| 7901 | Oil & Gas Operations | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 7902 | Oil & Gas Properties | Midland, TX 79704 | Oil & Gas Operator | Dec 2025 |
| 7903 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 7904 | Oil Coast Corp. | S Houston, TX 77587 | Oil & Gas Operator | Dec 2025 |
| 7905 | Oil Lease Operating Co. | Coldspring, TX 77331 | Oil & Gas Operator | Aug 2003 |
| 7906 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 7907 | Oil Patch Operators Co., L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 7908 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Dec 2025 |
| 7909 | Oil Projects, LLC | Houston, TX 77027 | Oil & Gas Operator | Dec 2025 |
| 7910 | Oil Rock Resources, LLC | Weatherford, TX 76088 | Oil & Gas Operator | Jan 2024 |
| 7911 | Oil Well Buyers Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 7912 | Oil, Gas, Etc. LLC | Katy, TX 77449 | Oil & Gas Operator | Dec 2025 |
| 7913 | Oil-X Corp., The | FT Stockton, TX 79735 | Oil & Gas Operator | Dec 2025 |
| 7914 | Oilex Int'L Investments, Inc. | Luling, TX 78648 | Oil & Gas Operator | Dec 2025 |
| 7915 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 7916 | Oilrox Resources LLC | San Antonio, TX 78258 | Oil & Gas Operator | Sep 2025 |
| 7917 | Oilton Resources, Inc. | Laredo, TX 78041 | Oil & Gas Operator | Dec 2025 |
| 7918 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 7919 | Oily Dog Operators Texas, LLC | Allen, TX 75002 | Oil Operator | Dec 2025 |
| 7920 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Sep 2025 |
| 7921 | Ojb, Inc. | Buda, TX 78610 | Oil & Gas Operator | Mar 2013 |
| 7922 | Ojt, LLC | Richmond, TX 77469 | Oil Operator | Dec 2025 |
| 7923 | Ok Arena Operating Company | Oklahoma City, OK 73101 | Oil & Gas Operator | Dec 2025 |
| 7924 | Ok Oil Company, Inc. | Bivins, TX 75555 | Oil & Gas Operator | Feb 2013 |
| 7925 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |
| 7926 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2025 |
| 7927 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 7928 | Oklahoma Arrowhead Energy, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 1996 |
| 7929 | Oklahoma Ea II, L.L.C. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2004 |
| 7930 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 7931 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 7932 | Oklahoma Operating Company | Midland, TX 79708 | Oil & Gas Operator | Dec 2025 |
| 7933 | Oklahoma Operating, LLC | Holliday, TX 76366 | Oil Operator | Nov 2003 |
| 7934 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 7935 | Oklahoma Sterling Oil & Gas Corp | Tulsa, OK 74170 | Oil & Gas Operator | Jun 1997 |
| 7936 | Oklatex Energy, Inc. | Beaumont, TX 77702 | Oil Operator | Dec 2025 |
| 7937 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 7938 | Okreek Oil Company | Weatherford, TX 76086 | Oil & Gas Operator | Dec 2025 |
| 7939 | Okt Resources, LLC | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 7940 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 7941 | Ol' Boys Operations LLC | Pampa, TX 79065 | Oil & Gas Operator | Dec 2025 |
| 7942 | Old Cedron, L.L.C. | Lubbock, TX 79410 | Oil & Gas Operator | May 2004 |
| 7943 | Old Chief Oil, LLC | New Braunfels, TX 78132 | Oil Operator | Dec 2025 |
| 7944 | Old Pine Energy Corporation | Austin, TX 78755 | Oil Operator | Dec 2025 |
| 7945 | Old Timers Oil | Saratoga, TX 77585 | Oil & Gas Operator | Nov 2014 |
| 7946 | Old Timers Oil Company, LLC | Saratoga, TX 77585 | Oil Operator | Aug 2022 |
| 7947 | Old Timers Oil No. 2 Incorporated | Saratoga, TX 77585 | Oil Operator | Dec 2025 |
| 7948 | Old Union Operating Company | Austin, TX 78716 | Oil & Gas Operator | Dec 2025 |
| 7949 | Older Than Dirt LLC | Weatherford, TX 76086 | Oil & Gas Operator | Dec 2025 |
| 7950 | Oldfield Acquisition LP | Austin, TX 78733 | Oil & Gas Operator | Sep 1996 |
| 7951 | Ole Chaparral On Possum Kingdom | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1997 |
| 7952 | Ole, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 7953 | Oleum Exploration, LLC | Brodheadsvill, PA 18322 | Oil & Gas Operator | Mar 2023 |
| 7954 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 7955 | Oleum Partners, LLC | Frisco, TX 75034 | Oil & Gas Operator | Dec 2025 |
| 7956 | Olifant Energy LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jun 2019 |
| 7957 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Dec 2025 |
| 7958 | Oliver Oil & Gas | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 7959 | Olmos Partners, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 7960 | Olney Oil LLC | Boerne, TX 78006 | Oil Operator | Dec 2025 |
| 7961 | Olney Properties, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2003 |
| 7962 | Olsan Brothers, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Apr 1994 |
| 7963 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 7964 | Olson, S. A. | Kenedy, TX 78119 | Oil & Gas Operator | Aug 1994 |
| 7965 | Oltex Production | Idalou, TX 79329 | Oil & Gas Operator | Dec 2025 |
| 7966 | Omar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 7967 | Omber Petroleum & Energy Corp. | New Braunfels, TX 78131 | Oil & Gas Operator | Dec 2025 |
| 7968 | Omega Alpha Resources, LLC | Dallas, TX 75219 | Oil Operator | Dec 2025 |
| 7969 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 7970 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Dec 2025 |
| 7971 | Omega Operating, Inc. | Odessa, TX 79769 | Oil & Gas Operator | Mar 2001 |
| 7972 | Omimex Energy, Inc. | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2025 |
| 7973 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 7974 | Omni E & P, Inc. | San Antonio, TX 78229 | Oil Operator | Apr 2010 |
| 7975 | Omni Oil & Gas, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2017 |
| 7976 | Omni Operating Company(A) | Dallas, TX 75370 | Oil & Gas Operator | Dec 2025 |
| 7977 | Omni Petroleum Corporation | Austin, TX 78738 | Oil & Gas Operator | Dec 2025 |
| 7978 | Omta Operating LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Dec 2025 |
| 7979 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Dec 2025 |
| 7980 | Onaroll Operating LLC | Levelland, TX 79336 | Oil Operator | Dec 2025 |
| 7981 | One Epoch Energy, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 7982 | One Nickel Operating LLC | Ashland, MA 01721 | Oil Operator | Dec 2025 |
| 7983 | One Tec Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2007 |
| 7984 | One World Operating, LLC | Tampa, FL 33602 | Oil & Gas Operator | Dec 2025 |
| 7985 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 7986 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 7987 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Sep 2025 |
| 7988 | Onyx Industries LTD, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 7989 | Onyx Producing Company, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2008 |
| 7990 | Opal Energy, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2009 |
| 7991 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 7992 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 7993 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 7994 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 7995 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 7996 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 7997 | Optimum Exploration LLC | Dallas, TX 75254 | Oil & Gas Operator | Dec 2025 |
| 7998 | Orange Petroleum Co. | Orangefield, TX 77639 | Oil & Gas Operator | May 1995 |
| 7999 | Orangefield East Corp | Dallas, TX 75382 | Oil Operator | Dec 2025 |
| 8000 | Orangefield Operating Corporation | Dallas, TX 75382 | Oil Operator | Dec 2025 |