Facebook Stock Is On Track For Its Worst Day Ever

(CNN)– Facebook shares fell 19 percent at the opening bell Thursday. The company warned investors on Wednesday that sales growth would slow in the coming quarters as the company adjusts its strategy to focus on privacy.The drop wiped out nearly $120 billion in market value, one of the biggest losses ever for a public company. CEO Mark Zuckerberg’s net worth plummeted more than $11 billion, according to Forbes, which tracks billionaires’ portfolios.Facebook Chief Financial Officer David Wehner said on a conference call with investors that Facebook is "putting privacy first" after the Cambridge Analytica scandal triggered a wave of horrible press, customer angst and regulatory scrutiny around the world.As an example of its new strategy, Wehner said Facebook will put more development muscle behind the company’s Stories feature. That will put a drag on sales because Facebook makes more money on its core News Feed than its other products.Facebook says it will spend a lot of money to accomplish its goals. Wehner said the company will invest billions of dollars per year improving safety and security after a bruising period of headlines about Facebook’s role in enabling fake news and election meddling."We think that’s the right thing to do for the business," he said.The company’s previous worst single-day performance was July 27, 2012, when the stock fell 11.7 percent. The stock tanked that day after the company failed to convince investors that it could sell mobile advertising. Mobile now makes up 91 percent of the company’s advertising revenue.