Transpower's annual earnings have fallen 11% to $126 million.
Chairman Mark Verbiest says the decline was due to several one-off charges, including a reduction of almost $50 million in the value of its North Island property.
Transmission revenue rose 3% to $675 million, reflecting new investments in the national grid.
However, that was less than forecast due to a reduced regulated return and the deferral of a planned commissioning date for the new Pole 3.
Both impacted fourth quarter revenue, by $11 million and $8 million respectively.