| 401 | Placer Oil Co. | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2008 |
| 402 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 403 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 404 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 405 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 406 | Portal Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Mar 1993 |
| 407 | Preferred Pipeline Corp. | Victoria, TX 77902 | Oil & Gas Operator | Mar 2025 |
| 408 | Premier Operating Company | Tulsa, OK 74153 | Gas Operator | Nov 1996 |
| 409 | Premium Exploration Company | Early, TX 76803 | Oil & Gas Operator | Apr 2025 |
| 410 | Primera Energy, LLC | Longview, TX 75606 | Oil & Gas Operator | Mar 2016 |
| 411 | Principal Oil Corp. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2002 |
| 412 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 413 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Apr 2025 |
| 414 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2025 |
| 415 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 416 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 417 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Jan 2025 |
| 418 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 419 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | Apr 2025 |
| 420 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 421 | Redding, Bobby L. | Three Rivers, TX 78071 | Oil & Gas Operator | Mar 2004 |
| 422 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 423 | Remora Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Apr 2025 |
| 424 | Repsol Oil & Gas USA, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Apr 2025 |
| 425 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | Apr 2025 |
| 426 | Resaca Resources, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Apr 2025 |
| 427 | Reserve Operating Corp. | Houston, TX 77040 | Oil & Gas Operator | Apr 2025 |
| 428 | Rexcom, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 429 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Apr 2025 |
| 430 | Ridgemar Energy Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jan 2025 |
| 431 | Riley Exploration Opg Co, LLC | La Grange, TX 78945 | Oil & Gas Operator | Apr 2025 |
| 432 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Apr 2025 |
| 433 | Rio Exploration Company | San Antonio, TX 78209 | Gas Operator | Dec 2005 |
| 434 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 435 | Rock Resources, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Apr 2025 |
| 436 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2025 |
| 437 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 438 | Ross Gas And Oil, LTD. Co. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Apr 2025 |
| 439 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 440 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2025 |
| 441 | Royko Oil Company | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Apr 2025 |
| 442 | RTZ Energy, LLC | Kilgore, TX 75663 | Gas Operator | Apr 2006 |
| 443 | Rutherford Oil Corporation | Houston, TX 77046 | Oil & Gas Operator | Jun 2019 |
| 444 | S & L Oil Field Services | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Jan 1999 |
| 445 | S & S Energy | Englewood, CO 80112 | Oil & Gas Operator | Mar 2015 |
| 446 | Sabalo Exploration Operating,LLC | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jan 2021 |
| 447 | Safari Production Company, Inc. | McAllen, TX 78501 | Oil & Gas Operator | Apr 2025 |
| 448 | San Cajo Oil Company | Edmonds, WA 98020 | Oil & Gas Operator | Apr 2025 |
| 449 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | Apr 2025 |
| 450 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 451 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Apr 2025 |
| 452 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 453 | Sandpoint Operating, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2024 |
| 454 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Apr 2025 |
| 455 | Sbog, LLC | Granbury, TX 76048 | Oil & Gas Operator | Feb 2021 |
| 456 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 457 | Sea Eagle Ford, LLC | Denver, CO 80265 | Oil & Gas Operator | Jun 2022 |
| 458 | Secondary Oil Corp., Inc. | Austin, TX 78750 | Oil Operator | Apr 1999 |
| 459 | Sedco Resources Inc | Kerrville, TX 78029 | Oil & Gas Operator | Apr 2025 |
| 460 | Shell Trading Us Company | Houston, TX 77210 | Oil & Gas Operator | Jan 2025 |
| 461 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 462 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 463 | Shoreham Oil & Gas Company, Inc. | Katy, TX 77492 | Oil & Gas Operator | Apr 2025 |
| 464 | Sierra Resources, LLC | Houston, TX 77219 | Oil & Gas Operator | Aug 2021 |
| 465 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Jan 2025 |
| 466 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 467 | Simray GP, LLC | Richardson, TX 75080 | Oil & Gas Operator | Dec 2015 |
| 468 | Simray Oil & Gas, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Sep 2003 |
| 469 | Simray Operating Corp. | Richardson, TX 75080 | Oil & Gas Operator | Mar 2009 |
| 470 | Single Barrel Oil And Gas LLC | Granbury, TX 76048 | Oil & Gas Operator | Apr 2025 |
| 471 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2025 |
| 472 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2025 |
| 473 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Apr 2025 |
| 474 | SN Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 475 | South Texas Limited Partnership | Houston, TX 77060 | Oil & Gas Operator | Feb 1994 |
| 476 | South Texas Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2025 |
| 477 | Southern Oil & Gas LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2025 |
| 478 | Southern Resource Company | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2022 |
| 479 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 480 | Southwest Energy LP | Houston, TX 77002 | Oil & Gas Operator | Jan 2025 |
| 481 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 482 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Apr 2025 |
| 483 | Sparkman Energy, LLC | Fort Worth, TX 76147 | Oil & Gas Operator | Apr 2025 |
| 484 | Spiller, Robert S. | San Antonio, TX 78213 | Oil & Gas Operator | Oct 1995 |
| 485 | Starr Operating, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2025 |
| 486 | Statoil Texas Onshore Prop LLC | Austin, TX 78730 | Oil & Gas Operator | Dec 2018 |
| 487 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 488 | Stephenson, Light | Whitsett, TX 78075 | Oil & Gas Operator | Nov 2000 |
| 489 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 490 | Stoneham Oil Company | Houston, TX 77002 | Oil & Gas Operator | Sep 1995 |
| 491 | Stout Consulting Services, Inc. | Alice, TX 78333 | Oil & Gas Operator | May 1999 |
| 492 | STZ Petroleum Inc. | Houston, TX 77268 | Oil & Gas Operator | Dec 1997 |
| 493 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Apr 2025 |
| 494 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 495 | Suemaur Exploration, Inc. | Corpus Chrsti, TX 78470 | Oil & Gas Operator | Mar 2008 |
| 496 | Suncoast Technical Services Inc | Dallas, TX 75251 | Oil & Gas Operator | Apr 2025 |
| 497 | Sundance Energy Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2014 |
| 498 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 499 | Sure Flow Oil & Gas, Inc. | Victoria, TX 77902 | Oil & Gas Operator | Apr 2025 |
| 500 | Sutton Producing Corp. | San Antonio, TX 78270 | Oil & Gas Operator | Apr 2025 |