The Serious Fraud Office is investigating Whangarei foreign exchange trader, CFX Trade Safe.
SFO acting director Simon McArley says it appears the company suffered a major financial loss.
The SFO is alleging it falsified documents to hide these losses from investors.
The firm traded foreign currency on behalf of about 50 clients in New Zealand and overseas.
The SFO was alerted to the case by an employee of CFX Trade Safe.