| 5101 | Yasny Corporation | | Oil Operator | Nov 1991 |
| 5102 | Yates Oil Company | | Oil Operator | Jul 1990 |
| 5103 | Yellow Dog Oil Company | | Oil Operator | Apr 1988 |
| 5104 | Yellow Rock, LLC | | Oil & Gas Operator | Dec 2024 |
| 5105 | Yentzen Investments, Inc. | Sugar Land, TX 77478 | Oil Operator | May 1993 |
| 5106 | Yentzen Production, Inc. | | Oil Operator | Mar 1987 |
| 5107 | Youngblood Enterprises | | Gas Operator | Dec 1983 |
| 5108 | Youngblood Enterprises, Inc. | | Oil & Gas Operator | Jan 1992 |
| 5109 | Yuma E & P Company, Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 5110 | Yuma Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | Aug 2002 |
| 5111 | Z C Ambrose-G L Blaxton, Jr. | | Oil & Gas Operator | Apr 1983 |
| 5112 | Zachry Exploration, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 5113 | Zachry Exploration, LLC | San Antonio, TX 78224 | Oil & Gas Operator | May 2025 |
| 5114 | Zachry Exploration, LTD. | San Antonio, TX 78205 | Oil & Gas Operator | Jan 2009 |
| 5115 | Zad, Inc. | | Oil Operator | May 2001 |
| 5116 | Zadeck Energy Group Inc | | Oil & Gas Operator | Dec 2011 |
| 5117 | Zam'S Production Company | | Oil Operator | Sep 2004 |
| 5118 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 5119 | Zeagler Enterprises, Inc. | | Oil & Gas Operator | Jun 2008 |
| 5120 | Zeit Exploration Co., Inc. | | Oil & Gas Operator | May 1994 |
| 5121 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2025 |
| 5122 | Zenergy Operating Company, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2016 |
| 5123 | Zercon Oil & Gas, Inc. | | Oil Operator | Oct 2003 |
| 5124 | Zero Mass Mining, LLC | | Oil Operator | Jan 2025 |
| 5125 | Zgen, Inc. | | Oil & Gas Operator | Jul 1990 |
| 5126 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 5127 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |
| 5128 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |
| 5129 | Zone Energy, LLC | Houston, TX 77251 | Oil & Gas Operator | Jan 2025 |