| 301 | JTB Oil Company, Inc. | Refugio, TX 78377 | Oil & Gas Operator | May 2025 |
| 302 | K-Bar Oil LLC | McPherson, KS 67460 | Oil Operator | Jan 2025 |
| 303 | K.M.A. Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 304 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 305 | Kaler Energy Corp. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 306 | Kamlok Oil & Gas, Inc. | Houston, TX 77240 | Oil & Gas Operator | Jun 1996 |
| 307 | Karbuhn Oil Company | Tomball, TX 77375 | Oil & Gas Operator | May 2025 |
| 308 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 309 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 310 | Keft Oil Company | Pleasanton, TX 78064 | Oil & Gas Operator | Feb 2003 |
| 311 | Kenne Exploration, Inc. | Missouri City, TX 77489 | Oil & Gas Operator | May 2025 |
| 312 | Kidd Production Co. | Luling, TX 78648 | Oil & Gas Operator | May 2025 |
| 313 | Kinder Morgan Production Co LP | Midland, TX 79701 | Oil & Gas Operator | Jul 2007 |
| 314 | Kovar Operating, LLC | Victoria, TX 77901 | Oil & Gas Operator | Sep 2021 |
| 315 | Kraker & Martin Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 316 | L & F Drilling Co., Inc. (1) | Corpus Chrsti, TX 78479 | Oil & Gas Operator | May 2025 |
| 317 | Lagarto Company, The | Fredericksbrg, TX 78624 | Oil & Gas Operator | Apr 1995 |
| 318 | Lagerquist, Walter G., Jr. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2005 |
| 319 | Lakehills Production, Inc. | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 320 | Lamay Corporation | Rosenberg, TX 77471 | Oil & Gas Operator | May 2025 |
| 321 | Lighthouse Operating, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jun 2021 |
| 322 | Lightning Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 323 | Lime Rock Resources A, L.P. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 324 | Lindholm Oil, Inc. | Mathis, TX 78368 | Gas Operator | Sep 2002 |
| 325 | Little, Lou Operating Co., Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2014 |
| 326 | LMN Oil And Gas, Inc. | Luling, TX 78648 | Oil & Gas Operator | Mar 2008 |
| 327 | LMP Exploration Operating, LLC | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Feb 2008 |
| 328 | Lodestone Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 329 | Lodi Drilling & Service Co. | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 330 | Lodi Operating Company LLC | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 331 | Loin Energy Corporation | La Grange, TX 78945 | Oil & Gas Operator | May 2025 |
| 332 | Loma Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2014 |
| 333 | Louisiana Jordan Oil Co, Inc. | Lake Charles, LA 70602 | Oil & Gas Operator | Dec 2024 |
| 334 | Louisiana Land & Exploration Co. | Houston, TX 77210 | Oil & Gas Operator | Sep 2013 |
| 335 | Lovelady, I. W. | Albuquerque, NM 87111 | Oil & Gas Operator | Jan 1996 |
| 336 | Lre Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2016 |
| 337 | Lucros International Corporation | Van Buren, AR 72956 | Oil & Gas Operator | May 2025 |
| 338 | Lundberg Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2002 |
| 339 | Lynch, W. W. | San Antonio, TX 78205 | Oil & Gas Operator | Jul 2006 |
| 340 | M IV Ops., Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 1998 |
| 341 | M-G Gas Company, Inc. | Plano, TX 75086 | Oil & Gas Operator | Jun 1999 |
| 342 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 343 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 344 | Magnum Engineering Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 345 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 346 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 347 | Marathon Oil Ef LLC | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 348 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 349 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 350 | Marshfield Oil & Gas, LLC | Houston, TX 77070 | Oil & Gas Operator | May 2025 |
| 351 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 352 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 353 | MB Energy, LLC | San Antonio, TX 78233 | Oil & Gas Operator | May 2025 |
| 354 | McCombs Energy LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2006 |
| 355 | McCombs Energy, LTD. | Houston, TX 77056 | Oil & Gas Operator | Aug 2017 |
| 356 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 357 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 358 | McGowan Working Partners, Inc. | Jackson, MS 39296 | Oil & Gas Operator | May 2025 |
| 359 | McGuffin, Joe S. Inc. | Mathis, TX 78368 | Gas Operator | May 2025 |
| 360 | McLeod, George L. Inc. | Houston, TX 77079 | Oil & Gas Operator | Sep 2002 |
| 361 | McMahon Operating Co., L.C. | Pampa, TX 79066 | Oil & Gas Operator | Dec 2004 |
| 362 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 363 | Mego Resources, LLC | Taft, TX 78390 | Oil & Gas Operator | May 2025 |
| 364 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 365 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 366 | Messy Oil And Gas, LLC | Garwood, TX 77442 | Oil & Gas Operator | May 2025 |
| 367 | Metano Energy, LP | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2008 |
| 368 | Michael Petroleum Corporation | Houston, TX 77040 | Oil & Gas Operator | Dec 2001 |
| 369 | Midas Resources, Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2025 |
| 370 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 371 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 372 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 373 | Mina Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2012 |
| 374 | Miramar Petroleum, Inc. | Corpus Chrsti, TX 78463 | Oil & Gas Operator | Sep 2017 |
| 375 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | May 2025 |
| 376 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 377 | Mna Enterprises LTD. Co. | Hobbs, NM 88242 | Oil & Gas Operator | May 2025 |
| 378 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 379 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 380 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | May 2025 |
| 381 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 382 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 383 | Mooringsport Energy Prod. Co. | Shreveport, LA 71162 | Oil & Gas Operator | May 2025 |
| 384 | Morgan Enterprises, Inc. | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 385 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 386 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 387 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 388 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 389 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 390 | Murphy Exploration & Production | Houston, TX 77024 | Oil Operator | Dec 2024 |
| 391 | National Onshore LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 392 | Nei Production, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 393 | Nelson, James L. | Pettus, TX 78146 | Oil & Gas Operator | May 2025 |
| 394 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | May 2025 |
| 395 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 396 | New Horizon Investments LTD. | George West, TX 78022 | Oil & Gas Operator | May 2025 |
| 397 | Newfield Expl. Mid-Con. Inc | Tulsa, OK 74172 | Oil & Gas Operator | Jan 2015 |
| 398 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 399 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 400 | Nog Production & Operating LLC | Goliad, TX 77963 | Oil & Gas Operator | May 2025 |