New Zealand's richest person - with a net worth of $US5.1 billion ($NZ6.36 billion) - features at number 201 on Forbes latest list of world billionaires.
Mr Hart was the only New Zealander on last year's billionaire list, ranking at 336, then estimated to be worth $2.7 billion.
In 2006, Mr Hart was rated by Forbes as number 451 in the world, with a value of $1.7 billion, trailing two other New Zealanders - the Chandler brothers Richard (49) and Christopher (48) at 382, with a combined net worth of $2 billion.
There was no mention of the Chandlers last year but they were back on the map this time, hundreds of places behind Mr Hart at 707 with net worths of $US1.7 billion respectively.
The drop comes after the pair split their assets in investment company Sovereign Global in late 2006 which they had run for 20 years. The younger brother has since started Legatum in Dubai, which has invested heavily in India's beverage and financial services industries.
The older Chandler's new venture, Orient Global, has largely picked up where Sovereign left off, focusing on long-term value investments in financial and social businesses.
The only other New Zealander on this year's list was Stephen Jennings at place 1014 with a net worth of $1.1 billion. The Kiwi expatriate founded Renaissance Capital, now Russia's leading investment bank.
Mr Hart, once a tow-truck driver, owns investment company Rank Group, which runs timber and paper business Carter Holt Harvey and food manufacturing company Burns Phillip.
The 52-year-old boasts a $20 million clifftop mansion in Auckland's Glendowie and a $100 million luxury motor yacht called Ulysses.
On this year's list, he is two places above Italian fashion designer Giorgio Armani, who has a net worth of $US5 billion, 35 places above airway tycoon Richard Branson, worth $US4.4 billion, and 167 places above real estate developer Donald Trump, who is worth $US3 billion.
He also trumps designer Ralph Lauren, movie director Steven Spielberg and talk-show host Oprah Winfrey.
American investor Warren Buffet topped the list with a net worth of $62 billion, up $10 billion from last year. The rise has put him ahead of Microsoft co-founder Bill Gates, who had been the richest man in the world for 13 years.
Mr Gates is now worth $58 billion and ranked third in the world. He is $2 billion up from a year ago but critics say he could have trumped Buffett had Microsoft not made an unsolicited bid for Yahoo! at the beginning of February.
Mexican telecom tycoon Carlos Slim Helu is the world's secondrichest man with an estimated net worth of $60 billion. His fortune has risen $11 billion since last year. - The New Zealand Herald.
