NEW YORK (BLOOMBERG) - It's been an expensive two months for the 500 wealthiest people on the planet.

Their combined net worth fell US$181 billion (S$238 billion) this week as the S&P 500 Index and Dow Jones Industrial Average suffered their steepest weekly drop in more than two years amid heated rhetoric over tariffs and retaliation. The group's wealth has shrunk US$436 billion (S$574 billion) since markets peaked on Jan 26.

Mark Zuckerberg bore the brunt this week with US$10.3 billion wiped from his fortune on the Bloomberg Billionaires Index. He dropped three places to seventh on the ranking as scandal unfolded at Facebook. The social network's shares tumbled 14 per cent following reports that it let Cambridge Analytica amass data on 50 million users.

The downdraft also caught Larry Ellison, down US$7 billion as Oracle Corp forecast slowing sales growth for cloud-related products. Berkshire Hathaway's Warren Buffett, Amazon.com's Jeff Bezos and Alphabet's Larry Page lost US$17 billion combined.

The world's 500 biggest fortunes now encompass US$5.2 trillion, according to the index.