| 1 | 3 & 1 Operating Inc | | Oil & Gas Operator | Aug 2015 |
| 2 | 442 Operating La, LLC | | Oil & Gas Operator | Dec 2024 |
| 3 | Ada Oil Exploration Corp | | Oil & Gas Operator | Jan 1986 |
| 4 | Adams Resources Expl. Corp. | Houston, TX 77001 | Oil & Gas Operator | Apr 2020 |
| 5 | Adobe Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Aug 2002 |
| 6 | Aegis Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Sep 1998 |
| 7 | Alpine Expl. Companies, Inc. | | Oil & Gas Operator | Jan 2024 |
| 8 | Amarillo Oil Company | | Oil & Gas Operator | Aug 1980 |
| 9 | Amax Oil & Gas Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Nov 2014 |
| 10 | Ambrit Energy Corporation | Garland, TX 75044 | Oil & Gas Operator | Jun 2003 |
| 11 | Amerada Hess Corporation | Houston, TX 77252 | Oil & Gas Operator | Aug 2013 |
| 12 | American Explorer, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Jan 1999 |
| 13 | Amoco Production Co. | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 14 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 15 | Annco Pet. Co & Equipment, Inc | | Oil & Gas Operator | Sep 1982 |
| 16 | Anr Pipeline Company | | Oil & Gas Operator | Jan 2025 |
| 17 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Oct 2025 |
| 18 | Apco Oil Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jun 1993 |
| 19 | Arco O & G Co-Div Atl Rich Co | | Oil & Gas Operator | Feb 1994 |
| 20 | Aroc (Texas) Inc | Houston, TX 77090 | Oil & Gas Operator | Dec 2014 |
| 21 | Aspect Energy, LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 22 | Aspen Exploration | | Oil & Gas Operator | Jan 1983 |
| 23 | Atinum Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 24 | Austral Oil & Exploration, Inc | | Oil & Gas Operator | Jun 2004 |
| 25 | Austral Oil Company Incorporated | Sulphur, LA 70663 | Oil & Gas Operator | Mar 2008 |
| 26 | Azimuth Energy, LLC | Denver, CO 80203 | Oil & Gas Operator | Sep 2006 |
| 27 | B & B Oil Company | Corsicana, TX 75110 | Oil & Gas Operator | Jun 2025 |
| 28 | B & M Operating Co., Inc. | Houston, TX 77006 | Oil & Gas Operator | Oct 2025 |
| 29 | B & S Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Jun 2025 |
| 30 | B M Oil, Inc. | | Oil & Gas Operator | May 2019 |
| 31 | B-B Production | Ira, TX 79527 | Oil & Gas Operator | Oct 2025 |
| 32 | Badger Oil Corporation | Lafayette, LA 70505 | Oil & Gas Operator | Nov 2011 |
| 33 | Baham Energy Services, LLC | | Oil Operator | Dec 2024 |
| 34 | Ball Marketing, Inc. | | Oil & Gas Operator | Sep 1999 |
| 35 | Barton Oil & Gas Co., Inc. | | Oil & Gas Operator | Sep 1993 |
| 36 | Baruch-Foster Corporation | Oklahoma City, OK 73126-6770 | Oil & Gas Operator | Feb 2001 |
| 37 | Basf Corporation | Houston, TX 77027 | Oil & Gas Operator | Nov 1992 |
| 38 | Basin Petroleum, Inc. | | Oil & Gas Operator | Jul 1995 |
| 39 | Bass Enterprises Production Co | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2006 |
| 40 | BBH Operating Company | | Oil & Gas Operator | Feb 1986 |
| 41 | Bel Oil Corporation | Jenks, OK 74037 | Oil & Gas Operator | Jun 2005 |
| 42 | Beta Operating, Inc | | Oil & Gas Operator | May 2001 |
| 43 | BHP Petroleum (Americas) Inc | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 44 | BKV Ventures, LLC | | Oil & Gas Operator | Nov 2020 |
| 45 | Black Pool Energy, LP | Houston, TX 77070 | Oil & Gas Operator | Jul 2024 |
| 46 | Block "T" Petroleum, Inc. | Tyler, TX 75707 | Oil & Gas Operator | Oct 2025 |
| 47 | Block T Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 48 | Booher Energy, LLC | | Oil Operator | Dec 2024 |
| 49 | Booher Engineering, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Oct 2025 |
| 50 | Borden, Inc. | Columbus, OH 43215 | Oil & Gas Operator | May 1990 |
| 51 | BP America Production Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 52 | Bradco Oil & Gas Company | | Oil & Gas Operator | Dec 1980 |
| 53 | Bridge Oil Company LP | Midland, TX 79702 | Oil & Gas Operator | May 1999 |
| 54 | Bridwell Oil Management, LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 55 | Britlind Oil LLC | | Oil & Gas Operator | Dec 2020 |
| 56 | Brown & McKenzie, Inc. | | Oil & Gas Operator | May 1984 |
| 57 | Browning Oil Company, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Oct 2025 |
| 58 | Bta Oil Producers, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 59 | Bull Operating, LLC | Houston, TX 77010 | Oil & Gas Operator | Oct 2025 |
| 60 | C. V. Radke | | Oil Operator | Jan 1993 |
| 61 | Cabot Oil & Gas Corporation | Houston, TX 77024 | Oil & Gas Operator | Jun 2025 |
| 62 | Caddo Management, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 63 | Cajun Minerals, Inc. | | Oil & Gas Operator | Mar 1997 |
| 64 | Cajun Operating, Inc. | | Oil & Gas Operator | Jun 2011 |
| 65 | Callon Offshore Production, Inc. | Natchez, MS 39121 | Oil & Gas Operator | Dec 2005 |
| 66 | Callon Petroleum Company | Natchez, MS 39120 | Oil & Gas Operator | Jan 2000 |
| 67 | Callon Petroleum Operating Co | Houston, TX 77042 | Oil & Gas Operator | Jul 2024 |
| 68 | Camex Operating Company | | Oil & Gas Operator | Dec 2024 |
| 69 | Camex, Inc. | | Oil & Gas Operator | Jun 1992 |
| 70 | Cardinal Oil & Gas, Inc. | | Oil & Gas Operator | Jun 1995 |
| 71 | Carl E. Hansford | | Oil Operator | Oct 1980 |
| 72 | Carl Oil & Gas Co. | Bakersfield, CA 93309 | Oil & Gas Operator | Dec 1995 |
| 73 | Carrollton Resources Corp. | | Oil & Gas Operator | Sep 2000 |
| 74 | Caskids Operating Company | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 75 | Castle Exploration Company Inc | Blue Bell, PA 19422 | Oil & Gas Operator | May 2018 |
| 76 | Cayman Exploration Corp. | Tulsa, OK 74119-1323 | Oil & Gas Operator | Jun 2001 |
| 77 | Celeron Oil & Gas Company | | Oil & Gas Operator | Dec 1987 |
| 78 | Century Mineral Corporation | | Oil & Gas Operator | Dec 1990 |
| 79 | Chambers Exploration Inc. | | Oil & Gas Operator | Dec 1986 |
| 80 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 81 | Charles Holston, Inc. | | Oil Operator | Jan 2025 |
| 82 | Charles Holston, Inc. Dba GTTS | | Oil Operator | Apr 2009 |
| 83 | Cheniere Petroleum Corporation | | Oil & Gas Operator | Feb 1989 |
| 84 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 85 | Christopher Oil & Gas Inc | Fulshear, TX 77441 | Oil & Gas Operator | Apr 2015 |
| 86 | Chroma Operating, Inc. | Washington, DC 20036 | Oil & Gas Operator | Jun 2016 |
| 87 | Cibco Resources, LLC | | Oil & Gas Operator | Nov 2024 |
| 88 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Oct 2025 |
| 89 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 90 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 91 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 92 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 93 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 94 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 95 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 96 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 97 | Coastal Production Inc. | | Oil & Gas Operator | Aug 2000 |
| 98 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 99 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2025 |
| 100 | Collet Oil Ventures, Inc. | Denver, CO 80217 | Oil & Gas Operator | Jun 2004 |