| 301 | Western Oil And Gas Development Corp | Oklahoma City, OK 73103-3735 | Oil & Gas Operator | Oct 2025 |
| 302 | WM KS Energy Resources LLC | Shreveport, LA 71101 | Oil & Gas Operator | Nov 2019 |
| 303 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 304 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 305 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Oct 2025 |
| 306 | Z G Operating LLC | Oklahoma City, OK 73134-5038 | Oil & Gas Operator | Nov 2009 |
| 307 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 308 | Zephyr Operating Co LLC | Oklahoma City, OK 73118-6035 | Oil & Gas Operator | Oct 2025 |
| 309 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |