| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | H & O Oil Co. | Oil & Gas Operator | Dec 1989 | |
| 2 | Hathaway Company | Oil & Gas Operator | Dec 2025 | |
| 3 | Hellman Properties LLC | Oil & Gas Operator | Feb 2026 | |
| 4 | Herley Olive Holdings LLC | Oil & Gas Operator | Mar 2026 | |
| 5 | Hoag Memorial Hospital Presbyterian | Gas Operator | Mar 2026 | |
| 6 | Huntington Beach Company | Oil & Gas Operator | Dec 1998 | |
| 7 | Huntington Beach Pacific Coast Enterprises LLC | Oil & Gas Operator | Jan 2018 | |
| 8 | Huntington Signal Oil Company | Oil & Gas Operator | Dec 1997 | |
| 9 | Hvi Cat Canyon Inc. | Oil & Gas Operator | Dec 2025 |