| 401 | O.G.O. Refining | Luling, TX 78648 | Oil & Gas Operator | Jun 2013 |
| 402 | Oakridge Energy, Inc. | Wichita Falls, TX 76302 | Oil & Gas Operator | Apr 2025 |
| 403 | Ohlhausen Oil Company | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 404 | Okreek Oil Company | Weatherford, TX 76086 | Oil & Gas Operator | Apr 2025 |
| 405 | Orth Oil Company, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Apr 2025 |
| 406 | Ouida Oil | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2008 |
| 407 | Overland Operating Company, LLC | Abilene, TX 79601 | Oil Operator | Apr 2025 |
| 408 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 409 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Apr 2025 |
| 410 | P. R. L. Oil Company | Albany, TX 76430 | Oil & Gas Operator | Apr 2008 |
| 411 | P.B. Blue Dot Properties | Wexford, PA 15090 | Oil & Gas Operator | Apr 2025 |
| 412 | P.I.D. Drilling Inc | Clyde, TX 79510 | Oil & Gas Operator | Apr 2025 |
| 413 | Pace Oil And Gas Company | Austin, TX 78715 | Oil & Gas Operator | Apr 2025 |
| 414 | Pace Operating | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 415 | Pace Production Co. | San Angelo, TX 76902 | Oil & Gas Operator | Apr 2025 |
| 416 | Pace West Production LC | San Angelo, TX 76904 | Oil & Gas Operator | Sep 1995 |
| 417 | Palo Petroleum, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Apr 2025 |
| 418 | Pan Petroleum Corp. | Abilene, TX 79608 | Oil & Gas Operator | Mar 2008 |
| 419 | Paragon Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 420 | Paragon Oil & Gas, LLC | Aledo, TX 76008 | Oil & Gas Operator | Apr 2025 |
| 421 | Pardue Oil | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 2006 |
| 422 | Park & Park Oil Co. | Allen, TX 75002 | Oil & Gas Operator | Apr 2025 |
| 423 | Parker Operating Co., Inc. | Aledo, TX 76008 | Oil & Gas Operator | Sep 2000 |
| 424 | Patterson Oil Company, The | Eastland, TX 76448 | Oil & Gas Operator | Jan 2025 |
| 425 | Patton, E. N. Oil Company, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 426 | Payne Petroleum | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 427 | Peak Pipeline Company | Plano, TX 75093 | Oil & Gas Operator | Oct 2007 |
| 428 | Pendragon Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Apr 2025 |
| 429 | Permian Surveys | Midland, TX 79707 | Oil & Gas Operator | Oct 1999 |
| 430 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2025 |
| 431 | Petro-Beth Oil & Gas, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2006 |
| 432 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Apr 2025 |
| 433 | Petrotex, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 434 | Phillips 66 Company | Bartlesville, OK 74004 | Oil & Gas Operator | Aug 1997 |
| 435 | Pillans, Benjamin P. | Abilene, TX 79605 | Gas Operator | Aug 2012 |
| 436 | Pintail Production Co., Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Apr 2025 |
| 437 | Pitcock, Inc. | Graham, TX 76450 | Oil & Gas Operator | Apr 2025 |
| 438 | Plantation Operating, LLC | Houston, TX 77041 | Oil & Gas Operator | Nov 2011 |
| 439 | Plateau Energy, LLC | Smyer, TX 79367 | Oil & Gas Operator | Dec 2023 |
| 440 | PM Oil & Gas, Inc. | San Angelo, TX 76903 | Oil Operator | Apr 2025 |
| 441 | Porter, E. J. | Mingus, TX 76463 | Gas Operator | Jan 2011 |
| 442 | Powell Properties, Inc. | Los Altos, CA 94024 | Oil & Gas Operator | Apr 2025 |
| 443 | Powell, A. Brandt | Coleman, TX 76834 | Oil & Gas Operator | Mar 1999 |
| 444 | Premier Royalties, L.L.C. | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 445 | Prickly Pair Production | Albany, TX 76430 | Oil & Gas Operator | Apr 2025 |
| 446 | Principal Oil Corp. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2002 |
| 447 | Privateer Energy LLC | Warren, NJ 07059 | Oil Operator | Apr 2025 |
| 448 | Pro Oil & Gas Inc | Frankfort, IL 60423 | Oil & Gas Operator | May 2014 |
| 449 | Probe Exploration Company | Abilene, TX 79605 | Oil & Gas Operator | Apr 2025 |
| 450 | Production Marketing Assoc Inc | Plano, TX 75075 | Oil & Gas Operator | Apr 2025 |
| 451 | Prospecta Energy Group, Inc. | Brownwood, TX 76801 | Oil Operator | Apr 2025 |
| 452 | Pryor, Curtis | Lubbock, TX 79424 | Oil & Gas Operator | Dec 1998 |
| 453 | Putnam Oil Production | Abilene, TX 79603 | Oil & Gas Operator | Jun 2002 |
| 454 | Pyramid Production Co. | Abilene, TX 79608 | Oil & Gas Operator | Jun 1994 |
| 455 | Q A P Services, Inc. | Cross Plains, TX 76443 | Gas Operator | Apr 2025 |
| 456 | Quail Operating, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2025 |
| 457 | Quail Well Service, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 458 | Quantum Investments | Lubbock, TX 79424 | Oil Operator | Apr 2025 |
| 459 | Quest Emg, Inc. | Albany, TX 76430 | Oil & Gas Operator | Apr 2025 |
| 460 | Questar Expl. And Prod. Co. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jul 2011 |
| 461 | Quisto Energy Corp. | Kerrville, TX 78029 | Oil & Gas Operator | Jan 1998 |
| 462 | R & P Operating | Tuscola, TX 79562 | Oil & Gas Operator | Jun 1997 |
| 463 | R R Operation Inc | Cross Plains, TX 76443 | Oil & Gas Operator | Apr 2004 |
| 464 | R.D. Oil Company | Austin, TX 78755 | Oil & Gas Operator | Apr 2025 |
| 465 | Ratex Energy Inc. | Manchaca, TX 78652 | Oil & Gas Operator | Sep 2002 |
| 466 | Rayco Operating, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2025 |
| 467 | Red-Tex Petroleum, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Aug 2003 |
| 468 | Redwood Operating, Inc. | Houston, TX 77058 | Oil & Gas Operator | Apr 2025 |
| 469 | Reef Exploration, Inc. (A-1) | Richardson, TX 75080 | Oil & Gas Operator | Oct 2006 |
| 470 | Regal Operating | Cisco, TX 76437 | Oil & Gas Operator | Mar 2008 |
| 471 | Reilly, K. L. | Huntsville, TX 77342 | Oil Operator | Dec 2004 |
| 472 | Reliance Trusts | Dallas, TX 75244 | Oil & Gas Operator | Nov 1995 |
| 473 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Apr 2025 |
| 474 | Revard Petroleum, L.L.C. | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2025 |
| 475 | Rhodes Drilling Company | Abilene, TX 79608 | Oil & Gas Operator | Sep 2000 |
| 476 | Rhyne, J.V. | Cisco, TX 76437 | Oil & Gas Operator | Apr 2025 |
| 477 | Riata Energy Inc | Oklahoma City, OK 73101 | Oil & Gas Operator | Apr 2008 |
| 478 | Richardson Resources Inc | Brownwood, TX 76804 | Oil & Gas Operator | Apr 2025 |
| 479 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 480 | Ringo Rig LLC | Coleman, TX 76834 | Oil & Gas Operator | Apr 2025 |
| 481 | Rister, Dewey | Avoca, TX 79503 | Oil & Gas Operator | Apr 2025 |
| 482 | RJKB Foster Operating LLC | Cisco, TX 76437 | Oil & Gas Operator | Apr 2025 |
| 483 | Ro-Jo, Inc. | Highland VLG, TX 75077 | Oil & Gas Operator | Aug 2003 |
| 484 | Robinson Oil & Gas, Inc. | Chico, TX 76431 | Oil & Gas Operator | Aug 2003 |
| 485 | Robinson, Irvin | Abilene, TX 79608 | Oil & Gas Operator | May 1999 |
| 486 | Rock Operating | Abilene, TX 79608 | Oil & Gas Operator | Apr 2025 |
| 487 | Roco Petroleum, Incorporated | Abilene, TX 79605 | Oil & Gas Operator | Apr 2025 |
| 488 | Rodgers, William L. | Fort Worth, TX 76147 | Oil & Gas Operator | Jan 1995 |
| 489 | Rominger, R.L. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jan 2015 |
| 490 | Ropar Operating Co. | Wichita Falls, TX 76301 | Oil & Gas Operator | Apr 2025 |
| 491 | Rover Petroleum Operating, LLC | Plano, TX 75075 | Oil & Gas Operator | Apr 2025 |
| 492 | Royal Texan Resources Co. | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2025 |
| 493 | Royal Texas Petroleum | Lago VIsta, TX 78645 | Oil & Gas Operator | Apr 2025 |
| 494 | Ruby Operating Company, Inc | Clyde, TX 79510 | Oil & Gas Operator | Apr 2025 |
| 495 | Ruff | Albany, TX 76430 | Oil & Gas Operator | Aug 2017 |
| 496 | Ruff Oil Co. | Albany, TX 76430 | Oil Operator | Apr 2025 |
| 497 | Russell, Phillip | Colorado City, TX 79512 | Oil & Gas Operator | Apr 2025 |
| 498 | Ryholland Fielder, Inc | Delray Beach, FL 33446 | Oil & Gas Operator | Apr 2025 |
| 499 | S & H Resources | Abilene, TX 79605 | Oil & Gas Operator | Apr 2025 |
| 500 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |