| 6501 | Young Resources, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1999 |
| 6502 | Young Tommy Oil Inc | Woodward, OK 73802-0893 | Oil & Gas Operator | Jan 2026 |
| 6503 | Young Z Joe | Cement, OK 73017-0600 | Oil & Gas Operator | Mar 2015 |
| 6504 | Young Zoral J | Cement, OK 73017 | Oil & Gas Operator | Sep 2000 |
| 6505 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2026 |
| 6506 | Youngblood J Lee | Dallas, TX 75221 | Oil & Gas Operator | Feb 1996 |
| 6507 | Younger Enterprises Inc | Ada, OK 74821-1882 | Oil Operator | Jan 2003 |
| 6508 | Z G Operating LLC | Oklahoma City, OK 73134-5038 | Oil & Gas Operator | Nov 2009 |
| 6509 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 6510 | Zafar Oil & Gas, Inc. | Oklahoma City, OK 73132 | Oil Operator | Aug 2013 |
| 6511 | Zap Oil Company | Nowata, OK 74048-2640 | Oil & Gas Operator | Nov 2005 |
| 6512 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 6513 | Zca Gas Gathering Co., Inc. | Bartlesville, OK 74003 | Oil & Gas Operator | Apr 2020 |
| 6514 | Zeal Production Company | Sperry, OK 74073-4714 | Oil & Gas Operator | Feb 2026 |
| 6515 | Zeiders Bros. Oil & Gas Company, L.L.C. | Edmond, OK 73003 | Oil & Gas Operator | Jan 2026 |
| 6516 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 6517 | Zenith Oil & Gas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2026 |
| 6518 | Zephyr Operating Co LLC | Oklahoma City, OK 73118-6035 | Oil & Gas Operator | Feb 2026 |
| 6519 | Zephyr SWD LLC | Oklahoma City, OK 73118-6035 | Oil Operator | Feb 2026 |
| 6520 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 6521 | Zim Energy Corporation | Tulsa, OK 74153 | Oil & Gas Operator | Jan 1998 |
| 6522 | Zimtex Energy LLC | Perryton, TX 79070-5818 | Oil & Gas Operator | Nov 2017 |
| 6523 | Zinke & Trumbo LTD | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2017 |
| 6524 | Zion Energy Corporation | Peru, KS 67360 | Oil Operator | Aug 2000 |
| 6525 | Zollinger Veldon | Cresent, OK 73028 | Oil & Gas Operator | Apr 2009 |
| 6526 | Zollinger Veldon Inc | Crescent, OK 73028-9280 | Oil & Gas Operator | Nov 2018 |
| 6527 | ZP Disposal Systems LLC | Kingfisher, OK 73750 | Oil Operator | Feb 2026 |
| 6528 | Zuhone William H | Mattoon, IL 61938-4019 | Oil & Gas Operator | Jan 2015 |
| 6529 | Zumyers Inc | Newalla, OK 74857-0259 | Oil Operator | Apr 2003 |
| 6530 | ZZ Energy LLC | Norman, OK 73070 | Gas Operator | Jan 2026 |
| 6531 | Zzron Inc. | Midland, TX 79704 | Oil & Gas Operator | Aug 2003 |