| 401 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 402 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 403 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 404 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 405 | Ogris Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 406 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 407 | Older Than Dirt LLC | Weatherford, TX 76086 | Oil & Gas Operator | Jul 2026 |
| 408 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Jul 2026 |
| 409 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 410 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Jul 2026 |
| 411 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 412 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 413 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | May 2026 |
| 414 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 415 | Owl Ops II LLC | Midland, TX 79701 | Oil & Gas Operator | Jul 2026 |
| 416 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 417 | Oxy USA WTP LP | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 418 | Oxyrock Operating, LLC | Houston, TX 77046 | Oil & Gas Operator | Jul 2026 |
| 419 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Jul 2026 |
| 420 | P & A Operating, Inc. | Kerrville, TX 78028 | Oil & Gas Operator | Jul 2026 |
| 421 | P & P Petroleum | Midland, TX 79706 | Oil & Gas Operator | Oct 2002 |
| 422 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Jul 2026 |
| 423 | P4 Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 424 | Pa Prospect LLC | Columbus, MT 59019 | Oil & Gas Operator | Jul 2020 |
| 425 | Paladin Petroleum III, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Jul 2026 |
| 426 | Palmer, J. M. | Keller, TX 76244 | Oil & Gas Operator | Aug 2009 |
| 427 | Par Minerals Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2026 |
| 428 | Parallel Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Jan 2010 |
| 429 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 430 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 431 | Patriot Production LLC | Southlake, TX 76092 | Oil & Gas Operator | Apr 2023 |
| 432 | Patterson Petroleum LLC | Snyder, TX 79550 | Oil & Gas Operator | Oct 2007 |
| 433 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 434 | Pecanosa Oil & Cattle Co. | New Braunfels, TX 78132 | Gas Operator | May 2013 |
| 435 | Pecos Operating Company, LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2021 |
| 436 | Pedernales Production, LP | Houston, TX 77057 | Oil & Gas Operator | Mar 2022 |
| 437 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 438 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 439 | Pennzoil Petroleum Company | Houston, TX 77252 | Oil & Gas Operator | Nov 1999 |
| 440 | Penwell South Operating LLC | Austin, TX 78746 | Oil & Gas Operator | Jul 2026 |
| 441 | Perimeter Resource Company | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 442 | Permian Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 443 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2026 |
| 444 | Petro-Smith Operating LLC | Houston, TX 77010 | Oil & Gas Operator | Jul 2026 |
| 445 | Petroleum Technical Services Co. | Midland, TX 79707 | Oil & Gas Operator | Dec 2004 |
| 446 | Petroplex Energy Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 447 | Petroplex Equipment, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2019 |
| 448 | Petx Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 449 | Pharaoh Oil & Gas, Inc. | MC Camey, TX 79752 | Oil & Gas Operator | Jul 2026 |
| 450 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 451 | Phoenix Hydrocarbons Operating | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 452 | Pierce Production Company | Eunice, NM 88231 | Oil & Gas Operator | Oct 2012 |
| 453 | Pierce Production Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 454 | Pioneer Exploration Company | Houston, TX 77090 | Oil & Gas Operator | May 2026 |
| 455 | Pioneer Exploration, LLC | Houston, TX 77090 | Oil & Gas Operator | Jun 2026 |
| 456 | Pioneer Exploration, LTD. | Houston, TX 77090 | Oil & Gas Operator | Sep 2008 |
| 457 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Jul 2026 |
| 458 | Pitts Energy Co. | Midland, TX 79707 | Oil & Gas Operator | Jul 2026 |
| 459 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 460 | Plains Petroleum Operating Co | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 461 | Platform Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 462 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 463 | Pogo Producing Company LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 464 | Polaris Production Corp. | Midland, TX 79702 | Oil & Gas Operator | Jan 2024 |
| 465 | Porosity Oil LLC | Imperial, TX 79743 | Oil Operator | Jul 2026 |
| 466 | PPC Operating Company LLC | Houston, TX 77279 | Oil & Gas Operator | Jul 2019 |
| 467 | Preferred Pipeline Corp. | Victoria, TX 77902 | Oil & Gas Operator | Jun 2026 |
| 468 | Premier Natural Resources, L.P. | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2007 |
| 469 | Premier Natural Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jul 2026 |
| 470 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 471 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 472 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 473 | Purvis Operating Co. | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 474 | Purvis, J. H. | Midland, TX 79702 | Oil & Gas Operator | Dec 1994 |
| 475 | Pyramid Gas Co | Midland, TX 79701 | Oil Operator | Jul 2026 |
| 476 | Pyramid Oil Co. | Litchfield PK, AZ 85340 | Oil & Gas Operator | Jan 2018 |
| 477 | Q Natural Resources, LLC | Jones, OK 73049 | Oil & Gas Operator | Jul 2026 |
| 478 | QP, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 479 | Quay Valley, Inc. | Midland, TX 79710 | Oil & Gas Operator | Oct 2007 |
| 480 | Questar Expl. And Prod. Co. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jul 2011 |
| 481 | R K Petroleum Corp. | Midland, TX 79708 | Oil & Gas Operator | May 2024 |
| 482 | R. K. G. Engineering, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Jul 2026 |
| 483 | R.K.G. Operations, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Jun 2004 |
| 484 | R3 Operating Corporation | Greenwood VLG, CO 80111 | Oil & Gas Operator | Jul 2026 |
| 485 | Raider Oil & Gas Company | MC Camey, TX 79752 | Oil & Gas Operator | Jul 2026 |
| 486 | Rampart Petroleum, Incorporated | Buffalo Gap, TX 79508 | Oil & Gas Operator | Jan 2009 |
| 487 | Ramtex Energy LLC | Tulsa, OK 74114 | Oil & Gas Operator | Jul 2026 |
| 488 | Raptor Resources, Inc. | Austin, TX 78701 | Oil & Gas Operator | Jul 2026 |
| 489 | Rasmussen, Tom | San Angelo, TX 76904 | Oil & Gas Operator | Jul 2026 |
| 490 | Rayden | Southlake, TX 76092 | Oil & Gas Operator | Jul 2026 |
| 491 | Red Oak Energy Co | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2026 |
| 492 | Redstone Oil & Gas Company | Dallas, TX 75225 | Oil & Gas Operator | Jan 2020 |
| 493 | Reformed Resources, LLC | Midland, TX 79706 | Oil Operator | Jul 2026 |
| 494 | Reliance Energy, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jul 2026 |
| 495 | Reliance Operating Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2000 |
| 496 | Remo, Inc. | Odessa, TX 79760 | Oil & Gas Operator | May 2003 |
| 497 | Renaud Oil Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 498 | Resaca Operating Company | Houston, TX 77010 | Oil & Gas Operator | Sep 2013 |
| 499 | Rex Energy Operating Corp. | State College, PA 16801 | Oil & Gas Operator | Jun 2012 |
| 500 | Rhombus Operating Co., LTD | Littleton, CO 80160 | Oil & Gas Operator | Jun 2026 |