More than 2 years later the SFO's Hanover file has remained open, with no charges being laid.
Acting SFO chief executive Simon McArley told the Herald in February that the matter had been going on for a long time.
McArley said the investigation phase had concluded last year and some of the office's work had been peer-reviewed by external experts.
Separate to the SFO investigation, the Financial Markets Authority is taking civil action against six former Hanover directors and promoters over allegedly misleading or untrue statements made in offer documents.
The FMA is seeking compensation for investors who put $35 million into Hanover Finance, Hanover Capital and United Finance between December 2007 and July 22, 2008.
The market watchdog is also seeking penalty orders against the defendants, and if the claim is successful, the former directors and promoters could each face fines of up to $5 million.