| 1 | W & T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Dec 2024 |
| 2 | W & T Oil Properties, Inc. | | Oil & Gas Operator | Nov 1989 |
| 3 | W. B. McCarter, Jr., Inc. | | Oil & Gas Operator | Dec 1995 |
| 4 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2024 |
| 5 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 6 | Wallace Operating Company | | Oil & Gas Operator | Sep 1986 |
| 7 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 8 | Warhorse Oil & Gas, LLC | | Oil & Gas Operator | Dec 2018 |
| 9 | Warwick Oil & Gas, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 1993 |
| 10 | Watson Oil Corporation | | Oil & Gas Operator | Jun 1981 |
| 11 | WCC Energy Group LLC | | Oil & Gas Operator | Jul 2024 |
| 12 | Weaver Exploration Company | | Oil & Gas Operator | Jun 1991 |
| 13 | Weaver Oil & Gas Corporation | | Oil & Gas Operator | Dec 1984 |
| 14 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 15 | Westport Oil And Gas Company Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2002 |
| 16 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Dec 2024 |
| 17 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jul 2024 |
| 18 | Whitton Company, Inc. | | Oil & Gas Operator | Jul 2020 |
| 19 | Wilcox Operating Corporation | Shreveport, LA 71115 | Oil & Gas Operator | Dec 2024 |
| 20 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Dec 2024 |
| 21 | William Lagnion | | Oil & Gas Operator | Aug 1998 |
| 22 | Williams Exploration Company | | Oil & Gas Operator | Dec 1986 |
| 23 | Williams-Cody, Inc. | Houston, TX 77060 | Oil & Gas Operator | May 1994 |
| 24 | Wintershall Corporation | | Oil & Gas Operator | Oct 1989 |
| 25 | Wintershall Oil & Gas Corp | Houston, TX 77027 | Oil & Gas Operator | Jul 1989 |
| 26 | WM. T. Burton Industries, Inc. | | Oil & Gas Operator | Apr 1988 |
| 27 | Woolf & Magee, Inc. | | Oil & Gas Operator | Oct 1991 |
| 28 | WRT Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | May 1998 |