Rakon shares tumbled as much as 9% after the company warned it expects to lose $54 million this financial year.
The loss is largely due to poor sales and the sale of its Chinese subsidiary, and the company says its does not expect to make a profit again until the 2015 financial year.
The stock closed 4% lower to 22 cents in what was a fairly flat sharemarket on Friday, with the NZX Top 50 Index falling seven points to close at 4592.
The Australian sharemarket is down nearly 0.5% ahead of Saturday's election, to 512.
On the currency markets, the New Zealand dollar has also been relatively flat today, trading at 79.10 US cents.
But the kiwi is slightly stronger against all its other trading partners, buying 86.70 Australian cents, 50.70 pence and 79.01 yen.
