| 301 | North Operating Company | Canton, TX 75103 | Oil & Gas Operator | Jul 2025 |
| 302 | North Star Energy, Inc. | Strawn, TX 76475 | Oil & Gas Operator | Jan 2010 |
| 303 | Nutek Oil Inc | San Antonio, TX 78254 | Oil & Gas Operator | Feb 2006 |
| 304 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 305 | Oilton Resources, Inc. | Laredo, TX 78041 | Oil & Gas Operator | Jul 2025 |
| 306 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 307 | Olmos Partners, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Jul 2025 |
| 308 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Jul 2025 |
| 309 | Olson, S. A. | Kenedy, TX 78119 | Oil & Gas Operator | Aug 1994 |
| 310 | Omni Operating Company(A) | Dallas, TX 75370 | Oil & Gas Operator | Jul 2025 |
| 311 | Origin Prod Co Gonzales Prop LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Jul 2025 |
| 312 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Jul 2025 |
| 313 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | Jul 2025 |
| 314 | Orr Production Company | Austin, TX 78746 | Oil & Gas Operator | Dec 2000 |
| 315 | Oso Exploration Co. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2011 |
| 316 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 317 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |
| 318 | P-R-O Management, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 319 | P.S.N. Petroleum, Inc. | San Antonio, TX 78233 | Oil & Gas Operator | Jul 2025 |
| 320 | Pace Oil And Gas Company | Austin, TX 78715 | Oil & Gas Operator | Jul 2025 |
| 321 | Panther Exploration, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2017 |
| 322 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 323 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 324 | PDH Enterprises | Pittsburg, TX 75686 | Oil & Gas Operator | Apr 2019 |
| 325 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 326 | Pegasus Petroleum Corporation | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Jul 2025 |
| 327 | Penrod Oil Company Of Texas, Inc | Milano, TX 76556 | Oil & Gas Operator | Jul 2025 |
| 328 | Penwell Energy, Inc. | Houston, TX 77057 | Oil & Gas Operator | Jul 2025 |
| 329 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 330 | Petro Resources, Inc. | Fulton, TX 78358 | Oil & Gas Operator | Jul 2025 |
| 331 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 332 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 333 | Petrogas Operating Corporation | Garland, TX 75043 | Oil Operator | Feb 2010 |
| 334 | Petroleum Capital, L.C. | Dallas, TX 75367 | Oil & Gas Operator | Jul 2025 |
| 335 | Petrosaurus, Inc. | Somerset, TX 78069 | Oil Operator | Jul 2025 |
| 336 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 337 | Pintex Operating Inc. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Feb 2005 |
| 338 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 339 | Pre Oil Company | Seguin, TX 78155 | Oil & Gas Operator | Aug 1993 |
| 340 | Premier Minerals, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 341 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 342 | Pressly Oil Interest, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 343 | Prevail Energy, Inc | Corpus Chrsti, TX 78469 | Oil & Gas Operator | Jul 2025 |
| 344 | Primera Energy, LLC | Longview, TX 75606 | Oil & Gas Operator | Mar 2016 |
| 345 | Producers Engineering Company | Destin, FL 32541 | Oil & Gas Operator | Sep 1999 |
| 346 | Production Resources, Inc. | Castroville, TX 78009 | Oil & Gas Operator | Jul 2025 |
| 347 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Jul 2025 |
| 348 | Progenies Operating LLC | Austin, TX 78746 | Oil & Gas Operator | Jul 2025 |
| 349 | Pullin Lease Service, Inc. | Taft, TX 78390 | Oil & Gas Operator | Jul 2025 |
| 350 | Puls, W. L. | Houston, TX 77084 | Oil & Gas Operator | Sep 2002 |
| 351 | Pump-N-Production, LLC | Poth, TX 78147 | Oil Operator | Jul 2025 |
| 352 | Quanico Oil & Gas, Inc. | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2025 |
| 353 | Quatro Oil And Gas, Inc. | Joshua, TX 76058 | Oil & Gas Operator | Jul 2025 |
| 354 | Quest Research & Dev. Corp. | Weatherford, TX 76086 | Oil & Gas Operator | Jul 2025 |
| 355 | R & S Energy Company | Luling, TX 78648 | Oil & Gas Operator | Dec 2010 |
| 356 | R & S Oil Production Co. | Luling, TX 78648 | Oil & Gas Operator | Jul 2025 |
| 357 | Rafter L Resources, LLC | Bulverde, TX 78163 | Oil Operator | Jul 2025 |
| 358 | Rainer Energy, Inc. | Weatherford, TX 76086 | Oil & Gas Operator | Jul 2025 |
| 359 | Rampage Exploration, Inc. | Austin, TX 78737 | Oil & Gas Operator | Jul 2025 |
| 360 | Ratex Energy Inc. | Manchaca, TX 78652 | Oil & Gas Operator | Sep 2002 |
| 361 | Rayalto Oil & Gas, Inc. | MC Queeney, TX 78123 | Oil & Gas Operator | Mar 2004 |
| 362 | RBR Operating, Inc. | Luling, TX 78648 | Oil & Gas Operator | Jul 2025 |
| 363 | Reavis, Tommy | San Antonio, TX 78227 | Gas Operator | Jul 2025 |
| 364 | Rec Well Service, Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2008 |
| 365 | Recoil Resources Operating, Inc. | Houston, TX 77046 | Oil & Gas Operator | Mar 2024 |
| 366 | Red Fork Production, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 367 | Red Horse Petroleum | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 368 | Reef Exploration, Inc. (A-1) | Richardson, TX 75080 | Oil & Gas Operator | Oct 2006 |
| 369 | Reichmann Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2025 |
| 370 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Jul 2025 |
| 371 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | Jul 2025 |
| 372 | Ress Production Co. | Farmington, NM 87499 | Oil & Gas Operator | Jul 2025 |
| 373 | Rexcom, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 374 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 375 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2025 |
| 376 | Rife Oil Properties Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Jul 2025 |
| 377 | Riggs, Don R. | San Antonio, TX 78270 | Oil & Gas Operator | Aug 2003 |
| 378 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | Jul 2025 |
| 379 | Rio Grand Exploration, LLC | San Antonio, TX 78216 | Oil & Gas Operator | Jul 2025 |
| 380 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 381 | Roberts & Hammack, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 382 | Rocc Operating, LLC | Houston, TX 77084 | Oil & Gas Operator | Jul 2025 |
| 383 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | May 2025 |
| 384 | Rodenberg, Laura Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Jul 2025 |
| 385 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 386 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 387 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 388 | Ross Gas And Oil, LTD. Co. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Jul 2025 |
| 389 | Royko Oil Company | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Jul 2025 |
| 390 | RR Ventures Limited Partnership | San Antonio, TX 78239 | Oil & Gas Operator | Jul 2025 |
| 391 | Runion Oil, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Aug 2003 |
| 392 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2025 |
| 393 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | Jul 2025 |
| 394 | Sarita Energy Resources, LTD. | Houston, TX 77277 | Oil & Gas Operator | Jul 2025 |
| 395 | Sarrita Oil Co., Inc. | Floresville, TX 78114 | Oil & Gas Operator | Jul 2002 |
| 396 | Schroeder Oil Properties | Graham, TX 76450 | Oil & Gas Operator | Jul 2022 |
| 397 | Seaco Production | Dripping SPGS, TX 78620 | Oil & Gas Operator | Feb 2016 |
| 398 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 399 | Seay Oil & Gas, LTD. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Apr 2013 |
| 400 | Sedco Resources Inc | Kerrville, TX 78029 | Oil & Gas Operator | Jul 2025 |