| 401 | North Ridge Corporation | Duncanville, TX 75137 | Oil & Gas Operator | May 2025 |
| 402 | North Star Energy, Inc. | Strawn, TX 76475 | Oil & Gas Operator | Jan 2010 |
| 403 | North Texas Oil & Gas, LLC | Edmond, OK 73013 | Oil & Gas Operator | May 2025 |
| 404 | North Texas Plugging, LLC | Denton, TX 76205 | Oil & Gas Operator | May 2025 |
| 405 | NWG Operating LLC | Canyon, TX 79015 | Oil & Gas Operator | May 2025 |
| 406 | O'Neil, Pat | Wichita Falls, TX 76308 | Oil & Gas Operator | Nov 2005 |
| 407 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | May 2025 |
| 408 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 409 | Okreek Oil Company | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 410 | Older Than Dirt LLC | Palo Pinto, TX 76484 | Oil & Gas Operator | May 2025 |
| 411 | Ole Chaparral On Possum Kingdom | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1997 |
| 412 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 413 | Orr, Robert M. | Monahans, TX 79756 | Oil & Gas Operator | Oct 1998 |
| 414 | Orth Oil Company, Inc. | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 415 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 416 | Osborne Oil Co. | Dallas, TX 75244 | Oil & Gas Operator | Aug 2003 |
| 417 | Packard Gas Company | Irving, TX 75063 | Oil & Gas Operator | Nov 2006 |
| 418 | Paragon Corporation | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 419 | Pardue Energy Inc. | Dallas, TX 75230 | Oil & Gas Operator | Dec 2015 |
| 420 | Pardue Oil | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 2006 |
| 421 | Pardue Oil, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 422 | Pardue, William M., III | Fort Worth, TX 76116 | Oil & Gas Operator | Dec 1996 |
| 423 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 424 | Parker Energy Company | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 425 | Parks, Rhone Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 426 | Partech Investments LLC | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 427 | Paschal Petroleum, Inc. | Dallas, TX 75380 | Oil & Gas Operator | Apr 1994 |
| 428 | Patterson Oil Company, The | Eastland, TX 76448 | Oil & Gas Operator | Feb 2025 |
| 429 | Payne Petroleum | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 430 | Pendragon Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 431 | Perkins-Prothro Company | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2002 |
| 432 | Permian West Corp. | Odessa, TX 79762 | Oil & Gas Operator | May 2025 |
| 433 | Permico Corporation | Stafford, TX 77477 | Oil & Gas Operator | Nov 2003 |
| 434 | Perry Operating Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 435 | Peters Petroleum Corporation | Dallas, TX 75243 | Oil & Gas Operator | Jan 2014 |
| 436 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 437 | Petram Oil And Gas, LLC | Richmond, TX 77407 | Oil Operator | May 2025 |
| 438 | Petro-Beth Oil & Gas, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2006 |
| 439 | Petrobal Omega 1, LLC | Little Elm, TX 75068 | Oil & Gas Operator | May 2025 |
| 440 | Petrocat Innovations, LLC | Forney, TX 75126 | Oil Operator | May 2025 |
| 441 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 442 | Petroleum Property MGMT, Inc (A) | Fort Worth, TX 76101 | Oil & Gas Operator | May 1994 |
| 443 | Petropro Energy Partners, L.P. | Houston, TX 77024 | Oil & Gas Operator | Jan 2013 |
| 444 | PG-M International Operating,LLC | Borger, TX 79008 | Oil & Gas Operator | May 2025 |
| 445 | Phillips Operating Co. | Mineral Wells, TX 76067 | Oil & Gas Operator | Jan 2013 |
| 446 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 447 | Pintail Production Co., Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | May 2025 |
| 448 | Pittencrieff America Inc | Abilene, TX 79608 | Oil & Gas Operator | Feb 2003 |
| 449 | PK Gath & Oilfield SVCS, Inc. | Cleburne, TX 76031 | Oil & Gas Operator | May 2025 |
| 450 | Place Oil And Gas Co. | Eastland, TX 76448 | Oil & Gas Operator | May 2025 |
| 451 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 452 | Post Oak Operating, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 453 | Power, Scott | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 1997 |
| 454 | Price, W. H. | Granbury, TX 76048 | Oil & Gas Operator | Jun 2024 |
| 455 | Primexx Operating Corporation | Dallas, TX 75206 | Oil & Gas Operator | Mar 2024 |
| 456 | Pro Oil & Gas Inc | Frankfort, IL 60423 | Oil & Gas Operator | May 2014 |
| 457 | Pryor Petroleum Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2025 |
| 458 | PV Oil Services, LLC | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 459 | Quail Well Service, Inc. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 460 | R & B Energy Co. | Ranger, TX 76470 | Oil & Gas Operator | Mar 2008 |
| 461 | Rainbow Seven Oil & Gas, Inc. | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 462 | Ram Oil And Gas, Inc. | Walsh, CO 81090 | Oil & Gas Operator | May 2025 |
| 463 | Ranger Operating Co. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 464 | Ray Herring Estate | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 465 | Ray Herring Operating Co., LLC | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 466 | Red Fork Production, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Feb 2025 |
| 467 | Red Gap Oil & Gas LLC | Cisco, TX 76437 | Oil & Gas Operator | May 2025 |
| 468 | Red-Tex Petroleum, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Aug 2003 |
| 469 | Reef Exploration, Inc. (A-1) | Richardson, TX 75080 | Oil & Gas Operator | Oct 2006 |
| 470 | Resaca Resources, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 471 | Richey, Ray Management Co., Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | May 2025 |
| 472 | Ridge Oil Company | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 473 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | May 2025 |
| 474 | Riptide Energy LLC | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 475 | Ro-Jo, Inc. | Highland VLG, TX 75077 | Oil & Gas Operator | Aug 2003 |
| 476 | Rob-Joe Gas & Oil Co. | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 477 | Robert C. Brower, LLC | Southlake, TX 76092 | Oil & Gas Operator | May 2025 |
| 478 | Robuck Petroleum, LLC | Nacogdoches, TX 75965 | Oil & Gas Operator | May 2025 |
| 479 | Roco Petroleum, Incorporated | Abilene, TX 79605 | Oil & Gas Operator | May 2025 |
| 480 | Rodessa Management, Inc. | Longview, TX 75606 | Oil & Gas Operator | May 1995 |
| 481 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 482 | Romac Oil Company, Inc. | Throckmorton, TX 76483 | Oil & Gas Operator | May 2025 |
| 483 | Rominger, R.L. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jan 2015 |
| 484 | Ronning Gas And Oil LLC | Mesa, AZ 85203 | Oil & Gas Operator | May 2025 |
| 485 | Royal Petroleum Corp. | Dallas, TX 75229 | Oil & Gas Operator | Jan 2025 |
| 486 | Royal Texan Resources Co. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 487 | RSD Minerals LLC | Wichita, KS 67206 | Oil Operator | Oct 2024 |
| 488 | Ruff Drilling Company | Albany, TX 76430 | Oil & Gas Operator | Dec 2019 |
| 489 | Rusk Co. Well Service Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 490 | Russell Bros. Oil & Gas, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 491 | Russell Brothers Oil & Gas | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2004 |
| 492 | Russell, T. Operating Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Aug 2005 |
| 493 | Rwa, LLC | Boyd, TX 76023 | Oil & Gas Operator | May 2025 |
| 494 | Ryder Scott Oil Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 2005 |
| 495 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 496 | S.B. Street Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 497 | Sabre Oil And Gas Corp. | Houston, TX 77063 | Oil & Gas Operator | May 2025 |
| 498 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | May 2025 |
| 499 | Safari Resources, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | May 2025 |
| 500 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |