| 401 | Prospective Investment & Trading | Scottsdale, AZ 85261-4190 | Oil & Gas Operator | Jun 2016 |
| 402 | Proven Reserves Management, Inc. | Dallas, TX 75370 | Oil & Gas Operator | Apr 2026 |
| 403 | Pyro Energy Corp | Kingwood, TX 77339-2102 | Oil & Gas Operator | Mar 1998 |
| 404 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Apr 2026 |
| 405 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Apr 2026 |
| 406 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 407 | Questar Explor & Prod Co | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2017 |
| 408 | R L Clampitt & Associates LLC | Bartlesville, OK 74006 | Oil & Gas Operator | May 2026 |
| 409 | Rafter H Operating LLC | El Reno, OK 73036 | Oil & Gas Operator | Apr 2026 |
| 410 | Ramco Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2006 |
| 411 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 412 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 413 | Ratex Resources Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | May 2000 |
| 414 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 415 | Reading & Bates Petroleum Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 416 | Red Bluff Resources Operating LLC | Oklahoma City, OK 73112-5468 | Oil & Gas Operator | Apr 2026 |
| 417 | Red Wolf Operating LLC | Edmond, OK 73003-2179 | Oil & Gas Operator | May 2026 |
| 418 | Redline Energy LLC | Dover, OK 73734 | Oil & Gas Operator | May 2026 |
| 419 | Republic Energy Inc. | Decatur, TX 76234 | Oil & Gas Operator | Dec 2016 |
| 420 | Reserve Acquisition Group | Tulsa, OK 74153 | Oil & Gas Operator | Dec 1993 |
| 421 | Resolute Wyoming Inc | Denver, CO 80203 | Oil & Gas Operator | May 2018 |
| 422 | Resources Operating Co Inc | Rogers, AR 72756 | Oil & Gas Operator | Oct 2025 |
| 423 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | Apr 2026 |
| 424 | Reynolds J W & Associates | Sapulpa, OK 74066 | Oil & Gas Operator | Dec 2000 |
| 425 | Richland Resources Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2026 |
| 426 | Ricks Expl Acquisition Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2004 |
| 427 | Ricks Expl Acquisition LLC | Midland, TX 79701 | Oil & Gas Operator | Aug 2013 |
| 428 | Ricks Exploration Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 429 | Rimrock Resource Operating LLC | Tulsa, OK 74103-4462 | Oil & Gas Operator | Apr 2026 |
| 430 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 431 | Rja Energy LLC | Norman, OK 73069-8224 | Oil & Gas Operator | May 2026 |
| 432 | RKK Production Company | Mustang, OK 73064 | Oil & Gas Operator | May 2026 |
| 433 | RMS Monte Christo, LLC | Snowmass VLG., CO 81615 | Oil & Gas Operator | Mar 2023 |
| 434 | Rockwell Energy Corporation | Tulsa, OK 74105 | Oil & Gas Operator | Apr 2014 |
| 435 | Rocky Roads Operating LLC | Tulsa, OK 74103-4048 | Oil & Gas Operator | May 2026 |
| 436 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Jul 2026 |
| 437 | Rover Operating, LLC | Chicago, IL 60606 | Oil & Gas Operator | Apr 2026 |
| 438 | RTC Resources, LLP | Weatherford, OK 73096 | Oil & Gas Operator | Jul 2026 |
| 439 | Rupe Oil Company Inc | Wichita, KS 67278 | Oil & Gas Operator | Mar 2026 |
| 440 | Rush-Andrus Engineering | Royse City, TX 75189-1210 | Oil & Gas Operator | Feb 2022 |
| 441 | Russell D Meloy Oil & Gas Co | Enid, OK 73703-1623 | Oil & Gas Operator | Apr 2026 |
| 442 | S & G Operating LLC | McLoud, OK 74851 | Oil & Gas Operator | May 2026 |
| 443 | S & S Oil & Gas Corporation | Okemah, OK 74859-0659 | Oil & Gas Operator | Sep 2014 |
| 444 | S & S Star Operating, LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Jun 2026 |
| 445 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2026 |
| 446 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 447 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 448 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 449 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Jul 2026 |
| 450 | Sanguine Gas Exploration, LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jul 2026 |
| 451 | Santa Fe Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 452 | Santa Fe Energy Operating Partner LP | Midland, TX 79701 | Oil & Gas Operator | Sep 2004 |
| 453 | Santa Fe Minerals, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Sep 2013 |
| 454 | Santa Rita Resources Inc & Subs | | Oil & Gas Operator | Mar 2015 |
| 455 | Scana Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Dec 1999 |
| 456 | Scana Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2005 |
| 457 | Scarth Oil & Gas Co | Amarillo, TX 79101 | Oil & Gas Operator | Feb 1999 |
| 458 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 459 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 460 | Seagull Midcon Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 461 | Search Drilling Company | Houston, TX 77010 | Oil & Gas Operator | Feb 2001 |
| 462 | Shoreline Operating LLC | Oklahoma City, OK 73113 | Oil & Gas Operator | Apr 2026 |
| 463 | Singer Oil Co LLC | Hennessey, OK 73742 | Oil & Gas Operator | May 2026 |
| 464 | SK Plymouth LLC | Houston, TX 77079-1222 | Oil & Gas Operator | Apr 2026 |
| 465 | Skycap Energy, LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Jul 2026 |
| 466 | Slawson Donald C | Wichita, KS 67202 | Oil & Gas Operator | Oct 2025 |
| 467 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2026 |
| 468 | Sloan Petroleum Service Inc | Guthrie, OK 73044 | Oil & Gas Operator | May 2026 |
| 469 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Jul 2026 |
| 470 | Smith Edward F | Avant, OK 74001-0024 | Oil & Gas Operator | Nov 2014 |
| 471 | Sneed William A Bill | Cleveland, OK 74020-1007 | Oil & Gas Operator | Apr 2026 |
| 472 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 473 | Sooner Acquisition Corp | Wichita, KS 67206 | Oil & Gas Operator | Sep 1993 |
| 474 | Sooner Oil & Gas LLC | Fairview, OK 73737-1806 | Oil & Gas Operator | Apr 2026 |
| 475 | Sooner Oil & Gas Management Inc | Crescent, OK 73928 | Oil & Gas Operator | May 2026 |
| 476 | Southport Exploration Inc | Tulsa, OK 74103-4015 | Oil & Gas Operator | Nov 1998 |
| 477 | Southwest Energy LP | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2026 |
| 478 | Sparks Resources Inc | Bristow, OK 74010 | Oil & Gas Operator | May 2026 |
| 479 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | May 2026 |
| 480 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 481 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 482 | Staghorn Energy, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 483 | Staghorn Petroleum II LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | May 2026 |
| 484 | Staghorn Petroleum LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Apr 2026 |
| 485 | Stalwart Energy Co | Tulsa, OK 74103-3518 | Oil & Gas Operator | Apr 2014 |
| 486 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jul 2026 |
| 487 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | May 2026 |
| 488 | Stewart K Petroleum Corp | Edmond, OK 73013 | Oil & Gas Operator | Mar 2015 |
| 489 | Stone Oak Operating LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | May 2026 |
| 490 | Stride Energy LLC | Piedmont, OK 73078 | Oil & Gas Operator | May 2026 |
| 491 | Struck Rock Oil And Gas LLC | Geary, OK 73040 | Oil & Gas Operator | Apr 2026 |
| 492 | Summit Overseas Expl., Inc. | Lakewood, CO 80226 | Oil & Gas Operator | Apr 2007 |
| 493 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Jul 2026 |
| 494 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 495 | Sunterra Energy Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2009 |
| 496 | Superior Midstream, LLC | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2020 |
| 497 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 498 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 499 | Tack Operating LLC | Oklahoma City, OK 73172-1492 | Oil & Gas Operator | Aug 2021 |
| 500 | Tag Team Resources LLC | Eufaula, OK 74432 | Oil & Gas Operator | Apr 2026 |