| 1 | C & F Petroleum | | Oil & Gas Operator | Apr 1991 |
| 2 | C & K Offshore Company | | Oil & Gas Operator | Oct 1980 |
| 3 | C & K Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Apr 1984 |
| 4 | C.F. Braun & Company | | Oil & Gas Operator | Dec 1986 |
| 5 | Callon Petroleum Company | Natchez, MS 39120 | Oil & Gas Operator | Jan 2000 |
| 6 | Callon Petroleum Operating Co | Houston, TX 77042 | Oil & Gas Operator | Jul 2024 |
| 7 | Cameron Development Co., Inc. | | Oil & Gas Operator | Mar 1988 |
| 8 | Cameron LNG, LLC | | Oil Operator | Jan 2025 |
| 9 | Camex Operating Company | | Oil & Gas Operator | Dec 2024 |
| 10 | Camex, Inc. | | Oil & Gas Operator | Jun 1992 |
| 11 | Campbell Energy Corp. | | Oil & Gas Operator | May 1992 |
| 12 | Cardinal Oil & Gas, Inc. | | Oil & Gas Operator | Jun 1995 |
| 13 | Caroline Hunt Schoellkopf | | Oil & Gas Operator | Aug 1987 |
| 14 | Carter-Langham, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 15 | Caskids Operating Company | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 16 | Castex Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 17 | Catlett & Ferguson-Carl O & G | | Oil & Gas Operator | Jun 1978 |
| 18 | Cenco, Inc. | | Oil & Gas Operator | Mar 2022 |
| 19 | Central Crude, Inc. | | Oil & Gas Operator | Jul 2014 |
| 20 | Central Resources Inc | Denver, CO 80203 | Oil & Gas Operator | Dec 2019 |
| 21 | Centurion Exploration Company | Houston, TX 77042 | Oil & Gas Operator | May 2009 |
| 22 | Chaparral Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2009 |
| 23 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Oct 2025 |
| 24 | Charles F. Word & Associates | | Oil Operator | Dec 1978 |
| 25 | Charleston Oil & Gas, Inc. | | Oil & Gas Operator | Mar 1997 |
| 26 | Chevron Pipe Line Company | Houston, TX 77001 | Oil Operator | Feb 2015 |
| 27 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 28 | Christeve Oil Company, Inc. | Houston, TX 77068 | Oil & Gas Operator | Dec 2022 |
| 29 | Chroma Operating, Inc. | Washington, DC 20036 | Oil & Gas Operator | Jun 2016 |
| 30 | Clayton W. Williams, Jr., Inc. | | Oil & Gas Operator | May 1993 |
| 31 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 32 | Cliffs Oil And Gas Company | | Oil & Gas Operator | Oct 1997 |
| 33 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 34 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 35 | Coastal Minerals, Inc. | | Oil Operator | Aug 1991 |
| 36 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 37 | Coastal States Gas Prod. Co. | | Oil & Gas Operator | Jun 1996 |
| 38 | Cockrell Oil Corporation | Houston, TX 77002-7348 | Oil & Gas Operator | Feb 2001 |
| 39 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 40 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2025 |
| 41 | Columbia Gas Dev. Corp. | | Oil & Gas Operator | Apr 1996 |
| 42 | Columbia Gulf Transmission Company, LLC | | Oil Operator | Jan 2025 |
| 43 | Columbia Minerals Corp., Inc. | | Oil & Gas Operator | May 1996 |
| 44 | Commerce Energy, Inc. | | Oil & Gas Operator | Dec 1999 |
| 45 | Compadres, Inc. | | Oil & Gas Operator | Dec 1988 |
| 46 | Comstock Oil & Gas -- La, Inc. | | Oil & Gas Operator | Mar 2005 |
| 47 | Condor Petroleum Corporation | | Oil & Gas Operator | Aug 2020 |
| 48 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 49 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 50 | Consolidated Resources Inc | | Oil & Gas Operator | May 2004 |
| 51 | Corpus Christi Oil & Gas Co. | | Oil & Gas Operator | Dec 1991 |
| 52 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 53 | Covey Energy, Inc. | | Oil & Gas Operator | Jun 1998 |
| 54 | Cox Operating, L.L.C. | | Oil & Gas Operator | Jan 2024 |
| 55 | Crawford Hughes Operating Co. | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 56 | Creole Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 57 | Crimson Explor Operating, Inc. | | Oil & Gas Operator | Dec 2009 |
| 58 | Curt Weaver Et Al | | Oil Operator | Apr 1982 |
| 59 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 60 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 61 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Oct 2025 |