The first trading day of 2016 saw the world's five wealthiest individuals lose a total of US$8.7 billion (S$12.4 billion), according to figures from Bloomberg's Billionaires Index.
Jeff Bezos, founder of Amazon.com Inc, was the biggest decliner on Monday (Jan 4), losing US$3.7 billion, after the online retailer's stocks fell nearly six per cent, AFP reported.
Europe's richest person Amancio Ortega, the chairman of the Inditex fashion group, lost US$2.5 billion.
American business tycoon Warren Buffett, Mexico's Carlos Slim and Microsoft co-founder Bill Gates also suffered losses of US$870 million, US$868 million and US$739 million respectively.
The five were not the only billionaires to see losses. According to the Index, Asia's richest man, Wang Jianlin, was among the biggest decliners with losses of US$2.5 billion, while Facebook founder Mark Zuckerberg lost US$1.3 billion.
The biggest winner of the day was American businessman Carl Icahn, who gained US$210.3 million to increase his net worth to US$20.1 billion.
The Bloomberg Billionaires Index provides a daily ranking of the world's 400 richest people.