| 801 | Stinnett Oil Company | | Oil Operator | Dec 1997 |
| 802 | Stockdale Energy Co. | | Gas Operator | Dec 1992 |
| 803 | Stockdale Oil & Gas Inc. | | Oil & Gas Operator | Dec 2001 |
| 804 | Stone Cabin Resources LLC | | Oil & Gas Operator | Dec 2025 |
| 805 | Storm Industries | | Oil & Gas Operator | Dec 1988 |
| 806 | Stowe Killingsworth | | Oil & Gas Operator | Apr 2023 |
| 807 | Strata-X Inc. | | Oil & Gas Operator | Nov 2025 |
| 808 | Stream Energy, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2025 |
| 809 | Summit Energy LLC | | Oil & Gas Operator | Dec 2025 |
| 810 | Summit Exploration (California) LLC | | Oil & Gas Operator | Feb 2018 |
| 811 | Sumpf-Williams | | Gas Operator | Dec 1980 |
| 812 | Sun Mountain Oil & Gas | | Oil & Gas Operator | Dec 2020 |
| 813 | Sunray Petroleum Inc. | | Oil & Gas Operator | Nov 2025 |
| 814 | Sunrise Resources Inc. | | Gas Operator | Dec 1998 |
| 815 | Sunset Exploration Inc. | | Oil & Gas Operator | Nov 2025 |
| 816 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 817 | Superior Well Service Inc. | | Oil & Gas Operator | Sep 2007 |
| 818 | Sycamore Development Partners LLC | | Oil & Gas Operator | Dec 2025 |
| 819 | Synergy Oil & Gas LLC | | Oil & Gas Operator | Nov 2025 |
| 820 | Synergy Resources | Artesia, NM 88210 | Oil & Gas Operator | Jan 2015 |
| 821 | T. A. Atkinson Opr. | | Gas Operator | Dec 1997 |
| 822 | T. E. Adams Petroleum Corp. | | Oil & Gas Operator | Nov 2025 |
| 823 | Tamarack Energy Inc | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 824 | Tannehill Oil Company | | Oil & Gas Operator | Dec 1991 |
| 825 | Target Drilling | | Oil & Gas Operator | Feb 2018 |
| 826 | Tatum Petroleum Corp | Zanesville, OH 43702 | Oil & Gas Operator | Dec 2008 |
| 827 | TB Properties | | Oil & Gas Operator | Nov 2025 |
| 828 | Team Operating, L.L.C. | Pinehurst, TX 77362 | Oil & Gas Operator | Feb 2026 |
| 829 | Ted Koble Operator | | Oil & Gas Operator | Nov 2007 |
| 830 | Tej Ventures | | Oil & Gas Operator | Dec 2002 |
| 831 | Temblor Petroleum Co. LLC | | Oil & Gas Operator | Nov 2025 |
| 832 | Temescal Resources LLC | | Oil & Gas Operator | Dec 2025 |
| 833 | Temple Resources LLC | | Oil Operator | Nov 2025 |
| 834 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Nov 2025 |
| 835 | Tenneco West, Inc. | | Oil & Gas Operator | Dec 1983 |
| 836 | Termo Company Of Texas | | Oil & Gas Operator | Dec 1986 |
| 837 | Terra Exploration & Production Co. Inc. | | Oil & Gas Operator | Dec 2009 |
| 838 | Tetra Oil Company | | Oil & Gas Operator | Nov 2025 |
| 839 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 840 | Texalta Oil And Gas Inc. | | Gas Operator | Dec 1990 |
| 841 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 842 | Texas Pacific Oil Co. | | Oil & Gas Operator | Dec 1980 |
| 843 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 844 | Texinia Oil & Gas Inc | Dallas, TX 75214 | Oil & Gas Operator | Nov 2025 |
| 845 | The Arvin Company | | Oil Operator | Dec 2004 |
| 846 | The Hampton Oil Corporation | | Oil & Gas Operator | Aug 2014 |
| 847 | The Harter Family Trust Of 1995 | | Oil Operator | Dec 2003 |
| 848 | The Krik Company | | Oil Operator | Dec 2004 |
| 849 | The Lansdale Co. | | Oil & Gas Operator | Dec 2025 |
| 850 | The Nahabedian Exploration Group LLC | | Oil & Gas Operator | Nov 2025 |
| 851 | The Port Of Long Beach | | Oil & Gas Operator | Dec 1997 |
| 852 | The Procter And Gamble Co. | | Gas Operator | Dec 1989 |
| 853 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Dec 2025 |
| 854 | Thomas C. King | | Oil & Gas Operator | Dec 1995 |
| 855 | Thomas Oil Company | | Oil & Gas Operator | Dec 2008 |
| 856 | Thomas Oilers | | Oil & Gas Operator | Dec 2025 |
| 857 | Thomas R. Banks | | Oil Operator | Nov 2025 |
| 858 | Thompson Energy Resources LLC | | Oil & Gas Operator | Dec 2025 |
| 859 | Thompson Oil Co. | Corsicana, TX 75151 | Oil & Gas Operator | Nov 2025 |
| 860 | Thriftway Company | Farmington, NM 87401 | Oil & Gas Operator | Dec 1996 |
| 861 | Thums Long Beach Co. | | Oil & Gas Operator | Dec 2025 |
| 862 | Thurner Energy Corporation | | Oil & Gas Operator | Dec 2001 |
| 863 | Tidelands Oil Production Co. | | Oil & Gas Operator | Dec 2025 |
| 864 | Tiger Oil Company | Dallas, TX 75221 | Oil & Gas Operator | May 2007 |
| 865 | Timco Oil Co. | | Oil & Gas Operator | Dec 1987 |
| 866 | Titan Energy, Inc. | Austin, TX 78703 | Oil & Gas Operator | Feb 2026 |
| 867 | TJ Ballantyne Living Trust | | Oil & Gas Operator | Dec 2019 |
| 868 | TJ Scott Family Investments LLC | | Oil & Gas Operator | Dec 2025 |
| 869 | Tonka Energy Inc. | | Oil & Gas Operator | Dec 2004 |
| 870 | Tonner Hills SSP LLC | | Oil & Gas Operator | Dec 2012 |
| 871 | Tooby Farms | | Gas Operator | Dec 1989 |
| 872 | Topko N. Wilmington Prtnrship. | | Oil & Gas Operator | Dec 1995 |
| 873 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 874 | Torrance Petroleum Inc. | | Oil & Gas Operator | Dec 2003 |
| 875 | Tosco Enhanced Oil Recovery Corporation | | Oil Operator | Dec 1981 |
| 876 | Towne Exploration Company LP | | Oil & Gas Operator | Dec 2025 |
| 877 | TPC Operating Inc. | | Oil & Gas Operator | Nov 2025 |
| 878 | Transco Oil & Gas Inc. | | Gas Operator | Dec 1992 |
| 879 | Transpac Petroleum Inc. | | Oil & Gas Operator | Dec 1995 |
| 880 | TRC Cypress Group LLC | | Oil & Gas Operator | Nov 2025 |
| 881 | TRC Operating Company Inc. | | Oil & Gas Operator | Dec 2025 |
| 882 | Tri-Valley Oil & Gas Co. | | Oil & Gas Operator | Nov 2025 |
| 883 | Trident Oil & Gas Corporation Inc. | | Oil & Gas Operator | Dec 1993 |
| 884 | Trio Petroleum LLC | | Oil & Gas Operator | Nov 2025 |
| 885 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 886 | TS Leasing Operations Inc. | | Oil & Gas Operator | Dec 2025 |
| 887 | Two Bay Petroleum | | Oil & Gas Operator | Dec 2010 |
| 888 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 889 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 890 | Underground Energy Inc. | | Oil & Gas Operator | Nov 2025 |
| 891 | Union Development Company Inc | | Oil & Gas Operator | Dec 1992 |
| 892 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 893 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 894 | United Energy, Inc. | Wichita, KS 67230 | Oil & Gas Operator | Dec 2002 |
| 895 | Vaca Energy LLC | | Oil & Gas Operator | Nov 2025 |
| 896 | Valid Energy Company | | Oil & Gas Operator | Nov 2025 |
| 897 | Valley Energy Expl. | | Oil & Gas Operator | Dec 1984 |
| 898 | Valley Energy Resources Inc. | | Oil & Gas Operator | Dec 2006 |
| 899 | Vaquero Energy Inc | Bakersfield, CA 93309 | Oil & Gas Operator | May 2023 |
| 900 | Vaquero SJV LLC | | Oil & Gas Operator | Dec 2022 |