In response to the FMA's concerns, he agreed to retire from providing financial advice in 2014 and sold Financial Vision's client list to a licensed provider.
He also deregistered from the Financial Services Providers Register.
And more than 18 months later, Duff has signed enforceable undertakings with the FMA.
Duff agreed, last week, that for the next five years, would not:
• Provide financial advice;
• Deal with client investments;
• Receive client money;
• Serve as a director or manager of any company involved in providing financial advice.
This matter is not the only time that Duff has run into issues with the FMA.
Last year the regulator told the High Court that Frimley Estate - a property development company Duff directed - had contravened the Securities Act by failing to issue a prospectus. The FMA considered the "contraventions by Frimley were serious".
After failing to convince a judge to direct otherwise, Frimley was liable to repay shareholder investment because of this alleged breach.
The company was set up by Stephen and Alan Duff in 2004 and proposed to subdivide and sell sections of a 7.86 hectare block of land in Hawkes Bay.
While some sections were developed and sold, the development was not completed and, overall, not a success.
The company is now both in liquidation and receivership.
Liquidators said in January that IRD was claiming $167,870 and unsecured creditors were seeking an additional $206,410.