| 301 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 302 | Kinder Morgan Production Co LLC | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 303 | Klotzman, M. S. Exploration Co. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 304 | KWS Oil & Gas, LLC | El Campo, TX 77437 | Oil & Gas Operator | May 2025 |
| 305 | L.J.M. Corporation | Houston, TX 77025 | Oil & Gas Operator | Jun 2012 |
| 306 | Lacy, F. B. Inc. | Houston, TX 77055 | Oil & Gas Operator | Sep 1997 |
| 307 | Lamay Corporation | Rosenberg, TX 77471 | Oil & Gas Operator | May 2025 |
| 308 | Lavaca Canyon Petroleum LLC | Houston, TX 77094 | Oil & Gas Operator | May 2025 |
| 309 | Lavaca River Operating Co., LLC | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 310 | Lewis Petro Properties, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | May 2025 |
| 311 | LGDC Corporation | Shreveport, LA 71101 | Oil & Gas Operator | May 2025 |
| 312 | Lighthouse Operating, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jun 2021 |
| 313 | Little, Lou Operating Co., Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2014 |
| 314 | Live Oak Op & Production, L.L.C. | Austin, TX 78759 | Oil & Gas Operator | Nov 2011 |
| 315 | Lode Holdings, LLC | Wichita Falls, TX 76301 | Oil Operator | May 2025 |
| 316 | Lodi Drilling & Service Co. | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 317 | Lomak Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1998 |
| 318 | Lone Oak Energy Inc | Kyle, TX 78640 | Oil & Gas Operator | May 2025 |
| 319 | Lonestar Operating, LLC | Houston, TX 77084 | Oil & Gas Operator | Nov 2022 |
| 320 | LTX Productions, Inc. | Houston, TX 77095 | Oil & Gas Operator | Jul 2008 |
| 321 | Lundberg Oil Co. | Dallas, TX 75360 | Oil & Gas Operator | Jan 2003 |
| 322 | Lundberg Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2002 |
| 323 | Lytle Creek Operating, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 324 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 325 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 326 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 327 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 328 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 329 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 330 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 331 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 332 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 333 | Mascot Oil Company | Schulenburg, TX 78956 | Oil & Gas Operator | May 2025 |
| 334 | Matrix Petroleum, LLC | Houston, TX 77077 | Oil & Gas Operator | May 2025 |
| 335 | Matrix Production Company | Sugar Land, TX 77478 | Oil & Gas Operator | Mar 2025 |
| 336 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 337 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | May 2025 |
| 338 | McCarter, A. Nelson | Houston, TX 77063 | Oil & Gas Operator | Aug 2003 |
| 339 | McCauley, F. R. | Houston, TX 77002 | Oil & Gas Operator | Apr 2000 |
| 340 | McCombs Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2006 |
| 341 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 342 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 343 | Mego Resources, LLC | Taft, TX 78390 | Oil & Gas Operator | May 2025 |
| 344 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 345 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 346 | Meridian Resource & Expl LLC,The | Houston, TX 77094 | Oil & Gas Operator | Nov 2012 |
| 347 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 348 | Merit Energy Company, LLC | Dallas, TX 75240 | Oil & Gas Operator | Jan 2025 |
| 349 | Merrimac Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 350 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | May 2025 |
| 351 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 352 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 353 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 354 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 355 | Millennium Exploration Co. LLC | San Antonio, TX 78232 | Oil & Gas Operator | May 2025 |
| 356 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 357 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 358 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 359 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 360 | MLF, Inc. | Houston, TX 77096 | Gas Operator | Nov 2009 |
| 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 | May 2025 |
| 363 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | May 2025 |
| 364 | Moose Oil & Gas Co. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 365 | Moose Operating Co., Inc. | Houston, TX 77006 | Oil & Gas Operator | May 2025 |
| 366 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 367 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | May 2025 |
| 368 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 369 | Mosley Oil &Gas Inc | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 370 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 371 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 372 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 373 | Munson, Charles C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2002 |
| 374 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2025 |
| 375 | Nacogdoches Oil & Gas Inc | Nacogdoches, TX 75963 | Oil & Gas Operator | May 2025 |
| 376 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 377 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | May 2025 |
| 378 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 379 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 380 | NFR Energy, LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2017 |
| 381 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 382 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | May 2025 |
| 383 | North American Drilling Corp | Plano, TX 75093 | Oil & Gas Operator | May 2025 |
| 384 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 385 | North Shore Energy, L.L.C. | Austin, TX 78750 | Oil & Gas Operator | May 2025 |
| 386 | North Star Energy, Inc. | Strawn, TX 76475 | Oil & Gas Operator | Jan 2010 |
| 387 | Nuevo Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2002 |
| 388 | Null, W.M. Operations, Inc. | Corpus Chrsti, TX 78475 | Oil & Gas Operator | Jun 2002 |
| 389 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 390 | O'Tool Oil & Gas, LLC | Dallas, TX 75219 | Oil & Gas Operator | May 2025 |
| 391 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 392 | Oil Lease Operating Co. | Coldspring, TX 77331 | Oil & Gas Operator | Aug 2003 |
| 393 | Oldfield Acquisition LP | Austin, TX 78733 | Oil & Gas Operator | Sep 1996 |
| 394 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | May 2025 |
| 395 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 396 | Opal Energy, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2009 |
| 397 | Osyka Producing Company, Inc. | Houston, TX 77242 | Oil & Gas Operator | May 2025 |
| 398 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 399 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | May 2025 |
| 400 | Overton Park Oil & Gas LP | Fort Worth, TX 76109 | Oil & Gas Operator | May 2025 |