| 20601 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 20602 | Oil Mountain Energy Inc | Casper, WY 82609 | Oil Operator | Feb 2026 |
| 20603 | Oil Operations Inc | | Oil & Gas Operator | Apr 2011 |
| 20604 | Oil Operators Inc. | | Oil & Gas Operator | Nov 2024 |
| 20605 | Oil Palace, Inc. | | Oil Operator | Jun 2016 |
| 20606 | Oil Partners | Salina, KS 67401 | Oil Operator | Jun 2001 |
| 20607 | Oil Partners, LLC | Salina, KS 67401 | Oil Operator | Dec 2025 |
| 20608 | Oil Patch Energy LLC | Broken Arrow, OK 74014 | Oil & Gas Operator | Nov 2025 |
| 20609 | Oil Patch Operators Co., L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2026 |
| 20610 | Oil Patch Operators, LLC | | Oil & Gas Operator | Jul 2005 |
| 20611 | Oil Pool Inc | Tulsa, OK 74132-2659 | Oil & Gas Operator | Jan 2026 |
| 20612 | Oil Producers In | | Oil & Gas Operator | Dec 1996 |
| 20613 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Apr 2026 |
| 20614 | Oil Production Management Inc | Squaw Valley, CA 93675-9725 | Oil & Gas Operator | Dec 2002 |
| 20615 | Oil Production S | | Oil Operator | Sep 1993 |
| 20616 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 20617 | Oil Projects, LLC | Houston, TX 77027 | Oil & Gas Operator | Apr 2026 |
| 20618 | Oil Prop Company | | Oil & Gas Operator | Sep 1995 |
| 20619 | Oil Prop Investm | | Oil Operator | Dec 1995 |
| 20620 | Oil Properties Co., Inc. | Wichita, KS 67208 | Gas Operator | Dec 2009 |
| 20621 | Oil Property Man | | Oil & Gas Operator | Jun 1995 |
| 20622 | Oil Property Management Inc | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 20623 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Jan 2026 |
| 20624 | Oil Recovery, Inc. | | Oil Operator | Sep 1992 |
| 20625 | Oil Reserves Corp Of America | | Oil & Gas Operator | May 2002 |
| 20626 | Oil Rock Oil Company, Inc. | Elizabeth, WV 26143 | Oil & Gas Operator | Dec 2021 |
| 20627 | Oil Rock Resources, LLC | Weatherford, TX 76088 | Oil & Gas Operator | Jan 2024 |
| 20628 | Oil Search (Alaska), LLC | | Oil & Gas Operator | Mar 2026 |
| 20629 | Oil Search Inc | Brookfield, OH 44403 | Oil & Gas Operator | Dec 2024 |
| 20630 | Oil Securities Inc. | | Gas Operator | Dec 2003 |
| 20631 | Oil State Petroleum Inc | Jennings, OK 74038 | Oil & Gas Operator | Feb 2026 |
| 20632 | Oil Tech Producers Corporation | Moundridge, KS 67107 | Gas Operator | Dec 2025 |
| 20633 | Oil Ventures LTD | | Oil & Gas Operator | Jan 2013 |
| 20634 | Oil Well Buyers Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 20635 | Oil Well Management Co. | | Oil & Gas Operator | Dec 1989 |
| 20636 | Oil, Gas, Etc. LLC | Katy, TX 77449 | Oil & Gas Operator | Apr 2026 |
| 20637 | Oil,Gas & Other Minerals, Inc. | | Oil & Gas Operator | Apr 1996 |
| 20638 | Oil-Tech Prod Co | | Oil & Gas Operator | Oct 1992 |
| 20639 | Oil-X Corp., The | FT Stockton, TX 79735 | Oil & Gas Operator | Apr 2026 |
| 20640 | Oilbank Production LLC | Norman, OK 73072 | Oil Operator | Jan 2026 |
| 20641 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 20642 | Oildigger Resources Fund L LLLP | Billings, MT 59101 | Oil & Gas Operator | Feb 2026 |
| 20643 | Oilex Int'L Investments, Inc. | Luling, TX 78648 | Oil & Gas Operator | Apr 2026 |
| 20644 | Oilfield Consultants | | Oil & Gas Operator | Dec 1987 |
| 20645 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | Apr 2026 |
| 20646 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 20647 | Oilfield Research, Inc | | Oil Operator | Dec 2021 |
| 20648 | Oilfield Salvage & Service Company | Littleton, CO 80120 | Oil & Gas Operator | Jan 2026 |
| 20649 | Oilfield Search | | Oil Operator | Mar 1990 |
| 20650 | Oilfield Services And Supply Co. Inc. | | Oil Operator | Sep 1989 |
| 20651 | Oilfield Services, LLC | Winfield, KS 67156 | Oil Operator | Nov 2017 |
| 20652 | Oilfield Truck Service | | Oil Operator | Jun 2014 |
| 20653 | Oilrox Resources LLC | San Antonio, TX 78258 | Oil & Gas Operator | Feb 2026 |
| 20654 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 20655 | Oiltech Inc | Yuba City, CA 95991 | Oil & Gas Operator | Dec 1984 |
| 20656 | Oiltex, Inc. | Baltimore, MD 21221 | Oil & Gas Operator | Dec 2013 |
| 20657 | Oilton Petroleum Inc | Oilton, OK 74052-0459 | Oil & Gas Operator | Oct 2001 |
| 20658 | Oilton Resources, Inc. | Laredo, TX 78041 | Oil & Gas Operator | Apr 2026 |
| 20659 | Oilwell Acquisition Co | | Oil & Gas Operator | Jun 1999 |
| 20660 | Oilwell Operator | | Gas Operator | Dec 1994 |
| 20661 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Apr 2026 |
| 20662 | Oily Dog Operators Texas, LLC | Allen, TX 75002 | Oil Operator | Apr 2026 |
| 20663 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Dec 2025 |
| 20664 | Ojb, Inc. | Buda, TX 78610 | Oil & Gas Operator | Mar 2013 |
| 20665 | Ojt, LLC | Richmond, TX 77469 | Oil Operator | Apr 2026 |
| 20666 | Ok Arena Operating Company | Oklahoma City, OK 73101 | Oil & Gas Operator | Apr 2026 |
| 20667 | Ok Oil Company, Inc. | Bivins, TX 75555 | Oil & Gas Operator | Feb 2013 |
| 20668 | Ok Operating Co | Midland, TX 79702 | Oil & Gas Operator | Aug 1999 |
| 20669 | Ok Production Services Inc | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2026 |
| 20670 | Ok-La-Tex Production, Inc. | | Oil & Gas Operator | Jan 1982 |
| 20671 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 20672 | Okemah Production Inc | | Oil Operator | Dec 2005 |
| 20673 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 20674 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 20675 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2026 |
| 20676 | Okkatahula, Inc. | | Oil Operator | Nov 1978 |
| 20677 | Okla Sub-Surface Pump & Supply Co | Ada, OK 74820 | Oil & Gas Operator | Sep 2024 |
| 20678 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 20679 | Oklahoma Arrowhead Energy, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 1996 |
| 20680 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 20681 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Feb 2026 |
| 20682 | Oklahoma Crude Inc | Morris, OK 74445 | Oil & Gas Operator | Nov 2025 |
| 20683 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | Feb 2026 |
| 20684 | Oklahoma Ea II, L.L.C. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2004 |
| 20685 | Oklahoma Energy & Exploration, Inc. | Tulsa, OK 74114 | Oil Operator | Jan 1996 |
| 20686 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Feb 2026 |
| 20687 | Oklahoma Energy Exchange LLC | Duncan, OK 73534-1105 | Oil & Gas Operator | Sep 2012 |
| 20688 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Apr 2025 |
| 20689 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 20690 | Oklahoma Gas & Oil Corp | | Oil Operator | Oct 2018 |
| 20691 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Dec 2025 |
| 20692 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 20693 | Oklahoma Natural Resources Inc | Woodward, OK 73801 | Oil & Gas Operator | Sep 1996 |
| 20694 | Oklahoma O & G Royalties Inc | Duncan, OK 73533 | Oil & Gas Operator | Nov 2000 |
| 20695 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Jan 2026 |
| 20696 | Oklahoma Oil And Gas Resources LLC | Guthrie, OK 73044-8095 | Oil & Gas Operator | Jan 2026 |
| 20697 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 20698 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 20699 | Oklahoma Operating Company | Midland, TX 79708 | Oil & Gas Operator | Apr 2026 |
| 20700 | Oklahoma Operating, LLC | Holliday, TX 76366 | Oil Operator | Nov 2003 |