operator | May 2025 |
| 354 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | May 2025 |
| 355 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 356 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 357 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | May 2025 |
| 358 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 359 | Outline Oil Company LLC | Beeville, TX 78104 | Oil Operator | May 2025 |
| 360 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 361 | Pace Oil And Gas Company | Austin, TX 78715 | Oil & Gas Operator | May 2025 |
| 362 | Pace Production Co. | San Angelo, TX 76902 | Oil & Gas Operator | May 2025 |
| 363 | Palace Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 364 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 365 | Partners Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Aug 1995 |
| 366 | PDH Enterprises | Pittsburg, TX 75686 | Oil & Gas Operator | Apr 2019 |
| 367 | Penn VIrginia Oil & Gas Corp | Houston, TX 77024 | Oil & Gas Operator | Dec 2023 |
| 368 | Penn VIrginia Oil & Gas, L.P. | Houston, TX 77084 | Oil & Gas Operator | Nov 2022 |
| 369 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 370 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 371 | Permian Natural Resources | Pflugerville, TX 78660 | Oil & Gas Operator | May 2025 |
| 372 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 373 | Petro Resources, Inc. | Fulton, TX 78358 | Oil & Gas Operator | May 2025 |
| 374 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Jan 2025 |
| 375 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 376 | Petropro Energy Partners, L.P. | Houston, TX 77024 | Oil & Gas Operator | Jan 2013 |
| 377 | Petrotex Engineering Company | Cypress, TX 77429 | Oil & Gas Operator | May 2025 |
| 378 | Petrotex, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 379 | PG&E Resources Offshore Company | Dallas, TX 75206 | Oil & Gas Operator | Oct 1994 |
| 380 | PH Exploration, Inc. | Houston, TX 77008 | Oil & Gas Operator | Nov 2001 |
| 381 | Phylko Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Aug 2003 |
| 382 | Pierce Junction Petroleum Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2010 |
| 383 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | May 2025 |
| 384 | Pitchfork Oil & Gas, Inc. | Orchard, TX 77464 | Oil & Gas Operator | May 2025 |
| 385 | Plantation Operating Co., Inc. | Holliday, TX 76366 | Oil & Gas Operator | May 2025 |
| 386 | Poco Oil Co. | Houston, TX 77069 | Oil & Gas Operator | Mar 1997 |
| 387 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 388 | Ponderosa Oil & Gas, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2025 |
| 389 | Premier Natural Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | May 2025 |
| 390 | Premium Exploration Company | Early, TX 76803 | Oil & Gas Operator | May 2025 |
| 391 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 392 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | May 2025 |
| 393 | Progenies Operating LLC | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 394 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | May 2025 |
| 395 | Pyramid Exploration | Houston, TX 77241 | Oil & Gas Operator | Sep 1995 |
| 396 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 397 | Rap Operating, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | May 2025 |
| 398 | Rawhide Operating, Inc. | New Braunfels, TX 78131 | Oil & Gas Operator | May 2025 |
| 399 | Rcy Mineral Group, Inc. | El Campo, TX 77437 | Oil Operator | Jul 2010 |
| 400 | Red Wolf Oil Company, Inc. | Brenham, TX 77833 | Oil & Gas Operator | May 2025 |