The FCA is holding £2.5m in funds relating to a land banking scheme but the majority of investors owed compensation money have not come forward.
A total of 870 investors placed £32.8m into unauthorised collective investment schemes operated from a company marketed as Countrywide Land Holdings between 2005 and 2010.
The watchdog has now received £2.5m from a related Panamanian company Paradigm Consultancy, which it intends to return to the original investors.
To date, 392 investors involved have contacted the FCA.
Executive director of enforcement and market oversight Mark Steward says: ‘If you believe you were an investor in one of these unauthorised schemes, please get in contact with us.
“We will work to resolve this matter and return funds to eligible investors as soon as is possible but we need to demonstrate to the court that we have taken reasonable steps to identify everyone affected.”
Four men were jailed for around seven years each for their involvement in the scam in 2012 making them eligible for release in the coming year.