Shares in Mighty River Power sank fell 4.5% on Monday taking the price well below the government issue price early this month.
Mighty River Power shares fell 11 cents to $2.36 down on the issue price of $2.50.
An analyst at Devon Funds Management, Phill Anderson, says he was surprised the electricity company's shares held up so well last week, given the fall in the shares of fellow electricity company Contact Energy recently.
He says Monday's fall reflected Mighty River Power falling into line with the market's views on energy stocks.
Mr Anderson says the fall in both companies' share prices has been driven by global sentiment.
He says that sentiment is being influenced by a softening currency and a feeling that some shares could be slightly over-valued.
Mr Anderson says global investors have pulled back a little from New Zealand and Australia.
