The sharemarket has been blindsided by the news that mining giant Rio Tinto is looking at shutting down the country's biggest power consumer, the Tiwai Point aluminium smelter, less than a year after a fourth potline was reopened at the facility.

Shares in Meridian - the biggest power generator and the NZX's biggest company - dropped 8.7 per cent to $4.95 on heavy turnover.

Contact Energy, which like Meridian also has significant South Island generation assets, fell by 9.7 per cent to $7.69.

Owners of Tiwai Pt seek talks with the Govt, raising possibility of closure


Mercury NZ