Facebook shares posted their worst daily loss in almost six years on Monday after the social media giant was rattled by news report that revealed one of the worst data leaks in company history.
London-based private data analysis firm Cambridge Analytica acquired private information of more than 50 million Facebook users without their permission and used that information in U.S. elections in 2014 and 2016, as well as during Brexit, according to reports by The New York Times and The Observer of London.
After closing Friday at $185.09 per share, Facebook stock price fell to as low as $170.12 a share on Monday, posting an 8.1 percent decline -- its worst performance in more than five and a half years.
Facebook shares lost 11.7 percent on Jul 27, 2012, after the firm's financial results showed decline in ad revenue growth and its stocks plunged to an all-time lowest level.
On Monday, the company's market value also decreased $43 billion, falling from $537 billion on Friday to $494 billion around 12:00 p.m. EST.
Facebook co-founder and CEO Mark Zuckerberg saw more than $5 billion of his net worth evaporate, from $74.5 billion to $69.3 billion.
The world's youngest billionaire fell to the seventh spot from the fifth place around 2:00 p.m. EST in Forbes' World's Billionaires real time ranking list.