Graeme Hart has once again made Forbes magazine's rich list, and is the world's 133rd-richest billionaire, New Zealand's richest person, and up 45 places on last year.
The 61-year-old investor is worth $US9.5b ($NZ13.5b), $US3b richer than March 2016 when his net worth was $US6.4b.
New Zealand's second richest man is Singapore-based investor Richard Chandler, but comes in well down in 1098th place and is worth $US1.91b.
The 58-year-old's wealth dropped this year from $US2.45b in 2016.
Mr Gates maintained his No. 1 spot on the list for the fourth year in a row, with his $US86 billion fortune up from last year's $US75 billion.
Mr Buffett, the legendary value investor known as the "Oracle of Omaha," reclaimed the No. 2 berth after a two-year hiatus. His net worth surged to $US75.6 billion from $US60.8 billion.
Third place went to Mr Bezos, who apparently was the biggest winner on the 2017 list. His wealth jumped to $US72.8 billion, a gain of $US27.6 billion from last year, Forbes said.
Donald Trump's net worth takes a dive
While Donald Trump's political fortunes were rising, his net worth was dropping to a mere $US3.5 billion - that's roughly a third of what he claimed during his successful campaign for the US presidency, according to the latest Forbes list of the world's billionaires.
Mr Trump tumbled more than 100 spots to No. 544 on the magazine's 31st annual list, largely because of the impact of the slumping New York real estate market on his holdings.
"Midtown Manhattan real estate is down; therefore, so is Donald Trump's fortune," the business magazine said in a statement.
The developer-turned-politician, who ranked No. 205 last year, fell further behind to Bill Gates, the list's perennial leader.
Mr Trump's current $US3.5 billion net worth compares with $US3.7 billion in October, when Forbes published its list of the 400 wealthiest Americans and a month before his Election Day upset against Democrat Hillary Clinton.
While campaigning for the Republican presidential nomination in May, Mr Trump's team filed a personal financial disclosure form that said his net worth was more than $US10 billion.
Critics have said he has inflated the true value of his wealth, saying his tax returns would provide a more accurate snapshot of his financial status. But Mr Trump has defied convention and refused to release his returns.
Neither the White House nor the Trump Organisation, which Mr Trump's sons have run since their father's inauguration, immediately responded to a request for comment on the Forbes list.