| 301 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 302 | Midpar L.P. | Midland, TX 79702 | Oil & Gas Operator | Feb 1995 |
| 303 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 304 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 305 | Milam, Inc. | Oklahoma City, OK 73118 | Oil & Gas Operator | May 2026 |
| 306 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | May 2026 |
| 307 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | May 2026 |
| 308 | MLC Operating, LP | Houston, TX 77063 | Oil & Gas Operator | May 2026 |
| 309 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 310 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 311 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | May 2026 |
| 312 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | May 2026 |
| 313 | Mortimer Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2003 |
| 314 | Murphy Expl. & Prod. Co. - USA | Houston, TX 77024 | Oil & Gas Operator | May 2026 |
| 315 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 316 | MV Purchasing LLC | Wichita, KS 67206 | Oil & Gas Operator | Dec 2019 |
| 317 | Naifco Oil & Gas LLC | Oklahoma City, OK 73107 | Oil & Gas Operator | Mar 2026 |
| 318 | Natural Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Jul 1997 |
| 319 | Nelson, James L. | Pettus, TX 78146 | Oil & Gas Operator | May 2026 |
| 320 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2026 |
| 321 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | May 2026 |
| 322 | Newfield Exploration Company | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2017 |
| 323 | Newpek, LLC | Irving, TX 75039 | Oil & Gas Operator | Sep 2016 |
| 324 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | May 2026 |
| 325 | Nog Production & Operating LLC | Goliad, TX 77963 | Oil & Gas Operator | May 2026 |
| 326 | Nomeco Oil & Gas Co. | Jackson, MI 49204 | Oil & Gas Operator | Dec 1994 |
| 327 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 328 | Null, W.M. Operations, Inc. | Corpus Chrsti, TX 78475 | Oil & Gas Operator | Jun 2002 |
| 329 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 330 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 331 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 332 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 333 | One Tec Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2007 |
| 334 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | May 2026 |
| 335 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | May 2026 |
| 336 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 337 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | May 2026 |
| 338 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2026 |
| 339 | P1 Energy, LLC | Judson, TX 75660 | Oil & Gas Operator | May 2026 |
| 340 | Pal Energy LLC | Guymon, OK 73942-1950 | Gas Operator | Aug 2009 |
| 341 | Paleo Oil Company LLC | Corpus Christ, TX 78411 | Oil & Gas Operator | May 2026 |
| 342 | Paloma Operating, LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | May 2026 |
| 343 | Paloma Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2018 |
| 344 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 345 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 346 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 347 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 348 | Patterson Energy Corporation | Dallas, TX 75367 | Oil & Gas Operator | May 2026 |
| 349 | Payne Producing Co. | Fredericksbrg, TX 78624 | Oil & Gas Operator | Jun 2008 |
| 350 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 351 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 352 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 353 | Petro Resources, Inc. | Fulton, TX 78358 | Oil & Gas Operator | May 2026 |
| 354 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | May 2026 |
| 355 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2026 |
| 356 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 357 | Petrolero Corp. | San Antonio, TX 78205 | Oil & Gas Operator | Feb 1998 |
| 358 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | May 2026 |
| 359 | Pintex Operating Inc. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Feb 2005 |
| 360 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2026 |
| 361 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 362 | Pipeline Management, Inc. | Lubbock, TX 79401 | Oil & Gas Operator | Dec 2002 |
| 363 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 364 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 365 | Platinum Oil & Gas, L.L.C. | San Juan, TX 78589 | Oil & Gas Operator | May 2026 |
| 366 | PPC Operating Company LLC | Houston, TX 77279 | Oil & Gas Operator | Jul 2019 |
| 367 | Premium Exploration Company | Early, TX 76803 | Oil & Gas Operator | May 2026 |
| 368 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 369 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2026 |
| 370 | Proco Operating Co., Inc. | Graford, TX 76449 | Oil & Gas Operator | May 2026 |
| 371 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | May 2026 |
| 372 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | May 2026 |
| 373 | Property Development Group, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | May 2026 |
| 374 | Protege Energy III LLC | Houston, TX 77024 | Oil & Gas Operator | Sep 2024 |
| 375 | Quinn, Karen | Round Rock, TX 78681 | Oil Operator | Sep 2018 |
| 376 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 377 | Rampage Exploration, Inc. | Austin, TX 78737 | Oil & Gas Operator | May 2026 |
| 378 | Ranger Oil Company | Canada, 00100 | Oil & Gas Operator | Sep 2001 |
| 379 | Recoil Resources Operating, Inc. | Houston, TX 77046 | Oil & Gas Operator | Mar 2024 |
| 380 | Renaissance Petroleum Co LLC | Houston, TX 77058 | Oil & Gas Operator | Nov 2011 |
| 381 | Repsol Oil & Gas USA, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | May 2026 |
| 382 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | May 2026 |
| 383 | Resaca Resources, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | May 2026 |
| 384 | Resource Expl & Prod, Inc. | Salado, TX 76571 | Oil & Gas Operator | May 2026 |
| 385 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | May 2026 |
| 386 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | May 2026 |
| 387 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 388 | Rio Bravo Royalty Co. | Bandera, TX 78003 | Oil & Gas Operator | Aug 2003 |
| 389 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 390 | Rising Star Energy, L.L.C. | Dallas, TX 75219 | Oil & Gas Operator | Aug 2006 |
| 391 | Robert T. Epperson Prod Co, LLC | Tyler, TX 75713 | Gas Operator | Dec 2017 |
| 392 | Rocc Operating, LLC | Houston, TX 77084 | Oil & Gas Operator | May 2026 |
| 393 | Rockwell Energy, LLC | Spring, TX 77386 | Oil & Gas Operator | Sep 2014 |
| 394 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | May 2026 |
| 395 | Rodenberg, Laura Oil Co. | Luling, TX 78648 | Oil & Gas Operator | May 2026 |
| 396 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2026 |
| 397 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 398 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | May 2026 |
| 399 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | May 2026 |
| 400 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |