"In total, we believe the Facebook information of up to 87 million people" was wrongly distributed to Cambridge Analytica, Facebook announced Wednesday afternoon. Previous estimates indicated around 50 million people's Facebook information was compromised.
The data analytics company purports to help political candidates win elections with targeted digital ads. CA was initially funded by billionaire GOP donor Robert Mercer. The company was also one of the principal firms directing Donald Trump's digital strategy during the 2016 US presidential elections.
"We will also tell people if their information may have been improperly shared with Cambridge Analytica" starting April 9, Facebook said.
Facebook stock is down about 1.3 percent following the news.
Facebook has revealed in the course of the unfolding scandal that the way it shares people's email addresses and phone numbers has been targeted by "malicious actors." While the company has collected this data to help people find their friends by just searching for their numbers or email addresss, it turns out that external forces have been extracting this information from Facebook pages and then saving it to local files.
"Malicious actors have also abused these features to scrape public profile information by submitting phone numbers or email addresses they already have through search and account recovery. Given the scale and sophistication of the activity we've seen, we believe most people on Facebook could have had their public profile scraped in this way," Facebook said.