The $18m was placed in a trust account following the FMA's intervention, to be distributed once Forestlands director Rowan Kearns' advisers devised a formula that was fair to all shareholders, an FMA statement said.
Nearly a year later, the formula is yet to be agreed, despite suggestions from Kearns in December it would be ready by the end of January.
Dunedin man Ewen McDonald is among hundreds of southern investors demanding to know when they would see their money.
McDonald said he invested about $16,000, and, despite promises by Kearns, investors like him were "running out of January fast".
"Ours isn't a huge investment ... but I guess at our stage of life, any loss is a bad loss.
"The bottom line is everyone is somewhat fearful for their investments."
Another investor, Judith Meikle, of Oamaru, invested $24,000 over a decade, beginning when she was a shop assistant, and encouraged her daughter to do the same.
She and her husband had just retired, and had hoped for a return of about 25 per cent to add to their "nest egg".
"He [Kearns] wrote the most amazing newsletters to everybody . . . there was always a couple of chocolates in the envelope, but no money."
Debbie Gutsell, of Invercargill, said she, her husband and two adult children had together spent $39,000 since 2001, paying monthly installments initially because they were "struggling"but wanted an investment.
She was now "extremely angry" about the situation.
"Our money, if it was paid back to us, would changes our family's life.
"This was to help us with our retirement, our son is struggling to get a deposit for a house, and our daughter is bringing up our little granddaughter on her own."
Another investor, Des Howard, who started a Facebook page to keep investors informed, said about 4500 "Mum and Dad shareholders" remained in limbo.
They had bought "B shares" which gave them no voting rights when the company decided to sell up, and many had seen their financial plans "shattered", he said.
"There are many stories of seriously ill investors who are desperate for their payout, albeit now only likely to be near their initial investment."
The FMA had posted updates on its website, but offered little new information other than reiterating the investigation was ongoing.
The $18m remained in a trust account, pending an agreement on the formula for dispersal, and could not be released without a court order or the FMA's approval.
The FMA and SFO, in statements last week, would not be drawn on timeframes or any other details.
Kearns released a statement through Dan Hughes, a partner at law firm Anthony Harper.
It said Kearns was "fully committed"to the FMA process, but a payout could not be made "at this stage" because "matters are yet to be resolved to the FMA's satisfaction".
He had hoped a formula would be ready in January, but that required audited accounts, which could not be obtained while the FMA investigation continued, the statement said.
An alternative process had been proposed but required FMA agreement, it said.