| 301 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 302 | Plano Petroleum Corporation | McKinney, TX 75070 | Oil & Gas Operator | Jan 2025 |
| 303 | Plantation Operating Co., Inc. | Holliday, TX 76366 | Oil & Gas Operator | May 2025 |
| 304 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 305 | Poco LLC | Houston, TX 77270 | Oil & Gas Operator | May 2025 |
| 306 | Poff, H. Bryan | Fort Worth, TX 76103 | Oil & Gas Operator | Mar 2008 |
| 307 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | May 2025 |
| 308 | Precise Development, Inc. | Austin, TX 78709 | Oil & Gas Operator | May 2005 |
| 309 | Price Drilling & Exploration Co. | Benavides, TX 78341 | Oil & Gas Operator | Jul 2013 |
| 310 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 311 | Progenies Operating LLC | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 312 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | May 2025 |
| 313 | Purvis Oil Corp | Midland, TX 79702 | Oil & Gas Operator | Jul 1994 |
| 314 | Purvis, J. H. | Midland, TX 79702 | Oil & Gas Operator | Dec 1994 |
| 315 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 316 | R & S Oil Production Co. | Luling, TX 78648 | Oil & Gas Operator | May 2025 |
| 317 | R&R Resources Corporation | Houston, TX 77056 | Oil & Gas Operator | Dec 2015 |
| 318 | Rainbow Producing Company | Dallas, TX 75204 | Oil & Gas Operator | Aug 2003 |
| 319 | Ramrod Oil And Gas (U.S.A.) Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2025 |
| 320 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | May 2025 |
| 321 | Rancho Blanco Corporation | San Antonio, TX 78205 | Oil & Gas Operator | Apr 1995 |
| 322 | Randolph Company, The | Houston, TX 77219 | Oil & Gas Operator | Aug 2003 |
| 323 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 324 | Ratex Energy Inc. | Manchaca, TX 78652 | Oil & Gas Operator | Sep 2002 |
| 325 | Rathburn Land & Devel, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Aug 2003 |
| 326 | RBR Operating, Inc. | Luling, TX 78648 | Oil & Gas Operator | May 2025 |
| 327 | Redbud E & P, Inc. | Spring, TX 77379 | Oil & Gas Operator | May 2025 |
| 328 | Redwood Energy, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Jul 1997 |
| 329 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 330 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | May 2025 |
| 331 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | May 2025 |
| 332 | Research Exploration, LLC | Kingwood, TX 77339 | Oil & Gas Operator | Feb 2018 |
| 333 | Reserve Production, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Mar 2008 |
| 334 | Retamco Operating Inc | Red Lodge, MT 59068 | Oil & Gas Operator | Mar 2025 |
| 335 | RHC Energy (USA) LLC | Houston, TX 77027 | Oil Operator | May 2025 |
| 336 | Rialto Oil & Gas Corporation | Houston, TX 77098 | Oil & Gas Operator | Oct 2012 |
| 337 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 338 | Riley Exploration Opg Co, LLC | La Grange, TX 78945 | Oil & Gas Operator | May 2025 |
| 339 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | May 2025 |
| 340 | Riley Permian Operating Co, LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | May 2025 |
| 341 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | May 2025 |
| 342 | Rme Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2002 |
| 343 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 344 | Rocc Oil & Gas, L.P. | Houston, TX 77084 | Oil & Gas Operator | Apr 2024 |
| 345 | Rocc Operating, LLC | Houston, TX 77084 | Oil & Gas Operator | May 2025 |
| 346 | Rockefeller Hughes (USA) LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2015 |
| 347 | Rod Oil & Gas LTD. | Houston, TX 77261 | Oil & Gas Operator | Jun 1995 |
| 348 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | May 2025 |
| 349 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 350 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 351 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | May 2025 |
| 352 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | Mar 2025 |
| 353 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 354 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 355 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 356 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | May 2025 |
| 357 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | May 2025 |
| 358 | SBJ Energy Partners, L.L.C. | Waco, TX 76710 | Oil & Gas Operator | May 2025 |
| 359 | Seago Petroleum, Inc. | Abilene, TX 79606 | Oil & Gas Operator | May 2025 |
| 360 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 361 | Seguro Well Service, Inc. | Gonzales, TX 78629 | Oil & Gas Operator | May 2025 |
| 362 | Sellers Lease Service, Inc. | Flatonia, TX 78941 | Oil & Gas Operator | May 2025 |
| 363 | Sellers' Lease Service | Flatonia, TX 78941 | Oil & Gas Operator | Jul 1994 |
| 364 | Senora Resources, Inc. | Dime Box, TX 77853 | Oil & Gas Operator | May 2025 |
| 365 | Sha-Jam Operating Corp. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 366 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | May 2025 |
| 367 | Showdown Energy Corporation | Dallas, TX 75230 | Oil & Gas Operator | Aug 2003 |
| 368 | Showdown Operating, Inc. | Dallas, TX 75230 | Oil & Gas Operator | May 1996 |
| 369 | Silver Oak Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 2009 |
| 370 | Silver Oak Operating, LLC | Longview, TX 75604 | Oil & Gas Operator | May 2025 |
| 371 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Feb 2025 |
| 372 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 373 | SN Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 374 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 375 | Somont Oil Co., Inc. | Spring, TX 77379 | Oil & Gas Operator | Mar 2025 |
| 376 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 377 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 378 | Southwest Oil & Land, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 1999 |
| 379 | Southwest Resources, Inc. | Brenham, TX 77834 | Oil & Gas Operator | May 2025 |
| 380 | Spiral Energy Corp. | Midland, TX 79705 | Oil & Gas Operator | Dec 2019 |
| 381 | Square One Corporation | Giddings, TX 78942 | Oil & Gas Operator | Dec 2012 |
| 382 | Stanton Mineral Development Inc | Austin, TX 78759 | Oil & Gas Operator | May 2025 |
| 383 | Sto Operating Company | San Antonio, TX 78258 | Oil & Gas Operator | May 2025 |
| 384 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 385 | Stroud Energy, LTD. | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2006 |
| 386 | Stroud Oil Properties, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | May 2013 |
| 387 | Summit Exploration, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2008 |
| 388 | Sutton Producing Corp. | San Antonio, TX 78270 | Oil & Gas Operator | May 2025 |
| 389 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 390 | Tal-Con, Inc. | Houston, TX 77279 | Oil & Gas Operator | May 2025 |
| 391 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 392 | Tanglewood Oil & Gas Co. | Gouldbusk, TX 76845 | Oil & Gas Operator | May 2025 |
| 393 | Taos Resources Operating Co LLC | Houston, TX 77037 | Oil & Gas Operator | Dec 2019 |
| 394 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | May 2025 |
| 395 | TC3 Energy Services Company | Bryan, TX 77805 | Oil & Gas Operator | Jan 2005 |
| 396 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 397 | Te-Ray Resources, Inc. | Oklahoma City, OK 73108 | Oil & Gas Operator | Mar 2015 |
| 398 | Te-Ray Resources, LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | May 2025 |
| 399 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 400 | Tekna Synergy Corporation | Midland, TX 79702 | Oil & Gas Operator | May 2025 |