| 301 | L.C.S. Production Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2025 |
| 302 | Lacy Operations, LTD. | Longview, TX 75606 | Oil & Gas Operator | Oct 2012 |
| 303 | Lacy, R., Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2002 |
| 304 | Lamay Corporation | Rosenberg, TX 77471 | Oil & Gas Operator | Dec 2025 |
| 305 | Largo Oil Company | Longview, TX 75606 | Oil & Gas Operator | Dec 2025 |
| 306 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | Dec 2025 |
| 307 | Lehnertz, G. M. | Tyler, TX 75702 | Oil & Gas Operator | Dec 1998 |
| 308 | Lehnertz-Faulkner, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Feb 2023 |
| 309 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 310 | Lions Den Operating LLC | Carthage, TX 75633 | Gas Operator | Dec 2025 |
| 311 | Lodi Drilling & Service Co. | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Dec 2025 |
| 312 | Long Trusts, The | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 313 | Long, Larry T. | Kilgore, TX 75663 | Oil & Gas Operator | Jun 2017 |
| 314 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Oct 2025 |
| 315 | Loutex Production Company | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 316 | LTS Oil & Gas | Lubbock, TX 79424 | Oil & Gas Operator | Dec 2025 |
| 317 | M A S Operators | Kilgore, TX 75663 | Oil & Gas Operator | Jul 1999 |
| 318 | M. E. Operating & Services, Inc. | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2025 |
| 319 | Machin & Associates, Inc. | Longview, TX 75606 | Oil & Gas Operator | Dec 2025 |
| 320 | Mako Exploration Management, LLC | Shreveport, LA 71105 | Oil & Gas Operator | Dec 2025 |
| 321 | Map Production Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 322 | Mar-Bec Energy Company, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | May 2001 |
| 323 | Mark Oil, Inc. | Chanute, KS 66720 | Oil Operator | Feb 2025 |
| 324 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 325 | Martin Cannon Interests, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 326 | Martin Oil LLC | Madison, KS 66860 | Oil Operator | Jun 2025 |
| 327 | Martineau Petroleum, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2025 |
| 328 | Mass Energy, Inc | Houston, TX 77056 | Oil & Gas Operator | Mar 2008 |
| 329 | Matador Operating Company | Dallas, TX 75240 | Oil & Gas Operator | Jul 2003 |
| 330 | Maximus Operating, LTD. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 331 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | Dec 2025 |
| 332 | McBride Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 333 | McBride, Jerrel L Enterprise Inc | Kilgore, TX 75663 | Oil & Gas Operator | Jun 1999 |
| 334 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Aug 2025 |
| 335 | McGoldrick Oil Company | Shreveport, LA 71129 | Oil & Gas Operator | Jul 2020 |
| 336 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 337 | McRae Exploration & Prod., Inc. | Houston, TX 77064 | Oil & Gas Operator | Feb 2017 |
| 338 | MDM Energy, Inc. | The Colony, TX 75056 | Oil & Gas Operator | Dec 2025 |
| 339 | Medallion Production Company | Tulsa, OK 74103 | Oil & Gas Operator | May 1997 |
| 340 | Memorial Exploration Company | Saint Louis, MO 63105 | Oil & Gas Operator | Aug 1996 |
| 341 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 342 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 343 | Meridian Oil Production Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 2024 |
| 344 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 345 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Dec 2025 |
| 346 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 347 | MGF Oil Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1998 |
| 348 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 349 | Miller Energy Inc | Houston, TX 77024 | Oil & Gas Operator | Oct 2016 |
| 350 | Miltuck Operating, Inc. | Elysian Field, TX 75642 | Oil & Gas Operator | Dec 1996 |
| 351 | MMGL East Texas III, LLC | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 352 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 353 | Mondo Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 354 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 355 | Munoco Company | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2021 |
| 356 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Oct 2025 |
| 357 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Jun 2025 |
| 358 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |
| 359 | Mustang Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2006 |
| 360 | Neostar Energy Co. | Crossville, TN 38572 | Oil & Gas Operator | Feb 2019 |
| 361 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | Dec 2025 |
| 362 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 363 | Newfield Expl. Mid-Con. Inc | Tulsa, OK 74172 | Oil & Gas Operator | Jan 2015 |
| 364 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 365 | NFR Energy, LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2017 |
| 366 | Nitschke, Dan E. | Henrietta, TX 76365 | Oil & Gas Operator | Dec 2025 |
| 367 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 368 | Nolte, Mike E., Inc. | Longview, TX 75606 | Oil & Gas Operator | Feb 2006 |
| 369 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Dec 2025 |
| 370 | North American Reserve Corp. | Houston, TX 77060 | Oil & Gas Operator | Oct 2010 |
| 371 | North Central Casing Pullers,Inc | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 372 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Dec 2025 |
| 373 | Now Development Co., Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2017 |
| 374 | Nuevo Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2002 |
| 375 | Nytex, L.L.C. | Edmond, OK 73083 | Oil & Gas Operator | Feb 2006 |
| 376 | O'Benco, Inc. | Shreveport, LA 71136 | Oil & Gas Operator | Dec 2025 |
| 377 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 378 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 379 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 380 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 381 | Omni Operating Company(A) | Dallas, TX 75370 | Oil & Gas Operator | Dec 2025 |
| 382 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 383 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 384 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 385 | Paladin Drilling Company | McLeod, TX 75565 | Gas Operator | Sep 2011 |
| 386 | Palmer Petroleum, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jun 2025 |
| 387 | Panther Creek Resources, LLC | Denver, CO 80202 | Oil & Gas Operator | May 2012 |
| 388 | Par Minerals Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2025 |
| 389 | Paragon Oil & Gas, LLC | Aledo, TX 76008 | Oil & Gas Operator | Dec 2025 |
| 390 | Park & Park Oil Co. | Allen, TX 75002 | Oil & Gas Operator | Dec 2025 |
| 391 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 392 | Patara Oil & Gas LLC | Dallas, TX 75219 | Oil & Gas Operator | Mar 2018 |
| 393 | Pecos Petroleum Company | Houston, TX 77057 | Oil & Gas Operator | Oct 1999 |
| 394 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 395 | Pedernales Petroleum Op, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 396 | Penn VIrginia Oil & Gas, L.P. | Houston, TX 77084 | Oil & Gas Operator | Nov 2022 |
| 397 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 398 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 399 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 400 | Permian Natural Resources | Pflugerville, TX 78660 | Oil & Gas Operator | Dec 2025 |