| 401 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 402 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 403 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 404 | Petrocorp Acquisition Company | Tulsa, OK 74121 | Oil & Gas Operator | Dec 2002 |
| 405 | Petrocorp Incorporated,A TX.Corp | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2005 |
| 406 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 407 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | May 2025 |
| 408 | Pintex Operating Inc. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Feb 2005 |
| 409 | Pioneer Natural Res. USA, Inc. | Irving, TX 75038 | Oil & Gas Operator | May 2025 |
| 410 | Pipeline Management, Inc. | Lubbock, TX 79401 | Oil & Gas Operator | Dec 2002 |
| 411 | Placer Oil Co. | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2008 |
| 412 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 413 | Pmi Energy Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2002 |
| 414 | Poco LLC | Houston, TX 77270 | Oil & Gas Operator | May 2025 |
| 415 | Pool Operating Corporation | Lago VIsta, TX 78645 | Oil & Gas Operator | Oct 2016 |
| 416 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 417 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | May 2025 |
| 418 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | May 2025 |
| 419 | Proton Energy, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2005 |
| 420 | Quisto Expl. & Production, L.C. | Sugar Land, TX 77478 | Oil & Gas Operator | Aug 1998 |
| 421 | Ramsower Minerals Corporation | Beeville, TX 78104 | Oil & Gas Operator | Sep 2013 |
| 422 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | May 2025 |
| 423 | Rec Well Service, Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2008 |
| 424 | Reddy Disposals, LLC | Beeville, TX 78104 | Oil Operator | May 2025 |
| 425 | Redhorn Resources, LLC | Spring, TX 77393 | Oil Operator | May 2025 |
| 426 | Regent Oil & Gas Company, L.P. | Dallas, TX 75225 | Oil & Gas Operator | Sep 2006 |
| 427 | Rego Development Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2002 |
| 428 | Reh Energy, Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | May 2025 |
| 429 | Remora Operating LLC | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 430 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | May 2025 |
| 431 | Repsol Oil & Gas USA, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 432 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | May 2025 |
| 433 | Richter Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2007 |
| 434 | Riddle Engineering Corp. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2011 |
| 435 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | May 2025 |
| 436 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78427 | Oil & Gas Operator | May 2025 |
| 437 | Rio Bravo Expl. & Prod. Co. | Houston, TX 77055 | Oil & Gas Operator | Apr 2020 |
| 438 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 439 | Rio Exploration Company | San Antonio, TX 78209 | Gas Operator | Dec 2005 |
| 440 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 441 | Rock Resources, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | May 2025 |
| 442 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 443 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 444 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 445 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 446 | RR Ventures Limited Partnership | San Antonio, TX 78239 | Oil & Gas Operator | May 2025 |
| 447 | Ruwco Oil And Gas Corp. | Austin, TX 78701 | Oil & Gas Operator | Aug 2021 |
| 448 | S & C Construction, Inc. | Whitefish, MT 59937 | Oil & Gas Operator | May 2025 |
| 449 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 450 | Salida Exploration, LLC | Abilene, TX 79603 | Oil & Gas Operator | May 2025 |
| 451 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 452 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 453 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | May 2025 |
| 454 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 455 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 456 | Santa Fe Energy Oper. Part., LP | Houston, TX 77057 | Oil & Gas Operator | Dec 1994 |
| 457 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | May 2025 |
| 458 | Saxum Oil & Gas, LLC | Beeville, TX 78104 | Oil & Gas Operator | May 2025 |
| 459 | Scully Energy Corporation | Salado, TX 76571 | Oil & Gas Operator | Mar 2012 |
| 460 | Sedona Oil & Gas Corporation | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 461 | Seguro Well Service, Inc. | Gonzales, TX 78629 | Oil & Gas Operator | May 2025 |
| 462 | Serco Operating LLC | Katy, TX 77450 | Oil Operator | May 2025 |
| 463 | Shale Hunter, LLC | Irving, TX 75039 | Oil & Gas Operator | Jan 2016 |
| 464 | Sharon Hunter Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Sep 2012 |
| 465 | Sharon Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Aug 2010 |
| 466 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 467 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | May 2025 |
| 468 | Shoreham Oil & Gas Company, Inc. | Katy, TX 77492 | Oil & Gas Operator | May 2025 |
| 469 | Siegfried R H Inc | Tulsa, OK 74104 | Oil & Gas Operator | Mar 2008 |
| 470 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Feb 2025 |
| 471 | Silverbrook Operating II LLC | Barker, TX 77413 | Oil & Gas Operator | May 2025 |
| 472 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 473 | Soco Gas Properties | Goliad, TX 77963 | Oil & Gas Operator | May 2025 |
| 474 | Sonat Exploration Co. - Houston | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 475 | South Texas Injection Company | Mineral, TX 78125 | Oil & Gas Operator | Dec 2016 |
| 476 | Southern Mineral Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2001 |
| 477 | Southern Resource Company | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2022 |
| 478 | Southern Royalty Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Feb 1997 |
| 479 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 480 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 481 | Spiller Operating Co., Inc. | Round Rock, TX 78665 | Oil & Gas Operator | May 2015 |
| 482 | Spindletop Drilling Co. | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 483 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 484 | SRS Properties, LLC | Whitehouse, TX 75791 | Oil & Gas Operator | May 2025 |
| 485 | SSC, Inc. | Lubbock, TX 79408 | Oil & Gas Operator | May 2025 |
| 486 | Stallion Oil Company | Lafayette, LA 70505 | Oil & Gas Operator | Jun 2004 |
| 487 | Staples, James W. | Tuleta, TX 78162 | Oil & Gas Operator | Sep 2014 |
| 488 | Staples, James W. Prod. Co. | Tuleta, TX 78162 | Oil & Gas Operator | May 2025 |
| 489 | Staples, Tommy Oil Co. | Pettus, TX 78146 | Oil & Gas Operator | Mar 2008 |
| 490 | Starco Exploration, Inc. | Dallas, TX 75360 | Oil & Gas Operator | May 2025 |
| 491 | Stark Petroleum | Tuleta, TX 78162 | Oil & Gas Operator | May 2025 |
| 492 | Statoil Texas Onshore Prop LLC | Austin, TX 78730 | Oil & Gas Operator | Dec 2018 |
| 493 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2025 |
| 494 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 495 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 496 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 497 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 498 | Suemaur Exploration, Inc. | Corpus Chrsti, TX 78470 | Oil & Gas Operator | Mar 2008 |
| 499 | Suemaur Operating LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 500 | Sun Exploration, Inc. | Alice, TX 78332 | Oil & Gas Operator | May 2025 |