| 401 | Principal Oil Corp. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2002 |
| 402 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 403 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Jul 2025 |
| 404 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Jul 2025 |
| 405 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 406 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 407 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Apr 2025 |
| 408 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 409 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2025 |
| 410 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 411 | Redding, Bobby L. | Three Rivers, TX 78071 | Oil & Gas Operator | Mar 2004 |
| 412 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 413 | Remora Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 414 | Repsol Oil & Gas USA, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Jul 2025 |
| 415 | Republic Resources, LLC. | San Antonio, TX 78212 | Oil & Gas Operator | Jul 2025 |
| 416 | Resaca Resources, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Jul 2025 |
| 417 | Reserve Operating Corp. | Houston, TX 77040 | Oil & Gas Operator | Jul 2025 |
| 418 | Rexcom, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 419 | Rickaway Energy, Corp. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2025 |
| 420 | Ridgemar Energy Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jul 2025 |
| 421 | Riley Exploration Opg Co, LLC | La Grange, TX 78945 | Oil & Gas Operator | Jul 2025 |
| 422 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Jul 2025 |
| 423 | Rio Exploration Company | San Antonio, TX 78209 | Gas Operator | Dec 2005 |
| 424 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 425 | Rock Resources, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Jul 2025 |
| 426 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 427 | Rosewood Resources, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 428 | Ross Gas And Oil, LTD. Co. | Dripping SPGS, TX 78620 | Oil & Gas Operator | Jul 2025 |
| 429 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 430 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2025 |
| 431 | Royko Oil Company | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Jul 2025 |
| 432 | RTZ Energy, LLC | Kilgore, TX 75663 | Gas Operator | Apr 2006 |
| 433 | Rutherford Oil Corporation | Houston, TX 77046 | Oil & Gas Operator | Jun 2019 |
| 434 | S & L Oil Field Services | Carrizo SPGS, TX 78834 | Oil & Gas Operator | Jan 1999 |
| 435 | S & S Energy | Englewood, CO 80112 | Oil & Gas Operator | Mar 2015 |
| 436 | Sabalo Exploration Operating,LLC | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jan 2021 |
| 437 | Safari Production Company, Inc. | McAllen, TX 78501 | Oil & Gas Operator | Jul 2025 |
| 438 | San Cajo Oil Company | Edmonds, WA 98020 | Oil & Gas Operator | Jul 2025 |
| 439 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | Jul 2025 |
| 440 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 441 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 442 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 443 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | Jul 2025 |
| 444 | Sandpoint Operating, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2025 |
| 445 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Jul 2025 |
| 446 | Sbog, LLC | Granbury, TX 76048 | Oil & Gas Operator | Feb 2021 |
| 447 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 448 | Sea Eagle Ford, LLC | Denver, CO 80265 | Oil & Gas Operator | Jun 2022 |
| 449 | Secondary Oil Corp., Inc. | Austin, TX 78750 | Oil Operator | Apr 1999 |
| 450 | Sedco Resources Inc | Kerrville, TX 78029 | Oil & Gas Operator | Jul 2025 |
| 451 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 452 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 453 | Shoreham Oil & Gas Company, Inc. | Katy, TX 77492 | Oil & Gas Operator | Jul 2025 |
| 454 | Sierra Resources, LLC | Houston, TX 77219 | Oil & Gas Operator | Aug 2021 |
| 455 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Apr 2025 |
| 456 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 457 | Simray GP, LLC | Richardson, TX 75080 | Oil & Gas Operator | Dec 2015 |
| 458 | Simray Oil & Gas, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Sep 2003 |
| 459 | Simray Operating Corp. | Richardson, TX 75080 | Oil & Gas Operator | Mar 2009 |
| 460 | Single Barrel Oil And Gas LLC | Granbury, TX 76048 | Oil & Gas Operator | Jul 2025 |
| 461 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2025 |
| 462 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 463 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Jul 2025 |
| 464 | SN Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 465 | South Texas Limited Partnership | Houston, TX 77060 | Oil & Gas Operator | Feb 1994 |
| 466 | South Texas Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2025 |
| 467 | Southern Oil & Gas LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2025 |
| 468 | Southern Resource Company | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2022 |
| 469 | Southern Union Exploration Co. | Austin, TX 78701 | Oil & Gas Operator | Feb 2002 |
| 470 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 471 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Jul 2025 |
| 472 | Sparkman Energy, LLC | Fort Worth, TX 76147 | Oil & Gas Operator | Jul 2025 |
| 473 | Spiller, Robert S. | San Antonio, TX 78213 | Oil & Gas Operator | Oct 1995 |
| 474 | Starr Operating, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 475 | Statoil Texas Onshore Prop LLC | Austin, TX 78730 | Oil & Gas Operator | Dec 2018 |
| 476 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 477 | Stephenson, Light | Whitsett, TX 78075 | Oil & Gas Operator | Nov 2000 |
| 478 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 479 | Stoneham Oil Company | Houston, TX 77002 | Oil & Gas Operator | Sep 1995 |
| 480 | Stout Consulting Services, Inc. | Alice, TX 78333 | Oil & Gas Operator | May 1999 |
| 481 | STZ Petroleum Inc. | Houston, TX 77268 | Oil & Gas Operator | Dec 1997 |
| 482 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Jul 2025 |
| 483 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 484 | Suemaur Exploration, Inc. | Corpus Chrsti, TX 78470 | Oil & Gas Operator | Mar 2008 |
| 485 | Suncoast Technical Services Inc | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |
| 486 | Sundance Energy Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2014 |
| 487 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 488 | Sure Flow Oil & Gas, Inc. | Victoria, TX 77902 | Oil & Gas Operator | Jul 2025 |
| 489 | Sutton Producing Corp. | San Antonio, TX 78270 | Oil & Gas Operator | Jul 2025 |
| 490 | SV Energy Company, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2017 |
| 491 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 492 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |
| 493 | Sydri Operating, LLC | Dallas, TX 75231 | Oil & Gas Operator | Jul 2025 |
| 494 | Talisman Energy USA Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2016 |
| 495 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 496 | Tanos Production, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2003 |
| 497 | Tare Resources, LLC | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Jul 2025 |
| 498 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 499 | Teal Operating, LLC | Dallas, TX 75225 | Oil & Gas Operator | Oct 2021 |
| 500 | Terrafina Energy, LLC | San Antonio, TX 78280 | Oil & Gas Operator | Jul 2025 |