Facebook’s value plummeted $119bn on Thursday, the most dramatic share price decline of any company in US stock-market history, after the social networking firm reported slowing growth in user numbers following a string of recent scandals.
Investors frantically sold Facebook shares in after-hours trading on Wednesday, pushing the company’s price down 18 per cent just after the bell went on the New York Stock Exchange.
It slipped further on Thursday to close down 19 per cent on the day.
The precipitous decline was triggered by Facebook's announcement that revenue gains would lag behind spending growth, meaning lower profits.
The sell-off eclipses the $91bn wiped off the value of Intel during the depths of the dot-com bust on one day in September 2000.
Apple's market cap fell $60bn on 24 January 2013 after the company reported its slowest profit growth in a decade, while Exxon Mobil's value was slashed by $53bn on one day in October 2008.
Mr Zuckerberg will be able to take comfort from the fact that Apple is now valued at more than three times the amount it was after its $60bn blip while Exxon is trading around 30 per cent up on its price in October 2008.
Chip maker Intel has yet to recover to the level it reached at the tech bubble's peak.
Still reeling from a backlash against its handling of fake news and privacy scandals, Facebook delivered further bad news on Wednesday in the form of its slowest growth in user numbers for more than two years.
However, that still meant facebook had 2.23 billion monthly active users - almost a third of the population of the planet - at the end of June, 11 per cent more than it had a year earlier.
A data privacy scandal involving the political consulting firm Cambridge Analytica and misinformation on WhatsApp contributing to mob killings in India have added to the pressure on Facebook to re-evaluate how its services maintain security.
The Cambridge Analytica scandal prompted several apologies from Mr Zuckerberg and generated calls for users to desert Facebook.
Facebook's revenue grew at its slowest pace in almost three years with sales up 14 per cent to $13.2bn (£10bn) in the second quarter.
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