"We conclude that the FY04 forecast was an untrue statement," Justices Glazebrook, O'Regan and Kos said in the written judgment.
"We stress that this stage of the inquiry is to determine if the prospectus contained an untrue statement. We have not considered the materiality of the shortfall. This is because materiality is, contrary to the approach of the High Court, not relevant when considering if a statement is untrue."
The judges set aside the Appeal Court findings that the untrue statement did not trigger liability under securities law and wasn't in breach of the Fair Trading Act, both of which were questions for the second stage of the trial.
The High Court will have to work out whether the untrue statement caused a loss for investors. The Supreme Court noted Justice Robert Dobson's observation that it will be necessary to determine a date for that assessment to be made.
"The respondents' arguments that the value of the Feltex shares, as reflected in its market price after the IPO, was at least equal to the IPO price will need to be assessed, as will their arguments that the reasons for the fall in the market price of the shares in Feltex in 2005–2006 were unrelated to the untrue statement in the prospectus," the judgment said.
"The argument made by Mr Houghton that the shares were worthless from inception will also need to be assessed."
The judges dismissed the appeal against First NZ Capital and Forsyth Barr as joint lead managers, saying the investment firms were not promoters under the act.
That leaves former directors Timothy Saunders, Samuel Magill, John Feeney, Craig Horrocks, Peter Hunter, Peter Thomas and Joan Withers, sale promoter Credit Suisse Private Equity and vendor Credit Suisse First Boston Asian Merchant Partners to face the second tranche of the trial.