| 301 | JPW Energy, L.L.C. | San Antonio, TX 78216 | Oil & Gas Operator | May 2025 |
| 302 | JSM Natural Resources, L.L.C. | Victoria, TX 77904 | Oil & Gas Operator | Dec 2018 |
| 303 | Jura Energy Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2023 |
| 304 | K And R Oil Company | Stanton, TX 79782 | Oil & Gas Operator | Aug 2003 |
| 305 | K-B Oil Company | Dallas, TX 75243 | Oil & Gas Operator | Dec 2020 |
| 306 | Kaler Energy Corp. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 307 | Kamlok Oil & Gas, Inc. | Houston, TX 77240 | Oil & Gas Operator | Jun 1996 |
| 308 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 309 | KDM Operating, LLC | The Woodlands, TX 77380 | Oil Operator | May 2025 |
| 310 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 311 | Ken Petroleum Corporation | Dallas, TX 75206 | Oil & Gas Operator | Feb 2019 |
| 312 | Kenne Exploration, Inc. | Missouri City, TX 77489 | Oil & Gas Operator | May 2025 |
| 313 | Key Operating & Equipment, Inc. | Midlothian, TX 76065 | Oil & Gas Operator | Nov 2024 |
| 314 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 315 | Killam Oil Company | Laredo, TX 78042 | Oil & Gas Operator | Mar 1994 |
| 316 | Kirkpatrick, John Oil LLC | Victoria, TX 77905 | Oil & Gas Operator | May 2025 |
| 317 | Klotzman, M. S. Exploration Co. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 318 | KP Exploration, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1997 |
| 319 | Kraker & Martin Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 320 | Kram Energy | Corpus Chrsti, TX 78404 | Oil & Gas Operator | May 2025 |
| 321 | KWS Oil & Gas, LLC | El Campo, TX 77437 | Oil & Gas Operator | May 2025 |
| 322 | Lakehills Production, Inc. | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 323 | Laron Oil Corporation | Seguin, TX 78155 | Oil & Gas Operator | Jul 1997 |
| 324 | LBN Oil Co., Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | May 1998 |
| 325 | Legacy Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 326 | Legend Energy Texas, LLC | Arlington, TX 76002 | Oil & Gas Operator | May 2025 |
| 327 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 328 | Linn Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 329 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 330 | Little, Lou Operating Co., Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2014 |
| 331 | LMP Petroleum, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Jan 2010 |
| 332 | Lodestone Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 333 | Lodi Drilling & Service Co. | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 334 | Lomak Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1998 |
| 335 | Low-End Oil LLC | Austin, TX 78748 | Oil Operator | May 2025 |
| 336 | Lundberg Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2002 |
| 337 | Lyon Operating Company Inc.(Iii) | Jacksboro, TX 76458 | Oil & Gas Operator | May 2025 |
| 338 | Lytle Creek Operating, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 339 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 340 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 341 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 342 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 343 | Majestic Resources, Inc. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Nov 2007 |
| 344 | Mandarin Oil & Gas Company | Austin, TX 78714 | Oil & Gas Operator | May 2025 |
| 345 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 346 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 347 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 348 | Maverick Energy & Dev. Corp. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 349 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 350 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 351 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 352 | McGowan Working Partners | Jackson, MS 39296 | Oil & Gas Operator | Dec 2000 |
| 353 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | May 2025 |
| 354 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 355 | Medders Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2025 |
| 356 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 357 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 358 | Merrimac Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 359 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 360 | Midway Drilling Co. | Richmond, TX 77469 | Oil & Gas Operator | May 2025 |
| 361 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 362 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 363 | Miner, R. C. Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 2002 |
| 364 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 365 | ML Resources, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Mar 2008 |
| 366 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 367 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | May 2025 |
| 368 | Mogul Energy International, Inc. | Houston, TX 77042 | Oil & Gas Operator | Oct 2017 |
| 369 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 370 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 371 | Moose Oil & Gas Co. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 372 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | May 2025 |
| 373 | Mse Operating Corp. | Beaverton, OR 97008 | Oil & Gas Operator | May 2025 |
| 374 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 375 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 376 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2025 |
| 377 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 378 | Nance Engineering Inc. | Houston, TX 77058 | Oil & Gas Operator | Mar 2002 |
| 379 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | May 2025 |
| 380 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 381 | New Source Oil & Gas, LLC | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 382 | Nomeco Oil & Gas Co. | Jackson, MI 49204 | Oil & Gas Operator | Dec 1994 |
| 383 | North Shore Energy, L.L.C. | Austin, TX 78750 | Oil & Gas Operator | May 2025 |
| 384 | O'Connor Energy Management, LLC | Victoria, TX 77902 | Oil Operator | May 2025 |
| 385 | Oblaen Resources LLC | Wallis, TX 77485 | Oil & Gas Operator | May 2025 |
| 386 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 387 | Omega Alpha Resources, LLC | Dallas, TX 75219 | Oil Operator | May 2025 |
| 388 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 389 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | May 2025 |
| 390 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 391 | Opal Energy, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2009 |
| 392 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 393 | Oro Resources, LLC | Dallas, TX 75219 | Oil & Gas Operator | May 2025 |
| 394 | Orr Production Company | Austin, TX 78746 | Oil & Gas Operator | Dec 2000 |
| 395 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 396 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | May 2025 |
| 397 | Osyka Permian, LLC | Houston, TX 77079 | Oil & Gas Operator | May 2025 |
| 398 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 399 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 400 | Pace West Production LC | San Angelo, TX 76904 | Oil & Gas Operator | Sep 1995 |