| 401 | Pledger Operating Co. Inc. | | Oil & Gas Operator | Jul 2025 |
| 402 | PLS Operating Co, Inc. | | Oil & Gas Operator | Jul 1989 |
| 403 | Pompano Resource Operator LLC | | Oil & Gas Operator | Jun 2025 |
| 404 | Post Hole Drilling Company, LLC | | Oil & Gas Operator | Nov 2023 |
| 405 | Poydras Energy Partners, LLC | | Oil & Gas Operator | Dec 2021 |
| 406 | Premier Natural Resources II,LLC | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2015 |
| 407 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2025 |
| 408 | Primal Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 409 | Professional Management Serv | | Oil Operator | Mar 1991 |
| 410 | Prospective Investment & Trading Co., LTD., The | Tulsa, OK 74170-2320 | Oil & Gas Operator | Apr 2014 |
| 411 | Pruet Production Co. | Jackson, MS 39201 | Oil & Gas Operator | Jul 2025 |
| 412 | Pursue Energy Corp | | Gas Operator | Sep 2016 |
| 413 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 414 | R & C Petroleum, Inc. | Flint, TX 75762 | Oil & Gas Operator | Oct 2025 |
| 415 | R & H Oil & Gas, Inc. | | Oil & Gas Operator | Apr 1992 |
| 416 | R. I. P. Operating | | Oil Operator | Oct 1986 |
| 417 | R. W. Tyson Producing Co.,Inc | | Oil & Gas Operator | Dec 2024 |
| 418 | Radiant Oil & Gas Operating Company, Inc | | Oil & Gas Operator | Aug 2015 |
| 419 | Radzewicz Expl. & DRLG. Corp. | | Oil & Gas Operator | Mar 2011 |
| 420 | Radzewicz Operating Corp. | | Oil & Gas Operator | Oct 2017 |
| 421 | Ram Petroleum, LLC | Tylertown, MS 39667 | Oil & Gas Operator | Jul 2025 |
| 422 | Rebel Drilling Company, L. P. | | Oil & Gas Operator | Sep 2004 |
| 423 | Recon Operating, Inc. | | Oil & Gas Operator | Jun 1991 |
| 424 | Red Sands Energy, LLC | | Oil & Gas Operator | Apr 2017 |
| 425 | Reeves Prod. Co. | | Oil & Gas Operator | Mar 1989 |
| 426 | Reformation Energy Inc | | Oil & Gas Operator | May 1984 |
| 427 | Remington Oil And Gas Corporation | | Oil & Gas Operator | Sep 2009 |
| 428 | Remora Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 429 | Resolve Energy Corp | | Gas Operator | May 2009 |
| 430 | Reynolds E & P, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Oct 2025 |
| 431 | Ringer Oil Co Inc | | Oil & Gas Operator | Aug 1989 |
| 432 | RLP Gulf States, L.L.C. | | Oil & Gas Operator | Apr 2012 |
| 433 | Robinson Resource Dev. Co.Inc. | | Oil & Gas Operator | Oct 1982 |
| 434 | Rock Oil, Inc. | | Oil Operator | Nov 1989 |
| 435 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | Jun 2025 |
| 436 | Roppolo Petroleum Co. | | Oil & Gas Operator | Jan 2000 |
| 437 | Rosson Et Al | | Oil Operator | Aug 1983 |
| 438 | Rosson Exploration Company | | Oil & Gas Operator | Apr 2005 |
| 439 | Roundtree & Associates, Inc. | | Oil & Gas Operator | Jun 2024 |
| 440 | Rover Operating, LLC | Chicago, IL 60606 | Oil & Gas Operator | Jun 2025 |
| 441 | S. Lavon Evans Jr Inc, Et Al | | Oil & Gas Operator | Jan 2010 |
| 442 | S. Lavon Evans, Jr. Operating Co., Inc. | | Oil & Gas Operator | Aug 2014 |
| 443 | Sabine Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 1996 |
| 444 | Samedan Energy Development Cor | | Oil & Gas Operator | Feb 1987 |
| 445 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 446 | Santa Fe Energy Op Partners LP | | Oil & Gas Operator | Oct 1989 |
| 447 | Santo Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 448 | Savannah Joint Ventures | | Oil & Gas Operator | Nov 2000 |
| 449 | Savannah Oil And Gas, L. L. C. | | Oil & Gas Operator | Oct 1998 |
| 450 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 451 | Scorpion Oil & Gas, LLC | Houston, TX 77036 | Oil & Gas Operator | May 2025 |
| 452 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 453 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 454 | Secan Oil Co., Inc. | | Oil & Gas Operator | May 1987 |
| 455 | Serio Energy Corporation | | Oil & Gas Operator | Jul 2000 |
| 456 | Serio Operating Company | | Oil & Gas Operator | Mar 2007 |
| 457 | Serio-Punches Oil Co | | Oil Operator | Jan 2008 |
| 458 | Shell Oil Co. -Nola | | Oil & Gas Operator | Jun 2000 |
| 459 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 460 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 461 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Oct 2025 |
| 462 | Shield Resources Inc | | Oil & Gas Operator | Nov 1987 |
| 463 | Sidney E. Pinkston, Jr, Trustee | | Oil & Gas Operator | Apr 1980 |
| 464 | Signal, LLC | | Oil & Gas Operator | Jul 2025 |
| 465 | Skelly Oil Co | | Oil & Gas Operator | Mar 2005 |
| 466 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Oct 2025 |
| 467 | Skrivanos Engineering, Inc. | Shreveport, LA 71164 | Oil & Gas Operator | Dec 2011 |
| 468 | Skye MS, LLC | | Oil & Gas Operator | Jul 2025 |
| 469 | Slik-Dril P & A Inc | | Oil & Gas Operator | Sep 1989 |
| 470 | Slik-Dril, Inc | | Oil & Gas Operator | Nov 1998 |
| 471 | Smith Operating & Management Co. | Shreveport, LA 71161 | Oil & Gas Operator | Feb 2005 |
| 472 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 473 | Smith, Clyde H. Oper. Co., Inc. | | Oil & Gas Operator | Jun 1994 |
| 474 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 475 | Sooner Corporation | | Oil & Gas Operator | Oct 1990 |
| 476 | Southeastern Producing Co | | Oil Operator | Jul 1988 |
| 477 | Southern Energy Operating, LLC | | Oil & Gas Operator | Jun 2025 |
| 478 | Southern Hydrocarbons Inc | | Oil & Gas Operator | Jul 1989 |
| 479 | Southern Natural Gas Company LLC | | Oil & Gas Operator | Nov 2024 |
| 480 | Southwest Mississippi Oil & Gas, LLC. | | Oil Operator | Jul 2025 |
| 481 | Spooner Petroleum Company | | Oil & Gas Operator | Jul 2025 |
| 482 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 483 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 484 | Standard Operating Inc | | Oil Operator | Jun 1986 |
| 485 | Starr Operating Company | Austin, TX 78759 | Oil & Gas Operator | Oct 2025 |
| 486 | State Line Exploration, LLC | | Oil & Gas Operator | Dec 2024 |
| 487 | Stinson, Jan | | Oil Operator | May 1984 |
| 488 | Story Oil And Gas Inc | Magnolia, AR 71753 | Oil & Gas Operator | Jan 2025 |
| 489 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 490 | Streetman Inc | | Oil Operator | Oct 1987 |
| 491 | Strong Rock Operating Company, LLC | | Oil & Gas Operator | Jul 2025 |
| 492 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | Oct 2025 |
| 493 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 494 | Sun Oil Company | Dallas, TX 75373 | Oil & Gas Operator | Dec 2021 |
| 495 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Oct 2025 |
| 496 | Sunland Production Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2025 |
| 497 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 498 | Swampfox Oilfield Services, LLC | | Oil & Gas Operator | Dec 2024 |
| 499 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 500 | T. J. Oil And Gas, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2002 |