WASHINGTON (BLOOMBERG) - The world's richest people lost US$35 billion (S$48.7 billion) Wednesday when global equity markets were rocked by political turmoil in the United States, according to the Bloomberg Billionaires Index.

Bill Gates, the world's richest person with US$86.8 billion, lost US$1 billion as shares of Microsoft, his largest holding, tumbled 2.8 per cent, the most in almost a year. Amazon.com co-founder Jeff Bezos, who came within US$4 billion of taking the top spot from Mr Gates earlier this week, dropped to No. 3 after losing US$1.7 billion as shares of the online retailer slid 2.2 per cent. Spanish retailing tycoon Amancio Ortega lost US$355 million to end the day in the second position with US$83.2 billion.

Global stock indexes tumbled as political turmoil enveloped the White House, with President Donald Trump's ties to Russia and his firing of FBI Director James Comey under scrutiny. US stocks posted their steepest declines since September, led by the Nasdaq Composite's 2.6 per cent slide. The MSCI All-Country World Index fell 1.2 per cent, and bank stocks were the worst performers.

Facebook founder Mark Zuckerberg was hardest hit in the tumult, dropping US$2 billion when the social media giant dropped 3.3 per cent. Mr Zuckerberg is the fifth-richest person on the planet with US$62.3 billion, according to the index. Mr Trump, the first billionaire to serve as US president, has a net worth of US$3 billion and doesn't have a spot on the Bloomberg index, a daily ranking of the world's 500 richest people. They have a combined net worth of US$4.9 trillion, up US$455 billion in 2017.