NBR Rich Lister Stephen Jennings is selling his 50% stake in the Russian investment bank he founded in 1995.
Moscow-based Mr Jennings – worth $900 million, according to the NBR Rich List – says his business partner Russian billionaire Mikhail Prokhorov will buy his shares in Renaissance Capital.
Mr Jennings is also stepping down as ceo of the company.
Mr Prokhorov's investment vehicle Onexim bought the other half of the business for $US500 million in 2008.
According to a Reuters report, Mr Jennings will continue to head Renaissance Group, which includes asset management, African land development, consumer finance and real estate businesses.
Mr Prokhorov owns the New Jersey Nets basketball team and stood against Russian president Vladimir Putin in this year's presidential race, but came away with just 8% of the vote.
Taranaki-born Mr Jennings started his career as a free-market economist at Treasury before venturing to Moscow in the early 1990s.
There, he privatised the first company after the fall of communism, the Bolshevik Biscuit Company, before setting up Renaissance Group in 1995 with CS First Boston colleague Boris Jordan.
Mr Jennings has survived tough times, nearly losing his fortune twice. In 1998 when the Russian currency crashed he cut staff levels by 30% and bought out his partners to become the sole owner of Renaissance.
In 2008, with 40% of the company's staff facing the axe, he raised capital by selling half the company to Mr Prokhorov.
Mr Jennings has become known for daring to put his money into developments in emerging markets, such as a $4 billion property development in Kenya dubbed Tatu City.
In 2009 Renaissance Capital was linked to an alleged 11.2 billion roubles ($NZ506 million) fraud against the Russian state, but the company denied this.
The sale of his stake in his company caps off a colourful year for Mr Jennings, whose ex-wife Tina started dating 80-year-old Lord Nigel Lawson, former Chancellor of the UK Exchequer and father of celebrity baker Nigella Lawson.
He was also accused by a neighbour to his seaside home at Oakura in Taranaki of being "negligent" by letting a large pohutukawa tree grow out of control, blocking views of the sea.
Mr Jennings was once the richest New Zealander in the world, worth $5.2 billion, according to Forbes.