| 401 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | Mar 2025 |
| 402 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 403 | Plains Marketing, LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 404 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 405 | Pogo Producing Company LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2025 |
| 406 | Pressly Oil Interest, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 407 | Preston, John WM. | Houston, TX 77004 | Oil & Gas Operator | May 2004 |
| 408 | Production Resources, Inc. | Castroville, TX 78009 | Oil & Gas Operator | Mar 2025 |
| 409 | Property Development Group, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Mar 2025 |
| 410 | Prospectors LTD., The | Somerset, TX 78069 | Oil & Gas Operator | Jun 2002 |
| 411 | Protege Energy III LLC | Houston, TX 77024 | Oil & Gas Operator | Sep 2024 |
| 412 | Pullin Lease Service, Inc. | Taft, TX 78390 | Oil & Gas Operator | Mar 2025 |
| 413 | Pyle Petroleum, Inc. | Tyler, TX 75703 | Oil & Gas Operator | Mar 2025 |
| 414 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 415 | Quest Research & Dev. Corp. | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2025 |
| 416 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 417 | Quintanilla, Tony C. | Atascosa, TX 78002 | Oil & Gas Operator | Mar 2025 |
| 418 | Quorum Energy Company | Dallas, TX 75201 | Oil & Gas Operator | Mar 2025 |
| 419 | R & B Oil Company, LLC | Willis, TX 77318 | Oil & Gas Operator | Mar 2025 |
| 420 | R W Ranch | San Antonio, TX 78211 | Oil Operator | Mar 2025 |
| 421 | R-A-R Interests | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2003 |
| 422 | Ragars Oil & Gas Co. | Austin, TX 78716 | Oil & Gas Operator | Mar 2025 |
| 423 | Rainer Energy, Inc. | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2025 |
| 424 | Ralyn Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Mar 2025 |
| 425 | Rampage Exploration, Inc. | Austin, TX 78737 | Oil & Gas Operator | Mar 2025 |
| 426 | Raol Company, The | Natalia, TX 78059 | Oil & Gas Operator | Mar 2025 |
| 427 | Ray Jr. Co., Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Mar 2025 |
| 428 | Rec Well Service, Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2008 |
| 429 | Rec, LLC | Pleasanton, TX 78064 | Oil & Gas Operator | Mar 2025 |
| 430 | Recoil Resources Operating, Inc. | Houston, TX 77046 | Oil & Gas Operator | Mar 2024 |
| 431 | Red Chalk Resources LLC | Houston, TX 77218 | Oil Operator | Mar 2025 |
| 432 | Redman Operating Company | Houston, TX 77042 | Oil & Gas Operator | May 2008 |
| 433 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 434 | Regency Energy, Inc. | Crystal City, TX 78839 | Oil & Gas Operator | Mar 2025 |
| 435 | Reh Energy, Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Mar 2025 |
| 436 | Repsol Eagle Ford North, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Jul 2023 |
| 437 | Repsol Oil & Gas USA, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Mar 2025 |
| 438 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | Mar 2025 |
| 439 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Mar 2025 |
| 440 | Ridgemar Energy Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 441 | Rife Oil Properties Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2025 |
| 442 | Rio Exploration Company | San Antonio, TX 78209 | Gas Operator | Dec 2005 |
| 443 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 444 | Rodenberg, Laura Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Mar 2025 |
| 445 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Mar 2025 |
| 446 | Roland Oil Company | Charlotte, TX 78011 | Oil & Gas Operator | Mar 2025 |
| 447 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 448 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2025 |
| 449 | Rosner, S. | San Antonio, TX 78216 | Oil & Gas Operator | Aug 1996 |
| 450 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 451 | Royal Seahorse Developments Inc | San Antonio, TX 78209 | Oil & Gas Operator | Oct 1994 |
| 452 | RR Ventures Limited Partnership | San Antonio, TX 78239 | Oil & Gas Operator | Mar 2025 |
| 453 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 454 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 455 | Sandia Operating Corp. | San Antonio, TX 78270 | Oil & Gas Operator | May 2010 |
| 456 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Mar 2025 |
| 457 | Schroeder Oil Properties | Graham, TX 76450 | Oil & Gas Operator | Jul 2022 |
| 458 | Sea Eagle Ford, LLC | Denver, CO 80265 | Oil & Gas Operator | Jun 2022 |
| 459 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 460 | Sedco Resources Inc | Kerrville, TX 78029 | Oil & Gas Operator | Mar 2025 |
| 461 | Seeker Oil Company II, Inc. | San Antonio, TX 78209 | Oil Operator | Jan 2016 |
| 462 | Seeker Oil Company, Incorporated | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2025 |
| 463 | Serra Energy, Inc. | Hailey, ID 83333 | Oil & Gas Operator | May 2011 |
| 464 | Shale Hunter, LLC | Irving, TX 75039 | Oil & Gas Operator | Jan 2016 |
| 465 | Sharon Hunter Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Sep 2012 |
| 466 | Shell Trading Us Company | Houston, TX 77210 | Oil & Gas Operator | Dec 2024 |
| 467 | SHWJ Oil & Gas Co., Inc. | Oil City, LA 71061 | Oil Operator | Mar 2025 |
| 468 | Sierra Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2008 |
| 469 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 470 | Sisters Operating Company | Victoria, TX 77904 | Oil & Gas Operator | Nov 2010 |
| 471 | Skidmore Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Jul 1997 |
| 472 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 473 | Somex Energy Company | San Antonio, TX 78230 | Oil & Gas Operator | Mar 2002 |
| 474 | Sonat Exploration Co. - Houston | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 475 | Sonora Petroleum Corp. | Austin, TX 78734 | Oil & Gas Operator | Mar 2025 |
| 476 | South Texas Drilling & Expl, Inc | San Antonio, TX 78217 | Oil & Gas Operator | Jan 1999 |
| 477 | Southwest Energy LP | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 478 | Southwest Loop 1604, LTD. | San Antonio, TX 78209 | Oil Operator | Sep 2022 |
| 479 | Spain Oil Company | Somerset, TX 78069 | Oil & Gas Operator | Mar 2025 |
| 480 | Spicewood Operating Company, LLC | Austin, TX 78746 | Oil & Gas Operator | Mar 2025 |
| 481 | Spiller, Robert S. | San Antonio, TX 78213 | Oil & Gas Operator | Oct 1995 |
| 482 | Spur Operating Co. | Austin, TX 78701 | Oil & Gas Operator | Mar 2025 |
| 483 | Starr Operating Company | Austin, TX 78759 | Oil & Gas Operator | Mar 2025 |
| 484 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 485 | Sto Operating Company | San Antonio, TX 78258 | Oil & Gas Operator | Mar 2025 |
| 486 | Stone, M. L. | Kerrville, TX 78029 | Oil & Gas Operator | Aug 2003 |
| 487 | Stoneburner Exploration, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Oct 1997 |
| 488 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 489 | Strata Star Petroleum Corp. | Uvalde, TX 78801 | Oil Operator | Mar 2025 |
| 490 | Stubbs, J. W. | Suwanee, GA 30024 | Oil & Gas Operator | Mar 2008 |
| 491 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Mar 2025 |
| 492 | Syj Oil & Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2025 |
| 493 | Tandem Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2025 |
| 494 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 495 | Teal Operating, LLC | Dallas, TX 75225 | Oil & Gas Operator | Oct 2021 |
| 496 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 497 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Mar 2025 |
| 498 | Texas Royalty Corp. | Austin, TX 78746 | Oil & Gas Operator | Mar 2025 |
| 499 | Texas Secondary Oil Corporation | Devine, TX 78016 | Oil & Gas Operator | Mar 2025 |
| 500 | Texas Southern Petroleum Corp. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Mar 2025 |