The former financial adviser also make false statements in reports to hide the true picture from investors, the SFO said in May.
The actual losses to Robinson's investors was $2.3 million, the High Court heard this morning.
Robinson was the second authorised financial adviser to ever lose his license when the Financial Markets Authority cancelled it in December 2012.
He was already in custody when he appeared for sentencing this morning in the High Court at Auckland before Justice Matthew Muir.
SFO lawyer Rachael Reed said the actual amount stolen was more than $3 million and called the offending an "extensive, premeditated theft by very much a trusted adviser".
"The victims had 100 per cent trust in Mr Robinson with all of their funds," Reed said.
"Their lives have changed considerably as a result of the theft," she said.
The victims had suffered financial and emotional harm from the offending and the total losses, the prosecutor submitted.
Two of Robinson's victims have died in the last few months, the court heard.
Reed pushed for a minimal period of imprisonment for Robinson to send a strong deterrent to other financial advisers.
He could not be entitled to much credit for his late guilty plea days before his trial was due to begin, she said.
Robinson's lawyer Jeremy Bioletti submitted that his client wasn't driven by greed or a desire to live a "champagne lifestyle".
This wasn't a situation where a person was stealing money and using it for a their own "aggrandisement", the defence lawyer said.
"The defendant was a person of good character when the offending commenced.
"The fact he return voluntarily from Australia to face what is the inevitable consequence of what has occurred...demonstrates that element of recognition or accountability of facing up to what happened," he said.
The defendant was remorseful, Bioletti said, and had written a letter detailing this that was provided to the judge.
Justice Muir, when sentencing Robinson, said the offender used clients' money to cover trading losses and "quickly the whole charade became akin to a Ponzi scheme".
On one instance, Robinson sold $258,000 worth of a client's shares without their knowledge.
The scheme had all the hallmarks of a premeditated fraud that exploited 13 victims, the judge said.
Robinson had cultivated the trust of many "elderly and vulnerable" people who now "have seen their lives decimated", Justice Muir said.
Some victims now have to continue working despite being ill and will never recover from what has happened, the judge said.
They were at a time of their lives when they could least afford what had happened, he said.
"All feel an acute betrayal of trust," said the judge.
Some victims planned to use the money for their grandchildren's education and the offending therefore had an inter-generational effect.
"You grossly betrayed the trust your investors had in you," Justice Muir told Robinson.
The offending had robbed many victims of their "golden years".
The judge imposed a sentencing starting point of 7 and a half years in jail.
Robinson was given a 10 per cent discount for previous good character, his co-operation with authorities and "some feelings of remorse".
He was also given a 10 per cent discount for his guilty plea, bringing the total sentence to six years in jail.
Justice Muir imposed a minimum term in 2 years 9 months jail, which is what Robinson must serve before he is eligible for parole.
In a separate case, Robinson was last year found by a High Court judge to have been negligent to a former client and ordered to pay damages and interest of $1.59 million.
This client made "six disastrous investments" on Robinson's recommendations and then sued him for damages for the losses.
Robinson was declared bankrupt in April.
