Britain is investigating whether Facebook did enough to protect data after a whistleblower said a London-based political consultancy hired by Donald Trump improperly accessed information on 50 million Facebook users to sway public opinion.
Facebook shares closed down nearly 7 percent on Monday, wiping nearly $40 billion off its market value as investors worried that damage to the reputation of the world's largest social media network would deter users and advertisers.
Elizabeth Denham, the head of Britain's Information Commission, is seeking a warrant to search the offices of consultancy Cambridge Analytica after a whistleblower revealed it had harvested the private information of millions of people to support Trump's 2016 U.S. presidential campaign.