Three of Nobilo & Co's employees also shifted to Mrs Nobilo's new company.
Last November Mr Nobilo went to the High Court at Auckland seeking leave to take action in Nobilo & Co's name to recover losses of between $250,000 and $400,000 he argued the company had suffered.
Mr Nobilo argued the letters his now estranged wife wrote to clients breached her duties to Nobilo & Co.
He also claimed the Family Court did not have jurisdiction to make orders in respect of the 98 per cent Nobilo & Co's shares that are held in a trust.
Mrs Nobilo opposed the application for leave and denied any breach of duty.
In his decision on the application in March, Associate Judge David Abbott declined Mr Nobilo the leave he was seeking.
"I am satisfied that NCL [Nobilo & Co] was in danger of collapsing due to the tensions between Mr and Mrs Nobilo and that they recognised this fact (and had been contemplating an inevitable division of the client base for a considerable time). Although I accept that there is a dispute over relative inputs to the build up of NCL's client base, [it] appears to be common gound that each managed specific clients, with whom they had an established relationship. There is no evidence to suggest Mrs Nobilo wrote to any client whose work she was not either managing or undertaking herself," the judge said.
Associate Judge Abbot said there was a strong argument that Mrs Nobilo was trying to put into effect what the pair had been discussing:
"In those circumstances what might otherwise have been seen to be a reasonably strong case for breach of duty becomes a marginal one at best," the judge said.
The judge said that if the issues with the trust cannot be resolved within existing relationship property proceedings then there were other potential avenues the parties could take.
Mr Nobilo is appealing the decision not to grant him leave to bring action on behalf of Nobilo & Co.
While his notice of appeal got to the Court of Appeal a day late, the court last month granted him extra time to file it.