| 301 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2024 |
| 302 | Keyway Oil & Gas Operating LLC | Kilgore, TX 75663 | Oil Operator | Oct 2020 |
| 303 | Kimball Production Co. | Houston, TX 77042 | Oil & Gas Operator | Jul 2002 |
| 304 | King Operating Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Mar 2025 |
| 305 | Kingwood Exploration LLC | Shreveport, LA 71101 | Oil & Gas Operator | Mar 2025 |
| 306 | Kornye-Tillman Company | Cleburne, TX 76031 | Oil & Gas Operator | Mar 2025 |
| 307 | L & R Petroleum | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 308 | L-Texx Petroleum, LP | Arlington, TX 76013 | Oil & Gas Operator | Mar 2025 |
| 309 | Lacy, R., Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2002 |
| 310 | Laddex, LTD. | Amarillo, TX 79102 | Oil & Gas Operator | Mar 2025 |
| 311 | Lake Ronel Oil Company | Tyler, TX 75710 | Oil & Gas Operator | Jul 2017 |
| 312 | Landmark Drilling, L.L.C. | Waskom, TX 75692 | Oil Operator | Mar 2025 |
| 313 | Largo Oil Company | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 314 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Mar 2025 |
| 315 | Lehnertz, G. M. | Tyler, TX 75702 | Oil & Gas Operator | Dec 1998 |
| 316 | Lehnertz-Faulkner, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Feb 2023 |
| 317 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 318 | Little & Whyte Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Mar 2008 |
| 319 | Little Cypress Oil & Gas, L.L.C. | Fullerton, CA 92834 | Oil Operator | Mar 2025 |
| 320 | Long-Tex Exploration, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Mar 2025 |
| 321 | Louisiana Energy Consultant Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 322 | Loutex Production Company | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 323 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2025 |
| 324 | M-C Production & Drilling Co,Inc | Longview, TX 75608 | Oil & Gas Operator | Mar 2025 |
| 325 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Mar 2025 |
| 326 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 327 | Magnolia Production Co | Atlanta, TX 75551 | Oil & Gas Operator | Mar 2025 |
| 328 | Manziel Management Corporation | Tyler, TX 75711 | Oil Operator | Feb 2014 |
| 329 | Mar-Bec Energy Company, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | May 2001 |
| 330 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 331 | Maroon Energy LLC | Spring, TX 77379 | Oil & Gas Operator | Mar 2025 |
| 332 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 333 | Marshall, Sam | Granbury, TX 76048 | Oil & Gas Operator | Aug 2010 |
| 334 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 335 | Matador Production Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 336 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 337 | Maxum Energy Corp | Plano, TX 75025 | Oil & Gas Operator | Jan 2003 |
| 338 | McBee Company, The | Dallas, TX 75219 | Oil & Gas Operator | Dec 1997 |
| 339 | McBride Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 340 | McBride, Jerrel L Enterprise Inc | Kilgore, TX 75663 | Oil & Gas Operator | Jun 1999 |
| 341 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 342 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Mar 2025 |
| 343 | McDonnold Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 344 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 345 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 346 | Mercury Operating, LLC | Dallas, TX 75208 | Oil & Gas Operator | Mar 2025 |
| 347 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 348 | Merrion Oil & Gas Corp | Farmington, NM 87401 | Oil & Gas Operator | Jan 2025 |
| 349 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 350 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 351 | Midcoast G & P (East Texas) L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 352 | Millennium Minerals Corporation | Fredericksbrg, TX 78624 | Oil Operator | Mar 2025 |
| 353 | Miller, R. A. Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2003 |
| 354 | MJ Energy Company, LLC | Kilgore, TX 75663 | Oil Operator | Mar 2025 |
| 355 | MMGL East Texas III, LLC | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 356 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 357 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 358 | Montgomery Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2007 |
| 359 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 360 | Moransco Energy Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 361 | Morris, W. Dale Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Mar 2025 |
| 362 | MT Energy LLC | Waskom, TX 75692 | Oil & Gas Operator | Mar 2025 |
| 363 | Munoco Co. | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2021 |
| 364 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Nov 2024 |
| 365 | Murphy Exploration & Production | Houston, TX 77024 | Oil Operator | Oct 2024 |
| 366 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 367 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 368 | Natural Gas Pipeline Co Of Amer. | Houston, TX 77002 | Gas Operator | Jul 2008 |
| 369 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 370 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | Mar 2025 |
| 371 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | Mar 2025 |
| 372 | Newfield Expl. Mid-Con. Inc | Tulsa, OK 74172 | Oil & Gas Operator | Jan 2015 |
| 373 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 374 | Newman Corporation | Harleton, TX 75651 | Oil & Gas Operator | Aug 2024 |
| 375 | NFR Energy, LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2017 |
| 376 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 377 | Nolte, Mike E. | Longview, TX 75606 | Oil & Gas Operator | Jun 1995 |
| 378 | Nolte, Mike E., Inc. | Longview, TX 75606 | Oil & Gas Operator | Feb 2006 |
| 379 | Nolteco, Inc. | Longview, TX 75606 | Oil & Gas Operator | Mar 2025 |
| 380 | North Central Casing Pullers,Inc | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 381 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Mar 2025 |
| 382 | North Texas Oil & Gas, LLC | Edmond, OK 73013 | Oil & Gas Operator | Mar 2025 |
| 383 | Northeast Texas Production Co. | Marshall, TX 75671 | Oil & Gas Operator | Mar 2025 |
| 384 | Northland Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2003 |
| 385 | Now Development Co., Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2017 |
| 386 | Nupower Energy, LLC | Houston, TX 77058 | Oil & Gas Operator | Mar 2025 |
| 387 | O'Benco, Inc. | Shreveport, LA 71136 | Oil & Gas Operator | Mar 2025 |
| 388 | O'Brien Energy Company | Shreveport, LA 71136 | Oil & Gas Operator | Sep 2019 |
| 389 | Oak Valley Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2015 |
| 390 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 391 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 392 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 393 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 394 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 395 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 396 | Owl Creek Production Co., LLC | Denver, CO 80265 | Oil & Gas Operator | Jan 2006 |
| 397 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 398 | Pa Prospect LLC | Columbus, MT 59019 | Oil & Gas Operator | Jul 2020 |
| 399 | Pace Royalty Trust Fund, Inc. | Shreveport, LA 71135 | Oil & Gas Operator | Nov 2001 |
| 400 | Palmer Petroleum Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Mar 2025 |