| 901 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 902 | Anderson Oil Corporation | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Nov 1999 |
| 903 | Anderson Oil LTD. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Sep 2025 |
| 904 | Anderson Oil LTD.,LLP | Farmington, NM 87499 | Oil & Gas Operator | Jun 2025 |
| 905 | Anderson Operating LLC Of Mississippi | | Oil & Gas Operator | Jul 2018 |
| 906 | Anderson Petro-Equipment, Inc. | Montgomery, TX 77356 | Oil & Gas Operator | Sep 2025 |
| 907 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 908 | Anderson Production | Cisco, TX 76437 | Oil & Gas Operator | Sep 2025 |
| 909 | Anderson T Maxwell | Tulsa, OK 74136-0653 | Oil & Gas Operator | Dec 2013 |
| 910 | Anderson Thornto | | Oil & Gas Operator | Mar 1995 |
| 911 | Anderson, Allen M | Fleming, OH 45729 | Oil & Gas Operator | Dec 2023 |
| 912 | Anderson, Arden A. | | Oil & Gas Operator | Jun 1970 |
| 913 | Anderson, Carl T. | Wichita Falls, TX 76301 | Oil & Gas Operator | Feb 2014 |
| 914 | Anderson, Dorman | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 2012 |
| 915 | Anderson, E D | Cisco, TX 76437 | Oil & Gas Operator | Nov 2009 |
| 916 | Anderson, James K. Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 2025 |
| 917 | Anderson, James S. | Sinclairville, NY 14782 | Gas Operator | Dec 2024 |
| 918 | Anderson, Jerry | Floydada, TX 79235 | Oil & Gas Operator | Apr 2025 |
| 919 | Anderson, Kendra A. | Galva, KS 67443 | Oil Operator | Apr 2025 |
| 920 | Anderson, Kyle K. | Concord, NY 14055 | Gas Operator | Dec 2024 |
| 921 | Anderson, Roger W. Corp. | Clyde, TX 79510 | Oil & Gas Operator | Apr 2020 |
| 922 | Anderson, Steven C. | Victoria, TX 77902 | Gas Operator | Jun 2004 |
| 923 | Ando Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 1998 |
| 924 | Andover Oil Comp | | Oil & Gas Operator | Oct 1989 |
| 925 | Andover Oil Company | | Oil Operator | Sep 1982 |
| 926 | Andrea Operating Company | Edmond, OK 73013-6627 | Oil & Gas Operator | May 2025 |
| 927 | Andress Bill O | Tulsa, OK 74135-3553 | Oil & Gas Operator | Sep 2003 |
| 928 | Andrew Alan Exploration, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2017 |
| 929 | Andrew L. Newkirk | | Oil Operator | Jun 2025 |
| 930 | Andrew, Robert Oneal | Olney, TX 76374 | Oil & Gas Operator | Sep 1998 |
| 931 | Andrews & Corkran, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Feb 2000 |
| 932 | Andrews, B. C. | Graham, TX 76450 | Oil & Gas Operator | Sep 2025 |
| 933 | Andries Oil Company | | Oil Operator | Jan 2025 |
| 934 | Andrikopoulos A G | Cheyenne, WY 82009 | Oil & Gas Operator | Dec 1994 |
| 935 | Andrikopoulos Resources* A G | | Oil & Gas Operator | Jul 2015 |
| 936 | Andrus Resources Corporation | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 937 | Anegada Energy LLC | Canonsburg, PA 15317-0400 | Gas Operator | Jun 2025 |
| 938 | Anegada Resources | Kerrville, TX 78029 | Oil & Gas Operator | Jan 2002 |
| 939 | Anejo Production, LLC | Electra, TX 76360 | Oil & Gas Operator | Sep 2025 |
| 940 | Angel Exploration Company | Oklahoma City, OK 73102-8868 | Oil & Gas Operator | Jan 2019 |
| 941 | Angel Exploration LLC | Oklahoma City, OK 73116-3603 | Oil & Gas Operator | Jun 2025 |
| 942 | Angel Operating LLC | Metairie, LA 70033 | Oil Operator | Sep 2025 |
| 943 | Angel Rose Energy, LLC | Olney, IL 62450 | Oil Operator | Dec 2023 |
| 944 | Angelo, Ernest, Jr. | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 945 | Angerman Assoc Inc | Pittsburgh, PA 15238-1359 | Oil & Gas Operator | Dec 1998 |
| 946 | Angerman Associates Inc | | Oil & Gas Operator | Mar 1998 |
| 947 | Angle Exploratio | | Oil Operator | Jan 1987 |
| 948 | Angle George A | | Gas Operator | Dec 1986 |
| 949 | Angle Oil Compan | | Oil Operator | Jun 1994 |
| 950 | Angle Oil Company | Hays, KS 67601 | Oil Operator | Sep 2002 |
| 951 | Anglo Production Company | | Oil & Gas Operator | Nov 1983 |
| 952 | Anglo-Dutch Energy, LLC | | Oil & Gas Operator | Sep 2022 |
| 953 | Angus Petroleum Corporation | Chicago, IL 60660 | Oil & Gas Operator | Dec 2022 |
| 954 | Anja Resources | Bridgeport, WV 26330 | Oil & Gas Operator | Dec 2021 |
| 955 | Anjet Petroleum Company Inc | Gulfport, MS 39507-1301 | Oil & Gas Operator | Aug 2017 |
| 956 | Ankor E&P Holdings Corporation | | Oil & Gas Operator | Jan 2021 |
| 957 | Anloc, LLC | Houston, TX 77024 | Oil & Gas Operator | Apr 2019 |
| 958 | Ann Brindle | | Oil Operator | Jun 2025 |
| 959 | Ann Marie Tiers | | Oil Operator | Dec 1996 |
| 960 | Annarock Petroleum LLC | Winter Garden, FL 34787 | Oil & Gas Operator | Dec 2024 |
| 961 | Annco Pet. Co & Equipment, Inc | | Oil & Gas Operator | Sep 1982 |
| 962 | Annex Oil Corp | | Oil & Gas Operator | Jun 2000 |
| 963 | Annona Productions, Inc. | | Gas Operator | May 2019 |
| 964 | Annulus Energy LLC | | Gas Operator | Dec 2021 |
| 965 | Anr Limited Inc/Coastal | Houston, TX 770460995 | Oil & Gas Operator | Dec 1987 |
| 966 | Anr Pipeline Company | | Oil & Gas Operator | Jan 2025 |
| 967 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 968 | Ansbro Petroleum Company, LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2008 |
| 969 | Anschutz Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2016 |
| 970 | Anschutz Drilling Co. | | Oil Operator | Jul 1961 |
| 971 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2025 |
| 972 | Anschutz Oil Co. | | Oil & Gas Operator | Jul 1984 |
| 973 | Anschutz Oil Company LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2020 |
| 974 | Anschutz Pinedale Corporation | Denver, CO 80202 | Oil & Gas Operator | Dec 2015 |
| 975 | Anshutz Oil | | Oil Operator | Dec 2009 |
| 976 | Anson Charles Dba Anson Oil | Seminole, OK 74868 | Oil Operator | May 2025 |
| 977 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 978 | Anson Gas Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | May 1997 |
| 979 | Anson J W | Seminole, OK 74818-1280 | Oil & Gas Operator | Oct 2020 |
| 980 | Anson Robert L & Teresa M | Seminole, OK 74868 | Oil & Gas Operator | Jun 2025 |
| 981 | Anstine & Musgrove Inc | Ponca City, OK 74602 | Oil & Gas Operator | May 2025 |
| 982 | Anstine Oil Company | | Oil Operator | Apr 2025 |
| 983 | Anstine-Musgrove | Ponca City, OK 74602 | Oil & Gas Operator | Feb 2017 |
| 984 | Anstine-Musgrove Oil Company | Ponca City, OK 74602-0391 | Oil & Gas Operator | Jan 2013 |
| 985 | Ansythe Exploration Co., Inc. | | Oil & Gas Operator | Oct 1982 |
| 986 | Ant Hills Production | Lusk, WY 82225 | Oil & Gas Operator | Jul 2025 |
| 987 | Antara Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 2004 |
| 988 | Antares Energy Company | Houston, TX 77010 | Oil & Gas Operator | Sep 2025 |
| 989 | Antares Oil Corp | Denver, CO 80202 | Oil & Gas Operator | Oct 2015 |
| 990 | Antares Ventures, L.L.C. | | Oil Operator | Oct 2016 |
| 991 | Antelope Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 992 | Antelope Energy Partners, LLC | Houston, TX 77027 | Oil & Gas Operator | Sep 2025 |
| 993 | Antelope Production Co. | Midland, TX 79701 | Oil & Gas Operator | Oct 1995 |
| 994 | Antelope Resources Inc | Billings, MT 59101 | Oil & Gas Operator | May 2017 |
| 995 | Antero Energy LLC | Denver, CO 80202 | Gas Operator | Nov 2003 |
| 996 | Antero Resources Bluestone LLC | | Gas Operator | Dec 2013 |
| 997 | Antero Resources Corporation | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 998 | Antero Resources I, LP | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 999 | Antero Resources II, LP | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 1000 | Antero Resources Piceance LLC | | Oil & Gas Operator | Dec 2012 |