| 401 | Oso Oil & Gas Properties LLC | Price, UT 84501 | Gas Operator | Jun 2016 |
| 402 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 403 | Oxbow Properties Inc | Centennial, CO 80122-1422 | Oil & Gas Operator | Jan 2025 |
| 404 | P & M Petroleum Management | Denver, CO BAD ADDR | Oil & Gas Operator | Apr 2010 |
| 405 | P-2 Oil | Vernal, UT 84078 | Oil & Gas Operator | Jul 2000 |
| 406 | Pacific Energy & Mining Company | Reno, NV 89511 | Oil & Gas Operator | Sep 2022 |
| 407 | Pacific Natural Gas Explor | | Oil & Gas Operator | Dec 1974 |
| 408 | Pacific Trans Supply | Vernal, UT 84078 | Oil & Gas Operator | Jul 1987 |
| 409 | Page Petroleum Inc | Calgary, AB T2P3M-3000 | Oil & Gas Operator | Nov 1998 |
| 410 | Paiute Oil & Mining Corp | Salt Lake City, UT 84117 | Oil & Gas Operator | Jun 1989 |
| 411 | Pan American Petroleum Cor | | Oil & Gas Operator | Dec 1981 |
| 412 | Pannonian Energy Inc | Englewood, CO 80112 | Oil & Gas Operator | Mar 2004 |
| 413 | Paradox Upstream, LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 414 | Parker Energy Tech Inc | Salt Lake City, UT 84171 | Oil Operator | Nov 2013 |
| 415 | Patara Oil & Gas LLC | Dallas, TX 75219 | Oil & Gas Operator | Mar 2018 |
| 416 | Pease Oil & Gas Company | Grand Junction, CO 81506 | Oil & Gas Operator | May 2000 |
| 417 | Pease, Willard H | Grand Junction, CO 81502 | Gas Operator | May 1995 |
| 418 | Pendragon Energy Partners Inc | Midland, TX 79701 | Oil & Gas Operator | Nov 2009 |
| 419 | Pennzoil Company | Midland, TX 79710-0090 | Oil & Gas Operator | Mar 2000 |
| 420 | Pennzoil Explor & Prod Co | Houston, TX 77002 | Oil & Gas Operator | Mar 2000 |
| 421 | Perfection Oil & Gas Co | | Gas Operator | Sep 1937 |
| 422 | Petral Exploration LLC | Denver, CO 80217-5083 | Oil & Gas Operator | Dec 2001 |
| 423 | Petro Mex, LLC | Farmington, NM 87499 | Oil & Gas Operator | Dec 2025 |
| 424 | Petro-Canada Resources (USA) Inc | Denver, CO 80202-472 | Oil & Gas Operator | Feb 2010 |
| 425 | Petro-X Corporation | Houston, TX 77092 | Oil & Gas Operator | Jul 2002 |
| 426 | Petrodril Inc | Farmington, NM 87401 | Oil & Gas Operator | Jan 1987 |
| 427 | Petroglyph Operating Co | Boise, ID 83709 | Oil & Gas Operator | Jul 2017 |
| 428 | Petrovest International | Encino, CA 91436 | Gas Operator | Jun 1982 |
| 429 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 430 | Phelps Dodge Corp | | Gas Operator | Sep 1957 |
| 431 | Phillips Oil Company | Casper, WY 82602 | Oil & Gas Operator | Sep 1986 |
| 432 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 433 | Phillips Petroleum, LLC | Ballard, UT 84066 | Oil & Gas Operator | Dec 2025 |
| 434 | Phillips, Jack L. | Gladewater, TX 75647 | Oil & Gas Operator | Dec 1997 |
| 435 | Phoenix Hydro Oper Corp | Midland, TX 79702 | Oil & Gas Operator | Dec 1993 |
| 436 | Phoenix Hydrocarbons Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 1993 |
| 437 | Pioneer Natural Resources USA Inc | Irving, TX 75039 | Oil & Gas Operator | Sep 2025 |
| 438 | Pioneer Oil & Gas | South Jordan, UT 84095 | Oil & Gas Operator | Jan 2014 |
| 439 | PO&G Operating, LLC (Pogo) | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 440 | Polumbus Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 1982 |
| 441 | Post Petroleum Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Aug 2013 |
| 442 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 443 | Price River Energy, LLC | Houston, TX 77024 | Gas Operator | Nov 2025 |
| 444 | Pride Ventures LLC | Moab, UT 84532 | Oil & Gas Operator | Sep 2025 |
| 445 | Prima Exploration, Inc. | Denver, CO 80206 | Oil & Gas Operator | Dec 2025 |
| 446 | Priority Oil & Gas LLC | Lakewood, CO 80227 | Gas Operator | Dec 2019 |
| 447 | Producers Operating Co Inc | Amarillo, TX 79105 | Oil & Gas Operator | Feb 2026 |
| 448 | Proven Petroleum, Inc. | Lakewood, CO 80228 | Oil & Gas Operator | Dec 2025 |
| 449 | Pubco Petroleum Corp | Albuquerque, NM 87104 | Oil & Gas Operator | Dec 1981 |
| 450 | Pumpelly, Raphael SR | Pac Palisades, CA 90272 | Oil & Gas Operator | Feb 1991 |
| 451 | Pure Oil Co | | Oil & Gas Operator | Dec 1996 |
| 452 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 453 | Qep Uinta Basin Inc | Salt Lake City, UT 84145-0601 | Oil & Gas Operator | Mar 2007 |
| 454 | Questar Energy Company | Salt Lake C Ity, UT 84147 | Gas Operator | May 1991 |
| 455 | Questar Expl. And Prod. Co. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jul 2011 |
| 456 | Quinex Energy Corp | Bountiful, UT 84010 | Oil & Gas Operator | Nov 2025 |
| 457 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 458 | R & R Well Service | Fort Worth, TX 76120 | Oil & Gas Operator | Jan 2005 |
| 459 | Ramco Operating Company | Tulsa, OK 74135 | Oil & Gas Operator | Jan 1998 |
| 460 | Ranken Energy Corporation | Edmond, OK 73013 | Oil & Gas Operator | Oct 2025 |
| 461 | Reserve Oil & Gas | | Oil & Gas Operator | Feb 1980 |
| 462 | Resource Development Technology, LLC | Morrison, CO 80465 | Oil & Gas Operator | Oct 2020 |
| 463 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 464 | Retamco Operating Inc | Red Lodge, MT 59068 | Oil & Gas Operator | Aug 2025 |
| 465 | Reynolds Mining Corp | | Oil & Gas Operator | Aug 1968 |
| 466 | RG Exploration, LLC | Midland, TX 78705 | Oil & Gas Operator | Feb 2020 |
| 467 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Nov 2025 |
| 468 | Rig II LLC | Woods Cross, UT 84087 | Oil & Gas Operator | May 2018 |
| 469 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Feb 2026 |
| 470 | Rim Southwest Corp | Farmington, NM 87499-2058 | Oil & Gas Operator | Dec 2025 |
| 471 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 472 | River Gas Corporation | Tuscaloosa, AL 35406-2233 | Gas Operator | Dec 2000 |
| 473 | River Gas Of Utah Inc | Northport, AL 35476 | Gas Operator | Feb 1995 |
| 474 | Road Runner Inc | Park City, UT 84060 | Oil & Gas Operator | Aug 2005 |
| 475 | Robert L Bayless Producer, LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2025 |
| 476 | Rockies Standard Oil Company | Provo, UT 84604 | Oil & Gas Operator | Oct 2020 |
| 477 | Roddy Production Company Inc | Farmington, NM 87401 | Oil & Gas Operator | Nov 2025 |
| 478 | Roemer Oil Company | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 479 | Rose Petroleum (Us), LLC | Parker, CO 80134 | Oil & Gas Operator | Jul 2016 |
| 480 | Rose Petroleum (Utah) LLC | Annapolis, MD 21401 | Oil & Gas Operator | Nov 2025 |
| 481 | Rose, Verl | Spring Creek, NV 89815 | Oil & Gas Operator | Feb 2011 |
| 482 | Roseland Oil & Gas Inc | Rockwall, TX 75087 | Oil & Gas Operator | Feb 2003 |
| 483 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 484 | Ross Exploration,Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2013 |
| 485 | Royale Energy Inc | San Diego, CA 92108-4518 | Oil & Gas Operator | Nov 2025 |
| 486 | Ruby, Glen Et Al | | Oil & Gas Operator | Dec 1981 |
| 487 | Running Foxes Petroleum Inc. | Centennial, CO 80112 | Oil & Gas Operator | Sep 2025 |
| 488 | S O A L LLC | Farmington, NM 87499-2165 | Oil & Gas Operator | Jun 2023 |
| 489 | S O Utah | Irvine, CA 92715 | Oil & Gas Operator | Sep 1994 |
| 490 | S W Energy Corporation | Salt Lake City, UT 84102 | Oil & Gas Operator | May 2020 |
| 491 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Feb 2026 |
| 492 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 493 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 494 | San Juan Minerals Explor | Mexican Hat, UT 84531 | Oil & Gas Operator | Apr 2006 |
| 495 | Sanchez-Obrien Oil & Gas | | Oil & Gas Operator | Aug 1986 |
| 496 | Santa Fe Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 497 | Santa Fe Snyder Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2000 |
| 498 | Sapient Energy Corp | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2002 |
| 499 | Saturn Resources Corp | Springboro, OH 45066 | Oil & Gas Operator | Dec 1998 |
| 500 | Savoy Energy, LLC | Ephraim, UT 84627 | Gas Operator | Dec 2025 |