| 901 | American Lariat | | Oil Operator | Jun 1994 |
| 902 | American National Petroleum Co. | Houston, TX 77057 | Oil & Gas Operator | Aug 1995 |
| 903 | American Natural Energy Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 904 | American Natural Gas Inc | Saint Clairsville, OH 43950 | Oil & Gas Operator | Dec 2020 |
| 905 | American Natural Resources LLC | Tulsa, OK 74145-1117 | Oil & Gas Operator | May 2020 |
| 906 | American Oil & Gas, Inc. | | Oil & Gas Operator | Nov 2010 |
| 907 | American Oilfield Systems, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2001 |
| 908 | American Operating Company | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2003 |
| 909 | American Petrofina Co Of Texas | | Oil & Gas Operator | Jun 1985 |
| 910 | American Petrofina Co Of TX | Dallas, TX 75221-2159 | Oil & Gas Operator | Nov 2000 |
| 911 | American Petrole | | Oil & Gas Operator | Dec 1996 |
| 912 | American Petroleum & Environmental Consultants Inc | Edmond, OK 73013-8801 | Oil & Gas Operator | Dec 2025 |
| 913 | American Petroleum & Mineral Co Inc | Seminole, OK 74868 | Oil & Gas Operator | Aug 2019 |
| 914 | American Petroleum Corp | Addison, TX 75001 | Oil & Gas Operator | Apr 2026 |
| 915 | American Petroleum Energy Co | | Gas Operator | Jan 2026 |
| 916 | American Pumping & Trucking | New Braunfels, TX 78131 | Oil & Gas Operator | Apr 2026 |
| 917 | American Quasar Petroleum | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 1985 |
| 918 | American Quasar Petroleum Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2014 |
| 919 | American Quasar-Southland Roy. | | Oil & Gas Operator | Oct 1980 |
| 920 | American Resources, Inc. | Houston, TX 77079 | Oil & Gas Operator | Apr 2026 |
| 921 | American Royalty | Caldwell, TX 77836 | Oil & Gas Operator | Oct 2005 |
| 922 | American Shoreline, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2026 |
| 923 | American Southwest Corp. | | Oil & Gas Operator | Dec 1989 |
| 924 | American Star Energy & Min. Corp | Katy, TX 77449 | Oil & Gas Operator | Apr 2026 |
| 925 | American Star Energy & Mineral Corp | Amarillo, TX 79102-2283 | Oil & Gas Operator | Jun 2015 |
| 926 | American Tank Service LLC | Hays, KS 67601 | Oil Operator | Dec 2025 |
| 927 | American Trad.&Prod. | | Oil Operator | Dec 1995 |
| 928 | American Trading | | Oil & Gas Operator | Dec 1995 |
| 929 | American Trading & Prod Corp | Houston, TX 77040-6471 | Oil & Gas Operator | Nov 2014 |
| 930 | American Trading Et Al | | Oil & Gas Operator | May 1979 |
| 931 | American Warrior | | Oil & Gas Operator | Dec 2025 |
| 932 | American Warrior Inc | Garden City, KS 67846 | Oil & Gas Operator | Dec 2025 |
| 933 | American West | Burkett, TX 76828 | Oil & Gas Operator | Apr 2026 |
| 934 | American West Resources, Inc | Fort Worth, TX 76161 | Oil & Gas Operator | Apr 2026 |
| 935 | Americana Energy Inc | Byng, OK 74820 | Oil & Gas Operator | Dec 2025 |
| 936 | Americana Petroleum Corp | Waco, TX 76710 | Oil Operator | Aug 1992 |
| 937 | Americase Production Co. | Dallas, TX 75252 | Oil Operator | May 2002 |
| 938 | Americo Energy Resources, LLC | Houston, TX 77063 | Oil & Gas Operator | Apr 2026 |
| 939 | Americo Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2012 |
| 940 | Americus Resources, Inc. | | Oil & Gas Operator | Feb 1993 |
| 941 | Amerikan Oil, LLC | Mound City, KS 66056 | Oil Operator | Dec 2025 |
| 942 | Amerind Oil Co L P | Midland, TX 79701 | Oil & Gas Operator | Nov 2004 |
| 943 | Amerind Oil Company, LTD. | Midland, TX 79701 | Oil & Gas Operator | Nov 2004 |
| 944 | Ameristate Exploration LLC | Austin, TX 78701 | Oil & Gas Operator | Nov 2009 |
| 945 | Ameritech Oil & Gas Corporation | Dallas, TX 75248 | Oil & Gas Operator | May 1996 |
| 946 | Amerkan Resource | | Oil Operator | Jan 1994 |
| 947 | Amerril Energy LLC | Houston, TX 77042 | Oil & Gas Operator | Apr 2026 |
| 948 | Amerroyal Energy LLC | Shawnee, OK 74804-4163 | Oil & Gas Operator | Dec 2022 |
| 949 | Ames Financial, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 950 | Ames Oil | Cross Plains, TX 76443 | Oil & Gas Operator | Apr 2026 |
| 951 | Ames Oil And Gas | | Oil & Gas Operator | Apr 1986 |
| 952 | Ames Oil Corporation Of Texas | Austin, TX 78720 | Oil & Gas Operator | Mar 2015 |
| 953 | Ames, C B Dba Ames Oil & Gas | | Oil Operator | Dec 2004 |
| 954 | Ames, Debra B. | Dewittville, NY 14728 | Gas Operator | Dec 2024 |
| 955 | Amex Energy Consults Inc | Columbus, OH 43214 | Oil & Gas Operator | Dec 1988 |
| 956 | Amexco, LLC | San Antonio, TX 78259 | Oil & Gas Operator | Apr 2026 |
| 957 | Amherst Energy Holdings, LLC | Highland VLG, TX 75077 | Oil Operator | Apr 2026 |
| 958 | Aminex USA, Inc. | Somerset, TX 78069 | Oil & Gas Operator | May 2018 |
| 959 | Aminoil Of Louisiana, Inc. | | Oil & Gas Operator | Dec 1981 |
| 960 | Aminoil USA Inc | | Oil & Gas Operator | Jan 1985 |
| 961 | Amirmex Inc. | Denver, CO 80234 | Oil & Gas Operator | Apr 2026 |
| 962 | Amistad Energy Services, LLC | Katy, TX 77450 | Oil & Gas Operator | Oct 2017 |
| 963 | Amity Oil Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1977 |
| 964 | Amkay Petroleum Co., Inc. | | Oil Operator | Dec 1991 |
| 965 | Ammonite Energy Texas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2003 |
| 966 | Ammons, Dean E | | Oil Operator | Jan 2021 |
| 967 | Amoco Prod Co-Banner Pet LTD | | Oil & Gas Operator | Mar 1981 |
| 968 | Amoco Production | | Oil & Gas Operator | Jun 2012 |
| 969 | Amoco Production Co And C M S Oil And Gas | | Oil & Gas Operator | Sep 1996 |
| 970 | Amoco Production Co And Peninsular Oil And Gas Co | | Oil & Gas Operator | Sep 1998 |
| 971 | Amoco Production Co-Ratliff City | Ratliff City, OK 73081 | Oil Operator | May 1998 |
| 972 | Amoco Production Company | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 973 | Amoco Rocmount Company | Denver, CO 80201 | Oil & Gas Operator | Jan 1998 |
| 974 | Amos, Joe | Wichita, KS 67233 | Oil Operator | Jul 1990 |
| 975 | Ampak Oil Company | Plano, TX 75074 | Oil & Gas Operator | Apr 2026 |
| 976 | Ample Resources Inc. | | Oil & Gas Operator | Dec 2025 |
| 977 | Amplify Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2026 |
| 978 | Amplify Oklahoma Operating LLC | Houston, TX 77002-4800 | Oil & Gas Operator | Dec 2025 |
| 979 | Ampolex (Texas), Inc. | | Oil & Gas Operator | May 1993 |
| 980 | Ampolex Wy Inc | Gillette, WY 82716 | Oil & Gas Operator | Mar 1997 |
| 981 | Amreco, LLC | El Dorado, AR 71730 | Oil Operator | Jan 2025 |
| 982 | Amrich Energy Inc. | | Oil & Gas Operator | Dec 2025 |
| 983 | Amron Petroleum, Inc. | Midland, TX 79708 | Oil & Gas Operator | Jan 1996 |
| 984 | Ams Energy LLC | Herman, PA 16039-0156 | Oil & Gas Operator | Jan 2026 |
| 985 | Ams Energy Solutions LLP | Katy, TX 77493 | Oil Operator | Apr 2026 |
| 986 | Amsito Oil Company LLC | Denton, TX 76206-0689 | Oil Operator | Apr 2001 |
| 987 | Amsler Jerry & Denese | Enid, OK 73703-9300 | Oil & Gas Operator | Jul 2020 |
| 988 | Amt Resources, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Apr 2026 |
| 989 | Amtech Energy Inc | Plymouth, IL 62367-1016 | Oil & Gas Operator | Dec 2021 |
| 990 | Amtex Energy | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 991 | Amtex Energy, Inc. | Fort Worth, TX 76147 | Oil & Gas Operator | Apr 2026 |
| 992 | Amtex Oil & Gas Inc | Canton, OH 44711 | Oil & Gas Operator | Dec 2004 |
| 993 | Amtuck Oil | Logan, OH 43138 | Oil & Gas Operator | Dec 2010 |
| 994 | Amvest Osage Inc | Skiatook, OK 74070-0970 | Oil & Gas Operator | Dec 2025 |
| 995 | Amwes Exploration, LLC | Barbourville, KY 40906 | Oil & Gas Operator | Dec 2023 |
| 996 | Amx Energy, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Apr 2026 |
| 997 | An-Car Oil Co Inc | Owensboro, KY 42302-1329 | Oil & Gas Operator | Dec 2014 |
| 998 | An-Son Corp | Oklahoma City, OK 73124 | Oil & Gas Operator | Jan 2006 |
| 999 | Anabaco Operating Company | Stillwater, OK 74076-1958 | Oil & Gas Operator | Mar 2014 |
| 1000 | Anacapa Oil Corporation | | Gas Operator | Dec 2025 |