| 301 | Kasle Energy Inc. | Cross Plains, TX 76443 | Oil & Gas Operator | Mar 2017 |
| 302 | Kilpatrick Production Company | Tye, TX 79563 | Oil & Gas Operator | May 2025 |
| 303 | King Energy Resources | Kerrville, TX 78029 | Oil & Gas Operator | May 2025 |
| 304 | King Oil & Gas Co. | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 305 | Kingery, Johnny | Clyde, TX 79510 | Oil & Gas Operator | Oct 1997 |
| 306 | KLH Oil & Gas, Inc. | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 307 | Klingberg, Roger | Cross Plains, TX 76443 | Oil & Gas Operator | Jan 2017 |
| 308 | KNK Oil & Gas | Abilene, TX 79602 | Oil & Gas Operator | Dec 1996 |
| 309 | Ko Operating | Merkel, TX 79536 | Oil & Gas Operator | May 2025 |
| 310 | Kokomo Energy, Inc. | Gorman, TX 76454 | Oil & Gas Operator | May 2025 |
| 311 | Kollao Properties LLC | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 312 | Kroh Operating LLC | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 313 | KTC Oil Enterprises, LLC | Dallas, TX 75247 | Oil & Gas Operator | May 2025 |
| 314 | L.C.S. Production Company | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 315 | La Aceite Energy, Inc. | Abilene, TX 79605 | Oil & Gas Operator | May 2025 |
| 316 | Laguna Petroleum Corporation | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 317 | Lakewood Operating, LTD. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 318 | Lamesa Crude | Abilene, TX 79605 | Oil & Gas Operator | Feb 2015 |
| 319 | Landmaster Partners, Inc. | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 320 | Laneer Resources Company | Abilene, TX 79608 | Oil & Gas Operator | May 2025 |
| 321 | Largo Oil Company | Longview, TX 75606 | Oil & Gas Operator | May 2025 |
| 322 | Lawrence Energy Company | Abilene, TX 79602 | Oil & Gas Operator | May 2025 |
| 323 | Leclair Operating Co., Inc. | Abilene, TX 79602 | Oil & Gas Operator | May 2025 |
| 324 | Leclair Operating, L.L.C. | Abilene, TX 79602 | Oil & Gas Operator | May 2025 |
| 325 | Leffel'S, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jun 2020 |
| 326 | Leroy Oil Co. | Gainesville, TX 76240 | Oil & Gas Operator | Jun 2002 |
| 327 | Lime Creek Enterprises | Aztec, NM 87410 | Oil & Gas Operator | Aug 2008 |
| 328 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 329 | Littlepage, Tommy | Graham, TX 76450 | Oil & Gas Operator | May 1996 |
| 330 | Live Oak Op & Production, L.L.C. | Austin, TX 78759 | Oil & Gas Operator | Nov 2011 |
| 331 | Lone Star Gas Co. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1999 |
| 332 | Lone Star Pipeline Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 1999 |
| 333 | Lorac, Inc. | Dallas, TX 75252 | Oil & Gas Operator | May 2025 |
| 334 | Low-End Oil LLC | Austin, TX 78748 | Oil Operator | May 2025 |
| 335 | Luvwell Holdings | Tyler, TX 75701 | Oil Operator | May 2025 |
| 336 | Lynx Oil Co., Inc. | Denton, TX 76207 | Oil & Gas Operator | Sep 2003 |
| 337 | Lytle Creek Operating, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 338 | M & K Operating LLC | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 339 | M & M Oil & Gas Exploration Inc | Abilene, TX 79601 | Oil & Gas Operator | Mar 2008 |
| 340 | M H W, Inc. | Dallas, TX 75230 | Oil & Gas Operator | Jul 1996 |
| 341 | M2 Squared Operating, LLC | Rockwall, TX 75032 | Oil Operator | May 2025 |
| 342 | Madera, R. F. | Palm Desert, CA 92210 | Oil & Gas Operator | Sep 2000 |
| 343 | Magnet Oil LP | Bronte, TX 76933 | Oil & Gas Operator | May 2025 |
| 344 | Martin Oil Co. | Aspermont, TX 79502 | Oil & Gas Operator | Jul 2023 |
| 345 | Masada Oil & Gas | Quanah, TX 79252 | Oil & Gas Operator | May 2025 |
| 346 | Masada Oil & Gas Company LTD. | Abilene, TX 79603 | Oil & Gas Operator | May 2025 |
| 347 | Masters Rat Hole Service, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Nov 1998 |
| 348 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 349 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 350 | Mayo, Paul R. | Quinlan, TX 75474 | Oil & Gas Operator | May 1999 |
| 351 | MC Glover, LLC | Albany, TX 76430 | Oil Operator | May 2025 |
| 352 | McClymond, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2001 |
| 353 | McClymond, LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2009 |
| 354 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 355 | Mehaffey Investments, Inc. | Eastland, TX 76448 | Oil & Gas Operator | May 2025 |
| 356 | Mercury Exploration Co | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 357 | Mercury Operating, LLC | Dallas, TX 75208 | Oil & Gas Operator | May 2025 |
| 358 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 359 | Merkaz Drilling, LLC | Dallas, TX 75229 | Oil Operator | May 2025 |
| 360 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 361 | Mid Texas Natural Gas | Kyle, TX 78640 | Oil & Gas Operator | May 2019 |
| 362 | Mid-Continental Exploration,Inc. | Sanger, TX 76266 | Oil & Gas Operator | May 2025 |
| 363 | Mid-Tex Energy Inc. | Costa Mesa, CA 92626 | Oil & Gas Operator | Jan 1999 |
| 364 | Midland Oil And Gas, Inc. | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 365 | Midsco | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 366 | Miller, Bob I. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 367 | Miller, Donny | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 368 | Miller, Rex M. | Putnam, TX 76469 | Oil & Gas Operator | Sep 2022 |
| 369 | Mingus Oil & Gas | Mingus, TX 76463 | Oil & Gas Operator | May 2025 |
| 370 | Misener Operating, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2010 |
| 371 | Mission Energy Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 372 | Mist Prod. & Exploration Corp. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 373 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 374 | Mixon, Robert N. | Lometa, TX 76853 | Oil & Gas Operator | May 2025 |
| 375 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 376 | MKS Consulting Corporation | Weatherford, TX 76086 | Oil & Gas Operator | Jul 2005 |
| 377 | MKS Natural Gas Company | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2016 |
| 378 | Mogul Resources, LLC | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 379 | Momentum Operating Co., Inc. | Albany, TX 76430 | Oil & Gas Operator | May 2025 |
| 380 | Montgomery Royalty | Moran, TX 76464 | Oil & Gas Operator | May 2025 |
| 381 | Moore Investment Co. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 382 | Moore, Miles Inc. | Moran, TX 76464 | Oil & Gas Operator | May 2025 |
| 383 | Morris Operating Co | Lovington, NM 88260 | Oil & Gas Operator | May 2025 |
| 384 | Morris, W. Dale Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | May 2025 |
| 385 | Morrison DRLG. & Prod. Co., Inc. | Abilene, TX 79606 | Oil & Gas Operator | Nov 2008 |
| 386 | Mountain Creek Oil Company, Inc. | Saint Jo, TX 76265 | Oil & Gas Operator | May 2025 |
| 387 | Mr Oil Company | Monahans, TX 79756 | Oil & Gas Operator | Nov 2004 |
| 388 | Munson, E. P., Jr. | Fort Worth, TX 76121 | Oil & Gas Operator | Oct 1995 |
| 389 | MWS Producing, Inc. | Stanton, TX 79782 | Oil & Gas Operator | May 2025 |
| 390 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 391 | Neal, Jack Engineering, Inc. | Abilene, TX 79603 | Oil & Gas Operator | Feb 2011 |
| 392 | Neatherlin, Earl Inc. | Avoca, TX 79503 | Oil & Gas Operator | May 2025 |
| 393 | Neeb, H. L. | Abilene, TX 79606 | Oil & Gas Operator | Jul 1994 |
| 394 | Neely, H. K. | Abilene, TX 79604 | Oil & Gas Operator | Dec 1995 |
| 395 | Neumann Ventures, Inc. | Cisco, TX 76437 | Oil Operator | Jan 2005 |
| 396 | Norman Oil Corporation | Abilene, TX 79608 | Oil & Gas Operator | Mar 2000 |
| 397 | North American Exploration Co. | Abilene, TX 79602 | Oil & Gas Operator | Apr 1998 |
| 398 | Nosivad Oil, Inc. | Clyde, TX 79510 | Oil & Gas Operator | May 2025 |
| 399 | Novo Exploration Corporation | Hurst, TX 76053 | Oil & Gas Operator | Jun 2020 |
| 400 | O.G.O. Refining | Luling, TX 78648 | Oil & Gas Operator | Jun 2013 |