| 21401 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Mar 2025 |
| 21402 | Osage Energy, LLC | Colony, KS 66015 | Oil Operator | Nov 2023 |
| 21403 | Osage Exploration & Development Inc | San Diego, CA 92131-3807 | Oil & Gas Operator | Oct 2016 |
| 21404 | Osage Hot Oil Service | Newcastle, WY 82701 | Oil & Gas Operator | Jul 1997 |
| 21405 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 21406 | Osage Operating Company LLC | Seattle, WA 98133 | Oil Operator | May 2006 |
| 21407 | Osage Partners LLC | | Oil & Gas Operator | Apr 2025 |
| 21408 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 21409 | Osage Resources, LLC | Wichita, KS 67202 | Oil & Gas Operator | Jan 2025 |
| 21410 | Osair Inc | Mentor, OH 44061 | Oil & Gas Operator | Dec 2021 |
| 21411 | Osborn Energy, L.L.C. | Bucyrus, KS 66013 | Oil & Gas Operator | Jul 2017 |
| 21412 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2025 |
| 21413 | Osborn Heirs Com | | Oil & Gas Operator | May 1995 |
| 21414 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Feb 2025 |
| 21415 | Osborn Oil & Gas | | Oil & Gas Operator | Jun 1991 |
| 21416 | Osborn,W.B. Oil & Gas Operations | San Antonio, TX 78217 | Oil & Gas Operator | Jun 2025 |
| 21417 | Osborne Oil Co. | Dallas, TX 75244 | Oil & Gas Operator | Aug 2003 |
| 21418 | Osburn Gerald Dba Ozzy & Son Oil & Gas | Drumright, OK 74030-5467 | Oil Operator | Oct 2020 |
| 21419 | Oscar Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2004 |
| 21420 | Oscar'S Well Service Inc | Okemah, OK 74859 | Oil & Gas Operator | Apr 1998 |
| 21421 | Osceola Oil & Gas Corporation | Somerset, TX 78069 | Oil & Gas Operator | Aug 1994 |
| 21422 | Osci Oil And Gas, Inc. | Parker, KS 66072 | Oil Operator | Jun 1998 |
| 21423 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 21424 | Osman Global Services LLC | | Oil & Gas Operator | Jan 2025 |
| 21425 | Oso Exploration & Production, LLC | Houston, TX 77269 | Oil Operator | Jun 2025 |
| 21426 | Oso Exploration Co. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2011 |
| 21427 | Oso Oil & Gas Properties LLC | Price, UT 84501 | Gas Operator | Jun 2016 |
| 21428 | Oso Perdido Services LLC | Flatonia, TX 78941 | Oil Operator | Mar 2025 |
| 21429 | Oso Resources LLC | Oklahoma City, OK 73118-5022 | Oil & Gas Operator | Mar 2025 |
| 21430 | Ososki Edward D Dba Federal Oil Company | | Oil & Gas Operator | Jun 2022 |
| 21431 | Osprey Petroleum Company, Inc. | Manvel, TX 77578 | Oil & Gas Operator | May 2020 |
| 21432 | Osr Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Jul 2000 |
| 21433 | Osr Oil & Gas Corp | Midland, TX 79710 | Oil & Gas Operator | Dec 2024 |
| 21434 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 21435 | Ostrich Oil & Gas, LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 21436 | Oswego Arbuckle Enterprise Inc | S Coffeyville, OK 74072-9702 | Oil & Gas Operator | Mar 2015 |
| 21437 | Oswego Oil & Gas | | Oil & Gas Operator | Jun 1984 |
| 21438 | Oswego, Inc. | Amarillo, TX 79109 | Oil & Gas Operator | Jun 2004 |
| 21439 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | Jun 2025 |
| 21440 | Osyka Permian, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2025 |
| 21441 | Osyka Producing Company, Inc. | Houston, TX 77242 | Oil & Gas Operator | Jun 2025 |
| 21442 | Otb Operating, LLC | Stanton, TX 79782 | Oil & Gas Operator | Jun 2025 |
| 21443 | Otc Investors Inc | | Oil Operator | Jan 2025 |
| 21444 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 21445 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 21446 | Otex Inc | N Canton, OH 44720 | Oil & Gas Operator | Dec 1988 |
| 21447 | Otex LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Jun 2025 |
| 21448 | Otex Resources LLC | Baytown, TX 77520 | Oil & Gas Operator | Jun 2025 |
| 21449 | Otis C. Coles, Jr. | | Oil & Gas Operator | Jan 1998 |
| 21450 | Oto, Co. | Woodward, OK 73802 | Oil & Gas Operator | Jun 1998 |
| 21451 | Ott Inc | Casper, WY 82602 | Oil Operator | Dec 2024 |
| 21452 | Otter Exploration Inc | Warren, PA 16365-9689 | Oil & Gas Operator | Dec 2021 |
| 21453 | Ouachita Development Corp. | | Gas Operator | Mar 2014 |
| 21454 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Mar 2025 |
| 21455 | Ouida Oil | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2008 |
| 21456 | Ouida Oil Co. | | Oil & Gas Operator | Apr 1999 |
| 21457 | Outback Oil, Inc. | Pratt, KS 67124 | Gas Operator | Sep 2019 |
| 21458 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 21459 | Outlaw Oil LLC | Caldwell, TX 77836 | Oil & Gas Operator | Jun 2025 |
| 21460 | Outlaw Well Service LLC | Hays, KS 67601 | Oil Operator | Oct 2024 |
| 21461 | Outline Oil Company LLC | Beeville, TX 78104 | Oil Operator | Jun 2025 |
| 21462 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Jun 2025 |
| 21463 | Outlook Petroleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Jan 2001 |
| 21464 | Outman, Joshua J. | Andover, NY 14806 | Oil & Gas Operator | Dec 2023 |
| 21465 | Output Acquisition Corp. | | Oil & Gas Operator | Jul 2010 |
| 21466 | Output Exploration LLC | | Oil & Gas Operator | Dec 2006 |
| 21467 | Ouut Investing LLC | Mineral Wells, TX 76068 | Oil Operator | Mar 2020 |
| 21468 | Ovaco Energy Inc. | | Oil & Gas Operator | Nov 2009 |
| 21469 | Ovation Energy II, LP | Houston, TX 77279 | Oil & Gas Operator | Jun 2011 |
| 21470 | Ovation Energy, LP | N Richlnd HLS, TX 76180 | Oil & Gas Operator | Sep 2004 |
| 21471 | Overfield, Lee R | Waverly, KY 42462 | Oil Operator | Dec 2016 |
| 21472 | Overflow Energy Stack LLC | Booker, TX 79005 | Oil Operator | Sep 2022 |
| 21473 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Jun 2025 |
| 21474 | Overland Exploration Company | | Oil Operator | Jan 2025 |
| 21475 | Overland Investments Inc | Coweta, OK 74429 | Oil & Gas Operator | Mar 2025 |
| 21476 | Overland Operating Company, LLC | Abilene, TX 79601 | Oil Operator | Jun 2025 |
| 21477 | Overland Resources LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Jul 2019 |
| 21478 | Overly Operating Co. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 21479 | Overstreet, Jamie L | Hondo, TX 78861 | Oil & Gas Operator | Jun 2025 |
| 21480 | Overton Park Oil & Gas LP | Fort Worth, TX 76109 | Oil & Gas Operator | Jun 2025 |
| 21481 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Apr 2025 |
| 21482 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 21483 | Owco Production Co., Inc. | | Oil Operator | Aug 1997 |
| 21484 | Owen Production Co | | Oil Operator | May 2001 |
| 21485 | Owen'S Pumping Service | | Oil Operator | Feb 2025 |
| 21486 | Owen, Matthew | Hamilton, KS 66853 | Oil Operator | Sep 2016 |
| 21487 | Owens James W | Tulsa, OK 74114-1425 | Oil & Gas Operator | Oct 2022 |
| 21488 | Owens Oil | | Oil Operator | Dec 2000 |
| 21489 | Owens Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2008 |
| 21490 | Owens Oil Company, LLC | Yates Center, KS 66783 | Oil Operator | Feb 2025 |
| 21491 | Owens Pet Inc | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 21492 | Owens Petroleum | | Oil Operator | May 2006 |
| 21493 | Owens Petroleum LLC | Yates Center, KS 66783 | Oil & Gas Operator | Feb 2025 |
| 21494 | Owens Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 21495 | Owi Operating Co. LC | Ottawa, KS 66067 | Oil & Gas Operator | Dec 2009 |
| 21496 | Owl Creek Operating Co., Inc. | Denver, CO 80206 | Oil & Gas Operator | Jun 2025 |
| 21497 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 21498 | Owl Creek Production Co., LLC | Denver, CO 80265 | Oil & Gas Operator | Jan 2006 |
| 21499 | Owl Operating Ventures L.L.C. | Midland, TX 79708 | Oil & Gas Operator | Dec 2022 |
| 21500 | Owl Ops II LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |