The court had earlier heard the amount of money linked to the fraud - which targeted mostly used-car importers - was disputed.
The SFO alleged some $3m was lost, while Maher argued it was less than $1m.
In a statement, Julie Read, the SFO's director, said: "Mr Maher's dishonest, repetitive and premeditated offending resulted in significant financial losses to his clients. He abused his position of trust to create the illusion that his business was successful when it was not.
"Such deceitful behaviour damages New Zealand's reputation as a safe place to invest and do business."
The SFO previously described Maher's crimes as "arrogant".
Maher had operated FBL from 1995 until 2017. He was the sole director and shares of the company were held by him and his wife.
Car yards and other importers used FBL's services.
The SFO began investigating FBL in 2017 after it collapsed and $500,000 in bullion was found in an office safe and creditors were reportedly owed $15m.
The company, founded in 1995, was placed into liquidation in April 2017 and Maher was declared bankrupt in November 2018.
A liquidators' report for FBL, prepared by Christopher McCullagh and Stephen Lawrence of PKF, claimed Maher breached his duties under the Companies Act by continuing to trade for four years while incurring "significant losses".
Liquidators said they considered Maher was personally liable for some debts of the company and had served him a demand for $4m - but recovery was unlikely.
"Maher responded advising that he did not have the means to settle the demand and therefore intended to declare himself as bankrupt shortly," the report said.
Maher had earlier told liquidators he blamed the failure on "too many 'out of money' contracts" and competition that forced him to adopt an overly-large position.
"I had tried to devise a plan to start returning investor funds and start scaling back the company until I could close it down, but I ran out of time and cash flow," Maher said.
The website for FBL claimed Maher had "over 20 years experience in the foreign currency industry" and "an extremely high level of business integrity and customer service".
Several of the company's clients have told the Herald payment delays with FBL seemed to accelerate from late 2016, while Maher also offered high-risk foreign exchange investment services.